Vitamin D can be helpful in many ways. Not only can it help prevent rickets, a crippling weakening of the bones, but it may also decrease falls and fractures, improve asthma and reduce the risk of upper respiratory infection. These are tremendous benefits for small amounts of a Vitamin D. Studies showed that older adults with adequate vitamin D levels experienced significantly less decline in cognitive function than those with lower levels of vitamin D.These benefits result from correcting vitamin D deficiency or inadequacy, not overdosing.

Various studies have showed that people given higher dose of Vitamin D every two months (averaging 2,000 IU per day) for a year are more likely to develop upper respiratory infections than those given a low dose (400 IU per day), and their infections lasted longer. Other studies have shown that people with the highest levels of vitamin D in their blood (over about 40 ng/mL, typically due to excess supplement use) are more likely to develop heart disease, cancer, and die when compared to people with moderate levels. Vitamin D supplements that provide thousands, rather than hundreds, of IUs per dose(amounts you’d only want if you were seriously deficient). Be aware that supplement makers can legally put any amount of vitamin D they want in a pill and it’s not necessarily the right amount for you.