Summer Solstice and Vitamin D

Winter is here and the days are short. A lack of sunlight is not only depressing, but it’s actually unhealthy. Sunlight provides us with the greatest source of vitamin D, which is one of the most important vitamins for the body. It’s also a common deficiency. The benefits of vitamin D are still being discovered, and awareness of its deficiency is becoming more common. Trainers, coaches, dermatologists, and chemists are recommending that we get more. The American Academy of Pediatrics now recommends 400 IU per day and the FDA will more than likely increase its recommendations in 2010. But there are some myths, facts, and half-truths that you need to know before you start supplementing.

Claim: Vitamin D is a hormone
True

Vitamin D is actually a misnomer; it’s not a vitamin. Some doctors wouldn’t consider it a hormone, but calcitdiol (25D3) is the metabolic product of cholecalciferol, or D3, which is made at the skin. When sunlight hits the skin it converts 7-dehydrocholesterol to vitamin D3, which then turns into 1.25 d3 in the kidneys. Calcidiol (1, 25D3) is what’s actually measured in a drug test and is a prehormone. Calcitriol is made in the kidneys and a steroid hormone

Claim: 400 IU is enough
False

The government’s recommendation was made almost 40 years ago. 400 IU is just enough to maintain bone health and prevent rickets, but even this is probably far too low. Recommendations from most dermatologists are at least 1,000 IUs. The vitamin D council recommends 5,000 IU or 50 ng/dl. Robert Heaney at Crieghton University recommends 3,000 IU per day. A healthy level of vitamin is about 35-50 ng/ml, although the vitamin D council recommends up to 80 ng/dl. 3000 IU would be the minimum to reach 35 ng/ml. To find your level of vitamin D, measure 25-hyrdoxyvitamin D (calcidiol) in your next blood test. Reinhold Vieth, a leading researcher of vitamin D at the University of Toronto, recommends 4,000 IU.

Claim: Vitamin D can boost athletic performance
Maybe

German swimmers actually used sunlamps 80 years ago to increase performance. Athletes have used sunlamps since to increase endurance, speed, muscle strength, and improve reaction time. The American Council of Sports Medicine published a study showing that vitamin D enhanced athletic performance. Vitamin D, along with calcium, helps strengthen bones, which could help runners and prevent osteoporosis in swimmers, cyclists, and other athletes in non-weight-bearing sports. The Russians and German both showed improvements in their athlete’s performance in the 1930s and ‘40s. German children were given large doses of vitamin D showed improvements in strength and fitness. The theory is that vitamin D can increase protein synthesis.

Claim: Vitamin D can facilitate fat loss
Maybe

Dermatologist Shalamar Sibley says that vitamin D can help with fat loss on a reduced-calorie diet, and even preserve muscle mass. Preserving muscle mass would help prevent any decrease in metabolism. Vitamin D might also stabilize insulin levels and reduce cravings for junk food. Vitamin D can decrease the release of insulin and maintain blood glucose levels. UV-B and vitamin can regulate blood sugar and appetite. A healthy weight is correlated with adequate amounts of vitamin D. Obesity is linked with impaired production of vitamin D from UV-B radiation. The theory is that low levels can increase the production of free fatty acids. This means calories turn into fat. Vitamin D and calcium can help prevent fatty acid synthesis. Therefore, if you want to burn fat, get more vitamin D. However, most evidence for these roles comes from in vitro, animal, and epidemiological studies. Findings presented at the Endocrine Society's 91st Annual Meeting in Washington, DC, showed that higher levels of vitamin D were inversely related to weight loss. Researchers cautioned that “it is not clear whether or not inadequate vitamin D causes obesity or the other way around. Higher baseline vitamin D levels of both 25(OH) D and 1,25 (OH)2D were linked to increased loss of abdominal fat. UVB stimulates melanocytes to produce melanin and melanocyte--stimulating hormone, which is important in weight loss and energy production.

