- The Truth Behind the ‘Feed a Cold, Starve a Fever’ Saying
- This is the ultimate dehydration cure:
- Do You Feed a Cold and Starve a Fever?
- The Origin of Feed-or-Starve for Colds and Fever
- The Truth Behind Feed-or-Starve for Colds and Fever
- Medicine or Malarkey: Should You Feed a Cold and Starve a Fever?
- Should you feed a cold and starve a fever? Study investigates
- Glucose fatal to mice with bacterial infection
- Findings could be beneficial for sepsis research
- Calorie Counter
- Eating when sick: Should you feed a cold? Or starve a fever?
- The immune system: A primer
- Eating and immunity
- Prebiotics and probiotics
- To eat or not to eat: That is the question
- Whole foods and immunity
- Nutrients and immunity
- What you can do right now
- Passionate about nutrition and health?
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- Why it matters:
- The nitty gritty:
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- What they’re saying:
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- The bottom line:
- Cold and Flu Remedies That Work
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The Truth Behind the ‘Feed a Cold, Starve a Fever’ Saying
“Feed a cold, starve a fever.” The classic saying suggests that a cold can be squashed with adequate food intake, while a fever will burn off faster if you, well, fast. With flu season upon us, we couldn’t help but wonder: Is the medical motto fact or fiction?
“The old adage of ‘feed a cold, starve a fever’ started centuries ago when it was believed that colds were brought about by a drop in body temperature,” Albert Ahn, MD, a clinical instructor of internal medicine at NYU Langone Health, tells Health. The idea was that eating more could help raise the body’s temperature and thus kick the cold. “The ‘starve a fever’ recommendation likely arose from the belief that eating food activated the gastrointestinal system and raised the body temperature, thus negatively impacting the body if it was already suffering from a fever,” adds Dr. Ahn.
RELATED: 5 Most Common Myths About the Common Cold
So, are the recs sound? Yes—and no. When the body is combating a cold, it needs energy in the form of calories to fight off infection and recover. The catch? The same applies to a fever. “The body’s demand for calories increases in both scenarios in order to produce immune cells that defend against an invading pathogen,” says Sharon Horesh Bergquist, MD, an assistant professor of medicine at the Emory School of Medicine, which means, she adds, that the idea that we should starve fevers is a myth.
In fact, feeding (and hydrating) a fever might be even more critical than feeding a cold. “When you have a fever, it is essentially increasing your body’s temperature to fight an infection and in turn also increasing your metabolism and your body’s use of calories,” Dr. Ahn says. “Hence, you would likely benefit from more caloric intake during a fever.”
Fevers can coincide with other symptoms—like sweating, vomiting, or diarrhea—that result in an increased loss of body fluids, so adequate hydration is equally, if not more, important when suffering from a fever.
RELATED: 11 Signs It’s More Serious Than the Common Cold
But most of us aren’t exactly ravenous when we’re feeling under the weather. That’s because appetite is naturally suppressed when we’re sick so that energy can be directed toward the immune system rather than digestion, Dr. Bergquist says.
So, what’s a sickie to do? “While responding to the need for more calories is important to support the immune system, you don’t need to force yourself to eat,” she says. “Most of us can tap into our energy reserves.” Plus, eating too much might only make symptoms like nausea, vomiting, or diarrhea worse.
If you can’t fathom eating a full meal, prioritize fluids that contain calories, like coconut water or a sports drink, which contain electrolytes. “Staying well hydrated helps keep airway passages moist, which supports our first line of defense against germs,” explains Dr. Bergquist. If you’re feeling up to it, blend a smoothie made with vitamin C-rich fruits and veggies, like strawberries, kiwi, orange juice, and a handful of kale.
RELATED: 6 Foods to Eat to Help Prevent the Flu
Hot liquids like herbal tea or broth keep mucus runny, which can help expel unwanted materials from the nose and throat. Bonus points if they provide critical nutrients too. “Chicken soup always makes the list of healing foods because it’s a perfect mix of hot liquids that open up the sinus passages and provide electrolytes, antioxidant-rich vegetables, and spices that support the immune system,” Dr. Bergquist says.
Dr. Ahn recommends avoiding foods that are high in sugar or fat and limiting dairy when sick, since lactose digestion may be compromised by GI-related illnesses. “High-sugar foods can affect the immune system and actually have a pro-inflammatory effect, which is the opposite of what you want,” he says. “A high-fat meal will digest slowly and can exacerbate underlying stomach issues.” Steer clear of caffeinated coffee and tea as well as alcohol. All three are diuretics, meaning they can further increase your risk of dehydration.
The bottom line: Whether you’re dealing with a cold or a fever, never starve yourself. Fuel your body with fluids and nutrient-dense whole foods as much as you comfortably can. Start with soft, easily digestible foods, then progress to heartier meals. And above all, listen to your body. Chances are it knows better than medical folklore does.
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Maxims typically date back many years, but “feed a cold, starve a fever” may beat them all. This saying has been traced to a 1574 dictionary by John Withals, which noted that “fasting is a great remedy of fever.” The belief is that eating food may help the body generate warmth during a “cold” and that avoiding food may help it cool down when overheated.
But recent medical science says the old saw is wrong. It should be “feed a cold, feed a fever.”
Let’s take colds first. When your body fights an illness it needs energy, so eating healthy food is helpful. Eating can also help the body generate heat—although wearing an extra layer of clothes or slipping into bed can keep you warm, too. There’s no need to overeat, however. The body is quick to turn recently digested food into energy, and it’s also efficient at converting stored energy in fat.
The reasons to eat for fever are more interesting. Fever is part of the immune system’s attempt to beat the bugs. It raises body temperature, which increases metabolism and results in more calories burned; for each degree of temperature rise, the energy demand increases further. So taking in calories becomes important.
Even more crucial is drinking. Fever dehydrates your system, in part through increased sweating from that elevated temperature. Replacing fluids is therefore critical to helping the body battle the infection. The same is true for combating colds. “You have to make yourself drink fluids, even though all you want to do is collapse,” says William Schaffner, chair of the Department of Preventive Medicine at Vanderbilt University School of Medicine.
Dehydration also makes mucus in the nose, throat and lungs dry up, which can then clog sinuses and respiratory tubes. When mucus hardens it becomes more difficult to cough, Schaffner notes, which is our way of trying to expel mucus and the germs it contains. Staying hydrated helps keep the mucus running, which, even though it may be disgusting, is one of our natural defenses.
