Beta-carotene linked to reduced mortality risk in the elderly

In a new study published in the American Journal of Clinical Nutrition, researchers have found an association between plasma carotene levels and lower death rates among the elderly. This prospective study involved 1168 elderly men and women who were followed for 10 years. After the follow-up period, researchers looked at causes of mortality in the study population. The subjects with higher plasma carotene concentrations had a lower overall mortality risk, and a lower risk of mortality from cancer and cardiovascular disease specifically. To put the results in context, researchers performed a meta-analysis of 5 studies on plasma antioxidants and all-cause mortality in elderly populations.

These findings are somewhat surprising since some of the previous supplemental trials have been negative or inconclusive. The researchers suggested that the confusing evidence so far may indicate that beta-carotene needs to be taken in concert with other antioxidants to have a beneficial effect on health.

American Journal of Clinical Nutrition, Vol. 82, No. 4, 879-886, October 2005

Folic acid lowers blood concentrations of homocysteine

A new study published in the October 2005 issue of the American Journal of Clinical Nutrition indicates that a dosage of at least 800 mcg of folic acid is needed to maximally reduce plasma homocysteine concentrations. Increased blood homocysteine levels are considered to be a risk factor for cardiovascular disease.

This meta-analysis of 25 studies evaluated the effect of various doses of folic acid on plasma homocysteine. Doses of 800 micrograms provided a significantly greater reduction in plasma homocysteine compared to 400 micrograms. Supplementation with 800 micrograms folic acid per day was associated with a 23 percent reduction in homocysteine, compared to a 20 percent reduction associated with 400 micrograms. A dosage of 200 mcg was associated with a 13 percent reduction. Higher doses provided only a slightly greater benefit. The addition of vitamin B12 was associated with a synergistic benefit.

Although some fortified foods contribute to daily intake in the U.S., many multi-nutrient supplements provide just 400 mcg of folic acid.

American Journal of Clinical Nutrition, Vol. 82, No. 4, 806-812, October 2005