John Cannell on Vitamin D

You can always count on Dr. John Cannell for unique perspectives on vitamin D. I reprint here his unfailingly entertaining and informative Vitamin D Newsletter on whether vitamin D replacement enhances physical performance.

The whole vitamin D "discovery" sometimes worries me. Vitamin D has proven to be an unbelievable, remarkable, dramatic boon to health, including facilitation in dropping CT heart scan scores. Yet the answer was always right in front of us. It worries me that you and I might have the answer to important questions right within our grasp all along--but don't know it. What if the same were true, say, for cancer? That is, a profound answer is right there, but our eyes just pass right over it.

Anyway, we should all keep our eyes open and perhaps you and I will continue to identify the most powerful tools available that return control over heart disease to us and take it away from the perverse, procedural hospital formula that still reigns.

If you haven't done so already, be sure to visit Dr. Cannell's website, www.vitamindcouncil.com.



The Vitamin D Newsletter
March, 2007

Peak Athletic Performance and Vitamin D

"No way doc." I had just finished telling my patient about the benefits of vitamin D, telling him he should take 4,000 IU per day, using all the techniques I had learned in 30 years of medical practice to convince someone proper treatment is important. But, he knew the U.S. government said he only needed 200 IU per day, not 4,000. He also knew the official Upper Limit was 2,000 IU a day. "What are you trying to do doc, kill me?" I told him his 25(OH)-vitamin D blood test was low, only 13 ng/ml. He had read about that too, in a medical textbook, where it said normal levels are between 10 and 40 ng/ml. "I'm fine doc;" adding "Are you in the vitamin business?" I explained I was not; that the government used outdated values; that recent studies indicate ideal 25(OH)D levels are about 50 ng/ml; and that they indicated that he needed about 4,000 IU per day to get his level up to 50. "No thanks doc, I'm fine."

So I tried a different tact. I brought him copies of recent press articles. "Look," I said, "look at these." Science News called vitamin D the Antibiotic Vitamin. The Independent in England says vitamin D explains why people die from influenza in the winter, and not the summer. U.S. News and World Report says almost everyone needs more. Newsweek says it prevents cancer and helps fight infection. In four different recent reports, United Press International says that: it reduces falls in the elderly, many pregnant women are deficient , it reduces stress fractures, and that it helps heals wounds.

He glanced at the articles, showing a little interest in stress fractures. Then he told me what he was really thinking. "Look doc, all this stuff may be important to old guys like you. I'm 22. All I care about are girls and sports. When I get older, maybe I'll think about it. I'm too young to worry about it. I'm in great condition." I couldn't argue. He was in good health and a very good basketball player, playing several hours every day, always on indoor courts.

What could I do to open his eyes? As an African American, his risk of early death was very high, although the risk for blacks doesn't start to dramatically increase until their 40's and 50's. Like all young people, he saw himself as forever young. The U.S. government was no help, relying on a ten-year-old report from the Institute of Medicine that is full of misinformation.

I tired to tell him that the 200 IU per day the U.S. government recommends for 20-year-olds is to prevent bone disease, not to treat low vitamin D levels like his. I pointed out the U.S. government's official current Upper Limit of 2,000 IU/day is the same for a 300 pound adult as it is for a 25 pound toddler. That is, the government says it's safe for a one-year-old, 25-pound, child to take 2,000 IU per day but it's not safe for a 30-year old, 300-pound, adult to take 2,000 and one IU a day. I mean, whoever thought up these Upper Limits must have left their thinking caps at home. Nevertheless, nothing worked. My vitamin D deficient patient was not interested in taking any vitamin D.

What are young men interested in? I remembered that he had told me: "Sex and sports." Two years ago I had researched the medical literature looking for any evidence vitamin D enhanced sexual performance. Absolutely nothing. That would have been nice. Can you imagine the interest?

Then I remembered that several readers had written to ask me if vitamin D could possibly improve their athletic performance? They told me that after taking 2,000 to 5,000 IU per day for several months, they seemed just a little faster, a little stronger, maybe had a little better balance and timing. A pianist had written to tell me she even played a better piano, her fingers moved over the keys more effortlessly! Was vitamin D responsible for these subtle changes or was it a placebo effect? That is, did readers just think their athletic performance improved because they knew vitamin D was a steroid hormone precursor (hormone, from the Greek, meaning "to set in motion")?

The active form of vitamin D is a steroid (actually a seco-steroid) in the same way that testosterone is a steroid and vitamin D is a hormone in the same way that growth hormone is a hormone. Steroid hormones are substances made from cholesterol, which circulate in the body, and work at distant sites by "setting in motion" genetic protein transcription. That is, both vitamin D and testosterone regulate your genome, the stuff of life. While testosterone is a sex steroid hormone, vitamin D is a pleomorphic (multiple function) steroid hormone.

All of a sudden, it didn't seem so silly. Certainly steroids can improve athletic performance although they can be quite dangerous. In addition, few people are deficient in growth hormone or testosterone, so when athletes take sex steroids or growth hormone they are cheating, or doping. The case with vitamin D is quite different because natural vitamin D levels are about 50 ng/ml and, since almost no one has such levels, extra vitamin D is not doping, it's just good treatment. I decided to exhaustively research the medical literature on vitamin D and athletic performance. It took me over a year.

To my surprise, I discovered that there are five totally independent bodies of research that all converge on an inescapable conclusion: vitamin D will improve athletic performance in vitamin D deficient people (and that includes most people). Even more interesting is who published this literature, and when. Are you old enough to remember when the Germans and Russians won every Olympics in the 60's and 70's? Well, it turns out that the most convincing evidence that vitamin D improves athletic performance was published in old German and Russian medical literature.

With the help of my wife and mother-in-law, both of whom are Russian, and with the help of Marc Sorenson, whose book Solar Power is a must read, I finally was able to look at translations of much of the old Russian and German literature. When one combines that old literature with the modern English language literature on neuromuscular performance, the conclusion is inescapable. The readers who wrote me are right.

