Key factors for mental function in older people.

Dietary factors may have an effect on conditions like memory loss, Alzheimer's disease, and dementia in older people. Scottish researchers compared two groups, one with participants between 76-78 years and one 61-63 years. The older group had higher levels of a substance called homocysteine in their blood (see the Nutrition Hotline on page 2, for information about homocysteine); this suggests that their diets did not have enough vitamin [B.sub.12] and/or folate. In the older group, subjects with higher levels of homocysteine did less well on some tests of mental function. It is certainly possible that the homocysteine itself is toxic to cells in the nervous system. It is also possible that high levels of homocysteine indicate a lack of vitamin [B.sub.12] and/or folate that could affect brain function. Older people can have difficulty absorbing vitamin [B.sub.12] so those age 51 years or older should use vitamin [B.sub.12]-fortified foods or supplements to meet most of their requirements, since the vitamin [B.sub.12] in fortified foods and supplements is usually well absorbed.

Duthie SJ, Whalley LJ, Collins AR, et al. 2002. Homocysteine, B vitamin status, and cognitive function in the elderly. Am J Clin Nutr 75:908-913.