In 2018, Karina Fischer and her colleagues examined a broad range of single foods, exploring whether there are universally applicable patterns of foods that are protective against Alzheimer’s disease and memory decline. They looked at the effect on memory of red wine, white wine, coffee, green tea, olive oil, fresh fish, fruits and vegetables, red meat, and sausages.
They found that only red wine had an impact—at least in men. For women, drinking red or white wine increased their risk of memory decline. However, in 2019, Jürgen Rehm and his colleagues reviewed twenty-eight studies on the connection between alcohol use and dementia performed between 2000 and 2017. Overall, Rehm found that light to moderate alcohol use in middle to late adulthood was associated with a decreased risk of cognitive impairment and dementia.
However, heavy alcohol use increased the risk of all types of cognitive impairment and dementia. Archana Singh-Manoux and his colleagues followed 9,087 people over twenty-three years to see how alcohol related to the incidence of dementia. In 2018 in the British Medical Journal, they reported that people who had abstained from alcohol completely or who consumed more than 14 drinks per week had a higher risk of dementia compared to those who drank alcohol in moderation.
Though international recommendations for alcohol use vary widely, according to the Centers for Disease Control, light alcohol use refers to fewer than 3 drinks per week. Moderate alcohol use refers to more than 3 but fewer than 14 drinks per week for men and fewer than 7 drinks per week for women. Heavy alcohol use refers to more than 14 drinks per week for men and more than 7 drinks per week for women.
However, given the findings of the studies mentioned here, for maximum memory protection I recommend staying between light drinking and moderate drinking guidelines. For my patients, that means roughly 3 drinks per week for women and 5 drinks per week for men. Of course, alcohol can have many negative health effects as well, so drinking according to either the CDC’s recommendations or the guidelines I suggest only makes sense after talking to your primary care physician about other risk factors.
In 2017, Boukje van Gelder and her colleagues reported on 676 elderly men they had studied over ten years to see if coffee protected them from cognitive decline. They found that men who drank coffee had less cognitive decline than those who didn’t. The greatest effect was seen in those who drank 3 cups of coffee a day, with those who drank more or less seeing less dramatic effects. In 2009, Marjo Eskelinen and her colleagues reported on a group of people they had followed over twenty-one years to see if coffee helped cognition.
They found that coffee drinkers at midlife had a lower risk of dementia and Alzheimer’s disease later in life compared with those who drank no coffee or up to 2 cups per day. The lowest risk of dementia was found in people who drank 3–5 cups of coffee per day. There are a number of ways in which coffee might protect the brain.
Caffeine, which increases serotonin and acetylcholine, may stimulate the brain and help stabilize the blood-brain barrier. The polyphenols in coffee may prevent tissue damage by free radicals as well as brain blood vessel blockage. Trigonelline, a substance found in high concentration in coffee beans, may also activate antioxidants, thereby protecting brain blood vessels.
However, not every substance in coffee is helpful. Unfiltered coffee contains natural oils called diterpenes, which increase LDL cholesterol levels, potentially resulting in thickening and hardening of the walls of the arteries in the brain (though they do have some helpful anti-inflammatory properties). Acrylamide, a chemical formed when coffee beans are roasted, can inhibit neurotransmission, destroy dopamine neurons, and increase oxidative stress.
The amount of acrylamide in coffee can vary; dark-roasted, fresh coffee beans generally have the lowest amount. The wide range of chemicals in coffee is probably why current researchers do not believe that the protective effect of coffee against dementia is conclusive enough to make a formal recommendation. However, know that there are more good effects than bad of moderate coffee consumption (about 2–4 cups per day) and that it could have benefits later in life. Remember to keep your overall caffeine consumption under 400 mg/day.