April 6, 2004
Low levels of vitamin B-12, a common B vitamin essential for a healthy brain and nervous system, may be linked to poor memory in certain older adults, a new study reports. The memory problems were evident in those seniors who had low levels of the vitamin and carried a common gene called APOE e4 that increases a person's risk of developing Alzheimer's late in life.
Carrying the gene (inherited from one or both parents) does not guarantee that you will develop Alzheimer's and other memory problems in old age. However, it does put you at increased risk for developing Alzheimer's as you enter old age. About 15 percent of the population is thought to carry the APOEe4 gene.
Previous research has also linked low levels of vitamin B-12 and another B vitamin, folic acid (also called folate), to memory problems and an increased risk of late-life dementia. However, the relationship between these nutrients and Alzheimer's remains unclear.
Genes and Nutrition
This study is among the first to look at the interaction of genetic and nutritional factors as they relate to memory skills in older people. Researchers from the U.K. and Sweden enlisted 167 elderly men and women, aged 75 and up, who were healthy and did not have any memory problems. They were tested for the APOE e4 Alzheimer's gene, as well as for levels of the B vitamins. They were also given a battery of memory tests to see how well they could recall words and other items and followed for up to six years.
Those seniors who had low levels of vitamin B-12 (also called cobalamin) and who carried the APOE e4 gene were most likely to score lower on the memory tests, particularly when they had to perform under tight time pressures. Not enough people were enlisted in the study to draw any firm conclusions about folic acid levels.
The researchers suggest that giving older adults vitamin supplements containing B-12 and folic acid may be an inexpensive and effective measure for helping to ease normal memory decline in old age. The value of these supplements may be greatest in those who carry the APOE e4 gene for Alzheimer's, their findings suggest. However, they caution that larger studies are needed to draw definitive conclusions about B vitamins and other nutrients as a possible preventive measure or treatment for Alzheimer's.
Many Seniors Are Deficient in B-12
Although B-12 is plentiful in most people's diets, one in five older adults are thought to be deficient in the vitamin. It is found in meats, fish, cheese, and other foods, and some breakfast cereals are fortified with B-12 as well. But as we age, we produce less stomach acid, so we can't absorb B-12 as well from foods. Therefore, many doctors recommend that seniors take a multivitamin containing B-12, as well as individual B-12 supplements in some cases, as an insurance policy to keep the nervous system working well.
Some elderly people develop a condition known as pernicious anemia, which usually arises when the body can't properly absorb enough vitamin B-12 and levels become severely depleted. Pernicious anemia, if left untreated, can result in dementia that may "masquerade" as Alzheimer's. In fact, patients suspected of having Alzheimer's are routinely tested for pernicious anemia, which can be effectively treated with regular injections of B-12.
Based on the results of this study, it is still too early to say whether seniors should routinely be taking high doses of vitamin B-12 supplements as a preventive measure against memory loss or Alzheimer's. Further study is needed. Still, experts recommend that everyone get plenty of heart-healthy foods like fresh fruits and vegetables and whole grains to assure a steady supply of many nutrients. A sound diet helps to maintain the health of the blood vessels, including those that supply oxygen and nutrients to the brain, which helps to keep the mind in top working order.
For more on APOE and other risks for Alzheimer's disease, including diet and genetic factors, visit www.ALZinfo.org.
The study appeared in the April 2004 issue of Neuropsychology, a research journal published by the American Psychological Association.
David Bunce, Miia Kivipelto, Ake Wahlin: "Utilization of Cognitive Support in Episodic Free Recall as a Function of Apolipoprotein E and Vitamin B12 or Folate Among Adults Aged 75 Years and Older." Neuropsychology: Volume 18, Number 2, April 2004.