Health professionals have known for decades about the role of vitamin D in building strong bones, yet an explosion of medical research in the last decade has shed light on the role of this nutrient in many other body systems and health conditions. Researchers now know that vitamin D receptors are found throughout the body. This means vitamin D is involved in a wide range of body functions.
Along with this, research has shown that correcting low levels of vitamin D can help in managing a number of chronic diseases, such as diabetes and high blood pressure. And higher vitamin D levels have been linked to a lower risk for many types of cancer.
So it’s worth boning up on this crucial vitamin. Below are answers to common questions and some guidelines to help you decide whether you need to supplement your intake in order to optimize your levels.
What is vitamin D? Despite its name, vitamin D is actually a hormone, not a vitamin, which is produced in the skin from a derivative of cholesterol. A type of ultraviolet ray from the sun, called UVB, acts on pro-vitamin D3 and converts it into pre-vitamin D3, which is then converted to D3, or cholecalciferol. D3 then is able to leave the skin and enter the bloodstream, through which it reaches various organs in the body. In the liver, it undergoes further changes and emerges in an activated form.
What does vitamin D do in the body? Scientists used to think that vitamin D had the sole role of regulating blood levels of calcium, thus contributing to bone health. In the last 15 years or so, researchers have realized that vitamin D plays a much larger role in the maintenance of our health and has an extensive impact on the organs, tissues and cells of our whole body. A 2010 publication from Kansas State University called Vitamin D: From Sunshine to Supplements does a nice job of summarizing these roles. Below is a nutshell overview, based on that resource:
• Vitamin D helps keep the immune system healthy. With adequate vitamin D levels, a person’s immune system is better able to resist infection and ward off disease. In a related function, vitamin D may help prevent autoimmune conditions such as rheumatoid arthritis and multiple sclerosis, in which the body attacks its own tissues.
• Vitamin D regulates a number of genes that appear to play a role in the development and progression of several types of cancer.
• Vitamin D may play a role in improving insulin sensitivity, which could lower diabetes risk. Maintaining adequate levels may help prevent complications for those who already have the disease.
• Several studies show that when vitamin D levels are higher, blood pressure is lower. Adequate levels may also help reduce inflammation, which decrease the chances for blocked and narrowed arteries and other forms of heart disease.
Who should be tested for vitamin D deficiency? In a word, everyone. Low vitamin D levels are common among all ages and all races, even among people living in sunny California or in the Middle East. Physician Sarfraz Zaidi, author of The Power of Vitamin D, writes, “Vitamin D deficiency is the true epidemic of our times. It is perhaps more common than any other medical condition at the present time.…Several studies have clearly demonstrated that vitamin D deficiency spans across all age groups.”
Those with a chronic disease may be especially likely to be deficient. Physician Soram Khalsa points out in his 2009 book, Vitamin D Revolution, that “vitamin D deficiency is now connected with 17 varieties of cancer, along with heart disease, high blood pressure, strokes, autoimmune diseases, diabetes, chronic pain, and osteoporosis.” (Whether low vitamin D contributes to or results from certain diseases is still under investigation. But either way, improving low levels can be beneficial.)
What are misconceptions people have about vitamin D? Many people I talk with assume that if they are taking a multivitamin and mineral capsule, or a calcium and vitamin D pill, they are getting enough vitamin D. Others tell me that because they spend lots of time outdoors and vitamin D is made by the sun, they are probably getting enough. Still others assume they are fine because they drink plenty of vitamin D-fortified milk.
The fact is, the great majority of these clients discover they have low vitamin D levels once they get tested. Naturally occurring vitamin D is found only in a few foods, such as oily fish like tuna, sardines, and salmon. Milk, butter, some cold cereals, and orange juice may be fortified with the vitamin, but the amounts are usually too small to correct a deficiency.
Why is there an epidemic of vitamin D deficiency? Dr. Khalsa lists 10 factors that may “come between you and vitamin D-producing UVB rays.” Half the factors have to do with the latitude where we live and the amount of sun exposure we get. The others have to do with our skin color and the amount of melanin we have, as well as our age and weight, and the amount of clothing covering our body – a concern for Orthodox Jews and others who dress modestly.
In fact, a study published in 2011 in the journal Osteoporosis International looked at the effects of different dress styles and amounts of time spent outdoors on vitamin D levels in healthy young Israeli males across the Orthodox spectrum in Israel. The researchers studied students from three different yeshivas, from a modern to a chareidi setting. All three groups turned out to be deficient, on average, with the chareidi students showing the lowest levels.
Other contributors to the epidemic, according to Dr. Khalsa, include drugs that may lower vitamin D levels, flaws in research on the topic , and recommendations for vitamin D that are too low for optimal functioning. Dr. Khalsa says that all these “conditions inherently contribute to an increased risk of having a vitamin D deficiency and thereby increase your chances of developing an illness or disease that is associated with vitamin D deficiency.”
