What foods are associated with Alzheimer’s disease?

Sugar

A prospective cohort study published in 2021 found that a higher intake of sugar-containing beverages was associated with a higher risk of Alzheimer’s disease.^[1] Similarly, a 2021 study covered here found that a diet high in sugar was associated with greater amyloid accumulation in two areas of the brain: the posterior cingulate gyrus and precuneus.

Fish

Fish Intake has been associated with a lower risk of Alzheimer’s disease. A 2014 meta-analysis of six prospective cohort studies found that a 100-gram increase in weekly fish intake was associated with an 11% lower risk of Alzheimer’s disease.^[2] A 2018 meta-analysis of five prospective cohort studies likewise found an association between higher fish intake and a lower risk of Alzheimer’s disease among people with a genetic predisposition to the disease.^[3]

Although a possible candidate for this protective association are the omega-3 fatty acids found in seafood, this does not appear to be the case. In the 2014 meta-analysis, a higher intake of long-chain omega-3s was not associated with a lower Alzheimer’s disease.

Coffee

A 2018 meta-analysis of five prospective cohort studies found no association between coffee consumption of up to 5 cups per day and risk of Alzheimer’s disease.^[4] However, at least one study found that drinking more than six cups of coffee per day was associated with a higher risk of Alzheimer’s disease.^[5] It’s worth noting that disturbed sleep appears to increase brain levels of amyloid beta,^[6] and a 2017 meta-analysis found that having sleep problems was associated with a higher risk of Alzheimer’s disease.^[7] Given that caffeine is one factor that can negatively impact sleep, being mindful of caffeine intake (from coffee and other sources) may be important in reducing Alzheimer’s risk.

Alcohol

Observational evidence has frequently found that light-to-moderate alcohol consumption is associated with a lower risk of Alzheimer’s disease compared with no alcohol consumption.^[8][9] One concern raised with this data, however, is that these findings could be the result of confounding factors (e.g., people who drink in moderation may be more likely to have other healthy habits).^[10] This would also explain why genetic evidence largely hasn’t found a beneficial link between alcohol and Alzheimer’s disease.^[11][9]

Meanwhile, one study, utilizing data from seven cohort studies, found that a history of drinking to the point of losing consciousness (i.e., passing out) was associated with roughly double the risk of Alzheimer’s disease.^[12]