Can eating a specific food or following a particular diet help prevent or delay dementia caused by Alzheimer’s disease? Many studies suggest that what we eat affects the aging brain’s ability to think and remember. These findings have led to research on general eating patterns and whether a person’s diet might make a difference.
Healthy eating patterns have been associated with cognitive benefits in studies, but more research is needed — and is underway — to determine if what we eat can prevent or delay Alzheimer’s or age-related cognitive decline.
How could what we eat affect our brains? It’s possible that eating a certain diet affects biological mechanisms, such as oxidative stress and inflammation, that underlie Alzheimer’s. Eating a certain diet might increase specific nutrients that may protect the brain through anti-inflammatory and antioxidant properties. It may inhibit beta-amyloid deposits, which are found in the brains of people with Alzheimer’s, or improve cellular metabolism in ways that protect against the disease.
Or perhaps a person’s diet works indirectly by affecting other Alzheimer’s risk factors, such as diabetes, obesity, and heart disease. For example, the typical Western diet increases cardiovascular disease risk, possibly contributing to faster brain aging. A growing area of research focuses on the relationship between gut microbes — tiny organisms in the digestive system — and aging-related processes that lead to Alzheimer’s. The important role of physical activity and exercise, and how this interacts with diet, cardiovascular health, and brain health must also be considered.
What do we know about individual foods?
Many foods — blueberries, leafy greens, and curcumin (found in the spice turmeric), to name a few — have been studied for their potential cognitive benefit. These foods have been thought to have anti-inflammatory, antioxidant, or other properties that might help protect the brain. However, so far, there is no evidence that eating or avoiding a specific food can prevent Alzheimer’s or age-related cognitive decline.
Still, scientists continue to look for clues. A recent study showed that a molecule in green tea breaks apart tangles of the protein tau, which builds up in the brain due to Alzheimer’s. Based on this finding, the team identified other potential Alzheimer’s drug candidates. Another study, based on older adults’ reports of their eating habits, found that eating a daily serving of leafy green vegetables such as spinach or kale was associated with slower age-related cognitive decline, perhaps due to the neuroprotective effects of certain nutrients.
Research has also shown that a diet that includes regular fish consumption is associated with higher cognitive function and slower cognitive decline with age. Another recent study, in mice, found that consuming too much salt increased levels of the protein tau, found in the brains of people with Alzheimer’s, and caused cognitive impairment.
The connection between the digestive system and the brain
There is growing evidence for connections between the brain and the gut microbiome — the community of viruses, bacteria, and other microbes in the digestive system. NIA-funded investigators are analyzing how factors such as aging, diet, and the environment can change the conduit of neurons, proteins, and chemicals linking the digestive system and the brain, and how those changes may impact cognitive health. You can learn more about the latest research on how the gut microbiome relates to brain health in our recent feature article, “Beyond the brain: The gut microbiome and Alzheimer’s disease.”
For more complete information: https://www.nia.nih.gov/health/alzheimers-and-dementia/what-do-we-know-about-diet-and-prevention-alzheimers-disease