If you are vitamin D deficient, the medical literature indicates that the right amount of vitamin D will make you faster, stronger, improve your balance and timing, etc. How much it will improve your athletic ability depends on how deficient you are to begin with. How good an athlete you will be depends on your innate ability, training, and dedication. However, peak athletic performance also depends upon the neuromuscular cells in your body and brain having unfettered access to the steroid hormone, activated vitamin D. In addition, how much activated vitamin D is available to your brain, muscle, and nerves depends on having ideal levels of vitamin D in your blood - about 50 ng/ml, to be precise.

Why would I write about such a frivolous topic like peak athletic performance when cancer patients all across this land are dying vitamin D deficient? Like many vitamin D advocates, I have been disappointed that the medical profession and the public don't seem to care about vitamin D. Maybe people, like my young basketball player, will care if it makes better athletes. So, Hey! You jocks! Listen up! I'm talking speed, balance, choice reaction time, muscle mass, muscle strength, squats, reps, etc. Important stuff. Here's the Vitamin D Council's first ever sports quiz.


1. Vitamin D-producing UVB radiation improves athletic performance and may have been widely practiced by German and Russian Olympic athletes in the 1960's and 70's.


True. I found tantalizing evidence the Russians and especially the Germans were on to this during the 60's and 70's when those two nations took turns placing number one and number two in the Olympics every year?


For example, in 1938, Russian researchers reported that a course of ultraviolet irradiations improved speed in the 100-meter dash in college students compared to matched controls, both groups undergoing daily training. Average 100-meter dash times decreased from 13.51 seconds to 13.28 seconds in the non-irradiated controls, but from 13.63 seconds to 12.62 seconds in the irradiated students. Here we see training improved times but training and irradiation improved times much more. Obviously, irradiation or vitamin D would not render the same magnitude of improvements in world-class sprinters, but they would be happy with a few milliseconds.


Gorkin Z, Gorkin MJ, Teslenko NE. [The effect of ultraviolet irradiation upon training for 100m sprint.] The Journal of Physiology of the USSR [Fiziol, z. (RSSR)] 1938; 25: 695-701. (In Russian)



If you want to know what early German thinking was on this, read this summation of the German literature:

"It is a well-known fact that physical performance can be increased through ultra-violet irradiation. In 1927, a heated argument arose after the decision by the German Swimmers' Association to use the sunlamp as an artificial aid, constituting an athletic unfairness, doping, so to speak. In 1926, Rancken had already reported the improving effect of sunlamp irradiation on muscle work with the hand-dynamo-graph. Heib observed an improvement in swimming times after repeated irradiations. In thorough experiments, Backmund showed that a substantial increase in muscle activity happens after radiation of larger portions of the body with an artificial sunlamp; that this performance increase is not caused through local - direct or indirect - effects on the musculature, but through a general effect. This general effect, triggered by ultra-violet irradiation, is caused by a systemic effect on the nervous system." (p. 17)


Parade GW, Otto H. Die beeinflussung der leistungsfahigkeit durch Hohensonnenbestrahlung. Zeitschrift fur Klinische Medizin (Z Klin Med),1940;137:17-21 [In German]


In 1945, two Americans measured the cardiovascular fitness and muscular endurance of 11 male Illinois subjects undergoing training in an indoor physical education class, comparing them to 10 matched controls. Both groups underwent similar physical training. Treatment consisted of ultraviolet irradiation, given in the nude, up to two minutes per session, three times per week, for ten weeks in the late fall and winter. After ten weeks, the treatment group had a 19% standard score gain in cardiovascular fitness compare to a 2% improvement in the control students. To regular readers of this newsletter, it should come as no surprise that the un-irradiated control group reported twice as many viral respiratory infections as the treatment group.


Allen R, Cureton T. Effects of Ultraviolet Radiation on Physical Fitness. Arch Phys Med 1945: 10: 641-44.


In 1952, the German sports medicine researcher, Spellerberg, reported on the effects of wholesale irradiation of athletes studying and training at the Sports College of Cologne - including many elite athletes - with a "central sun lamp." He irradiated the athletes in their bathing suits, on both sides of their bodies, for up to ten minutes, twice a week, for 6 weeks. He reported a "convincing effect" on athletic performance and a 50% reduction in sports injuries. Results were particularly impressive for swimmers, soccer, handball, hockey, and tennis players, as well as for boxers and most track and field athletes. He reported that irradiation leading to burns, further irradiation of athletes having achieved peak performance, and irradiation within 24 hours of competition, all impaired athletic performance. Their results were so convincing, the Sports College of Cologne officially notified the "national German and International Olympic committee." (p. 570)


Spellerberg AE. [Increase of athletic effectiveness by systematic ultraviolet irradiation.] Strahlentherapie 1952; 88: 567-70. [In German]


In 1952, Ronge exposed 120 German schoolchildren to UV lights installed in classrooms and compared them to 120 un-irradiated control children. Over a two-year period - excluding summer vacations - he tested both groups with a series of six cardiovascular fitness tests using a bike ergometer. Un-irradiated children showed a distinct seasonality in fitness, with the highest values right after summer break and the lowest values in the spring. Treated children showed no seasonal differences in physical performance. Differences in work performance between the irradiated and un-irradiated children were most conspicuous in the spring with 56% difference between the two groups. In a final experiment, he gave 30 children in the control classrooms 6.25 mg (250,000 IU) of vitamin D as a single dose in February and found their performance had "increased considerably," one month later but did not report the actual numbers. He concluded that vitamin D, either as a supplement or induced via UV irradiation, improved physical performance.


