Beware of Too Much Vitamin D

Disclaimer: Results are not guaranteed*** and may vary from person to person***.

—A Special Report from Victor Marchione, MD

Hardly a week goes by without vitamin D popping up in medical news. We all know it is an important nutrient and one you would be wise to supplement if you don’t see the sun much for a few months.

But that said, there are different ways to take a supplement. And a new study has highlighted the best way to take vitamin D and, more to the point, the way you should not take it.

The study, based out of Australia, has found that a “megadose” of vitamin D is just not as good as taking smaller, more frequent doses. A megadose can be taken just once a year, the idea being that your body takes in a huge amount, giving your health a major boost. But in the case of postmenopausal women looking for protection against falls and fractures, this megadose does not offer as much protection.

In fact, researchers have found that if an older woman ingests a yearly megadose of vitamin D, it may actually raise the risk of falling by 15% — and the risk of bone fractures by 26%. In this case, they’d be better off not taking vitamin D at all.

The researchers say that this evidence, until proven otherwise, shows that adults should not take high-dose vitamin D tablets. Their study included 2,256 women older than 70, who were at high risk of fracture. They were given either an annual dose of vitamin D at 500,000 international units (IU) or placebo for three to five years.

Those in the megadose group suffered 171 bone fractures, compared to 135 in the placebo group. Those in the megadose group fell nearly 2,900 times compared to 769 times for the placebo group. In the first three months after taking the megadose of vitamin D, the risk of falling increased 31%. The study was published last week in the venerable “Journal of the American Medical Association.”

Researchers do not know why the megadose led to the increased risk. Older studies have found mixed results pertaining to vitamin D’s role in bone health. Some found that 700 to 800 IU a day lowers fracture risk by upward of 30%. Other studies have found no effect at all.

In any event, what remains true is that vitamin D is incredibly important to the body. Along with calcium and magnesium, the vitamin is vital to producing new bone, along with so many other critical roles. We absorb it best by sunlight on our skin, and also in some foods — particularly the grocery store items now “enriched” with vitamin D.

Taking 1,000 IU of vitamin D a day — a far cry from a megadose — is an excellent step toward disease prevention and a healthy, well-functioning body.