Why am I not getting enough vitamin D?
Vitamin D deficiency can happen when a person:
- does not consume enough vitamin D
- is unable to absorb or metabolize the vitamin D
- does not spend enough time in ultraviolet B (UVB) sunlight
Share on PinterestA person’s diet may contribute to vitamin D deficiency.
Various factors can increase the risk of a deficiency.
Diet: People who do not eat enough vitamin D-rich foods, including fortified dairy products and cereals, may have low levels of vitamin D.
Lifestyle factors: Some people spend little time outdoors due to work, ill health, a lack of outdoor space in their neighborhood, or other factors. These people have less opportunity to expose their skin to sunlight. Those who wear clothes that cover all of their body, whether to protect it from the sun or for cultural or religious reasons, may also have a higher risk of a deficiency.
The Office of Dietary Supplements (ODS) recommend that people who use a lot of sunscreen or wear clothing that covers the body should include sources of vitamin D in their diet.
Geographical factors: People living in certain parts of the word — Northern Canada and Alaska, for example — may have less access to the sun’s UVB rays, especially in winter. People who live in a hot climate may also be at risk, as they often try to avoid the heat and strong sunlight by staying indoors.
Pollution: Particles in the air can block UVB rays and prevent them from reaching the skin. People who live in highly polluted areas may also be more likely to avoid spending time outside.
Absorption problems: Crohn’s disease, celiac disease, and other conditions can affect how the intestines absorb nutrients, including vitamin D.
Medications: Some drugs reduce the body’s ability to absorb or synthesize vitamin D. These include steroids and some drugs for lowering cholesterol, among others.
Smoking: Levels of deficiency appear to be higher among smokers. Some experts have suggested that smoking may affect the gene that activates the production of vitamin D-3 in the body.
Obesity: Research has found lower vitamin D levels in people with obesity, or a body mass index (BMI) of 30 or more. This link may be stem from the ways in which body fat affects vitamin D absorption. Some people with obesity may spend less time outdoors due to mobility issues. Those who have undergone bariatric surgery may also have absorption problems. Conversely, people whose BMI of 25–29.9 classified them as overweight appeared to have a lower risk of a deficiency than those who were not overweight. The authors suggest that dietary factors are responsible for this difference.
Skin type: People with darker skin need more sunlight exposure to produce vitamin D than those with lighter skin. People with pale skin or a history of skin cancer may avoid sun exposure to protect their skin from damage.
Age: The ability to convert vitamin D to calcitriol may decline with age due to decreased kidney function. As a result, calcium absorption will fall.
Kidney and liver health: People with liver disease and kidney disease tend to have lower vitamin D levels. These diseases can affect the body’s ability to synthesize vitamin D or turn it into its active form.
Pregnancy: The need for vitamin D may increase during pregnancy, but experts remain unsure whether supplements are a good idea. The authors of a 2019 Cochrane review concluded that taking supplements during pregnancy may reduce the risk of preeclampsia, gestational diabetes, low birth weight, and severe bleeding after delivery. However, it may also increase the risk of preterm birth, which is birth before 37 weeks. The authors called for further research.
Breastfeeding infants: Human milk is low in vitamin D, which means that breastfeeding infants are at risk of a deficiency. The Centers for Disease Control and Prevention (CDC) recommend giving a vitamin D supplement to all breastfeeding infants from the first few days of life until they consume 1 l or more of formula milk each day. Supplementation becomes unnecessary at this point because formula milk contains added vitamin D.
Groups with a higher risk
A major study in the United States from 2001–2006 found that 24% of the population were at risk of low vitamin D levels, while 8% were at risk of a deficiency. On the other hand, 1% of the population had levels of vitamin D that were so high that they could be harmful.
In 2019, experts published a report on data from 2011–2012. They looked at how vitamin D deficiencies affect specific populations in the U.S. The findings suggested that African American adults have the highest risk of a deficiency, followed by Hispanic people.
Vitamin D deficiency is a global health problem. With all the medical advances of the century, vitamin D deficiency is still epidemic. Over a billion people worldwide are vitamin D deficient or insufficient.(1) Yet no international health organization or governmental body has declared a health emergency to warn the public about the urgent need of achieving sufficient vitamin D blood levels.