The challenge, of course, is that when you’re sick you may not feel much like drinking and even less like eating. Loss of appetite is common, and might be part of the body’s attempt to focus its energy on pounding the pathogens. Given the wisdom noted above, Schaffner says, don’t force yourself to eat if you don’t feel like it. “But drink,” he adds. “It’s the liquids that are important.” Avoid caffeine and alcohol. Caffeine enhances dehydration. So does alcohol, and it is also a depressant, holding us down.
What about some other common conceptions for beating colds and fevers, such as eating chicken soup? Chicken soup doesn’t possess any magic ingredients, but it has calories as well as the all-important liquids again. The warm vapor rising from the bowl can also moisten and loosen dried mucus. The same goes for vapor from hot tea, with or without lemon or honey. Taking a hot shower can soften mucus, too—and if you dare, you can get rid of it by gently blowing your nose one nostril at a time while you’re in there.
Supplements are dubious at best. The data from studies about taking vitamin C are inconclusive, as they are for zinc. Solid studies of echinacea show no benefit. If there’s any positive effect at all from any of these compounds, it is very small, Schaffner concludes.
Over-the-counter remedies may or may not help, but that’s a whole ‘nother story. They can relieve symptoms but they do not kill off viruses or bacteria. Cold and fever germs usually run their course, and the immune system eventually gets the upper hand. In the meantime, drink drink drink. And sleep as much as you can, to give your body the rest it needs to fight the good fight.
This story is part of the Healthyish Guide to Feeling Better Already, a collection of recipes, remedies, and distractions to get you back on your feet.
Feed a cold, starve a fever. This refrain is something I think about a lot, mostly when I am sick and looking to justify my choices. As in: I do deserve this $14 ramen; I am feeding my cold. This is what the old wives would want.
Where exactly the phrase comes from is murky, but according to Quackery: A Brief History of the Worst Ways to Cure Everything, you can trace it back to a 1574 dictionary by the English lexicographer John Withals, who wrote “fasting is a great remedy of fever.” And that does make some intuitive sense, sort of. Fevers produce heat, and heat takes energy. So if you don’t give your body energy to produce the fever, then the fever should go away. Meanwhile, writes Smithsonian, colds were believed to be caused by “a drop in temperature,” which required food to help “stoke the fire.” It is persuasive logic, in a 16th century kind of way.
But, in 2018, I could not find a doctor ready to back up the wisdom of the elders. “First of all, there’s no truth to ‘feed a cold, starve a fever,’” says Catherine Troisi, Associate Professor at the Center for Infectious Diseases at the University of Texas School of Public Health. “That would not be guidance I would give my patients,” agrees Ian Nelligan, Assistant Clinical Professor at Stanford School of Medicine, tactfully.
Which is not to say that there is no evidence that the old adage could have (some) merit. In recent years, a number of studies have suggested that, depending on the illness, eating or not eating may in fact bolster recovery. A very buzzy 2002 Dutch study “found that eating a meal boosts the type of immune response that destroys the viruses responsible for colds, while fasting stimulates the response that tackles the bacterial infections responsible for most fevers,” New Scientist explained. (Also, though, the study had six people in it.)
Then, in 2016, an immunologist at Yale was trying to figure out if there might be some unknown protective benefit to not eating while sick—why else do we so often lose our appetites?—and found that the tentative answer seemed to be yes. Mice injected injected with listeria (a foodborne bacterium) had better survival rates if they weren’t force-fed. Mice with a flu virus, though, were drastically more likely to survive if they were. For our purposes, what matters here isn’t the specific diseases, but rather the possibility that what and whether to eat may indeed depend on exactly what’s wrong with you. But it’s early. People aren’t mice. If there’s an immediate takeaway, the study’s lead author, Ruslan Medzhitov told The Atlantic, it’s to listen to your body when you’re sick.
That is what everyone keeps telling me. “You want to make sure that your body has enough energy to fight whatever it is that you’re fighting,” says Molly Broder, a pediatrician at the Children’s Hospital at Montefiore. But if you can’t stomach it, she adds, that’s also fine. As Troisi points out, “you’re not going to starve to death in the week or ten days that a cold lasts.”
The one thing you do have to do when you’re sick is stay hydrated, whether your body tells you to or not. It is a boring truth, but necessary. “You really should drink even if you’re not thirsty,” Troisi says. Drink water. Drink herbal tea. If you’re worried about a dearth of calories, drink fruit juice for god’s sake. Just drink. Not coffee. Not alcohol. But what about a healing shot of whiskey? That’s a question for another day.
This is the ultimate dehydration cure:
BA Brad’s Classic Tonic
This also makes a tasty spritzer—use club soda in place of water. View Recipe
Do You Feed a Cold and Starve a Fever?
The old saying, “feed a cold, starve a fever,” may be only partially good advice, according to experts.
Starving a fever by eating fewer calories may actually make it more difficult for your body to fight off the flu virus. “‘Starve a fever’ has been medical folklore for hundreds of years because some medical historians believe that doctors in the 1500s and 1600s thought fever meant that your metabolism was in overdrive or working overtime, which is true to some degree,” says Mark A.Moyad, MD, MPH, Jenkins/Pokempner director of preventive and alternative medicine at the University of Michigan Medical Center in Ann Arbor,Mich.
The Origin of Feed-or-Starve for Colds and Fever
People thought that eating would activate digestive processes which could lead to more fever, according to Dr. Moyad. “They believed less of the body’s energy would be able to fight fever because it was expending energy for digestion,” adds Moyad. The origin of the saying may date back to 1574, when writer John Withals suggested that fasting would cure a fever. At the time, colds were blamed on a drop in body temperature, which could be helped by eating and drinking. Eating less, on the other hand, was believed to stop stoking the heat of a fever.
The Truth Behind Feed-or-Starve for Colds and Fever
The truth, according to researchers, suggests that eating less during the early stages of an infection can actually be dangerous. “The body requires large amounts of energy to create and assemble the large number of immune cells necessary to fight the enemy. Good nutrition and calories provide this energy,” says Moyad. Most experts dismiss starve-a-fever as folklore. In addition, fevers often decrease appetite naturally as part of the body’s defense system, so your immune system can focus its energy on fighting the cold and flu pathogens.
Medicine or Malarkey: Should You Feed a Cold and Starve a Fever?
Popular wisdom has taught us that we should “feed a cold and starve a fever, but scientists are now questioning the notion. Starving, in any situation, is never the answer. But experts believe it’s what you eat, not how much you eat, that seems to have the most health benefit—easing symptoms of both the common cold and the flu.
Will eating food when I’m sick make me feel better?
One study reported by WebMD suggests that eating a nutritional, well-balanced diet while ill may positively influence short-term immune function. However, everyone’s immune system responds differently to disease.
