And the best places to find them!
By Austin Perlmutter, MD
Our brains are powered by the food we eat, and some foods are better for our brains than others. A major reason for this is the nutrient content of our foods, which can vary depending on degree of processing, how the food was grown and even how the food was prepared. So what are the nutrients with the most data for supporting brain health, and where can we find them? Here are 3 of the top candidates:
1. Fiber
Unlike nutrients like fats, carbs and proteins, fiber (by definition) isn’t absorbed by our gut. Instead, it makes its way through the GI tract relatively intact. You may have heard about the distinction between soluble and insoluble fiber. Soluble fiber dissolves in water and creates more of a gel in our gut, helping with digestion. Insoluble fiber doesn’t dissolve in water, but promotes healthier GI motility and regularity. Yet the real importance to fiber as it relates to the brain concerns its ability to influence the microbiome.
Research over the last decades has shown us that the health and makeup of the 30 trillion or so bacteria in our gut may have dramatic effects on our brain. We’ve learned that the gut microbiome makeup is altered in Alzheimer’s disease, depression, anxiety and so much more. So what alters the microbiome? Our diet, and in particular, the fiber in our diet, seems to be key.
Across a number of largely preclinical studies, an increase in fiber intake has been correlated with improved brain function and changes in the gut microbiome. One recent study in people found that consuming around 12 grams of fiber a day was linked to improvements in cognition and alterations in a specific gut microbe. When it comes to mood, more fiber intake has been linked to less risk of depression in both adults and adolescents. Another study reviewed 1070 older adults and compared fiber intake to cognitive status, finding that more fiber intake (up to 34 grams a day) correlated with better cognitive testing.
Most people get around half of the recommended amount of fiber. Looking to step up your game? some excellent sources of dietary fiber believed to beneficially influence the microbiome include:
Jerusalem Artichoke: Also known as the sunchoke, this root vegetable has a high concentration of inulin and is known for its beneficial effects on gut health. It’s delicious baked with olive oil and salt!
Garlic: Garlic acts as a prebiotic by promoting the growth of beneficial Bifidobacteria in the gut. It may also help suppress the growth of disease-promoting bacteria from growing.
Onions: Similar to garlic, onions are rich in prebiotic fibers which help boost gut flora
Leeks: Leeks belong to the same family as onions and garlic and are another good source of inulin and fructooligosaccharides.
Asparagus: This vegetable is another great source of the fiber inulin, which can help promote healthy gut bacteria. It’s also rich in folate (another key brain nutrient)
Mushrooms: Mushrooms are rich in a host of prebiotic fibers, and also contain some great vitamins and minerals to boot!
Looking to get a better sense as to how much fiber is in your food?
Apples - Two small apples (with skin) provides about 10 grams of fiber.
Raspberries - About one cup of raspberries offers roughly 8 grams of fiber.
Almonds - A little over one-third cup of almonds provides around 10 grams of fiber.
Whole Wheat Pasta - About one and a half cups of cooked whole wheat spaghetti yields about 10 grams of fiber.
Avocado - One whole medium avocado has approximately 10 grams of fiber.
Split Peas - About one-half cup of cooked split peas contains about 8 grams of fiber.
Oatmeal - One and a half cups of cooked oatmeal typically have about 6 grams of fiber
Chia Seeds - Just one and a half tablespoons of chia seeds contain around 10 grams of fiber.
Broccoli - About three cups of chopped, raw broccoli provides about 9 grams of fiber.
Black Beans - Half a cup of cooked black beans offers about 7.5 grams of fiber
For a deep dive into the role of fiber in our health, check out this episode of the Get the STUCK Out podcast Dr. Will Bulsiewicz
2. Polyphenols
Polyphenols are a group of thousands of compounds found in plants. For years, these molecules have been studied for their potential antioxidant benefits. Now we’re learning that polyphenols work through several other pathways in our bodies. And recent work shows that they may help our brains.
The polyphenol compounds are categorized by groups, and the most studied of these are the flavonoids. Flavonoids include molecules like quercetin and catechins. As it relates to the brain, polyphenols may help boost brain-derived neurotrophic factor (BDNF) which is linked to better mood and cognition. In a 2024 review, it was found that people who ate more flavonoid polyphenols were at a lower risk for developing dementia. Interestingly, the mechanisms by which polyphenols improve brain health may have more to do with the gut microbiome and immune system than antioxidant effects.
Polyphenols can be found in just about any minimally-processed plant food, but some foods are better sources than others. Some of the most polyphenol-rich foods are actually herbs and spices. Generally speaking, colorful fruits and vegetables are great also sources of polyphenols. Coffee is also rich in these molecules (caffeinated or decaf), as are nuts and seeds. Some more exotic sources include cacao fruit and Tartary buckwheat. The key here seems to be to consume a diversity of plant foods. Some data also suggest that organically grown foods are richer in polyphenols than conventionally raised foods.
For a deep dive on the link between polyphenols and brain health, check out this episode of the Get the STUCK Out Podcast
3. Omega-3 Fatty Acids
Omega-3 fatty acids (more commonly called “omega-3 fats”) are a type of polyunsaturated fat. They are “essential” fatty acids because the body is not able to produce them, which means we must get them from our diet. While omega-3s are important to every part of our bodies, they’re especially key to the brain, where they make up around 35% of the fat.
Among the omega-3 fats, there are two that have received special attention as it relates to brain health. These are EPA (Eicosapentaenoic acid) and DHA (Docosahexaenoic acid). Each of these can be made in the body when we eat their precursor molecule, alpha-linolenic acid (ALA) which is found in plant foods, but practically speaking it’s tough to get enough EPA and especially DHA from plant sources.
Omega-3 fats, in particular EPA and DHA are believed to benefit the brain by helping ensure healthier structure and function, keeping inflammation in check and promoting healthy neuroplasticity (for example, they appear to increase BDNF). More importantly, consuming a diet richer in omega-3 fats is linked to better memory, faster processing speed and less brain atrophy.
Great sources of natural DHA and EPA include fatty fish like salmon, mackerel, herring and anchovies, shellfish like oysters and mussels. Seaweed and algae are also rich in these molecules (and if you’re vegan there are great algae-based omega-3 products). You can also get ALA from nuts and seeds.
