Vitamin D Part 2

In Part 1 Brainum covered some vitamin D history and the consequences of a deficiency, including higher incidence of cardiovascular disease. In Part 2 he discusses more diseases related to not getting enough of the sunshine vitamin, including cancer and obesity.

The Cancer Connection

As with cardiovascular disease, people who live at higher latitudes and are exposed to less sun appear to be at greater risk for various cancers, including Hodgkin’s lymphoma and colon, pancreatic, ovarian and breast cancers, than those who live at lower latitudes. Having counts of 25-hydroxyvitamin D in the blood of less than 20 nonograms per milliliter is associated with a 30 to 50 percent increase in the risk of getting colon, prostate or breast cancer and more chance of death resulting from it. Several studies have found an increased incidence of colon cancer in subjects low in 25-hydroxy D.

A study of prostate-cancer patients found that the disease developed three to five years later in those who worked outdoors than in those who worked indoors. Data obtained from 980 women revealed that those highest in vitamin D had a 50 percent reduced risk of breast cancer; vitamin D inhibits estrogen-stimulated breast cancer. One study even found that those who developed malignant melanoma, the most deadly form of skin cancer, had less death risk than those who had less sun exposure.15

Since the kidneys don’t increase production of the active, or hormonal, form of vitamin D in response to sunlight, how can vitamin D offer cancer protection? The organs and tissues affected by cancer contain the enzyme that converts 25-hydroxyvitamin D—the circulating form in the blood—to the activated hormonal form. Most of the conversion occurs in the kidneys. The local production of hormonal D controls genes that put the brake on the cell proliferation that is the hallmark of cancer. If a cell does become malignant, hormonal D supports apoptosis, or suicide, of tumor cells, and prevents angiogenesis, or the development of new blood vessels required for tumor growth. That done, hormonal D stimulates a gene that leads to its own destruction, which prevents it from entering the blood and affecting calcium metabolism.

Recent research showed how vitamin D may help prevent prostate cancer, the second leading cause of cancer death in men.16 In the course of normal cell metabolism, abundant oxygen leads to the formation of free radicals, which are unpaired electrons. They damage cellular DNA, leading to cellular mutations and cancer. With hormonal D levels high, the D links to an enzyme called glucose-6-phosphate dehydrogenase, which deactivates excess free radicals in prostate tissue.

That protects against DNA mutation and subsequent cancer formation. The process occurs only in healthy prostate cells. Vitamin D also inhibits two enzymes—matrix metalloproteinase and cathepsin—that are required for prostate cancer to spread. (Taking DHEA eliminates this effect because it inhibits G6PD.)

Not all studies confirm D’s protective mechanism. When researchers from the National Cancer Institute compared blood counts of vitamin D in 749 men diagnosed with prostate cancer to the counts in 781 men without cancer, they found no significant differences in the groups. They did identify an increased risk of aggressive prostate cancer with higher levels of D, but it wasn’t considered statistically significant.17

On the other hand, a study of 3,299 cancer patients showed that death was reduced by 55 percent among those who had more vitamin D in their blood.18 Another study confirmed those results and found that patients with the most vitamin D were 48 percent less likely to die from any cause, and 39 percent less likely to die from colon cancer than those whose blood was low on D.19 Cedric Garland, a cancer-prevention specialist in San Diego, estimates that 250,000 cases of colorectal cancer and 350,000 cases of breast cancer could be prevented by increasing intake of vitamin D, especially in countries north of the equator.

In another study from the National Cancer Institute that involved 16,818 subjects, vitamin D was found not to protect against most cancers, with the exception of colon cancer. Those with the greatest vitamin D in their bodies were 72 percent less likely to die from colon cancer than those with the least.20 Studies also show that vitamin D counteracts the tumor-growth effects of IGF-1 in both prostate and breast cancers.

Bodyfat, Bodybuilding and Vitamin D

The incidence of type 2 diabetes is increasing exponentially around the world. Primary risk factors for the disease include genetic predisposition and greater bodyfat. Animals with vitamin D deficiencies have impaired function of the beta cells of the pancreas that produce insulin. Insufficient D is also linked to insulin resistance, which is now considered a prediabetic state.

A recent study of 4,423 men and women aged 40 to 69 found an inverse relationship between vitamin D intake and diabetes.21 Another study showed that a combined daily intake of 1,200 milligrams of calcium and 800 units of vitamin D lowered the risk of type 2 diabetes by 33 percent.22 The most recent study monitored men and women aged 40 to 74 who did not have diabetes when they enrolled in a health survey.23 After 22 years 412 had developed type 2 diabetes, while 986 showed no signs of the disease. Men with the highest blood vitamin D were 72 percent less likely to develop diabetes than the men with the lowest. Women didn’t show any relationship between D and diabetes, although the women in the study did have lower amounts of D in their bodies than the men.