Claim: Vitamin D can be easily obtained in food
False

The best sources of vitamin D include eggs, halibut, salmon, mackerel, cheese, beef , and fortified milk. Just to get 400 IU, you’d have to drink four glasses of milk. If it’s so hard to get vitamin D through diet, then how did human ancestors obtain it? They used to eat shellfish, oily fish, and insects but today we don’t eat those foods for social reasons. Humans would eat the fur and skin of animals, which was loaded with vitamin D. They would eat the tissues and organs of their animals but organs are not a part of modern society’s diet. It also hurts that many people avoid egg yolks, which contain all the D in an egg. Vegetarians get almost no vitamin D naturally. Human ancestors, it is estimated, obtained 3000-6000 IU daily. Best sources per 100 grams:

Cod Liver Oil: 10000 IU
Pork fat: 2800 IU
Herring: 680 IU
Oyster 640 IU
Catfish: 500 IU
Sardines: 480 IU
Mackeral 450 IU
Smoked Chinook Salmon: 320 IU
Sturgeon Roe: 232 IU
Shrimp, canned and drained 172 IU
Egg yolk: 150 IU
Almond Milk: 100 IU
Orange juice, fortified 100 IU

Claim: Vitamin D can increase longevity
Maybe

The New England Journal of Medicine recently showed a correlation between several diseases and vitamin D deficiency. Other studies clearly show that a supplementing with vitamin D can reduce mortality. The vitamin D council says that a D deficiency is a factor in 17 forms of cancer. Vitamin D is inversely proportional to the rates of diabetes. High levels can reduce fatigue, depression and season affective disorder (SAD). Increasing vitamin D can also reduce your risk of Alzheimer’s and Parkinson’s. A study in the Archieves of Internal Medicine linked vitamin D to lower mortality rates. In a miraculous study, Dr. Anu Prabhala treated five paralyzed patients with 50000 IU of vitamin D and all become mobile within six weeks. Vitamin D has also been show to contribute to immune health, muscle strength and hormone production. In the 2000s researchers have shown that vitamin D is one of the most potent antioxidents. Low vitamin D is associated with Sjogren’s syndrome, rheumatoid arthritis, thyroiditis and Crohn’s disease, all common auto-immune disorders. Breast, prostate, skin and colon cancer are linked to low levels of vitamin D. Vitamin D can improve fertility and increase production of dopamine, epinephrine, and norepinephrine, which means vitamin D can treat Seasonal Affective Disorder with just two hours of exposure to a light box. However, the Women's Health Initiative, in which 36,282 postmenopausal women of various races and ethnicities were randomly assigned to receive 400 IU vitamin D plus 1,000 mg calcium daily or a placebo, found no significant differences between the groups in the incidence of colorectal cancers over 7 years. However, more recently, a clinical trial focused on bone health in 1,179 postmenopausal women residing in rural Nebraska found that subjects supplemented daily with calcium (1,400-1,500 mg) and vitamin D3 (1,100 IU) had a significantly lower incidence of cancer over 4 years compared to women taking a placebo. The different result could be attributed to the higher doses in the Nebraska study.

Claim: Vitamin D can prevent heart disease
Maybe

Again, correlation is not cause. Research in the last ten years have shown that low levels of vitamin D can contribute to syndrome X, the combination of hypertension, obesity, diabetes, and heart disease. When high levels of calcium, but low levels of D are present in the blood, leads to calcification of arteries, joints, and kidneys. Deposition of calcium in the arteries can cause atherosclerosis. This might be the missing link between industrial society and high levels of cardiac disease. Even the Vitamin D council warns that associations are not causes. While there are correlations between vitamin D and a litany of ailments, it’s impossible to pinpoint a single deficiency as a cause of any disease.