Ronge HE. [Increase of physical effectiveness by systematic ultraviolet irradiation.] Strahlentherapie 1952; 88: 563-6. [In German]

In 1954, another researcher, at the Max-Planck Institute for Industrial Physiology in Dortmund, Germany, administered three different wavelengths of UV light over 8 weeks to university students. He found that ultraviolet light in the vitamin D-producing UVB range was consistently effective in reducing resting pulse, lowering the basal metabolic rate, and increasing athletic performance. UVA had no effect; interestingly, artificial UVC irradiation (the atmosphere normally completely filters out UVC radiation and thus it's not naturally present on earth) also gave some positive results.


Lehmann G. [Significance of certain wave lengths for increased efficacy of ultraviolet irradiation.] Strahlentherapie. 1954 Nov;95(3):447-53. [In German]


In 1956, Hettinger and Seidel irradiated seven subjects in two different experiments: athletic performance on bike-ergometers and forearm muscle strength. They found that UV radiation induced a significant improvement in both muscle strength and athletic performance.



Hettinger T, Seidl E. [Ultraviolet irradiation and trainability of musculature.] Internationale Zeitschrift für angewandte Physiologie, einschliesslich Arbeitsphysiologie 1956; 16: 177-83. [In German]


Another German researcher, at the Institute for Medical Physics and Biophysics at the University of Gottiingen, studied reaction times (the time needed to recognize a light and switch it off) during October and November in a series of controlled experiments on 16 children and an unspecified number of adults. He first controlled for practice effects (getting better by practicing) and then administered nine full-body UV radiation treatments over three weeks to the two treatment groups, using placebo radiation in the two control groups. UV radiation improved choice reaction time by 25% in children and 20% in adults while reaction time worsened in controls. The improvements in the irradiated groups peaked at the end of the three weeks of UV treatments and reverted to baseline levels three weeks later. In the two control groups, he found distinctly improved reaction times in the sunnier months.


Sigmund R. [Effect of ultraviolet rays on reaction time in man.] Strahlentherapie. 1956; 101: 623-9. [In German]


The next study threw me because it was very well conducted, meticulously designed, and completely negative. In 1963, Berven reported on the effects of ultraviolet irradiation and vitamin D supplementation in a group of 30 Stockholm schoolchildren, aged 10 -11, comparing them to appropriate controls. He found no seasonality of fitness in the control group and no effect from either irradiation or two different vitamin D supplementation protocols (1500 IU of cholecalciferol daily for two months and a single dose of 400,000 IU of ergocalciferol) on performance on a bike ergometer.


Berven H. The physical working capacity of healthy children; seasonal variations and effect of ultraviolet irradiation and vitamin-D supply. Acta paediatrica. Supplementum 1963; 148: 1-22.


However, two things were not right and got me thinking. One, Berven found no seasonality of physical fitness and was the only author who found no such seasonal variations in athletic performance. Second, he found no effect from irradiation, again, the only author. Then I realized he was working with Swedish children in the late 1950's. Supplementation of children with high doses of vitamin D - often as cod liver oil - was routine in Scandinavia in the past, particularly in children. For example, in neighboring Finland, the official recommended daily dose of vitamin D for children - including infants - was 4,000 IU per day until 1964, when authorities reduced it to 2,000 IU/day. (That's right, you read that correctly, 4,000 IU per day for infants, which is too much by the way.)



In 1975, Finnish authorities reduced it to 1,000 IU per day, and, in 1992, to 400 IU per day. I emailed Professor Elina Hypponen who confirmed that the Swedish recommendations were similar to the Finnish ones. Therefore, it seems highly unlikely that many of Berven's Swedish children, studied in 1958 and 1959, all from "families with a good standard of living," were vitamin D deficient. Therefore, this study showed that vitamin D will not improve athletic ability in vitamin D replete people. That's very important because it indicates more is not necessarily better. More is only better if you are not taking enough.

Hypponen E, et al. Intake of vitamin D and risk of type 1 diabetes: a birth-cohort study. Lancet. 2001 Nov 3;358(9292):1500-3.

In the 1960's, three American researchers conducted experiments with university students. Rosentswieg studied the effects of a single six-minute dose of UV light on each side of the trunk in 23 college women, recording changes in various tests of muscle strength at one and five hours. He found a trend towards significance after five hours in white but not African American students. In 1968, Cheatum found that a six-minute administration of UV light, on each side of the trunk, increased the speed of 15 college women in the 30-yard dash. In 1969, Rosentswieg found a six-minute dose of UV light, on each side of the trunk, finding improved performance on a bicycle ergometer in college women. However, unlike the Germans and Russians, I could find no evidence that any of these American findings interested any American professionals involved in the care or training of athletes.


Rosentsweig J. The effect of a single suberythemic biodose of ultraviolet radiation upon the strength of college women. J Assoc Phys Ment Rehabil. 1967 Jul-Aug;21(4):131-3.

Cheatum BA. Effects of a single biodose of ultraviolet radiation upon the speed of college women. Res Q. 1968 Oct;39(3):482-5.

Rosentswieg J. The effect of a single suberythemic biodose of ultraviolet radiation upon the endurance of college women. J Sports Med Phys Fitness. 1969 Jun;9(2):104-6.


2. Athletic performance peaks in the summer when vitamin D levels peak, and is at its lowest in the winter when vitamin D levels are at their lowest.

A. True
B. False


True. The studies below - all I could find in the literature - show tests of physical performance peak in the summer, when vitamin D levels peak, start to decline in early autumn, as vitamin D levels decline, and athletic performance reaches its lowest point in late winter, when vitamin D levels bottom out. However, it is reasonable to assume that any associations between athletic performance and summer season may be due to "reverse causation." That is, improved athletic performance in the summer might be secondary to increased outdoor physical and recreational activity in the warmer weather with an indoor sedentary lifestyle during the colder months. Maybe people have better athletic ability in the summer because they exercise more. If that is true - and using the same logic - athletic performance should not begin to decline until late autumn, because at most temperate latitudes early fall weather is ideal for outdoor physical activities.


