Folate nutrition and older adults: challenges and opportunities.J Am Diet Assoc. 1997 Feb; 97(2):167-73.JA
Folate fortification of bread and grains has been directed to prevent neural tube birth defects. Research has also challenged previous concepts of folate nutritional status and suggested that folate may play a role in reducing the risk of vascular disease. Although folate status of many elderly people is adequate according to traditional, hematologic criteria, some elderly persons have elevated blood concentrations of the metabolite homocysteine, which indicates subclinical deficiency of folate or vitamin B-12. Higher homocysteine concentrations, even within the normal range, are associated with increased risk of vascular disease. Elderly people with better folate and vitamin B-12 status have lower homocysteine concentrations and may have lower risk for vascular disease. Although the new folate fortification rules provide the benefit of increasing folate in the food supply, they could be a risk for the elderly because excess folate intake can mask vitamin B-12 deficiency, thereby delaying diagnosis. Elderly people have a higher prevalence of vitamin B-12 deficiency as a result of absorption problems. Those deficient in vitamin B-12 should be treated to prevent irreversible neurologic damage. Modern approaches to screening the elderly include using higher cutoff points for serum vitamin B-12 and obtaining blood concentrations of the metabolite methylmalonic acid, which is elevated in deficiency of vitamin B-12 but not folate. To examine current folate intake and food sources, food frequency questionnaires were administered to 308 elderly volunteers aged 65 to 94 years. Mean (+/-standard error) folate intake from food was 299.6+/-5.8 microg/day. Supplements (median dose=400 microg/day) were consumed by 47% of participants. Only 3.2% of the sample had total folate intake greater than 1,000 microg/day, the recommended upper limit, and these were taking high-dose folate supplements (> or = 800 microg/day). Breakfast cereals provided 25.6% of folate intake; vegetables, 23.2%; fruit, 20.8%; refined breads/grains, 6.7%; dark bread, 5.0%; legumes/nuts, 5.9%; dairy products, 5.8%; meat/poultry/fish/eggs, 5.1%; other, 1.9%. Mean folate intake would increase 16.5% if enriched bread and grains were fortified. Such fortification could help some persons to lower serum homocysteine concentration and vascular disease risk. Dietitians should be aware of modern protocols for screening the elderly for vitamin B-12 deficiency.