In an article published by the National Center for Biotechnology Information, a division of the National Library of Medicine at the National Institutes of Health, a study showed that there may be a positive correlation between the nutritional content of food and the immune system’s response.
Although further studies are needed, experts suggest listening to your body. If you’re sick and feel hungry, eat something healthy and nutritious. And always remember to stay well hydrated by drinking water.
What should I eat if I’m sick?
Nutrient-rich foods help your body stay healthy and fight infections. Here are the top suggestions for what to eat from WebMD.
- What they do: help build a strong immune system. Examples: beta carotene and vitamins C and E
- What to eat: almonds; apricots; asparagus; beets; broccoli; cantaloupe; carrots; cauliflower; cod liver oil; kale; mangoes; mustard and collard greens; nectarines; peaches; pink grapefruit; pumpkin; red, green or yellow pepper; safflower oil; salmon steak; spinach; squash (yellow and winter); strawberries; sunflower seeds; sweet potato; tangerines; tomatoes; and watermelon
- What they do: help you stay healthy by activating your immune system.
- What to eat: the pulp and white core in the center of citrus fruits, green peppers, broccoli, and red and yellow onions
- What it does: helps to thin mucus and ensure proper hydration.
- What to drink: green and black tea (which is filled with strong antioxidants known as flavonoids)
- What they do: increase your overall wellness.
- What to eat: apples, apricots, broccoli, Brussels sprouts, cabbage, carrots, cauliflower, garlic, legumes, onions, red peppers, soybeans, sweet potatoes and tomatoes
- What it does: builds and repairs body tissue and fights viral and bacterial infections.
- What to eat: lean sources of protein, such as skinless chicken, lean beef and turkey, beans, and soy
- What it does: Eating a daily cup of yogurt can help reduce your susceptibility to colds. Researchers say the beneficial bacteria in yogurt may help your immune system fight germs.
- What to eat: low-fat or natural Greek yogurt
- What it does: Zinc is an antioxidant that assists your body’s resistance to infection, stimulates the immune system and helps repair tissues. Some studies show that taking zinc lozenges within 24 hours of getting a cold may reduce the duration of cold symptoms.
- What to eat: eggs, meats, nuts, seafood, seeds, wheat germ and whole grains
Is chicken soup really good for the soul?
According to WebMD, studies show that traditional chicken soup may have benefits for your health and well-being. Here’s how:
- The hot vapors from a bowl of broth help clear a stuffy nose.
- Research shows it has a mild anti-inflammatory effect that could reduce cold symptoms.
- Consuming liquid helps keep you hydrated.
- Chicken soup may improve your mood by reminding you of the love of a parent.
What do I do if I have a cold or a fever?
If you have cold or flu symptoms, CareSpot is here to help.
Should you feed a cold and starve a fever? Study investigates
“Feed a cold, starve a fever,” so the old saying goes, and according to a new study, it may hold some truth. Researchers found that mice with a bacterial infection died after being fed, while mice with a viral infection survived after eating.
Share on PinterestResearchers find the effect of food intake on infection may depend on whether the infection is bacterial or viral, as well as what foods are consumed.
Senior author Ruslan Medzhitov – David W. Wallace professor of immunobiology and a Howard Hughes Medical Institute investigator at Yale School of Medicine in New Haven, CT – and team report their findings in the journal Cell.
According to Medzhitov, most of our knowledge about bacterial and viral infections stems from studies that have investigated how the immune system responds to pathogens and how it works to eradicate them.
“But that’s not the only way we defend ourselves,” he notes. “There are also cases where we change and adapt so that microbes don’t cause harm.”
In the case of this latest study, the team found that food intake during infection may influence the immune system’s ability to fight pathogens, depending on whether the infection is bacterial or viral and what type of foods are consumed.
“We were surprised at how profound the effects of feeding were, both positive and negative,” says Medzhitov. “Our findings show that it has a strong protective effect with certain infections, but not with others.”
Glucose fatal to mice with bacterial infection
The researchers came to their findings by conducting a series of mouse experiments, in which they fed or starved mice that had been infected with bacteria or viruses.
Firstly, the team infected mice with Listeria monocytogenes – a bacterium known to cause food poisoning.
As expected, the mice stopped eating – a common occurrence with food poisoning – and eventually, they made a full recovery. However, when mice infected with L. monocytogenes were force-fed, they died.
On further investigation into the effects of each food component, the team found that it was glucose that proved fatal to the force-fed mice; proteins and fats appeared to have no effect.
What is more, on administering the chemical 2-DG – which inhibits glucose metabolism – to force-fed infected mice, glucose no longer proved fatal.
In another experiment, the team infected mice with the flu virus A/WSN/33.
Contrary to the results of the previous experiment, the team found that force-feeding the mice with glucose led to their survival, but the rodents died when they were given 2-DG or were starved of glucose.
By analyzing the brain scans of the mice that died from either bacterial or viral infection, the team found that each infection affected different brain regions.
The researchers say this suggests that the metabolic requirements of the mice may be determined by what parts of their immune system are switched on.
“Our study manipulated the ability of these mice to tolerate and survive infection without doing anything that had an effect on the pathogens themselves,” explains Medzhitov.
Findings could be beneficial for sepsis research
The researchers are now in the process of investigating how changes in sleep patterns affect the immune system’s ability to stave off infection.
They also plan to conduct follow-up studies, which will investigate what pathways play a role in food preferences, in an attempt to explain certain food craving people have when they are ill.
In the meantime, Medzhitov and colleagues believe their current findings may have important implications for research into sepsis – a potentially fatal blood infection.
“Sepsis is a critical problem in hospital ICUs that defies most modern medical approaches,” says Medzhitov.
“A number of studies have looked at nutrition in patients with sepsis, and the results have been mixed. But these studies didn’t segregate patients based on whether their sepsis was bacterial or viral. The implication is that patients should be stratified by the cause of their sepsis, and trials should be designed based on that.”
Read about how introducing simple steps to hospitals in Norway cut sepsis deaths by 40 percent.
Sorry, I don’t know offhand *how much* a fever of X degrees would increase a person’s metabolism, only that, in general, it *does* increase metabolism. Shivering and constriction of the blood vessels are major mechanisms to increase body temperature when you’re running a fever; both of these require the use of ATP; in order to build ATP, your cells (especially in your skeletal muscles and liver – major glycogen stores) must break down glycogen into glucose to fuel aerobic cellular respiration.
