Supplementation of vitamin D is effective in preventing overall mortality in a long-term. It is not significantly effective in a treatment duration shorter than 3 years.
Vitamin D therapy significantly decreased all-cause mortality with a duration of follow-up longer than 3 years. No benefit was seen in a shorter follow-up periods.
The following subgroups of long-term follow-up had significantly fewer deaths:
- female only,
- participants with a mean age younger than 80,
- daily dose of 800 IU or less,
- participants with vitamin D insufficiency and cholecalciferol therapy.
The combination of vitamin D and calcium significantly reduced mortality and vitamin D alone also had a trend to decrease mortality in a longer time follow up.
Zinc is a nutritionally essential mineral needed for catalytic, structural, and regulatory functions in the body.
The RDA (recommended daily allowance) for adult women and men is 8 mg a day and 11 mg a day of zinc, respectively.
Severe zinc deficiency is a rare, genetic or acquired condition. Dietary zinc deficiency, often called marginal zinc deficiency, is quite common in the developing world, affecting an estimated 2 billion people. Zinc deficiency can cause impaired growth and development in children, pregnancy complications, immune dysfunction, and increased susceptibility to infections. Long-term consumption of zinc in excess of the tolerable upper intake level of 40 mg a day for adults can result in copper deficiency.
Zinc bioavailability is relatively high in meat, eggs, and seafood. Zinc is less bioavailable from whole grains and legumes due to the inhibitory effects of phytic acid on absorption of the mineral.