Vitamin D is not really a vitamin as originally defined – “vital amines” are substances that act as co-factors (i.e. helpers) for the body’s enzymes. It turns out that Vitamin D is really a steroid (read “fat-soluble” so it can enter your cells without assistance) hormone that has a direct effect on the expression of over 2,000 genes by actually crossing the cellular membrane and gaining direct access to the cell nucleus where our DNA is housed. What genes are activated? Well, they include genes that regulate the absorption of Calcium from the intestines, the building of strong bones, and the efficient and coordinated activity of our immune systems. Vitamin D deficiency is most commonly known as “rickets” in children, or “osteomalacia” in adults – it is a disease of soft bones. However, new research is showing that this amazing “vitamin” plays an even stronger role in the prevention of disease, including heart disease, respiratory illnesses and cancer (specifically breast and colon). In the Framingham Heart Study, it was observed that men with higher vitamin D blood levels (measured as 25-OH vitamin D) were less likely to suffer a heart attack. Vitamin D levels are also inversely related to breast and colon cancer, meaning higher levels of vitamin D are associated with a lower likelihood of developing these cancers. Again, this is probably due to its ability to regulate the immune system — the body’s main watchdog against cancer cells.
Vitamin D, in its active form, prevents excessive expression of inflammatory mediators during an infection, and optimizes the functioning of immune system cells, which includes increasing the expression of anti-microbial proteins.1
How do we get vitamin D, anyway? Well, if you could eat oily, fatty fish for breakfast, lunch and dinner or drink multiple tablespoons of cod liver oil daily, you would be getting a few thousand units. However, if this is not your thing, the typical American diet (SAD = Standard American Diet) contains very little vitamin D. Milk, which does not naturally contain vitamin D, is fortified as mandated by the U.S. Government, to approximately 100 units per 8 oz. glass. This falls far short of the current recommendation for 2,000 I.U. daily to maintain adequate levels. You would have to drink 20 glasses of milk per day – not exactly possible, and not exactly healthy. In fact, a recent study comparing the results of the Third National Health and Nutrition Examination Survey (NHANES III), collected from 1988 through 1994, to the data collected from 2001 to 2004 (NHANES 2001-2004) confirms that Americans are not getting enough Vitamin D.2 The most recent data alarmingly showed that three-quarters of U.S. children and adults fall below the acceptable value for vitamin D levels (< 30 ng/ml), as measured in the blood. In other words, 75% of the population is vitamin D deficient! Wow! That is a staggering amount of vitamin D deficiency. When you’re young, you may not notice, but your future risk of osteoporosis is increased. Weak bones lead to a great deal of health problems in older age, including chronic pain, which will make those “Golden Years” much less enjoyable.
Your Safe Daily-Dose of Sunshine: For light-skinned individuals, approximately 10-15 minutes without sunblock; for darker-skinned individuals, up to 30 minutes without sunblock. This is the daily amount necessary to build up proper stores of vitamin D.
Why is this happening? Well, when you consider that the best source for Vitamin D is the sun, as the photoreaction catalyzed by the energy from UVB rays converts the inactive form of vitamin D stored in our skin to its active form, we begin to understand why this is. Only 10-20 minutes of summertime sun exposure triggers the production of approximately 10,000 – 20,000 I.U.’s of vitamin D in the body. In the last two decades the emphasis on sun avoidance and concern for skin cancer has increased exponentially. Dermatologists all over the country have been telling their patients to avoid the sun when possible, or at least wear sunscreen rated SPF 15 or higher for UVA/UVB at all times when in the sun. People’s fear of skin cancer and consequent sun-avoidance behavior and/or augmented sunscreen use has probably led to the current epidemic of vitamin D deficiency. We have lost the concept of what is safe sun exposure.