This is the same process used when you exercise (you need ATP to contract your muscles to lift weights or run, and you need ATP to contract your muscles to shiver…it’s the same fuel source, just different body conditions), but I would imagine that the *amount* of sugars you “burn” to build ATP and maintain a fever depends on your initial glycogen stores, your food consumption (blood sugar levels), your activity level, your dress (whether or not you’re wrapped up in blankets to help raise body temp, etc.) and whether or not you’ve taken any NSAIDs to reduce your fever (thus reducing your need to shiver and burn calories). There are a lot of factors to consider.
In all honesty, I would be interested to know a quantitative measure of this as well (I lost more than 5lbs earlier this year fighting a terrible cold that lasted 2+ weeks, with fever on-and-off… I couldn’t exercise if I tried and I ate whatever I could stomach; I’d be interested to know how off-kilter my metabolism was at the time), but a cursory glance through my school’s library database isn’t turning up any research papers that look even remotely helpful/informative on the subject (but I’ll definitely post if I come across any!). Hopefully somebody else has something more useful to add, sorry!
BTW, I’m honestly not just spouting BS I’ve learned on the internets – metabolism is not my specialty, but I do have a PhD (in neuroscience; from a Big10 school) and teach biology and psychology at the college level. I would give specific references for the info I’m stating about ATP/muscle contraction/aerobic respiration (and hypothalamic regulation of body temperature, inflammation & fever, and other general body responses to injury and illness), but I’m pulling from like 6-7 different textbooks that I use/have used in the past (some mentioned in my previous post), and multiple chapters from each. If it would be helpful to you (or others) to cite these books or elaborate on anything I said above, I will gladly do so (as long as I have spare time between class preps for the spring semester) :drinker:
Got a cold or the flu and feeling feverish? You may not want to be so quick to reach for a pill to get rid of it, a new study suggests.
Scientists have found more evidence that allowing your fever to burn out may actually help certain types of immune cells to work more efficiently. They say that a type of lymphocyte called CD8+Cytotoxic T-cell is capable of destroying virus-infected and tumor cells and low-grade fevers enhance them.
Researchers from the Department of Immunology at the Roswell Park Cancer Institute in Buffalo, N. Y. injected two groups of mice with an antigen and watched the T-cells activate. They raised the body temperature two degrees centigrade in half the mice, and the other half maintained a normal body temperature.
The warmed mice showed a greater number of the CD8 T-cells that were capable of destroying infected cells. Their findings were in the November 2011 issue of the Journal of Leukocyte Biology.
Scientists have long known that a fever is the body’s protective response to fight off bacteria and viruses. If you can stand the discomfort until your fever reaches 102, Dr. Amesh A. Adalja says it’s fine to let the fever go away on its own – but not always.
“Once the body temperature reaches certain levels, it becomes dangerous because it can be toxic to brain cells, and can also precipitate seizures as well as increase your heart rate and basal metabolic rate, causing people to more likely become dehydrated,” says Adalja, clinical assistant professor in the Department of Critical Care Medicine at the University of Pittsburgh Medical Center.
It’s probably best not to take the chance with a feverish child, or with an adult if the fever spikes higher than 102 degrees. A high fever in some children can result in seizures, he says. Adalja also warns it’s also not worth the risk to your own health if you have heart disease, have suffered a stroke or endure other medical complications.
“This is not a blanket recommendation,” he says. “Secondary consequences to the fever can cause other conditions in the patient to occur or worsen. If someone has a persistent fever of 104, it’s a sign of infection, and it’s not just some viral thing you are going to get over.”
Ouch! Does this year’s flu shot hurt more?
Flu shot not as effective as thought (but get one anyway)
Eating when sick: Should you feed a cold? Or starve a fever?
Feed a cold and starve a fever, goes the old saying. But how should you consider eating when sick?
Nutrition expert Brian St. Pierre examines the evidence. He also shares some guidelines on what to eat, and what to avoid, next time you come down with a virus or infection.
- Want to see our visual guide? Check out the infographic here…
Remember the swine flu pandemic that pummelled North America in 2009?
I do. Because I had it.
I was down and out. Fever, chills, aches, pains, fatigue — the full catastrophe. I could barely move. Barely think.
The last thing I wanted to do was eat. Flaked out on the sofa for days on end, I dutifully drank my fluids and hoped for the best.
Eventually, like most otherwise healthy people, I recovered. My energy and appetite came back.
Afterwards, I wondered: Would tweaking my diet have helped me recuperate faster? Better yet: Could the right combination of nutrients have protected me from contracting the virus in the first place?
In this article, I’ll explore those questions and offer a few guidelines.
This way, next time you get sick, you’ll know exactly what to eat for a faster, smoother recovery. You’ll even learn how to reduce your chances of getting sick again.
The immune system: A primer
Intricate, complex, amazing: That’s the human immune system.
Standing guard throughout every part of our bodies, it protects us from the hordes of germs, fungi, and viruses that threaten to (literally) tear us apart.
In fact, when we eat, our immune systems get into the act from the very first moment we pop the food into our mouths.
Bet you didn’t know that your saliva contains powerful antimicrobials like lysozyme, alpha-amylase, and lactoferrin!
And these antimicrobials are only the basic, front line defense. Any germs that sneak past will confront a much more formidable barrier: our stomachs’ hydrochloric acid.
Corrosive enough to remove the rust from steel, hydrochloric acid will pulverize most invaders in our stomachs before they can reach our intestines.
If our stomach acids lose the battle, we also have proteins and chemical compounds further down the digestive chain that can sense and fight any harmful bacteria that may have made it past.
Finally, our own personal bacterial population (those probiotics you hear so much about) help prevent harmful bacteria from entering our bloodstream or taking root in our small intestine and colon.
The foods we eat affect these bacteria and the complex compounds they release.
Nutrient-dense, fiber-rich whole foods tend to promote a healthy bacterial balance, whereas a diet rich in processed foods, fats and sugars can lead to dysbiosis — otherwise known as microbial imbalance.
That’s why a balanced whole foods diet is your best insurance against all kinds of viruses and infections.
In fact, our GI tract comprises over 70% of our immune system! (And it’s a whole lot more complicated than we can go into here.)
For now, it’s enough to understand that what we eat affects immunity on many levels.
Let’s take a closer look.
Eating and immunity
If your diet is lousy, you’ll get sick more often than someone who eats a healthier diet.
Viruses and bacterial infections will hit you harder and keep you out for longer. Meanwhile, eating poorly while you are sick will only make you sicker.
Good nutrition allows our bodies to respond to germy invaders quickly and efficiently.
And in order to function well, the cells of our immune system need plenty of vitamins, minerals, amino acids, and essential fatty acids.
Yet nutrient deficiencies are far more common than you might suppose. That’s why at PN, we recommend you work to prevent them.
