The Power of Vitamin D

Summer is almost over. Kids are back to school. I am back to writing my columns.

A friend wants to know: What should I make of all the news about vitamin D?

I said to him: If you haven’t started taking vitamin D everyday then you better talk to your doctor and start taking one. Talking to your doctor is important to make sure vitamin D is compatible with other medications you take.

We have always known vitamin D is needed for good health and strong bones and teeth. Your doctor will prescribe vitamin D supplements if you don’t get enough in your diet. Vitamin D is also used to treat rickets, low phosphate levels, and parathyroid problems.

In the last few months several reports have appeared which advance the case for universal intake of vitamin D on a daily basis.

A report published in the Journal of the American Geriatrics Society says vitamin D, taken in a high dose, may help prevent falls in the elderly. The study shows that nursing home residents who took a daily dose of 800 international units (IU) of vitamin D for five months were less likely to fall than those who took either lower doses or no vitamin D.

Another report appeared in the journal Nutrition Reviews suggests that adults should daily take 2,000 IU of vitamin D to help prevent some cancers.

The authors reviewed 29 observational studies and concluded that in North America, a projected 50 per cent reduction in colon and breast cancer incidence would require a universal intake of 2,000 to 3,500 IU per day of vitamin D.

A third report came out in the Archives of Internal Medicine. This review paper analyzed the results of 18 vitamin D studies says that taking vitamin D supplements may help people live longer. But it’s not yet clear exactly how vitamin D does that. But it appears to be a life extender.

So how much vitamin D should you take?

It has been previously determined that “adequate intake” of vitamin D is 200 IU per day for the first 50 years of life, 400 IU per day from 51-70, and 600 IU per day after age 71. Researchers now say that 2,000-IU daily dose of vitamin D is currently considered the “tolerable upper limit” for vitamin D. Most commercially available multivitamins contain between 400 and 600 IU.

The Canadian Cancer Society is now recommended taking 1,000 IU of vitamin D daily as a cancer prevention step. Experts suggest taking supplements of no more than 2,000 IU per day.

Some foods – for example, oily fish like salmon and sardines – are a natural source of the vitamin. Milk is commonly fortified with 100 IU per cup. The sun is the most potent source. When the sun’s ultraviolet rays hit the skin, the skin makes the vitamin, which is rapidly absorbed in the blood and can be stored for several months, mostly in the blood and fat tissue. However, excessive sun exposure is not recommended because of the well-known risk of skin cancer.

Are there any side effects if you take too much vitamin D?

Likely side effects are: Constipation, diarrhea, dry mouth, constant headache, thirst, metallic taste, irregular heartbeat, weakness, fatigue, loss of appetite, dry mouth, muscle pain, bone pain, irritability, nausea, and vomiting.

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