Vitamin D works on diabetes through cell receptors in the pancreas. Vitamin D tends to be sequestered in those with high bodyfat, explaining why another study found that 50.7 percent of patients with the metabolic syndrome, characterized by higher bodyfat, had a vitamin D deficiency.24 One hallmark of the metabolic syndrome is a low count of high-density lipoprotein, or HDL, the kind of cholesterol that helps prevent cardiovascular disease. Vitamin D is required to maintain the primary protein structure of HDL, explaining why low HDL may be prevalent in the metabolic syndrome. Another study found an inverse relationship between high counts of vitamin D and insulinlike growth factor 1 in the metabolic syndrome.25

A few emerging studies show a trend toward bodyfat reduction with higher blood vitamin D. For example, when 60 overweight women, aged 20 to 35, were put on two types of fat-loss diets, those with more blood vitamin D lost more bodyfat than those with less.26 Some studies have suggested that higher hormonal D levels lead to weight gain. Isolated-cell studies have demonstrated that high concentrations of hormonal D stimulate fat synthesis and inhibit fat breakdown.27

Other studies suggest that hormonal D may bring on fat gain by suppressing UCP-2, a primary thermogenic protein. On the other hand, the obese are often 50 percent lower in vitamin D because it gets sequestered in fat and is unavailable for metabolic needs. A recent study confirmed that those with more bodyfat do indeed have less active D, thus making the purported relationship between fat gain and vitamin D unlikely.28

Many bodybuilders complain about constant joint pain, and that may be related to less-than-optimal vitamin D intake. The adult form of rickets, known as osteomalacia, is characterized by bone pain. Common pain syndromes, such as fibromyalgia, can easily be mistaken for vitamin-D deficiency. One study showed that giving 2,000 units of vitamin D daily to those in pain produced a 67 percent increase in blood D, along with a 50 percent reduction in pain after three months. Another study suggests that one out of four patients suffering from chronic pain has inadequate blood D. Still another study provided 5,000 units of vitamin D to those suffering from idiopathic back pain29—meaning the cause of the pain was unknown. All back pain disappeared in those who had been deficient in vitamin D, which was 85 percent of the subjects.

Unless you get out in the sun every day, you’re not likely to have optimal levels of vitamin D. Even exposing yourself to sunlight won’t help if you live in northern latitudes in the winter. That’s because the sun’s angle during the winter in northern climes makes the atmosphere filter out UV rays. One researcher noted that you could walk around naked in Boston during the winter and not synthesize any vitamin D—though you’d probably get arrested for indecent exposure or freeze to death.

Most food supplements contain between 400 and 800 units of vitamin D, but that won’t optimize vitamin D in your blood. Cod liver oil is a good source of vitamin D, although the vitamin A it also contains interferes with D metabolism, but the omega-3 fish oils many athletes take contain none. Studies show that many athletes do not even meet the minimal suggested intake of D. One study of young Finnish runners and gymnasts found that 68 percent were deficient. A study of 85 East German athletes, aged eight to 27, also found that 37 percent were short on D.

Being D-deficient can predispose athletes to bone and stress fractures. One recent study of 800 women, aged 50 to 79, found that a lack of vitamin D increased the rate of hip fractures by 70 percent.30 Another study found that getting sufficient D intake lowers the risk of falls, which often precipitate hip fractures in older people, by 22 percent. Vitamin D receptors exist in skeletal muscle, where hormonal D is thought to play a role in muscle protein synthesis, and a lack of D causes muscular weakness. Studies of older people also show that vitamin D increases the size of type 2 muscle fibers.

Vitamin D may boost immunity in athletes through the release of antimicrobial peptides, which are small proteins that kill bacteria by destroying the cell membranes of the invading organism. That, coincidentally, is precisely how antibiotic drugs work. Some intriguing studies have found that higher blood concentrations of D help protect against colds and flu.

Excess inflammation delays muscle recovery, and D can help. It helps release anti-inflammatory cytokines, immune-cell substances that help temper inflammation. Indeed, some evidence points to vitamin D’s opposition to autoimmune diseases, in which the immune system begins to attack healthy body tissue. Examples include multiple sclerosis and rheumatoid arthritis.

As for direct improvements in sports performance, early Russian and German research showed that exposing hard-training athletes to ultraviolet light appeared to improve recovery from intense training.

Sources of Big D

Should you consider getting your vitamin D from sunlight or supplements? We’ve seen that food sources of D are notoriously minimal. Sunlight is available during summer months, but less so during the winter in northern latitudes. Many dermatologists strongly advise against any sun exposure, noting that UV light is a potent carcinogen. Using a tanning booth or machine can significantly increase blood D, but again, there’s a risk of cancer and accelerated skin aging.

