Eggs and soybeans might have something in common beyond their nutritional value: Both contain lecithin, a substance that researchers are investigating for its potential role in keeping our brains healthy as we age.
A new study of nearly 2,000 older adults in China found that those who consumed more lecithin were less likely to have mild cognitive impairment and performed slightly better on cognitive tests. Published in the Chinese Medical Journal, the observational study raises interesting questions about the relationship between diet and memory, although it doesn't establish whether eating more lecithin can actually prevent cognitive decline.
Lecithin is naturally found in foods such as eggs, soybeans and meat. It also provides choline, an essential nutrient the body uses to support brain function, including processes involved in memory and learning. While scientists have long understood choline's importance, they're still exploring whether dietary lecithin itself might help protect cognitive health.
For this study, researchers examined the eating habits and cognitive abilities of 1,917 Chinese adults ages 60 and older. More than half had mild cognitive impairment, a condition involving noticeable changes in memory or thinking that don't significantly interfere with everyday independence.
After accounting for differences in age, education, health conditions and other factors, the researchers found that participants with higher lecithin intake had approximately 20% lower odds of mild cognitive impairment than those who consumed less.
They also performed slightly better on a standard cognitive assessment, although the difference was small, averaging about half a point on a 30-point test. It's unclear whether a difference of that size would translate into noticeable improvements in everyday memory or thinking.
The findings are encouraging, but they come with important limitations. Researchers assessed participants' diets and cognitive abilities at the same time, meaning they couldn't determine whether lecithin contributed to better brain health or whether people with better cognitive function simply had different eating habits. Other lifestyle and dietary factors may also have influenced the results.
The study also doesn't tell us whether increasing lecithin intake could prevent Alzheimer's disease or other forms of dementia. And although lecithin supplies choline, the findings don't demonstrate that taking either nutrient as a supplement would improve memory.
For now, the research adds another piece to the growing body of evidence exploring how nutrition relates to brain health as we age. Foods containing lecithin can be part of a balanced diet, but more research is needed before scientists can determine whether the nutrient offers benefits beyond its established nutritional roles.
The study was supported by the National Natural Science Foundation of China, the Beijing Municipal Natural Science Foundation and the Chinese Nutrition Society Nutrition Science Foundation-Nutrilite Plant Functional Ingredients and Health Research Fund.