We often wonder what to blame for our poor memory as we age : genetics or diet?The key finding in a new Swedish study shows genes and nutrition interact to contribute to cognitive problems in old age.Scientists have known of a gene associated with higher risk for Alzheimer's disease, and they have also known that low levels of vitamins B12 and folate are risk factors for memory loss and Alzheimer's. However, they say this is the first study to look at the combined effect of inborn traits and environmental factors on memory.
The predisposition to Alzheimer's is found in a version of the APOE gene. Fifteen percent of the population are carriers of this genotype and have, on average, a smaller brain area associated with memory. Researchers studied 167 healthy people of average age 83 to look at the effect of a B12 deficiency.During the memory test, carriers of the high-risk genotype with normal levels of B12 recalled a greater number of words. The high-risk genotype/low B12 level group had a significant association with poorer memory. Also, having five seconds to look at and remember the words rather than two seconds created greater recall, especially in the high-risk genotype/low B12 level group.Ten percent of adults aged 75 and older have low B12 or folate.Thus researchers conclude that supplement treatment is relatively inexpensive and may be required as part of preventive health regimes for older persons.
