ormance 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.
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
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The reason why I've been blogging lightly these past few days is because, as a favor, I'm covering the practice for some colleagues who I'm (very) loosely affiliated with. The time demands have been great.
Nonetheless, it is a good reminder to me just how far wrong conventional cardiology remains. Judging by what I see around me, there is a startling lack of restraint in proceeding to the catheterization laboratory. Curiously, the internists and family practitioners have been brainwashed into accepting this path. I suppose that all it takes is an occasional real "save" for these physicians to develop a fear of ever missing real disease.
What I'm seeing is just how many people presenting with chest pain or similar symptoms end up going to the cath lab. I would crudely estimate 80%. That is, once you make it past the emergency room, there's a four out of five chance that you'll end up with a heart catheterization to "be sure your heart is okay", "make certain you're not going to die of heart disease", "see if there's a ticking time bomb in your chest". You've heard all the clever, scary phrases that get tossed around to scare the pants off you and justify putting catheters in your groin.
Despite the fact that tools for heart disease prevention have improved dramatically, the volume of heart catheterizations continues to grow nationwide.
I find it shocking and unacceptable. We're currently working behind the scenes to help change this situation through education of the public. Persuade a $1 million a year cardiologist that he is overdoing procedures? Unlikely in my experience. Educate the public about the shocking over-reliance on high-revenue procedures? Perhaps more practical.
Garlic May Not Lower Cholesterol Study Shows No Improvement in Cholesterol Levels From Raw Garlic or Garlic Supplements
Lots of reports continue to hit the press about a small study that hoped to determine whether garlic as whole cloves (4 to 6), an aqueous extract of garlic called Kyolic, or an oil extract called Garlicin (high in allicin), or placebo. No differences in lipid numbers including LDL cholesterol were observed.
(Full text at WebMD at http://www.webmd.com/cholesterol-management/news/20070226/garlic-may-not-lower-cholesterol?ecd=wnl_chl_030507. You may be required to log in or register.)
I believe that the researchers were sincere in their effort to follow an honest, scientfically sound clinical trial design. I'm personally not that surprised. The effect in prior studies has been modest, sometimes none. Does that mean that we should ignore the other studies that suggest there may be modest blood-thinning, anti-inflammatory, blood pressure-reducing, and cancer-preventing properties? No, it does not. Dr. Matt Budoff at UCLA even published a very small study in about 20 people that suggested a slowing of plaque growth by using Kyolic in persons tracked by CT heart scans.
Nonetheless, garlic is, at best, probably no more than a source of small benefits. The biggest fallout from this kind of report, however, is not the neutral results from garlic, but from the open door the drug companies sense when this happens.
If you read the WebMD report, you'll notice all sorts of advertisements from drug companies for statin cholesterol drugs ("Cholesterol health center"; "Understanding Cholesterol Numbers"; "There are two sources of cholesterol: food and family"), Niaspan (which I used to support but have been discouraged by the Kos companies excessively profiteering methods and recent big Wall Street sellout).
It doesn't follow. The failure of one nutritional strategy to reduce LDL does nothave to trigger a run to the drugs. Don't fall for it. Drugs have their place. So do supplements and food choices, which can be very powerful. Drug manufacturers and their marketing people salivate when something like this comes along, an open invitation to say, "If garlic doesn't work, _____ sure does."
Jason came to the office because of chest pain. At 34 years old, he works as manager of a (non-fast food) restaurant, but indulges in lots of the odds and ends. Among his indulgences: Diet Coke. Every time he'd have a diet Coke, he'd have chest pain. Not drinking diet Coke--no chest pain. If Jason drank coffee, no chest pain. Other foods, no chest pain. Anyway, just eliminating the diet Coke seemed to do the trick. (Aspartame?)
Anyway, that's not why I tell you Jason's story. In the midst of his evaluation, an echocardiogram showed a mildly enlarged aorta, measuring 4.0 cm in diameter. So we obtained lipoproteins. Jason showed lipoprotein(a) and small LDL particles, the dreaded duo. We talked about how to correct this pattern. Among the strategies we discussed was niacin.
But what bothered me was that neither of Jason's parents had a diagnosis of heart disease. Jason had to have gotten Lp(a) from either his mother or father, since you obtain the gene from one or the other parent. You cannot acquire Lp(a). So one of Jason's parents was sitting on a genetic time bomb of unrecognized Lp(a) and hidden heart disease.
Because Jason's paternal grandfather had a heart attack at age 62, only Jason's Dad had the heart scan (though I urged both to get one). Score: 1483. Recall that heart scan scores >1000 carry a risk of death or heart attack of 25% per year if no preventive action is taken. Now, of course, we have to persuade Jason's Dad that a program of prevention--intensive prevention is in order, including a measure of Lp(a).
So that's the curious story of how Diet Coke probably saved Jason's Dad's life. The lesson is that if you or someone you know has Lp(a), think about their children as well as their parents, each of whom carry a 50% chance of having the pattern.
