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Vitamin D

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Vitamin D and Cancer in Postmenopausal Women

Four years of supplemental vitamin D and calcium made no difference in cancer risk.

Researchers divided 2300 postmenopausal, healthy women aged 65 or older, into two groups. One group received 2000 IU/day of vitamin D3 and 1500 mg/day of calcium; the other a placebo. After 4 years, the difference in any new cancer incidence between groups was insignificant--including breast cancer. While more research is needed, this study indicates supplementation later in life may not make significant differences.

PositiveTip: Adequate vitamin D and calcium are essential throughout the life span, but supplementation may not be necessary.

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Vitamin D Supplementation and Fall Risk

High doses of Vitamin D increase the risk of falls in the elderly.

Swiss researchers evaluated monthly high-dose vitamin D supplementation in 200 adults 70 years and older with a history of a fall in the past year. They were randomized to receive one of three monthly regimens, including the control group. At 12 months, lower extremity function was the same in all groups, but fall rates were higher except in the control group. An editorial suggested those over 70 should consume 800 IU daily of vitamin D, preferably from a balanced diet.

PositiveTip: Adequate exposure to sunlight daily, combined with a balanced diet is important to assure sufficient vitamin D.

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Is there Benefit to Vitamin D Supplementation?

Neither high nor low dose supplementation increased bone mineral density in a 1 year trial.

Traditionally, low vitamin D levels have been associated with lower bone-mineral density (BMD). However, there is no universal agreement on how to define "low". Researchers studied 230 postmenopausal women 75 years or older who had 25-hydroxyvitamin D levels between 14 and 27 ng/ml. They were free of any diseases that interfere with vitamin D or calcium absorption. Participants were randomized to either a low-dose or high-dose (800 IU daily or 50,000 IU twice monthly) cholecalciferol or a placebo. After 1 year the three groups did not differ significantly in BMD.

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Mushrooms Could Be a Viable Source of Vit D

Mushrooms a plant source of vitamin D.

A small trial conducted at Boston University has shown that a preparation of dried mushrooms that were exposed to ultraviolet light may contain as much vitamin D as a vitamin D supplement. When mushrooms are exposed to ultraviolet light, they produce vitamin D2, similarly to how humans produce vitamin D3 in the skin. This is good news for people who want to get vitamin D from non-animal based foods. 

PositiveTip: Consuming mushrooms regularly can significantly contribute to vitamin D levels--as long as the mushrooms have been exposed to ultraviolet light.

Live Longer with Lower Vitamin D Levels

Vitamin D written in sand

Studies of the role of vitamin D in human physiology indicate that vitamin D is involved in bone formation, the growth and development of immune cells, and stimulation or inhibition of blood vessels in cancer. Those who have lower levels of vitamin D are found to have higher death rates from heart disease, diabetes mellitus, and several kinds of cancer. Low vitamin D levels also adversely affect, multiple sclerosis, allergies, asthma, infections, and depression.

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Vitamin D Disappoints in Knee Pain

Vitamin D supplements do not reduce osteoarthritis knee pain.

A small randomized, double-blind clinical trial exploring the effects of Vitamin D supplements on pain in adults with knee osteoarthritis (OA) has yielded disappointing results. After two years, the supplement group and placebo group showed no difference in knee pain, function, or loss of cartilage volume. Maybe two years was not long enough, but more research is needed.

PositiveTip: Save your money. Daily moderate physical activity is probably more helpful in preventing knee OA pain than Vitamin D supplements.

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Long Life and Vitamin D

Offspring of parents who lived long lives had lower vitamin D levels.

Dutch researchers found that individuals in families who tend to live long lives have low levels of 25(OH) vitamin D. Offspring of parents who lived to their 90s had significantly lower levels than controls. This surprising finding does not prove cause, and many questions remain. Genetic studies suggest these offspring may have higher levels of an "aging suppressor" protein. Much more research is needed.

PositiveTip: Do not neglect appropriate sun exposure which is needed for the production of Vitamin D in the skin.

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Kids, Colds, and Vitamin D

Mongolian children had fewer winter colds when drinking milk fortified with Vitamin D.

Vitamin D deficiency is common in Mongolian children. This is partly because of long, cold winters, which limit exposure to the sun for many months of the year, the lack of food fortification, and the limited availability of supplements. Researchers in the United States have found that Mongolian children who drank Vitamin D-fortified milk experienced nearly half the winter colds of those who used unfortified milk. Even in the United States, approximately 20% of children are Vitamin D deficient.

PositiveTip: Adequate exposure to sunlight or Vitamin D supplements might help prevent winter colds in children.

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Double Benefit from Being Outdoors

Exercise outdoors improves vitamin D levels and fitness.

Regular exercise, both moderate and vigorous, contributes to healthy hearts. Harvard researchers have found those who do vigorous exercise for three or more hours per week reduce their heart attack risk by 22%. This study also suggests it may be due in part to exposure to sunshine and the resulting increased vitamin D levels.

PositiveTip: Enjoy the double benefit of outdoor physical activity: Higher vitamin D levels and better fitness!

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High Calcium Intake May Actually Increase Risk of Hip Fractures

High Calcium Intake May Actually Increase Risk of Hip Fractures

A newly published Swedish study of over 61,000 women who were followed for more than 19 years provides the strongest evidence to date that high calcium intake is not beneficial for preventing bone fractures. The exceptions are women with very low amounts of calcium and vitamin D in their diet. Women in the top 25 percent of calcium intake showed no reduced risk of fractures or osteoporosis. Instead, they actually showed a 19 percent increase in hip fractures. The lowest fracture risk was found in women with total calcium intake of about 800 mg per day.