Claim: Vitamin D Enhances Bone Health
True

If you are predisposed to osteoporosis, than calcium is not enough. It’s recommended that you supplement with vitamin D. Not only does it control calcium levels in the blood, but it also aids in absorption of magnesium, iron, and zinc, minerals that are commonly deficient in our diet. Without sufficient vitamin D, bones can become thin, brittle, or misshapen. Osteomalacia is the result of weak muscles and bones.
Claim: Tanning/sunlight is a good way to get vitamin DTrueLying in a tanning bed for just 10-20 minutes can provide several thousand IUs of vitamin D. Tanning too long can burn the skin and cause cancer if done repeatedly. Going outside to get your vitamin D is probably the easiest, cheapest, and most effective way to get vitamin D. Length of exposure ranges from 5-30 minutes, and depends on cloud cover, the color of your skin, and pollution. It’s important to get sunlight during the late morning and early afternoon to get UVB exposure. Brief exposure to the sun probably is not enough. Tanning beds usually contain UV-A and a little UV-B. UV-A is now linked to non-melanoma skin cancers. UV-B interacts with cholesterol to produce vitamin D. To get maximum exposure, 85% of the body needs exposure during midday. Dark-skinned people need up to two hours per day! During the winter UV-B is less prolific. Living above 34 degrees north or south (almost all of North America and Europe) means that for several months per year, exposure to sunlight isn’t enough. The key is to get moderate amounts on a consistent basis. Single bouts of intense exposure can cause burn and suppress the immune system. A Sperti sun lamp provides just the right amount of UV-A and UV-B. Make sure your tanning bed contains more UV-B than UV-A. Humans can make up to 10,000 units of vitamin D within 30 minutes of full body exposure to the sun.

Claim: You Should Supplement with Magnesium and Calcium along with Vitamin D
True

High levels of Vitamin D without calcium can lead to calcium leaching. That is, vitamin D will take calcium from the bone, not from the blood. Accumulation of toxic materials can occur without magnesium and zinc. Aim for at least 1200 mg of calcium and at least 600 mg of magnesium. Calcium and magnesium should be taken several times per day, not once. Limit your intake of polyunsaturated fats (found in vegetables oils) and eat some fat when you take vitamin D, as vitamin D is a fat-soluble vitamin (or hormone). Too little vitamin D can reduce the number of binding proteins

Claim: Too much vitamin D is bad
Maybe

Some dermatologists believe anything higher than 65 ng/ml is too much. Dr. Reinhold Veith, a nutritional scientist at University of Toronto, and one of the world’s leading authorities on vitamin D believes 20000 IU can be toxic and recommends an upper limit of 10000 IU. Chronic supplementation should not exceed 4000 IU. High levels of D can lead to heart rhythm abnormalities, raise blood levels of calcium , and increase the chance of kidney stones. Veith reports human toxicity probably begins to occur after chronic daily consumption of approximately 40,000 IU/day (100 of the 400 IU capsules).

Claim:
You Should Supplement with Vitamin D
True

This should be clear by now. Because most people spend most of their days indoors, live in northern latitudes, use excessive sunscreen, and eat foods that are poor in vitamin D, supplementation is necessary. The Vitamin D council now recommends about 50 ng/dl, but 35 ng/dl should be the minimum. The daily recommended value of 400 IU is far too little. Taking a supplement of at least 3-5,000 IUs in the winter, and making a habit of exposing most of your body outside between 10 AM and 2 PM during the spring and summer for at least 10 minutes, should give you adequate amounts of vitamin D. While research hasn’t proved that vitamin D will prevent any disease, the number of correlations is hard to ignore. It’s important to get regularly tested for 25-hydroxyvitamin D, not 1,25-dihydroxyvitamin D.

Claim: Absorption is based on many factors
True

Recommendations regarding supplementation and exposure to UVB sunlight depends on the following:-Height-Weight-Race-Gender-Age-Location-Season-Pollution levelsTaller people need more. Heavier people need more. Black and Hispanic people need more. Females need more than males. Old people need more than young people. People in northern latitudes need more. Everybody needs more during the summer. And people in cities with pollution and tall buildings need more. Keep in mind that UVB cannot penetrate glass, so standing in a sunroom is not beneficial.

Kevin

P.S.- I just got my first tan yesterday. Tanning is a safe way to get vitamin D in the winter. Too bad Congress wants to tax it. Policy-makers obviously don't read this blog.