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Studies around the world continue to demonstrate the need for vitamin D, and two recent ones show how important it is at any age. In Egypt, four months of vitamin D supplementation significantly reduced autism symptoms in children when compared to a placebo. In Japan, falls among frail elderly people decreased by 42 percent with vitamin D supplements, and by 72 percent when supplements were combined with exercise. A dose of 1,000–2,000 IU daily is often recommended, but it’s best to get a blood test to identify individual needs.