The opposing effects of infection on nutrient availability and demand.
(Calder PC. Feeding the immune system. Proc Nutr Soc 2013;72:299-309.)
Prebiotics and probiotics
Prebiotics and probiotics deserve special mention for helping to prevent illness. Both are essential to gut health. And gut health is essential to immunity.
Prebiotics (a.k.a. food for bacteria) help nourish our good microbial friends. Usually this is some form of semi-digestible fiber that our bacteria can chow down on, and/or that helps move food through the GI tract.
And probiotics (the bacteria themselves) have been shown to help us recover faster, once we get sick.
That’s why all of us should ensure that our systems are well colonized by these friendly critters.
The best whole food sources of prebiotics are:
And the best whole food sources of probiotics are:
- Dairy: yogurt, cheese, and kefir with live and active cultures
- Fermented vegetables: pickles, sauerkraut, kimchi
- Fermented soy: miso, tempeh
- Miscellaneous: soy sauce, wine
Getting probiotics from food
If you’re healthy, aim for 1-2 servings of probiotic-rich foods each day. If you’re hoping to prevent or alleviate a medical problem, you may need to increase the dose.
Getting probiotics from supplements
Supplemental doses are typically expressed in billions of live organisms. Between 3 and 5 billion would be a starting dose. This could be increased to 10 billion if you are hoping to alleviate a specific health concern. Choose a reputable brand, and take it with food and water. See here for our recommendations.
Getting prebiotics from food
If you’re healthy, aim for 2-3 servings of prebiotic-rich foods each day.
Getting prebiotics from supplements
Taking 2-4 grams of prebiotics per day can help to feed healthy gut bacteria and keep things balanced. Supplementing pre- and probiotics at the same time might be a good idea.
Note: You may actually feel worse before you feel better, since bacteria release toxins. Ride it out for a few days and see what happens.
Also, immune-compromised people can develop infections from probiotic microbes. Be cautious if you:
- have AIDS,
- are taking immunosuppressive drugs,
- are receiving radiation or chemotherapy, and/or
- are in the hospital.
To eat or not to eat: That is the question
While a whole-foods diet rich in prebiotics and probiotics will go a long way towards protecting you from viruses and bacterial infections, even the healthiest diet can’t ward off every invader. And if you do get sick, of course you’ll want to recover faster.
Should you feed a cold and starve a fever, as the famous adage recommends?
Spoiler alert: There’s no definitive answer.
One small study did find that eating helps combat a cold virus. And fasting allows the body to fight fever-related infections.
But one study is far from conclusive. Especially when the reasons for its findings remain unclear.
What we do know is that moderate calorie restriction can:
- improve cell-mediated immunity and
- offset chemotherapy-induced and aging-related changes in immune function by helping to replenish stem cells.
On the other hand, during periods of very low food intake:
- our defenses against specific pathogens are lower, and
- the immune system is suppressed.
In the most severe cases, the malnutrition-infection cycle can ultimately lead to kwashiorkor (a severe type of malnutrition).
Sounds like a bit of a toss-up, doesn’t it?
Appetite and illness
With something to be said theoretically both for eating and fasting while sick, practically speaking, it’s best to rely on your own body’s signals.
In fact, when it comes right down to it, our own appetite cues probably give us the clearest picture of what we should eat (or avoid eating) when we get sick.
For example, very few of us want to eat when we’re hit by influenza or by gastroenteritis.
That’s because flu-like bugs and bacterial infections lead to higher levels of circulating TNF-alpha (an inflammatory cytokine), which promotes appetite suppression.
Maybe this is the body’s way of guarding its resources? After all, digestion takes a fair amount of energy — energy that may be better used to fight off invaders when we’re sick.
It’s an interesting possibility, but at this point it’s pure speculation.
The role of inflammation
We do know that behavioral and metabolic factors can influence immunity. Signalling mechanisms that control energy metabolism and immune function seem to be intertwined.
For example, our hunger hormone, ghrelin, may inhibit the creation of pro-inflammatory compounds.
And this can be a good thing or a bad thing — depending on circumstances.
How so? Well, inflammation helps us fight off invading pathogens. But too much inflammation will make our symptoms worse.
For example, a fever will increase metabolism as well as body temperature. This in turn improves the body’s chances of fighting off a bug — speeding it through the system.
At the same time, a fever can also dehydrate us, which makes it harder to move a pathogen through the body and out.
Meanwhile, infection itself can increase our body’s nutrient needs, especially for fluid, protein, and several micro- and trace nutrients.
Moreover, specific nutrients can affect immune function. A particular nutrient might be a source of fuel for an immune system cell, or it might influence other tissues that regulate overall immune function.
All in all, we’re talking about a very complex set of relationships. No wonder scientists have yet to get to the bottom of it all.
That said, considering that colds often result from viral infections, and fevers often result from bacterial infections, the advice to eat when you have a cold and fast when you have a fever does rest on some plausible biological arguments. Which is why, in cases of mild or moderate illness, it’s likely worth a try.
Especially if your own appetite agrees.
Whole foods and immunity
Let’s say you get sick despite all your precautions — and your appetite doesn’t entirely disappear. Are there any particular foods that could hasten recovery?
As a matter of fact, there are.
A few examples:
- Garlic. Acts as an antibiotic, and has consistently been found to lessen the severity of colds and other infections.
- Chicken soup. Commonly touted as a food for colds, chicken soup actually works! It provides fluids and electrolytes, is warm and soothing, and may also contain anti-inflammatory properties that decrease cold symptoms. You have to use real chicken soup though — the kind you make from simmering a chicken carcass — rather than stuff from a can or package.
- Green tea. Boosts the production of B cell antibodies, helping us rid ourselves of invading pathogens.
- Honey. Has antibacterial and antimicrobial properties, and is an effective cough suppressant. In one study it was as effective as a cough-suppressing drug. A few teaspoons in a cup of green tea is all you need. (Plus, you’ll get the benefits of green tea at the same time.)
- Elderberries. These have antiviral properties and are loaded with phytonutrients. A few small studies have found the elderberry extract reduces the duration of colds and other upper respiratory tract infections.
Nutrients and immunity
Nutrition science loves studying isolated nutrients. At Precision Nutrition, that’s not really our thing.
We know that focusing too much on the details can sometimes lead people to forget the bigger picture — which is what most of us need to know in order to make healthy decisions.
Still, looking at specific nutrients can provide unique insight into metabolic pathways, and the effects of individual nutrients on specific circumstances. Plus, if you’re a science nerd, this is the kind of thing you probably enjoy.