However, some of the studies below controlled for seasonal variations in time spent exercising. Furthermore, besides a consistent positive association of summer season with improved athletic performance, the below studies found an abrupt - and unexplained - reduction in athletic performance beginning in the early fall - when vitamin D levels decline - but when the weather is ideal for outdoor activities.


For example, in 1956, German researchers found a distinct seasonal variation in the trainability of musculature, studying wrist flexor strength in 21 German subjects undergoing daily training. They found highly significant seasonal differences with peak performance during the later part of the summer, nadirs in the winter, and an unexplained sharp autumn decline beginning in October.


Hettinger T, Muller EA. Seasonal course of trainability of musculature. Int Z Angew Physiol. 1956;16(2):90-4.

A study of Polish pilots and crew found physical fitness and tolerance to hypoxia were highest in the late summer with an unexplained sharp decline starting in September. The authors hypothesized that seasonal variations in an unidentified hormone best explained their results.


Kwarecki K, Golec L, Klossowski M, Zuzewicz K. Circannual rhythms of physical fitness and tolerance of hypoxic hypoxia. Acta Physiol Pol. 1981 Nov-Dec;32(6):629-36.


Cumulative work ability among 1,835 mainly sedentary Norwegian men during bicycle exercise tests showed an August peak, a sharp decline starting in the autumn, and a wintertime nadir. There were no seasonal changes in body weights, as might be expected if more caloric-demanding recreational activity during the sunnier months explained their results.


Erikssen J, Rodahl K. Seasonal variation in work performance and heart rate response to exercise. A study of 1,835 middle-aged men. Eur J Appl Physiol Occup Physiol. 1979 Oct;42(2):133-40.


Koch and Raschka reviewed the mostly German literature on the seasonality of physical performance, discussing studies indicating that muscle strength and stamina peak in the late summer. The authors then attempted to control for seasonal variations in the time spent exercising by instituting a controlled yearlong training regimen, beginning in December. The training regimen consisted of at least 20 push-ups per day and 2 or 3 long-distances races per week for the entire year. They found the both the number of push-ups and muscle strength peaked in late summer followed by a rapid decline in the fall, and a nadir in the winter, despite continued training. They concluded that seasonal variations in an unidentified hormone best explained their results. In addition, by now we all know that vitamin D is a seasonal hormone, and a steroid hormone precursor to boot.


Koch H, Raschka C. Circannual period of physical performance analysed by means of standard cosinor analysis: a case report. Rom J Physiol. 2000 Jan-Dec;37(1-4):51-8.

3. Vitamin D has direct muscle-building (anabolic) effects.


A. True
B. False

True, but only in vitamin D deficient subjects. Both animal and human studies have found that vitamin D directly affects muscle. That is, vitamin D increases muscle mass.



For example, Birge and Haddad found that vitamin D caused new protein synthesis in rat muscle.


Birge SJ, Haddad JG. 25-hydroxycholecalciferol stimulation of muscle metabolism. J Clin Invest. 1975 Nov;56(5):1100-7.


What about humans? In 1981, Young performed muscle biopsies on 12 severely vitamin D deficient patients before and after vitamin D treatment. They found type-II (fast-twitch) muscle fibers were small before treatment and significantly enlarged after treatment. Sorensen performed muscle biopsies on eleven older patients with osteoporosis before and after treatment with vitamin D. The percentage and area of fast twitch fibers increased significantly after treatment, despite the lack of any physical training.


Young A, Edwards R, Jones D, Brenton D. Quadriceps muscle strength and fibre size during treatment of osteomalacia. In: Stokes IAF (ed) Mechanical factors and the skeleton. 1981. pp 137-145.

Sorensen OH, Lund B, Saltin B, Lund B, Andersen RB, Hjorth L, Melsen F, Mosekilde L. Myopathy in bone loss of ageing: improvement by treatment with 1 alpha-hydroxycholecalciferol and calcium. Clin Sci (Lond). 1979 Feb;56(2):157-61.


Sato reported that two years of treatment with 1,000 IU of vitamin D per day significantly increased muscle strength, doubled the mean diameter, and tripled the percentage of fast-twitch muscle fibers, in the functional limbs of 48 severely vitamin D deficient elderly stroke patients. The placebo control group suffered declines in muscle strength, and in the size and percentage of fast-twitch muscle fibers.


Sato Y, Iwamoto J, Kanoko T, Satoh K. Low-Dose Vitamin D Prevents Muscular Atrophy and Reduces Falls and Hip Fractures in Women after Stroke: A Randomized Controlled Trial. Cerebrovasc Dis. 2005 Jul 27;20(3):187-192 [Epub ahead of print]

These studies clearly show that vitamin D when administered to vitamin D deficient people stimulates the growth and number of those muscle fibers critical to athletic ability, type-2, or "fast twitch," muscle fibers.

4. Many studies have found direct associations between physical performance and vitamin D levels. That is, the higher your vitamin D level, the better your athletic performance.

A. True
B. False

True. I found 13 positive studies of associations between vitamin D levels and various parameters of neuromuscular performance. However, they were all in old people. Of course, old people can be athletes too. Furthermore, age differences in physiology and pharmacology are quantitative, not qualitative. That is, what is true in old people will be true in young people, although the magnitude might be different. Higher vitamin D levels are associated with a wide variety of athletic performance but appear to have the strongest associations with balance, timing, and timed tests of physical performance.

The three largest studies had more than 7,000 elderly subjects. All found evidence of a vitamin D threshold of between 30 - 50 ng/ml, above which further improvements in athletic performance were not seen. Wicherts and her colleagues found a linear correlation between vitamin D and neuromuscular performance; scores were 78% better for those with vitamin D levels greater than 30 ng/ml compared to those with levels less than10 ng/ml.


