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Getting more bang from your vitamin D buck

Vitamin D has emerged in recent years as a “star” nutrient” based on numerous scientific discoveries about its role in human health. For years, vitamin D was most closely associated with calcium metabolism, since the activated form of vitamin D is required to promote calcium uptake into the body. But a few years ago, studies found that vitamin D was far more than just  a fat-soluble vitamin involved in calcium metabolism. It turns out that vitamin D is converted in the body into a hormone, and that the body contains hundreds of cellular receptors for the active or hormonal form of D. As such, hormonal D is involved in hundreds of vital body functions, ranging from effects in the brain to prevention of cancer, diabetes, and cardiovascular disease. Based on these findings, the research on D has exploded. Among the more interesting findings in this regard was a study that found that D is required to activate immune cells known as T-cells. Without D, these important cells simply won’t work. When that happens, you increase the risk of acquiring everything from cancer to upper respiratory infections, such as colds and flu. In fact, several studies have found that those who have optimal intakes of D are far less prone to infection from the influenza virus.

One unique aspect of vitamin D that many people know about is that your body can synthesize vitamin D in the skin after exposure to ultraviolet light. This is a complex reaction involving converting cholesterol compounds in the skin into vitamin D. You need to expose most of your skin surface to the sun for at least 20 minutes, and the sun ultraviolet rays have to be at a certain range in intensity to promote the reaction. In practical terms, this means that standing in the sun while in the nude for three hours during the winter in Boston will give you a frightful case of frostbite, but no vitamin D. The other option is to obtain D from food sources, but such sources are scarce. This is particularly true since it’s now known that you need far more D than was previously believed for optimal health and preventive effects. Exposing yourself to sunlight for 20 minutes will produce about 10,000 units of D in your body. This contrasts with the usual old recommendation to ingest about 800 units of D daily. The truth is that the optimal oral dose of D ranges from 2,000 to 5,000 units a day. How much you need depends on various factors, including age( older people need more),amount of sun exposure, and body fat level. In those with higher body fat levels, D is sequestered in fat tissues, and is less available, thus increasing the requirement for those with excess body fat levels.

An important, but often overlooked aspect, of vitamin d supplementation is that it’s a fat-soluble nutrient. This means that for optimal absorption, you need to ingest it with a meal containing fat. Taking  a D pill with a glass of water doesn’t cut it in this regard. The importance of timing of D intake was illustrated in a new study. The new study involved 13 women and 4 men, who were provided with doses of D ranging from 1,000 to 50,000 units daily. These subjects were told to ingest their D with the largest meal of the day, ostensibly because this meal would likely contain the highest fat content. D levels  were then monitored for 2 to 3 months. Ingesting the D with the largest meal led to a 56.7% increase in the level of active D in the blood, which would have significant health benefits. As such, when you take your D supplement, make sure you ingest it with a meal that contains the highest fat level of the day to promote optimal D uptake in the body.

Mulligan, G, et al. Taking vitamin D with the largest meal improves absorption and results in higher serum levels of 25-hydroxyvitamin D.J Bone Min Res 2010;25:928-30.

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  1. John Balik

    May 13, 2010 at 10:20 pm

    Jerry, is the most active form D-3? At what daily dosage level does it become toxic? What is the name of the specific test to measure D in the blood? Is there enough info to say what the optimum blood level is?

    Another terrific blog–thanks.


  2. Jerry Brainum

    May 13, 2010 at 11:26 pm

    There is still some contention regarding the optimum form of D. The natural form, and the form made in the skin from sun exposure, is D3. But as I wrote in my D article in Ironman a while back, studies show that D2, although synthetic, works as well as D3. I would still opt for D3, because it has a longer retention time in tissues. The toxic dose of D is usually stated as 50,000 units a day, but that dose is provided short-term to people with clinical D deficiency with no problems. The body will make a minimum of 10,000-20,000 units with 20-30 minutes of UV exposure. Any excess D from UV is rapidly degraded. Using a sun blocker prevents D formation by UV, and also may interfere with testosterone metabolism. The test to determine optimal D levels in blood is 25-hydroxy-vitamin D test, which is never provided during routine blood tests. Amazing when you consider the epidemic deficiency of D now in the U.S. Still another example of our “superior” health care. Getting enough D makes a real difference in preventing cancer, CVD, etc. The optimal blood levels of D as measured by the test are 30-50 ng/dl. Less than 15 means you are deficient. This level can be achieved by an intake of about 2,000-4,000 units of D in lean and younger people, up to 5,000-7,000 for the old and the obese.

  3. Ken O'Neill

    May 13, 2010 at 11:38 pm

    An issue plaguing studies, one certainly germaine to John’s question, is the relative metabolic condition of unique individuals. Sedentary persons, or the other at risk catabolic group, runners, differ considerably from strength training athletes – and within the latter group, those engaged in hiiit/epoc protocosl optimizing metabolic conditioning are apt to be the richest group for research consideration.
    Most studies fail due to lack of consideration of normative subjects. What baseline testing exemplifies or isolates unfit, fit, super fit in relation to other variables?

  4. TM

    May 14, 2010 at 7:26 am

    Good information Jerry… I’ve been taking supplements for over 20 years and I still find conflicting advice as to whether something should be ingested alone or with food. This may be a topic for a future article..but for now, are there other supplements that are best-utilized by the body when taken with fatty foods?

  5. Jerry Brainum

    May 14, 2010 at 5:04 pm

    It’s simple. Fat-soluble nutrients, such as vitamins E.D, K, and A, along with carotenoids, such as beta carotene and lycopene, should always be ingested with a meal containing fat. You don’t need to eat a lot of fat, just enough to promote a bile flow, since it’s the bile interacting with the fat-soluble nutrients that promotes uptake of these nutrients. Adding some butter to a peice of bread would be enough, or ingesting a fish oil supplement with the vitamins would also work in this regard.

  6. Joe DeAngelis

    May 15, 2010 at 9:08 am

    Great article Jerry….and I respect your opinion either way….but how can an article like this be written while tanning beds are lionized to the point of being given the first VAT tax starting July 1st. Is the argument that tanning beds put out a mysterious 4th type of UV that causes cancer faster than the sun? Why is everyone so afraid to recomend a tanning bed when the symptoms of Vitamin D deficiencies are so much worse and widespread than any side effect from tanning/sun exposure? Vitamin D, being deemed so important by Mother Nature that it can be produced WITHOUT food but by exposure to the EVIL sun, yet “Drs” still say the sun is “bad”…..even though the sun is the source of life on earth. im rambling….your thoughts?

  7. Joe DeAngelis

    May 15, 2010 at 9:11 am

    Oh, and Vitamin D produced by sun exposure is eliminated harmlessly once adequate levels are reached…unlike nutritional sources which could linger.

  8. Jerry Brainum

    May 15, 2010 at 7:50 pm

    Thanks, Joe. I always respect your opinion, too. I understand your concerns about the tanning beds, since you are in that business. I think the major problem with vitamin D in relation to tanning beds is that the D3 synthesized in the skin from sun exposure is largely the result of exposure to the UVB spectrum, while most commercial tanning beds are calibrated to emit about 95% UVA. This is done because UVA is more effective at producing a tan, and also less likely to promote a burn. But it’s also not the spectrum that produces D; that is UVB. I would like to see tanning beds that perhaps offer a better balance, or even tanning beds that specialize for the UVB spectrum, which would require minimal exposure because of the burn risk. And you are quite right about the built-in safety factor in relation to D3 production in the skin from sun exposure. Based on my research, I would estimate that at least half the population is deficient in D, and about 90% aren’t getting optimal amounts.

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