A few examples of note:
- A major drop in energy can depress the immune system. This may explain why many people get sick a week or so after starting a crash diet.
- Inadequate or excessive intake of protein, iron, zinc, magnesium, manganese, selenium, copper, and vitamins A, C, D, E, B6, B12, and folic acid may all decrease the ability of the body to enlist immune defenses.
- Long-term nutrient deficiency, whether minerals, vitamins, protein, or calories, can reduce the immune system’s ability to respond. It’s a side effect of malnutrition and certain types of disordered eating. Actually, malnutrition was the leading cause of acquired immune deficiency before HIV. Adding a deficient nutrient back to the diet can restore immune function.
- Consistently over-eating, or eating more than the body needs, might also compromise how the immune system responds to invaders. Much of this might have to do with the fats we eat and ultimately store in the body. Dietary fats become part of cell membranes in the body, and thus influence how cells respond to invaders. Some fats seem to disrupt immune functions.
- While certain fats (like omega-3s) may help regulate immunity through resolvins and protectins, too many saturated, omega-6, or even omega-3 fats might sometimes be perceived as bacterial invaders and trigger an immune response, leading to a dysfunctional gut (and compromised immune system).
- Fat cells release inflammatory substances that can activate a “false alarm” immune response. Over time, the body gets tired of this false alarm and the immune system doesn’t respond as it normally would. This is similar to what might happen if you continually triggered your home smoke alarm by burning the toast — until finally you decided to take the battery out. When you actually have a fire, you’re screwed.
- Added sugars and high glycemic load diets may reduce white blood cell function and be pro-inflammatory. Gluten might also have a similar response in folks with a certain genotype.
- Dietary protein insufficiencies may lower immunity. At each meal, men should eat about two palms of protein dense foods, and women should eat about one palm.
- Iron and zinc are essential for various metalloenzymes necessary for nucleic acid synthesis and cell replication. Fancy words, but key components of healthy and well-functioning immune system. If these processes aren’t functioning properly, it’s tough for bone marrow to produce more white blood cells, and this in turn harms our immunity.
- Iron is a critical nutrient, but too much can lead to oxidative reactions that damage immunocompetent cells.
- Some have proposed that glutamine shortage may cause immunosuppression since glutamine is necessary for white blood cell proliferation. But data doesn’t prove this as yet.
Overall, both nutrient deficiencies and over-supplementation can actually diminish the body’s natural antioxidant defense system.
As always, balance is key.
Components of the modern diet that might influence immunity.
(Myles IA. Fast food fever: Reviewing the impacts of the Western diet on immunity. Nutrition Journal 2014;13:61-78.)
In general we use whole foods to improve our immunity. But under certain circumstances, you might want to supplement.
Nutrients that can support immunity and that are generally well tolerated include:
- Vitamin C supplements
- elderberry extract
Quercetin may also assist in immune function (1,000 mg a day for 3 weeks). It’s found in onions, apples, red wine, broccoli, tea, and Gingko biloba.
Beta-glucan (found in oats) might help immunity.
Stevia might enhance white blood cell activity.
Selenium also appears to play a role in infection and changes in viral virulence (but be mindful of excessive supplementation).
Consuming foods rich in vitamin E (such as nuts, olive oil or avocadoes) may also help. This may enhance T cell function. And might lead to less influenza and fewer respiratory infections.
What you can do right now
To prevent getting sick:
- avoid over- or under-exercising
- avoid over- or under-eating
- maintain a healthy body weight
- wash your hands
- get enough sleep, consistently
- manage stress
- eat plenty of nutrient-dense foods
- feed your healthy bacteria
For some, periodic fasting might also be useful.
Also, consider supplementing vitamin D, probiotics, and a wide-spectrum food-based vitamin/mineral supplement.
But recognize that if you’re not eating a balanced, whole food diet, supplementing with probiotics won’t do a lot of good. An isolated supplement can’t fix a broken diet. Address your diet first.
If you’re already feeling sick:
- drink lots of fluids (especially water and green tea)
- rest and recover
- focus on immune-boosting foods
- supplement with pre- and probiotics
- use immune-boosting supplements
And above all, listen to your body cues.
If you’re hungry, eat. If not, don’t. Either way, Super Shakes may come in handy.
In the end, no matter how well you manage your nutrition, exercise, sleep, and stress, you will get sick sometimes. We all do.
Don’t be a hero and pretend you’re not. Instead, take the steps outlined here to get back on your feet as quickly as possible.
(Also see our comprehensive article on Exercising when you’re sick: Sweat it out? Or rest and recover?)
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“Feed a cold, starve a fever” is an adage that has been around for centuries. Now a new study in mice finds that it might actually have some truth — but it depends what exactly is the cause of your fever.
Why it matters:
Loss of appetite is common with sickness and Ruslan Medzhitov, an immunologist at Yale University, and his colleagues wanted to know why. Is it just a consequence of illness, or does it have some protective benefit we don’t fully understand?
The nitty gritty:
Researchers infected mice with either a bacteria that causes food poisoning or a flu virus.
All the mice began to eat less after falling ill, but some were force-fed food or given pure glucose. After 10 days all the bacteria-infected mice who had continued being fed had died, while more than half that had avoided food lived. But it was the opposite in those infected with the flu: More than 75 percent lived if they had been force-fed, while only about 10 percent lived if they hadn’t. Food was protective against the virus, but detrimental to the bacterial infection.
“To our complete surprise we found that force feeding was protective” in viral infections, Medzhitov said.
Intrigued, the team conducted more experiments, and found that glucose, but not proteins or fats, was the dangerous component of foods during a bacterial infection. The study was published Thursday in the journal Cell.
But keep in mind:
The work was done in mice, not people. But a 2002 study in humans found similar results: eating stimulates the kind of immune response needed to combat viral infections, while fasting might stimulate the immune response that takes down unfriendly bacteria.
What they’re saying:
“What it shows is that if we understand the infection, there might be simple ways that we can improve outcome,” said David Schneider, an immunomicrobiologist at Stanford University who wasn’t involved in the work.
But he noted more needs to be done before we know how far to generalize these findings, which used only one strain of mice and might not apply to every infection.
“We don’t want to say, ‘Ok, bacteria means we don’t feed patients.’ It’s not time for that yet,” he said. “There are always going to be exceptions.”
You’ll want to know:
The differences in nutrition seemed to influence survival not through a direct impact on the pathogen, but rather by changing the ability of the mice’s own tissue to withstand the metabolic stress that came with illnesses, said Janelle Ayres, an immunomicrobiologist at the Salk Institute in La Jolla, Calif., who was not involved in the study.