Bischoff-Ferrari HA, Dietrich T, Orav EJ, Hu FB, Zhang Y, Karlson EW, Dawson-Hughes B. Higher 25-hydroxyvitamin D concentrations are associated with better lower-extremity function in both active and inactive persons aged > or =60 y. Am J Clin Nutr. 2004 Sep;80(3):752-8.

Gerdhem P, Ringsberg KA, Obrant KJ, Akesson K. Association between 25-hydroxy vitamin D levels, physical activity, muscle strength and fractures in the prospective population-based OPRA Study of Elderly Women. Osteoporos Int. 2005 Nov;16(11):1425-31.


Wicherts IS, et al. Vitamin D status predicts physical performance and its decline in older persons. J Clin Endocrinol Metab. 2007 Mar 6; [Epub ahead of print]

Professor Heike Bischoff-Ferrari, now in Switzerland, did the largest study. She and her colleagues found a strong positive correlation and suggestion of a U-shaped curve with athletic performance on one test peaking with vitamin D levels of 50 ng/ml but deteriorating at higher levels. It is interesting to speculate that levels around 50 ng/ml may be optimal for athletic performance as such levels are common in humans living in a "natural" state of sun-exposure, such as lifeguards or tropical farmers.


Bischoff HA, Stahelin HB, Urscheler N, Ehrsam R, Vonthein R, Perrig-Chiello P, Tyndall A, Theiler R. Muscle strength in the elderly: its relation to vitamin D metabolites. Arch Phys Med Rehabil. 1999 Jan;80(1):54-8.


Interestingly, all three studies that looked for an association between mental abilities and vitamin D levels found one. A fourth study, unrelated to athletic function, also found an association. The obvious explanation for these findings is that cognitively impaired patients do not go outdoors as often as higher functioning patients and thus have lower vitamin D levels. However, Dhesi found the association after excluding all but mildly demented patients, making such an explanation more difficult. Flicker and - more recently - Przybelski and Binkley, found the association after controlling for outdoor activities, raising the possibility that the association of vitamin D levels with cognitive abilities is casual. Both the vitamin D receptor and the enzyme necessary to activate vitamin D are present in a wide-variety of human brain tissue. If vitamin D deficiency impairs cognitive abilities, it is likely that such deficiencies will also impair the brain's ability to process the complex circuits needed for peak athletic performance.


Dhesi JK, Bearne LM, Moniz C, Hurley MV, Jackson SH, Swift CG, Allain TJ. Neuromuscular and psychomotor function in elderly subjects who fall and the relationship with vitamin D status. J Bone Miner Res. 2002 May;17(5):891-7.

Kenny AM, Biskup B, Robbins B, Marcella G, Burleson JA. Effects of vitamin D supplementation on strength, physical function, and health perception in older, community-dwelling men. J Am Geriatr Soc. 2003 Dec;51(12):1762-7.

Flicker L, Mead K, MacInnis RJ, Nowson C, Scherer S, Stein MS, Thomasx J, Hopper JL, Wark JD. Serum vitamin D and falls in older women in residential care in Australia. J Am Geriatr Soc. 2003 Nov;51(11):1533-8.

Przybelski RJ, Binkley NC. Is vitamin D important for preserving cognition? A positive correlation of serum 25-hydroxyvitamin D concentration with cognitive function. Arch Biochem Biophys. 2007 Jan 8;

There can be no doubt that higher vitamin D levels are associated with improved athletic performance in the elderly. From what we know of physiology and pharmacology, the same associations should hold true in young people, including young athletes.

5. Numerous studies have found that vitamin D improves physical performance.

A. True
B. False.

True, but, again, most all the studies are in old persons, not young ones, and none of the studies are in world-class athletes. However, there is no medical reason why vitamin D would improve the athletic performance of vitamin D deficient old people but not vitamin D deficient young ones. Eleven studies found vitamin D improved physical performance, mainly on measures of balance and reaction time. The one study of younger subjects showed dramatic physical performance effects in 55 severely vitamin D deficient women.


Sorensen OH, Lund B, Saltin B, Lund B, Andersen RB, Hjorth L, Melsen F, Mosekilde L. Myopathy in bone loss of ageing: improvement by treatment with 1 alpha-hydroxycholecalciferol and calcium. Clin Sci (Lond). 1979 Feb;56(2):157-61.

Gloth FM 3rd, Smith CE, Hollis BW, Tobin JD. Functional improvement with vitamin D replenishment in a cohort of frail, vitamin D-deficient older people. J Am Geriatr Soc. 1995 Nov;43(11):1269-71.

Glerup H, Mikkelsen K, Poulsen L, Hass E, Overbeck S, Andersen H, Charles P, Eriksen EF. Hypovitaminosis D myopathy without biochemical signs of osteomalacic bone involvement. Calcif Tissue Int. 2000 Jun;66(6):419-24.

Prabhala A, Garg R, Dandona P. Severe myopathy associated with vitamin D deficiency in western New York. Arch Intern Med. 2000 Apr 24;160(8):1199-203.

Verhaar HJ, Samson MM, Jansen PA, de Vreede PL, Manten JW, Duursma SA. Muscle strength, functional mobility and vitamin D in older women. Aging (Milano). 2000 Dec;12(6):455-60.

Pfeifer M, Begerow B, Minne HW, Abrams C, Nachtigall D, Hansen C. Effects of a short-term vitamin D and calcium supplementation on body sway and secondary hyperparathyroidism in elderly women. J Bone Miner Res. 2000 Jun;15(6):1113-8.

Bischoff HA, Stahelin HB, Dick W, Akos R, Knecht M, Salis C, Nebiker M, Theiler R, Pfeifer M, Begerow B, Lew RA, Conzelmann M. Effects of vitamin D and calcium supplementation on falls: a randomized controlled trial. J Bone Miner Res. 2003 Feb;18(2):343-51.