Why are we concerned? With the passing of the seasons, from winter to summer, there is a seasonal variation in vitamin D levels, regardless of diet or supplementation. With the summer months, more sun means more inevitable exposure and a rise in vitamin D levels. As the winter solstice approaches, the sun is far below the equator, and consequently most of the UVB rays necessary for vitamin D conversion are filtered by the atmosphere before they reach the earth.3 This is why getting sun on a perfectly sunny winter day does not produce significant Vitamin D activation on the skin if you live north of the 35 degree latitude (about the level of Raleigh, NC). My patients often ask me this, and this is the explanation. This seasonal variation in Vitamin D was looked at as the possible “unknown factor” that British researcher, Dr. Edgar Hope-Simpson, postulated was the cause for the seasonal rise in influenza cases in the winter, and their incidental fall and disappearance in the summer months.1
I have seen my patients gain more energy, stronger immune systems, and experience reduced muscle aches by proper Vitamin D supplementation. For some, it seems that vitamin D deficiency is the hidden factor that leads to seasonal affective disorder (the “winter blues”). Correcting the low vitamin D level helps lift the winter blues. These are not all linear relationships, but some examples of how proper vitamin D levels can change people’s lives.
The recommended daily dose of Vitamin D for adults now is around 1,000 IU/day. However, in practice, I have found this to be too low, and for most adults it will not correct their low vitamin D level. From my experience with patients in New York City, I believe a more accurate amount is 2,000 IU daily for adults, and 400-800 IU daily for children. But don’t be fooled if you live in Florida — vitamin D deficiency can happen anywhere if you are hiding from the sun year-round! These numbers are average doses; however, some of my patients have required much higher levels, up to 5,000 – 10,000 IU daily in order to correct a severe deficiency. Your vitamin D level can be easily checked by a blood test for 25-OH Vitamin D. The best form to take as a supplement is vitamin D3, which is better absorbed orally than vitamin D2. High doses of vitamin D over the long-term can be toxic to the liver or create a relative vitamin A deficiency, and thus should never be initiated alone. High dose supplementation should be supervised by a physician or knowledgeable health professional.
The ideal blood levels for
Vitamin D[25-OH] are between 40 – 60 ng/mL.
Each person is their own unique set of circumstances, and when it comes to vitamin supplementation, we have to look at the whole, and not make the mistake of confusing a vitamin for a medication. All these nutrients coordinate together in the symphony that the body is.
Vitamin D resources:
The Vitamin D Council – a resource of information about vitamin D.
Vitamin D level testing – a link to a lab that can provide a vitamin D testing kit. Note that many doctors can check vitamin D levels in their offices, although your doctor may think it is not necessary. As recently as last month, I heard the resident doctor on Good Morning America saying that not all adults have to be screened for vitamin D deficiency. Really? With 75% of U.S. adults deficient, this surpasses any level that makes a widespread screening program cost-effective! In New York City, where I practice, I am surprised at how many people are vitamin D deficient, that I would have not thought would be. You cannot look at someone and know whether they are vitamin D deficient just based on how they look (unless they are ghost white and never go in the sun — then I’ll bet you $100 that they are). In my practice, it makes sense to me to check vitamin D levels on all adults (both male and female), especially since vitamin D deficiency can be asymptomatic, or the person may not notice the symptoms, simply attributing them to their work schedule or life stress. Many times mild symptoms are not noticed until they disappear. Screening for vitamin D deficiency should be part of any preventive medicine strategy to help mitigate the risk of future disease.
Excerpt from The Ultimate Swine Flu Survival Guide Dr. Vincent Pedre
find it on
- Cannell, et al: Epidemic influenza and vitamin D. Review Article. Epidemiology and Infection (2006), 134 : 1129-1140. Cambridge University Press.
- Ginde AA: Demographic Differences and Trends of Vitamin D Insufficiency in the US Population, 1988-2004. Arch Intern Med. 2009;169(6):626-632.
- MacLaughlin JA, Anderson RR, Holick MF. Spectral character of sunlight modulates photosynthesis of previtamin D3 and its photoisomers in human skin. Science. 1982;216:1001–1003.