“Conventional wisdom among most scientists and the general public is you have an infection, you have to take an antibiotic or you have to take an antiviral and you just have to kill it,” she said. “This nicely demonstrates that we need to be able to deal with metabolic stresses, or we can compromise our ability to defend against infection.”
Fevers can be caused by both bacteria and viruses — so the adage “Feed a cold, starve a fever” is an oversimplification. But knowing whether to feed patients based on the infection they have could be useful not just for chicken soup remedies but also for more serious infections like sepsis, which can be caused by both types of pathogens.
“Feed a cold, starve a fever” is an adage that’s been around for centuries. The idea most likely originated during the Middle Ages when people believed there were two kinds of illnesses. The illnesses caused by low temperatures, such as a cold, needed to be fueled, so eating was recommended. Illnesses caused by high temperatures, such as a fever, needed to be cooled down, so refraining from eating was thought to deprive the furnace of energy.
Nowadays, most doctors and years of research into the cold and flu say there’s only one tried-and-true treatment for colds and flu — plenty of rest and fluids. That’s because colds and flu are caused by viruses, for which there is no cure. But you can support your immune system as it struggles to prevail through proper nutrition and, even more importantly, proper hydration.
If anything, the adage should be, “feed a cold, feed a fever,” because bodies fighting illness need energy, so eating healthy food helps. Eating food when you have a cold can also help the body generate heat, although other methods of keeping warm, like wearing an extra layer of clothes or wrapping yourself in a blanket, do the trick as well.
There are many reasons you shouldn’t try to starve a fever. Fever is part of the immune system’s attempt to combat the virus. Fever raises body temperature, which increases metabolism and burns more calories. That’s one reason why taking in calories becomes important.
What’s far more crucial in combating both colds and the flu is staying hydrated. Fever dehydrates the body, in part through increased sweating from the elevated temperature. Vomiting and diarrhea, two common symptoms of the flu, also quickly dehydrate the body. Dehydration makes the mucus in the nose, throat, and lungs dry up, which can lead to clogged sinuses and respiratory tubes. When mucus hardens it becomes more difficult to cough, which is the body’s way of trying to expel mucus and the germs it contains.
Replacing fluids is critical to helping the body battle the virus. Water works just fine, as do fruit juices and electrolyte beverages. If you feel nauseated, try taking small sips of liquids, as gulps might cause you to throw up. You can be sure you’re getting enough fluids by looking at the color of your urine, which should be pale yellow, almost colorless.
Of course, when you’re sick, you may not feel much like drinking and even less like eating. Loss of appetite is common, and might be part of the body’s attempt to focus its energy on pounding the pathogens. Don’t force yourself to eat, but make sure to take in plenty of fluids. However, you should avoid coffee, caffeinated sodas, and alcohol, because caffeine and alcohol both contribute to dehydration.
Once you’ve contracted a cold or the flu, it should run its course in five to 10 days. And while nothing can cure a cold or the flu, some remedies can ease your symptoms and keep you from feeling so miserable.
Cold and Flu Remedies That Work
Wash your hands
For starters, frequent hand washing is one of the best things you can do to avoid catching whatever bugs might be going around. The key to making it count is using lots of soapy water and scrubbing for at least 20 seconds. If you’re in a public restroom, use a paper towel instead of your bare hand when you touch the door handle. At home, you should regularly disinfect doorknobs with Lysol spray or disinfectant wipes. And don’t forget about your germy computer keyboard and mobile phone. It’s a good idea to regularly run a disinfectant wipe over those keys and your phone.
Sip warm liquids
Taking in warm liquids such as chicken soup, hot tea (with lemon or honey), or warm apple juice can be soothing and the warm vapor rising from the bowl or cup can ease congestion by increasing mucus flow. Chicken soup is everyone’s favorite, but it’s not a miracle cure. It does provide needed calories and salt, as well as some nutritional benefits. Chicken soup is also generally easy on the stomach.
Soothe a sore throat
Gargling with salt water helps get rid of the thick mucus that can collect at the back of the throat, especially after you’ve been lying down. It can also help ease stuffy ears. Use 1/4 to 1/2 teaspoon salt dissolved in an eight-ounce glass of warm water. Please note that children younger than 6 years old will be unlikely to be able to gargle properly.
You can also try ice chips, sore throat sprays, lozenges, or hard candy. Don’t give lozenges or hard candy to children younger than 3 to 4 years old because they can choke on them.
Combat a stuffy nose
Over-the-counter saline nasal drops and sprays can help relieve stuffiness and congestion. In infants, experts recommend putting several saline drops into one nostril, then gently suctioning that nostril with a bulb syringe. Saline nasal sprays may be used in older children.
Another option to ease stuffiness is nasal irrigation with a neti pot, where you pour salt water into one nostril and let it run out the other, clearing out your nasal passages. You can buy pre-made saline solution or make it by mixing salt and lukewarm sterile or distilled water. Neti pots are available in health food stores and drugstores.
Add moisture to the air
Breathing moist air helps ease nasal congestion and sore throat pain. One good strategy is to indulge in a steamy shower several times a day — or just turn on the shower and sit in the bathroom for a few minutes, inhaling the steam. Another way to ease congestion is to use a steam vaporizer or a humidifier. Be sure to change the water daily and clean the unit often in order to be sure it’s free of mold and mildew.
Another quick way to open clogged airways is to make a “tent.” Bring a pot of water to a boil and remove it from the heat. Drape a towel over your head, close your eyes, and lean over the water under the “tent,” breathing deeply through your nose for 30 seconds. You may also want to add a drop or two of peppermint or eucalyptus oil to the water for extra phlegm-busting power. Repeat this as often as necessary to ease congestion.
For adults and children older than 5, over-the-counter decongestants, antihistamines, and pain relievers might relieve some symptoms. As far as pain relievers go, children six months or younger should only be given acetaminophen. For children older than six months, either acetaminophen or ibuprofen are appropriate. Adults can take acetaminophen, ibuprofen, or aspirin. Please note that none of these over-the-counter medications will prevent a cold or shorten its duration, and most have some side-effects.
Another great way to relieve headache or sinus pain is to place a warm cloth over your forehead and nose.
Your body needs time to heal, so listen to it. If your body’s urging you to spend all day in bed, then do so. Don’t press on with daily chores in the face of severe cold or flu symptoms. And don’t skimp on nighttime sleep. Good sleep cycles help the immune system work well, so it’s important to get a full eight hours of sleep each night.