The truth is that you can get 20,000 units of D in your body thorough exposing your face, arms and legs to sunlight for only five to 30 minutes. Doing that two times a week will significantly protect against D deficiency, unless you’re fat, old or both. On the other hand, a recent study found that older people who engage in regular outdoor activity when the sun is at its peak—about 12 noon—have blood D levels comparable to younger people.31 That, once again, wouldn’t apply to those living in northern areas during the winter.

Most vitamin D experts suggest that in the absence of sunlight or tanning-bed exposure, you need to take a minimum of 1,000 units of supplemental D daily. Since D is fat-soluble, it could be toxic, but that isn’t likely. Don’t forget, you make that 20,000 units with only 15 minutes of sun exposure. Cases of D intoxication have involved doses of 150,000 to some 2 million units taken for two years, resulting in elevated blood calcium and phosphorus—dangerous because those minerals cause soft-tissue calcification, high blood pressure and heart-rhythm disturbances.

On the other hand, taking 10,000 units of D daily for five months doesn’t lead to toxicity. One noted Canadian D researcher takes 8,000 units daily, and most users average around 4,000. Don’t take vitamin A with a D supplement; vitamin A interferes with D metabolism.

Maybe one day they’ll put vitamin D back in beer. I bet that will go a long way toward preventing D deficiency—and give new meaning to the line from the song, “Sunshine almost always makes me high.”

Editor’s note: Jerry Brainum has been an exercise and nutrition researcher and journalist for more than 25 years. He’s worked with pro bodybuilders as well as many Olympic and professional athletes. To get his new e-book, Natural Anabolics—Nutrients, Compounds and Supplements That Can Accelerate Muscle Growth Without Drugs, visit www.JerryBrainum.com.

References

15 Berwick, M., et al. (2005). Sun Exposure and mortality from melanoma. J Natl Cancer Instit. 97:195-199.

16 Bao, B.Y., et al. (2008). Protective role of 1A, 25-dihydroxyvitamin D3 against oxidative stress in nonmalignant human prostate cancer cells. Int J Cancer. 122:2699-2706.

17 Ahn, J., et al. (2008). Serum vitamin D concentration and prostate cancer risk: A nested case-control study. J Nat Cancer Inst. 100(11):796-804.

18 Pitz, S., et al. (2008). Low levels of 25-hydroxyvitamin D predict fatal cancer in patients referred to coronary angiography. Canc Epid Biomark Prevent. 17:1228-1233.

19 Ng, K., et al. (2008). Circulating 25-hydroxyvitamin D levels and survival in patients with colorectal cancer. J Clin Oncol. 26:2984-2991.

20 Freedman, D.M., et al. (2007). Prospective study of serum vitamin D and cancer mortality in the United States. JNCI. 99(21): 1594-1602.

21 Mattilla, C., et al. (2007). Serum 25-hydroxyvitamin D concentration and subsequent risk of type 2 diabetes. Diabetes Care. 30:2569-2570.

22 Pittas, A.G., et al. (2006). Vitamin D and calcium intake in relation to type 2 diabetes in women.Diabetes Care. 29:650-66.

23 Knekt, P., et al. (2008). Serum vitamin D and subsequent occurrence of type 2 diabetes. Epidemiology. 19:666-671.

24 Botella-Carretero, J., et al. (2007). Vitamin D deficiency is associated with the metabolic syndrome in morbid obesity. Clin Nutr. 26(5):573-80.

25 Hypponen, E., et al. (2008). 25-hydroxyvitamin D, IGF-1, and metabolic syndrome at 45 years of age. Diabetes. 57(2):298-305.

26 Ortega, R.M., et al. (2008). Preliminary data about the influence of vitamin D status on the loss of body fat in young, overweight/obese women following two types of hypocaloric diet. Brit J Nutr. 100(2):269-72.

27 Shi, H., et al. (2001). 1, 25-hydroxyvitamin D3 modulates human adipocyte metabolism via nongenomic action. FASB J. 15:2751-2753.

28 Konradsen, S., et al. (2008). Serum 1,25-dehydroxyvitamin D is inversely associated with body mass index. Eur J Nutr. 47:87-91.

29 Al Faraj, S., et al. (2003). Vitamin D deficiency and chronic low back pain in Saudi Arabia. Spine. 28:177-9.

30 Cauley, J.A., et al. (2008). Serum 25-hydroxyvitamin D concentrations and the risk for hip fractures. Ann Intern Med. 149:242-250.

31 Scragg, R., et al. (2008). Frequency of leisure-time physical activity and serum 25-hydroxyvitamin D levels in the U.S. population: Results from the third National Health and Nutrition Examination Survey. Am J Epid. 168:577-86. IM