Vitamin D, also described as “the Sun Vitamin” is a steroid with hormone like activity. It regulates the functions of over 200 genes and is essential for growth and development. There are two forms of vitamin D. Vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol).(2) Vitamin D status depends on the production of vitamin D 3 in the skin under the influence of ultraviolet radiation from sun and vitamin D intake through diet or vitamin D supplements. Usually 50 to 90% of vitamin D is produced by sunshine exposure of skin and the remainder comes from the diet. Natural diet, most human consume, contain little vitamin D. Traditionally the human vitamin D system begins in the skin, not in the mouth. However, important sources of vitamin D are egg yolk, fatty fish, fortified dairy products and beef liver.(3)
Vitamin D3 deficiency can result in obesity, diabetes, hypertension, depression, fibromyalgia, chronic fatigue syndrome, osteoporosis and neuro-degenerative diseases including Alzheimer’s disease. Vitamin D deficiency may even contribute to the development of cancers, especially breast, prostate, and colon cancers. Current research indicates vitamin D deficiency plays a role in causing seventeen varieties of different cancers as well as heart disease, stroke, autoimmune diseases, birth defects, and periodontal disease.(4) Vitamin D3 is believed to play a role in controlling the immune system (possibly reducing one’s risk of cancers and autoimmune diseases), increasing neuromuscular function and improving mood, protecting the brain against toxic chemicals, and potentially reducing pain.(5)
Serum 25-hydroxyvitamin D concentration is the parameter of choice for the assessment of vitamin D status. Recently, many studies have used 30 ng/mL as a cut-off value and most experts now recommend the normal level of 25-hydroxyvitamin D (25OHD) to be ≥30 ng/mL. Vitamin D insufficiency is defined when the levels are between 20–29 ng/mL and at levels of ≤20 ng/mL the patient is considered vitamin D deficient.(6)
Exposure to sunshine each day helps human body to manufacture the required amount of vitamin D. However, due to fear of developing skin cancer most people avoid the sun exposure. To prevent vitamin D deficiency, one should spend 15 to 20 minutes daily in the sunshine with 40% of the skin surface exposed. High concentration of melanin in the skin slows the production of vitamin D; similarly aging greatly reduces skin production of vitamin D. Use of sunblock, common window glass in homes or cars and clothing, all effectively block UVB radiation – even in the summer. People who work indoors, wear extensive clothing, regularly use sunblock, are dark skinned, obese, aged or consciously avoid the sun, are at risk of vitamin D deficiency.
Despite the abundance of sunshine in the Middle East allowing vitamin D synthesis all year round, the region registers some of the lowest levels of vitamin D and the highest rates of hypovitaminosis D worldwide. This major public health problem affects individuals across all life stages, especially pregnant women, neonates, infants, children and the elderly. Furthermore, while rickets is almost eradicated from developed countries, it is still reported in several Middle East countries. These observations can be explained by limited sun exposure due to cultural practices, dark skin color, and very hot climate in several countries in the gulf area, along with prolonged breast feeding without vitamin D supplementation, limited outdoor activities, obesity, and lack of government regulation for vitamin D fortification of food, in several if not in all countries.(7)
A study carried out recently among young healthy man living in eastern province of Saudi Arabia revealed the prevalence of vitamin D deficiency between 28% to 37%.(8) Similarly, other studies conducted in Saudi Arabia on population at high risk reported the vitamin D deficiency to be 50% to 80%.(9)
Long term strategies to address this deficiency problem should include public education, national health policies for screening and prevention through food fortification, and treatment with vitamin D supplementation. In conclusion vitamin D deficiency is epidemic worldwide, Saudi Arabia and many other sunny countries are no exception. Keeping in mind the consequences of vitamin D deficiency on Saudi population this health issue should be addressed with due attention and concrete steps.
Vitamin D Deficiency
Q: What happens when a person takes more than their recommended daily intake of vitamin D?
A: When a person’s regular intake of vitamin D is greater than the recommended daily dose, this can result in hypervitaminosis D (vitamin D toxicity), a rare but potentially serious condition that results from having much higher than recommended levels of vitamin D in one’s body. This can stimulate the development of a range of different health complications, including excessive thirst and urination, dehydration, high blood pressure, nausea and vomiting. Long-term hypervitaminosis D can result in serious problems, including cardiovascular malfunctions, calcification (hardening) of the arteries and soft tissues, and kidney problems.
Hypervitaminosis D is usually the result of taking too many supplements of vitamin D. It is therefore important to consult one’s doctor before starting to use a selection of different supplementary products, so as to ensure that there is no significant overlap between the kinds of nutritional compounds that they provide. Cod liver oil, for example, has a high vitamin D content and should therefore not be taken in conjunction with any other supplementary sources of vitamin D.
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5 Illnesses Linked to Vitamin D Deficiency
1. Dementia and Vitamin D Deficiency
A study published in August 2014 in the journal Neurology found that moderate and severe vitamin D deficiency in older adults was associated with a doubled risk for some forms of dementia, including Alzheimer’s disease. Dementia involves a decline in thinking, behavior, and memory that negatively affects daily life. Alzheimer’s disease is the most common form of dementia, accounting for as many as 80 percent of dementia cases, according to the Alzheimer’s Association.
The above study analyzed more than 1,600 people age 65 or older who did not have dementia at the beginning of the study. Compared with people with normal vitamin D levels, those with low levels of the vitamin had a 53 percent increased risk of developing all-cause dementia, while those who were severely deficient had a 125 percent increased risk, researchers observed. Also, study authors found people who had lower levels of vitamin D were about 70 percent more likely to develop specifically Alzheimer’s disease, and that those who were severely deficient were over 120 percent more likely to develop that neurodegenerative disorder.
Considering the devastating toll that dementia can have on patients and their families alike, those findings may seem alarming. But researchers noted their study was observational, meaning they didn’t prove a direct cause-and-effect relationship with vitamin D deficiency and dementia and Alzheimer’s. Nonetheless, they theorized that the sunshine vitamin might help clear plaques in the brain that are linked to dementia.