The popular proverb that we should eat when we have a cold, but not when we have a fever makes some sense intuitively. Since fevers usually only last a day a two and you tend not to have much of an appetite anyway, eating little isn’t difficult. But colds tend to last between seven and 10 days so you’re inclined to eat and would be left feeling pretty weak and wretched if you didn’t.
So it’s doable, but is there any evidence that following the saying makes you feel better more quickly? Liquids are, of course, essential and it’s the nutrients from food which enable cells to function. Yet illness commonly makes people lose their appetite altogether, and it has been suggested that this so-called “infection-induced anorexia” helps boost the immune system. But if this is the case, why should not eating have this effect only when we are ill?
One study dating back to 2002 gave rise to many a headline stating that “feed a cold, starve a fever” wasn’t an old wives’ tale after all. Dutch scientists asked volunteers to fast overnight before visiting their laboratory for tests on two separate occasions. On the first visit, they were given a liquid meal and on the second they received only water. Blood tests showed that levels of gamma interferon, a substance important in triggering immune responses against infection, particularly by viruses, increased by an average of 450% after participants had been given the meal, and decreased after consuming only water.
Meanwhile, fasting appeared to increase levels of another immune system signalling chemical called interleukin-4 on average fourfold – much more than the smaller increase seen in the study participants after they were given the liquid meal. Interleukin-4 plays a key role in fighting bacterial infection; it’s main role is in regulating immune reactions to infectious agents that have entered the blood and tissues, but that have yet to infiltrate individual cells.
So continuing to eat promotes the type of immunity that is particularly effective in combating the type of virus-based infection of cells you would have with a cold. And a fever might be caused by infectious bacteria, in which case starving yourself could promote the other type of immunity. So far, so good for those who saw the Dutch research as supportive of the “Feed a cold, starve a fever” maxim. Except that it’s not as neat as that.
A common cause of fever is flu which is caused by a virus, so the theory doesn’t quite fit. Moreover this study was tiny, with just six volunteers taking part. Even lead study author Gijis van den Brink warned people not to change their eating habits in response to illness on the basis of the study. Then there’s other evidence, admittedly only from mice, that when only 40% of the normal calories for a day are consumed, infection with flu was not only more likely, but symptoms were worse and the mice took longer to recover.
Although there has been work showing that calorie restriction both extends the lifespan of mice and rats by between 20% and 30%, and reduces the incidence of tumours, when it comes to flu, the evidence suggests that mice are better off eating.
But back to people. Not only is there a lack of scientific evidence to back up the proverb, but there are also historical and linguistic debates about its origins. Many credit Geoffrey Chaucer’s Canterbury Tales. Others insist the phrase does not appear in the late 14th century collection of stories. There have been suggestions that it’s a mistranslation and that the intended meaning was that feeding a cold would “stave off” a fever.
Those wanting a definitive answer will have to wait until we know more about the complexities of the immune system. Until then, appetite is probably your best guide. Whether you have a cold or a fever, it is important to keep taking fluids. As for food, you do want to keep your strength up if you can, but it depends on what you can stomach.
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By Michael Le Page
The maxim “feed a cold, starve a fever” may be right after all, researchers have discovered.
Until now, most doctors and nutritionists have rejected the idea as a myth. But Dutch scientists have found that eating a meal boosts the type of immune response that destroys the viruses responsible for colds, while fasting stimulates the response that tackles the bacterial infections responsible for most fevers.
“To our knowledge, this is the first time that such a direct effect has been demonstrated,” says Gijs van den Brink of the Academic Medical Center in Amsterdam. At a Christmas dinner, he and his colleagues decided to take blood samples to see if alcohol affected the immune system.
To their surprise, later analysis suggested that alcohol had no effect but food did. So the team got six people to fast overnight and then come into the lab for tests. On one occasion they were given a liquid meal, on the other just water to distend the stomach.
The results were striking. Six hours after the liquid meal, the volunteers’ levels of gamma interferon had more than quadrupled. Gamma interferon is a hallmark of the cell-mediated immune response, in which killer T cells destroy any cells that have been invaded by pathogens. “This type of immunity is mainly directed against viral infections,” van den Brink says. “It seems to be stimulated by food.”
But when the volunteers drank only water, levels of gamma interferon fell slightly, while levels of another chemical messenger, interleukin-4, nearly quadrupled. Interleukin-4 is characteristic of the humoral immune response, in which B cells produce antibodies that attack pathogens lurking outside our cells. This response is needed to tackle most bacterial infections, van den Brink says.
“It fits exactly with what we recently found,” say Paul van Leeuwen of the Free University Hospital, also in Amsterdam. His team has discovered that glutamine, an amino acid common in milk, meat and some nuts, boosts the cell-mediated immune response. Van Leeuwen’s colleague Petra Boelens presented the findings at a recent conference on intensive care in Australia.
The work followed an earlier study in The Lancet that showed intensive care patients are less likely to succumb to infections if given glutamine supplements.
Van den Brink speculates that the immune response that follows eating evolved as an energy-saving ploy. Whereas most bacterial infections need an immediate response, he says, tackling a virus to which we have already been exposed can wait until we have more energy.
He cautions that people should not change their behaviour based on such a small study. But he thinks finding out exactly what stimulates the different responses will be useful: “Certain foods could be given to critically ill patients to stimulate the right immune response.”
Journal reference: Clinical and Diagnostic Laboratory Immunology (vol 9, p 182)
In Depth: Fevers, Cold, and Flu
You see, when you have a cold or an illness that’s causing a fever, you may feel so crappy that you’re less motivated to eat and drink. And while most healthy people can handle not eating much solid food for a few days, you’ve got to keep drinking, says Dr. Chisolm-Straker. Staying hydrated is important even when you’re healthy, but it’s even more so when you have a fever. “Your body is working harder than it usually has to,” Dr. Chisolm-Straker explains, which can ultimately dehydrate you. Plus, if you have an infection that’s causing diarrhea or vomiting along with your fever, you’re at risk of making yourself even sicker if you don’t sip water here and there.
Steer clear of sports drinks, soda, and coffee, Dr. Chisolm-Straker says. “Drink Pedialyte, rehydration solutions, or water. Hydrate throughout the day, have ice pops, whatever you can do to get it into your system.”
While water is the very best thing you can consume when you’re sick, it might not help you get well faster. Ultimately, Dr. Chisolm-Straker says rest and time are the only things that can cure colds and fevers. “The best I can do is give you a note for work saying you can take time to sleep, and tell you to take acetaminophen or ibuprofen to make you feel better,” she says. “They won’t cure you, but they’ll make you feel less like crap.”
Anisa Arsenault Contributor Anisa Arsenault is a New York City-based writer and editor covering health, lifestyle, and parenting news.