Vitamin D-3 (cholecalciferol)

What Is It?

Vitamin D is called the sunlight vitamin because the body produces it when the sun's ultraviolet B (UVB) rays strike the skin. It is the only vitamin the body manufactures naturally and is technically considered a hormone. Essential for building strong bones and teeth, vitamin D also helps to strengthen the immune system.

While just 10 to 15 minutes in the summer sun a few days a week supplies adequate amounts of vitamin D, those who can't get out in the sun may need a supplement. In winter, people in northern climates who don't get enough sun may also need additional amounts of the vitamin. Unfortunately, the body's ability to manufacture vitamin D appears to decline with age, so older adults may need to get more vitamin D through diet or supplements, whether they're exposed to sunlight or not.

Surprisingly, even younger adults may have inadequate stores of this nutrient: In one study involving almost 300 patients of varying ages who were hospitalized for different types of ailments, 57% were found to have low levels of vitamin D.

Vitamin D is essential for the efficient utilization of calcium by the body

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Linus Pauling Institute

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Health Benefits

Heart failure

The heart's inability to pump enough blood to meet the body's requirements—is a leading cause of death in industrialized nations. Scientists believe that elevated levels of circulating pro-inflammatory cytokines may contribute to heart failure, and that vitamin D may offer heart-protective benefits by quelling these inflammatory mediators.

In a recent double-blind clinical trial, 123 patients with congestive heart failure were randomly assigned to receive either vitamin D3 (50 mcg [2000 IU] per day) plus 500 mg of calcium or placebo plus 500 mg of calcium. Over the nine months of the study, patients who supplemented with vitamin D had greatly increased levels of the anti-inflammatory cytokine interleukin-10 and lower levels of the pro-inflammatory cytokine tumor necrosis factor-alpha. Scientists believe that by reducing the inflammatory environment in congestive heart failure patients, vitamin D3 holds promise as an anti-inflammatory therapeutic for people suffering from heart failure.

A 2005 study reported on the use of vitamin D and other nutrients in chronic heart failure. In a randomized trial, 28 chronic heart failure patients supplemented with 200 IU of vitamin D, 150 mg of coenzyme Q10, minerals, antioxidants, and B vitamins or placebo for nine months. The supplemented patients had an impressive 17% decrease in the heart's left ventricular volume, which typically is increased in chronic heart failure and adds to the work required of the already-fatigued heart muscle. By contrast, left ventricular volume increased 10% in the placebo group. Supplemented patients also had a modest increase in quality-of-life scores. These findings indicate that vitamin D supplementation, in combination with coenzyme Q10, vitamins, and minerals, can offer important support for people with chronic heart failure.

Life Extension

Reduce systolic blood pressure

The effects of 8 weeks of supplementation with vitamin D3 (cholecalciferol) and calcium on blood pressure and biochemical measures of bone metabolism were studied. The sample consisted of 148 women. Sixty subjects (81%) in the vitamin D3 and calcium group compared with 35 (47%) subjects in the calcium only group showed a decrease in systolic blood pressure of 5 mm Hg or more. No statistically significant difference was observed in the diastolic blood pressures of the calcium-treated and calcium- plus vitamin D3 -treated groups.

A short-term supplementation with vitamin D3 and calcium is more effective in reducing systolic blood pressure than calcium alone. Inadequate vitamin D3 and calcium intake could play a contributory role in the pathogenesis and progression of hypertension and cardiovascular disease in elderly women.

The Journal of Clinical Endocrinology & Metabolism

Vitamin D May Help Prevent Diabetes

Vitamin D supplementation may reduce susceptibility to type II diabetes by slowing the loss of insulin sensitivity in people who show early signs of the disease.  Researchers studied 314 adults without diabetes and gave them either 700 IU of vitamin D and 500 mg of calcium daily or a placebo for three years. Among subjects who had impaired (slightly elevated) fasting glucose levels at the study's onset, those taking the active supplement had a smaller rise in glucose levels over three years than did the controls, as well as a smaller increase in insulin resistance. The researchers concluded that for older adults with impaired glucose levels, supplementing with vitamin D and calcium may help avert metabolic syndrome and type II diabetes.

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Prevent osteoporosis

The body cannot absorb calcium from food or supplements without an adequate intake of vitamin D. If calcium levels in the blood are too low, the body will steal the mineral from the bones and supply the muscles and nerves with the amount they need. Over time, the loss of calcium in the bones can lead to osteoporosis, a disease in which bones become porous and prone to fractures. After menopause, women are particularly at risk for developing this condition. Vitamin D taken along with calcium plays a critical role in maintaining bone density.

In a study of 176 men and 213 women over age 65 done at Tufts University, those who took 500 mg of calcium and 700 IU of vitamin D daily for three years experienced a decrease in bone density loss. Moreover, the incidence of fractures was cut in half. In another study, of 3,270 healthy elderly French women, a daily dietary supplement of 1,200 mg calcium plus 800 IU of vitamin D lowered the incidence of hip fractures by 43% in just two years. Considerable experimental and epidemiologic evidence now exists to support the need for calcium and vitamin D supplementation to reduce the risk of fracture and osteoporosis. Several more recent studies also have found that a daily dose of 800 IU of vitamin D, or 100,000 IU given three times a year, reduces the frequency of both falls and fractures.

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Immunity

A recent paper presented persuasive evidence that seasonal infections such as influenza may actually be the result of decreased vitamin D levels, not of increased wintertime viral activity, which has been the longstanding conventional wisdom.  This makes sense, because vitamin D receptors are present on many of the immune system cells responsible for killing viruses and deadly bacteria, and the vitamin—which is less environ-mentally available in the winter—appears to be a requirement for proper activation of these cells.

Life Extension

Protect against infection

A study by researchers at the University of California, San Diego (UCSD) School of Medicine shows that fluctuations in Vitamin D3 levels control the body's innate immune response, affecting a skin wound's ability to heal.

"Our study shows that skin wounds need vitamin D3 to protect against infection and begin the normal repair process," said Gallo. "A deficiency in active D3 may compromise the body's innate immune system which works to resist infection, making a patient more vulnerable to microbes."

Gallo's lab discovered that an antimicrobial peptide called cathelicidin is produced by wounds and is necessary to fight infections. Recently, several studies have begun to link vitamin D to cathelicidin. Researchers focused on white blood cells called macrophages that work to destroy invading bacterial microbes. Macrophages contain toll-like receptors that identify the invaders; when the receptors sense the presence of bacteria, they trigger cathelicidin production.

Gallo's team has now discovered that injury stimulates skin cells called keratinocytes, which surround the wound, to increase the production of vitamin D3 and that this in turn increases the expression of genes (CD14 and TLR2) that detect microbes. These genes, together with active vitamin D3, called 1,25D3, then lead to more cathelicidin. In both mice and humans, a deficiency in cathelicidin allows infections to develop more readily

Science Daily

Protect against multiple sclerosis

In a population study, women who were found to have the highest vitamin D intake via supplements (400 IU or higher per day) were found to be 40 percent less likely to have MS than women not taking vitamin D supplements. Additional population research in over 7 million people showed that higher levels of 25-hydroxyvitamin D levels are associated with significantly lower risk of developing MS. In white men and women, for every 50 nmol/L increase in 25-hydroxyvitamin D levels, there appears to be a 41 percent decrease in MS risk. However, in black and Hispanic men and women 25-hydroxyvitamin levels were not associated with MS risk.

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