Dhesi JK, Jackson SH, Bearne LM, Moniz C, Hurley MV, Swift CG, Allain TJ. Vitamin D supplementation improves neuromuscular function in older people who fall. Age Ageing. 2004 Nov;33(6):589-95.

Sato Y, Iwamoto J, Kanoko T, Satoh K. Low-Dose Vitamin D Prevents Muscular Atrophy and Reduces Falls and Hip Fractures in Women after Stroke: A Randomized Controlled Trial. Cerebrovasc Dis. 2005 Jul 27;20(3):187-192 [Epub ahead of print]



In summary, five converging - but totally separate - lines of scientific evidence leave little doubt that vitamin D improves athletic performance. (I actually left out a sixth line of evidence, something a little more complicated, studies of muscle strength and vitamin D receptor polymorphisms; the two studies I could find were both positive.) Anyway, the scientific evidence that UVB radiation, either from the sun or from sunbeds, will improve athletic performance is overwhelming and the mechanism is almost certainly vitamin D production. Peak athletic performance will probably occur with 25(OH)D levels of about 50 ng/ml, whether from sun, sunbeds, or supplements.


All that is missing is a big-time professional or college team identifying and then treating their elite athletes who are vitamin D deficient. Can you imagine what such performance-enhancing effects would do for basketball players, most of who are African American and who practice and play indoors all winter? Or gymnasts? Or weight lifters?


However, a word of caution. The above studies suggest that taking too much vitamin D (more than 5,000 IU per day) may actually worsen athletic performance. Take the right amount, not all you can swallow. Take enough to keep your 25(OH)D levels around 50 ng/ml, year round. Easier yet, regularly use the sun in the summer and sunbeds in the winter - with care not to burn. Once a week should be about right.


When you think about it, none of this should surprise anyone. Every body builder knows that steroid hormones can improve athletic performance, certainly increase muscle mass. Barry Bonds knows they increase timing and power. Moreover, activated vitamin D is as potent a steroid hormone as exists in the human body. However, unlike other steroids, levels of activated vitamin D in muscle and nerve tissue are primarily regulated by sun exposure. That's right, the rate-limiting step for the cellular function (autocrine) of activated vitamin D is under your control. It depends on how much you put in your both or go into the sun. It's ironic that many athletes now avoid the sun, organized baseball is even promoting sun avoidance and sunblocks. The ancient Greeks knew better; they had there elite athletes train on the beach and in the nude.



The medical literature indicates vitamin D levels of about 50 ng/ml are associated with peak athletic performance. Of course, recent studies show such levels are ideal for preventing cancer, diabetes, hypertension, influenza, multiple sclerosis, major depression, cognitive impairments, etc. But who cares about all that disease stuff old people get, we're talking about something really important: speed, balance, reaction time, muscle mass, muscle strength, squats, reps, etc. And guess who's now taking 4,000 IU/day? Yes he is, and he tells me his timing is better, he can jump a little higher, run a little faster, and the ball feels "sweeter," whatever that means.

John Cannell, MD

This is a periodic newsletter from the Vitamin D Council, a non-profit trying to end the epidemic of vitamin D deficiency. If you don't want to get the newsletter, please hit reply and let us know. We don't copyright this newsletter. Please feel free to reproduce it and post it on Internet sites and blogs. Remember, we are a non-profit educational organization. Our pathetic finances are available for public inspection. We rely on donations to publish our newsletter and maintain our website. Send your tax-deductible contributions to:


The Vitamin D Council (www.vitamindcouncil.com)
9100 San Gregorio Road
Atascadero, CA 93422

Comments (2) -

  • Anonymous

    3/19/2007 6:02:00 PM |

    D looks like the answer to a lot of problems and I have heard also it can reduce arteial build up of plaque and calcium.  True or False

  • Dr. Davis

    3/19/2007 9:53:00 PM |

    My view is that vitamin D replacement to 50 ng/ml is a powerful facilitator of plaque regression.

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America: The world’s diet laboratory

America: The world’s diet laboratory

Low-fat, low-carb, high-protein, Pritikin, Ornish, Atkins, South Beach, Sonoma, Sugar-Busters, Weight Watchers, vegetarian . . . Have Americans tried them all?

We’ve witnessed the relative success of diet habits in selected regions world-wide: the longevity of the Japanese on a spare soy and fish-based diet; the reduced heart disease incidence of the French despite an indulgent food-centered culture; the extreme heart disease-free lives of the Cretan Greeks.

Contrast this with the startling failure of the American diet experiment: We’re all (speaking for the collective whole) fat, diabetic, and miserably mired in the diseases of obesity. We’ve experimented with every possible iteration of diet from grapefruit or cabbage only, to calorie deprivation (a al Weight Watchers), to restricting this or that element of diet. The “official” organizations have made their contributions, as well: the American Heart Association’s Therapeutic Lifestyle Changes (formerly Step I and II diets), a program eerily similar to what Americans are already eating and resulting in failure; the American Diabetes Association diet, incomprehensibly embracing carbohydrates when they are the root of the nutrition-habit-gone-wrong that caused the disease in the first place; the USDA and their Food Pyramid, encompassing a design that contains the germ of wisdom but is so heavily overweighted in grains that it is a sure-fire way to increase weight and heart disease were you to follow their recommendations.

What have we learned from our grand experiment, our nationwide misadventure in nutrition?

I believe that we’ve learned how not to eat: Processed snack foods, meals delivered in a fast-food setting with the offer to “super-size” your order, make-believe food ingested in your car eaten for the sake of staving off the inevitable hunger pangs. Few would argue that these are certain paths to obesity and poor health.

Certainly, if we’ve learned how not to eat, can we extrapolate just how to eat? And not just for weight loss, since most diets focus just on that, but on health, particularly heart health?

If Americans have so far failed to learn the lessons of the nutritional world, we certainly have not failed at talking about it. From books to blogs, websites, information gurus to infomercials, we certainly celebrate the capacity to share our experiences, our grief over our nutritional “misfortune,” despite a world of plenty.