What should you do? Here is a suggested vitamin D action plan:
1) Start by taking the quiz below, developed by the Vitamin D Council. This group was started by well-known vitamin D expert Dr. John Cannell and is a very reliable source of information.
2) To help confirm the results one way or the other, ask your primary care physician or specialty care physician (if you regularly see one) to order a 25(OH) vitamin D blood test. The results are reported in ng/ml.
3) As you review the results with your practitioner, discuss what your ideal vitamin D level should be, given your individual health situation. Generally, vitamin D “insufficiency” is defined as 20-30 ng/ml, and a level lower than 20 mg/ml is considered a “deficiency. “ Dr. Khalsa and others recommend higher levels of vitamin D, in the 40-60 ng/ml range, for those with chronic diseases such as cancer and heart disease.
4) A licensed nutritionist (LDN) who practices medical nutrition therapy can help with food recommendations, supplement suggestions, and other lifestyle adjustments to promote optimal levels.
What is the difference between Vitamin D2 vs. Vitamin D3? There are two types of Vitamin D: ergocalciferol (D2) and cholecalciferol (D3). Although D2 is the type of vitamin D used in prescription medications, it may not be as efficacious at raising vitamin D levels in the body as vitamin D3, according to an article in American Journal of Nutrition (“The Case against Ergocalciferol (vitamin D2) as a Vitamin Supplement,” by Houghton and Vieth.)
The Vitamin D Council and Mark Moyard, MD, also recommend D3 over D2. According to the Medscape website, “A few studies have shown that cholecalciferol (vitamin D3) is better than ergocalciferol (vitamin D2) at increasing vitamin D levels, and better for various health outcomes and mortality risk. Also, since the body produces cholecalciferol rather than ergocalciferol, it is commonly thought that cholecalciferol is better for people than ergocalciferol.” Here is the information from Medscape:
1) Vitamin D3 may be less toxic than D2 because higher concentrations of D2 circulate in the blood when consumed, as compared to vitamin D3, and it does not bind as well to the receptors in the human tissues, as compared to vitamin D3.
2) Vitamin D3 is the more potent form of vitamin D, which is a potential benefit. For example, obesity tends to lower blood levels of vitamin D, so a more potent form is needed.
3) Vitamin D3 is more stable on the shelf, and is more likely to remain active for a longer period of time and when exposed to different conditions (temperature, humidity, and storage).
4) Vitamin D3 has been the most utilized form of vitamin D in clinical trials, and there have only been a few clinical trials of vitamin D2 to prevent bone fractures in adults.
With that said, most doctors will prescribe the high dose Vitamin D2, and some patients find it raises their level, while others find it does not. If it does not, after an adequate medically determined trial, I would advise that the patient try another strategy, such as daily doses of 2000 to 5000 IU (to be initially determined by blood test) of D3 for three to six months, and then retesting. Vitamin D3 is available in many forms – from capsules, tablets, liquids, and chewables – from kosher certified companies like Maxi-Health, Nutri-Health Supreme, and Freeda.
Lauren Mirkin CNS, LDN, LCPC is a licensed nutritionist and professional counselor. Please contact her for information about her comprehensive integrative nutrition counseling services, workshops and classes. She can be reached at 443-326-7023 or firstname.lastname@example.org.
What Is your Vitamin D Status?
Take this quiz to help determine whether you are getting enough vitamin D. Remember that it is only a guide and is not a guarantee of your level. You still may want to get tested, especially if you score in the lower range.
1) Do you get at least 30 minutes of midday (between 10 a.m. and 2 p.m.) sun exposure every day without wearing sunscreen?
2) Do you live between 35 degrees north (north of Atlanta and Los Angeles) and 35 degrees south (south of Sydney, Australia, or Buenos Aires, Argentina)? For those of us in Maryland, the answer is no.
3) Do you supplement with at least 30,000 IU/week?
4) Do you eat wild, oily fish (salmon, mackerel, herring, and sardines) at least three times a week?
5) Do you have pain in your muscles, bones, or joints? Do you have fatigue?
6. Do you take glucocorticoids? These are steroid hormones used to dampen immune activity, such as prednisone.
7) Is your BMI (body mass index) greater than 30?
8) Are you older than 50?
For questions 1 to 4, score one point for every question to which you answered “yes.” Subtract one point for every question to which you answered “no.” For questions 5 to 8, add one point for every question to which you answered “no.” Subtract one point for every question to which you answered “yes.” Calculate your total score and add 8 to it.
If your total score is between 0 and 5, you are likely not getting enough vitamin D and are deficient. If your total score is between 6 and 10, you are likely within a clinically normal range but can still benefit from more vitamin D. If your total score is between 11 and 16, you are likely getting enough vitamin D.