Regardless of the relationship between vitamin D and dementia, know that following tried-and-true health advice, like eating a healthy diet, exercising regularly, and tending to your mental health can help reduce your risk of dementia.
2. Prostate Cancer and Low Vitamin D
A study published in May 2014 in the journal Clinical Cancer Research found a link between low blood levels of vitamin D and aggressive prostate cancer in European-American and African-American men.
Researchers looked at vitamin D levels in 667 men ages 40 to 79 who were undergoing prostate biopsies. The connection between vitamin D and prostate cancer seemed especially strong in African-American men, with results suggesting that African-American men with low vitamin D levels were more likely to test positive for the cancer than the other men with normal vitamin D levels.
Though these findings were also observational — that is, the study didn’t prove low vitamin D leads to prostate cancer — you may help reduce your potential risk of the disease by ensuring you get adequate vitamin D. You can also make regular doctor’s visits, and watch out for common prostate cancer symptoms to receive a prompt diagnosis and treatment if you’re affected.
Also know that prostate cancer occurs mostly in older men, with the average age of diagnosis being about 66, according to the American Cancer Society. It’s the most common cancer in men, and the second most common cause of cancer death in American men.
3. Severe ED Linked to Low Vitamin D
A small study of 143 subjects published in August 2014 in the Journal of Sexual Medicine found that men with severe erectile dysfunction (ED) had significantly lower vitamin D levels than men with mild ED.
Study authors theorized that vitamin D deficiency may contribute to ED by impeding the arteries’ ability to dilate — a condition called endothelial dysfunction and a heart-disease marker that has been associated with vitamin D deficiency in other research.
For instance, a study published in July 2011 in the Journal of the American College of Cardiology suggested that lack of the vitamin was indeed linked with arterial stiffness in healthy people. One of the requirements for achieving an erection is proper function of the arteries, which are responsible for supplying the penis with blood so it can become engorged.
ED is the most common sexual problem among men, affecting up to 30 million American men, according to the National Institute of Diabetes and Digestive and Kidney Diseases. ED can stem from other health conditions like diabetes, prostate cancer, and high blood pressure.
Common ED treatments include hormone replacement therapy, counseling, and lifestyle changes like quitting smoking, limiting alcohol, and eating a balanced diet.
4. Vitamin D and Risk of Schizophrenia
Schizophrenia is a severe brain disorder that affects about 1.1 percent of American adults, according to the National Institute of Mental Health. Symptoms of schizophrenia, which commonly appear between ages 16 and 30, include hallucinations, incoherent speech, withdrawal from others, and trouble focusing or paying attention.
People who are vitamin D deficient may be twice as likely to be diagnosed with schizophrenia compared with people with sufficient vitamin D levels, suggests a review published in October 2014 in the Journal of Clinical Endocrinology & Metabolism. Researchers reviewed findings from 19 observational studies that analyzed the relationship between schizophrenia and vitamin D deficiency and observed a link between the two factors.
While they noted randomized controlled trials would be needed to determine whether treatment for low vitamin D may help prevent schizophrenia, they explained that the condition is more prevalent in places with high latitudes and cold climates, and that studies suggest children who relocate to colder climates appear to be at a higher risk of developing the condition compared with their parents. Considering what we know about the role of vitamin D in mental health, the researchers’ findings may have merit.
Although there is no cure for schizophrenia, treatments for schizophrenia include medication, psychosocial therapy, cognitive behavioral therapy, and even family education and support groups.
5. Vitamin D Deficiency and Heart Disease
Numerous studies have shown an association between low vitamin D blood levels and heart disease and related complications, according to a review published in January 2014 in Circulation Research, but science has not clearly established if supplementation can reduce these risks. The review cites research that points to vitamin D levels as a potential culprit for health problems related to heart disease such as atherosclerosis, hypertension, diabetes, and stroke.
You can reduce your risk of heart disease by maintaining a healthy weight, exercising regularly, and eating a diet rich in lean meat, nuts, and fruits and veggies, according to the American Heart Association.
How Much Vitamin D Do You Need, and How Do You Get It?
While some foods — like fortified dairy, egg yolk, beef liver, and fatty fish like salmon and canned tuna — can help you get vitamin D2, or ergocalciferol, direct sun exposure can help you get your fix of vitamin D3, or cholecalciferol. Sun exposure can also help your body better absorb calcium — a crucial nutrient for strong bones, according to the National Institutes of Health (NIH).
Most people need 600 international units (IU) of vitamin D daily, according to the NIH, but just a few minutes outdoors in the sunshine with some skin exposed can help you meet some of those needs. Just be sure to wear sunscreen if you spend an extended amount of time outdoors, as excess sun exposure can contribute to your risk of skin cancer.
If you are unable to get regular sun exposure because of your geographic location or weather conditions, consider taking a vitamin D supplement. You can work with a registered dietitian or your primary care provider to discover whether you need a high dose of vitamin D or a low dose of vitamin D, as well as which type you’re deficient in.