Yet we swim in a sea of information. Can we sift through the chaff to discover the essential truth?

Let me articulate an extreme (extreme meaning closer to the truth, I hope) interpretation of nutritional wisdom:

--If it requires a label or nutritional analysis, reject it. The wondrous green pepper, or bottle of olive oil, for instance, require no such qualifications. Some exceptions: milk, yogurt, cottage cheese (unless, of course, you purchase straight from a local producer). I am always impressed with the contortions and frustrations people experience trying to decipher labels. Ironically, the healthiest foods don’t even require labels.

--If it is ingested in a rush, it’s likely to add to poor health. True food is meant to be consumed at leisure, not in haste to satisfy some irrational, unthinking impulse.

--Search for natural, whole foods. Natural, whole foods require no marketing. You pay a premium for a company to adorn a product with glitz, glamour, and appeal. Repackage Cocoa Puffs as chocolate flavored, round overly-processed wheat flour, sans marketing spin, and what is left? Processed foods are?intentionally?addictive. They are added to, modified, high-fructose corn syruped, etc. to increase desirability, but also create addiction. Eliminate them just as a smoker eliminates cigarettes.

--A corollary to the above issue: purchase foods that appear as if you had grown it or raised it yourself. If you were to grow corn in your backyard garden, you would eat it on the cob or some similar way. You would not grind it, pulverize, process it, nor serve it as cornstarch and add to a pile of chemicals to make breakfast cereal. Eat foods in their natural state, not the highly processed food-product that requires a colorful package and advertising to sell.

--Don’t keep bags of chips, boxes of breakfast cereal and crackers, frozen dinners, all “just in case.” Don’t allow yourself that opportunity because you will more than likely seize it. An alcoholic who keeps a secret bottle of gin hidden in the cabinet is well aware that it’s there and will eventually give in to impulse.

--When you eat meat, try to find free-range, organic products. Even better, purchase from a local producer who you trust.

--For anyone with patterns like low HDL, small LDL, high triglycerides, and blood sugar >100 mg/dl, following a diet that is as free of wheat products as possible will yield enormous benefits. Wheat is a part of all breads, virtually all breakfast cereals, pretzels, crackers, bagels, cookies, cupcakes, pancakes, waffles, etc. Going wheat-free is also a surprisingly effective weight loss strategy.

That’s just a few thoughts. The approach we use in the Track Your Plaque program helps achieve weight loss, but also helps correct lipoprotein patterns, often dramatically.

Many diets have failed to keep pace with the changing nutritional habits of Americans. In 1960, we ingested close to zero high-fructose corn syrup. We’re now approaching 80 lbs per year per American. Breakfast cereal in 1950 consisted of a handful of products, eaten intermittently; today, it is a staple with enough products to fill a modern supermarket’s entire aisle. Meats have changed, thanks to the factory farm phenomenon feeding its animals corn in inhumanely restricted conditions, a dietary shift for livestock that has modified the fat composition to something far different than 50 years ago, not to mention the antibiotics and other chemicals used to accelerate growth and fight off infection from the artificial, overcrowded conditions.

The American nutritional shift, along with rampant obesity, have also caused a relatively new cause of coronary heart disease to explode: small LDL particles. The contribution of small LDL has been enormously underestimated, since most physicians don’t know what it is, don’t know how to check for it, and don’t know what to do with it. Yet it has emerged as the number one cause for heart attack and heart disease nationwide.

Stay tuned for our rewritten New Track Your Plaque diet to be released as a Special Report on the www.cureality.com website in future.

Comments (14) -

  • jpatti

    10/23/2007 2:34:00 AM |

    I agree wholeheartedly!

    I've been very heavily studying diet the past few months - reading widely from a lot of sources with a lot of different biases.

    The main conclusion I've come to is that hardly anyone one eats enough fresh low-sugar fruits and non-starchy vegetables; they should be the bottom of everyone's food pyramid.  

    We eat so much junk that you can't tease out what the problems are.  For instance, people say if there were a problem with artificial sweeteners, we'd have discovered it by now.  Well, we *have* discovered increasing rates of obesity, diabetes and heart disease.  We can't know it's the artificial sweeteners specifically anymore than we can know that it's any of the other individual things that have changed in the diet in the past 50 years or so.  Maybe some are worst than others, who knows?  There's too many changes to be able to tell exactly what the problems are in detail.  But we do know that all these lifestyle diseases increased tremendously when we all began eating so many highly-processed foods.  

    I think a lot of the problems in the typical western diet are additive - lost good effect from an unknown micronutrient in real foods plus bad effects from highly-processed stuff.

    So... maybe aspartame is perfectly safe, but I quit the Diet Pepsi for stevia-sweetened lemonade and limeade anyway.  Cause I *do* know that real whole foods are healthy, so I don't have to know the ultimate truth about aspartame.

  • Anonymous

    10/23/2007 4:24:00 AM |

    Excellent post, and you are quite right about high-fructose corn syrup.

    Michael Pollan's book "The Omnivore Dilemma's" has quite a lot of information about corn in the US.

    --Michael G.R. / michaelgr.com

  • Sue

    10/23/2007 8:11:00 AM |

    I agree with all this food tips.

  • Peter

    10/23/2007 8:29:00 AM |

    Hi Dr Davis,

    The only information I have been able to find on soy intake in Japan estimates that in men it is 8.00 g/d and in women 6.88g/d. I realise that quoting two decimal places from a food frequency questionnaire is a bit silly. The standard deviation is around 5g/d. This does not seem like very much to me. To suggest that 8g per day is associated with longevity makes soy protein powerful stuff, literally beyond belief. Are there any better data than this?

    I got my info from the bottom line of table 1 in the results section of:

    Nagata C, Takatsuka N, Kurisu Y, Shimizu H (1998) Decreased serum total cholesterol concentration is associated with high intake of soy products in Japanese men and women. J Nutr. 128(2):209-13

    Peter

  • Alan

    10/23/2007 10:18:00 AM |

    Thanks Doc.

    When choosing foods for purchase I use a fairly simple rule. I try to choose foods that owe more to the farmer than to the chemist for their production, and do as much of the processing as I can in my own kitchen rather than accept the results of a factory kitchen.

    As a diabetic I believe that cooking for oneself improves one's health. That way you get to choose exactly what you eat and there are no hidden surprises.

    You already know my thoughts on the AHA/ADA/USDA nutrition guidelines for cardiac and diabetic patients.

    Thanks for a marvellous post, which I will be passing on to many others.

    Cheers, Alan, Type 2 diabetes, Australia

  • Dr. Davis

    10/23/2007 11:52:00 AM |

    Actually, I'm referring to the epidemiologic data on length of life and incidence of cardiovascular events in Japanese. Obviously, pinpointing the aspect of diet--or other component of lifestyle or genetics--that confers longevity is not revealed by these observations. However, though I like soy products, I don't think they are responsible for the difference.

  • Anonymous

    10/23/2007 1:40:00 PM |

    I think you are a fan of the south beach diet except that he uses too much wheat. What do you think of his south beach diet
    "products" and why do you think he created them?
    Also- can you comment on the use of Splenda.
    Thanks!

  • Dr. Davis

    10/23/2007 5:06:00 PM |

    Yes, the South Beach Diet is a reasonable way to lose weight and improve lipoprotein patterns, provided you don't proceed fully to phase 3, in which grains are added back in abundance. Many people regain their weight in phase 3.

    I doubt Arthur Agatston plays much of a role in developing his packaged products. Nearly all of these are outsourced or licensed products, with which I suspect he has just passing acquaintance. I don't think they are good products, at least the ones I've seen and tried.

  • Dr. Davis

    10/23/2007 7:16:00 PM |

    Also, so far I've not witnessed nor heard of any ill-effects specific to Splenda. So far, so good.

  • Anonymous

    10/23/2007 8:53:00 PM |

    Dr. Davis have you readf the excellent new book Good Calories Bad Calories? If so I would love to hear your oppinion.

  • Dr. Davis

    10/23/2007 9:06:00 PM |

    I'm several chapters into Gary Taubes' book and loving every page. I have to say that many studies I accepted as gospel do indeed appear suspect when recast in his skeptical light. After reading the entire book, I believe a re-examination of the old studies will be necessary.

  • Anonymous

    10/24/2007 5:39:00 AM |

    Is there a practical diet available today that a normal, average person in US can follow to maintain decent health without getting bogged down with the ever increasing "DO NOT EAT" list?

    I think that this is a very tough question to answer; I hope you can share your thoughts on this issue in a future article.

    I have realized lately that people   like me who are conscientious of following a healthy lifestyle, would not realize the impact of religiously following the common
    health options propounded by the food industry.  

    Examples of healthy choices we think we are making:
    - eat more whole wheat, multi grain instead of white bread
    - drink fruit juice (with vitamin attractions) instead of soda pop or other beverages
    - eat more cereals (with vitamin, mineral benefits) and whole wheat, raisin bagels instead of eggs, bacon and cream cheese.

    But thanks to Track the plague research program, we now know that even these cause issues to our health.

    As I read about your total grain elimination diet, I keep wondering - What CAN one *practically* eat from a preventative aspect to maintain decent health?

    If you walk into any cafe, there is an abundance of sandwiches, snacks, pastry etc. What does one do in such cases? It's a common situation that I think we all must be facing from time to time, and I wonder what acceptable choice can we make in such situations?

    I believe that's why there should a new diet approach/guideline that both follows the principles as outlined in Track Your Plague or your blog, and also emphasizes on being practical for an average person. These guidelines will empower the average health conscious public to make healthy  diet choices.

    I find this analogous to our fuel situation today - Everybody knows that ideally we must stop our fuel consumption and switch over to alternative energy sources.
    Since this is not a feasible option today, an alternative practical approach (eg: hybrid cars) comes into place to start the slow but gradual transition

    Some questions/options that I would expect that this practical diet approach to answer/provide: -

    Breakfast options
    Ideal: Avoid all cereals, grains (But again, what would one eat then instead?)
    Acceptable (while on the road): oats, water, peanut butter on multi-grain bread, cereals, fruit juice
    Avoid: bacon

    Brunch options:
    seeds, nuts

    Lunch options
    Ideal: have lean meat, whole fruit
    Acceptable: fruit juice, sandwitch on multi-grain bread
    Avoid: fried food

    etc...

    If you know of any such guidelines that are published or available, I would be appreciate some pointers.

    Personally for a 28 year old person like me, just trying to stay on multi-grain and not trying any fried foods has been a major challenge for me to follow diet wise, but nevertheless I have still been able to maintain the discipline to continue on this.

    I am glad to know that elimination of all grains will bring a lot of health benefits; however it also reminds me on how gloomy the situation is for me when I have to eat outside; the choices then become extremely limited or in some cases the healthy options become non existent.

    thanks Doc. Keep up the good work!

  • Dr. Davis

    10/24/2007 11:59:00 AM |

    Thanks for the wonderful thoughts.

    The forthcoming new Track Your Plaque Diet will articulate many of the issues you discuss above. However, I need to emphasize that the diet is not meant for the average person to follow. It is meant to be part of an effort to seize control of heart disease risk, while providing an health effect. There is a difference.

    Also, I find it easier to understand food products offered in stores and restaurants when you see them as vehicles for profit, not health. Health claims often parrot the popular issue of the day, but the product is sold for profit.

  • Sue

    10/25/2007 11:59:00 PM |

    Good Calories, Bad Calories is brilliant - I hope a lot more professionals read it.

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