Nutrients for Brain Health & Performance

The episode opens with the host introducing himself as Andrew Huberman, a professor of neurobiology and ophthalmology at Stanford School of Medicine, and setting out two aims. The first is to identify foods that support focus, general brain health and the longevity of the brain, meaning the ability to maintain cognition and clear thinking over time. The second is to explain why people prefer some foods over others. For that second aim he previews three signals that combine to drive food choice. The first comes from the gut and is completely subconscious. He specifies that this is not the gut microbiome per se but neurons in the gut that send signals to the brain about the nutrient content of food without the person being aware of it.

The second signal is how metabolically accessible a food is, meaning how readily it can be converted into energy the brain, rather than the body, can use. The third is belief: what a person perceives and believes a food contains and what they think it can do for their health and energy. The host concedes this may sound "wishy-washy or vague" and promises mechanistic data, from animal models and more recent human studies, supporting the claim that people can change what they eat to the point of craving foods that are better for them than what they currently eat.

This is an incredibly powerful mechanism that we all have. It's one that I think is very underappreciated.

Before the main topic, the host summarizes key points from an earlier episode on time-restricted feeding, also called intermittent fasting. He lists the benefits in terms of weight loss or maintenance, fat loss, organ health, quality sleep and cognition. The feeding window should begin at least one hour after waking, though it can start later, and end at least two, and ideally three, hours before sleep. Some people can finish eating much earlier, for example at 6:00 p.m. with sleep at midnight, but he notes that many people struggle to get quality sleep if the window ends too early relative to bedtime.

The second point is consistency. According to the host, the research suggests the window should fall at roughly the same time of each 24-hour day. His counterexample is an eight-hour window that runs 10:00 a.m. to 6:00 p.m. one day, noon to 8:00 p.m. the next, then 2:00 p.m. to 10:00 p.m. He says small shifts for social or other reasons don't seem to be a big deal, but shifts of many hours from day to day work against the benefit. His reason is that the timing of the feeding window affects clock genes, which regulate a range of other processes in the body.

The host notes that the podcast is separate from his teaching and research roles at Stanford. He then says questions about food and the brain are among the most frequent he receives: what to eat or avoid for focus, memory and long-term brain health. He says there are now many data from good, quality peer-reviewed studies pointing to foods to eat, and perhaps some to avoid, to enhance brain function.

He widens "brain" to mean nervous system function, because movement and memory depend on the spinal cord and the neurons connected to the body's organs as well as on the neurons in the head. He then divides nutritional and lifestyle factors into two categories. Modulators, such as regular quality sleep, social connection and not being depressed, matter for overall health and affect brain function, but more or less indirectly. Mediators act on brain health directly, and the episode focuses on these, especially how certain foods enhance brain function. He adds that a few things that happen during sleep do benefit brain function and repair directly.

He still briefly covers two modulators he calls vital. On sleep, he calls regular, ample, quality sleep the foundation of mental and physical health and points to earlier episodes, including "Master Your Sleep," episode two. Without good sleep, he says, focus and learning suffer, and there are data linking poor sleep to dementia, or at least to worsening existing dementias. On cardiovascular health, he cites a general prescription from the literature, which he considers well supported, of 150 to 180 minutes of cardiovascular exercise per week. Resistance exercise is a welcome addition, not a replacement. His mechanism is that the brain consumes large amounts of oxygen, glucose and other factors delivered by the blood, so clogged arteries or poor vascular supply to any brain region harm the brain.

Turning to the mediators, he notes that cells other than neurons also shape brain function, most prominently the glia. "Glia means glue": these cells were long thought to hold things together passively. He says they play a very active role in neuronal metabolism and brain function, and "probably also" in cognition. The qualifier marks that last claim as less certain.

The host points out that discussions of neuron function usually start with fuel: neurons use large amounts of glucose, and in some cases ketones, especially in people on low-carbohydrate or ketogenic diets, a topic he defers. He argues that a prior question is what neurons are built from. That leads him to name fat as what he "would argue is the most important food element for brain function."

His reasoning is structural. Apart from the brain's very high water content, much of the integrity of neurons and other brain cells comes from fat. These cells have an outer double-layered membrane, two thin layers that form a boundary. What crosses that boundary regulates the electrical activity through which neurons fire and communicate. He distinguishes this structural fat from the storage fat around the belly and other organs. His central claim is that food provides the building blocks of the neurons people think with. He names the relevant fats as essential fatty acids and phospholipids, which he describes as "more or less the same thing" for the purpose of simplifying a large literature.

Among essential fatty acids, the host mentions the EPA and DHA varieties and the omega-3 and omega-6 categories. He says most people, though not everybody, get enough omega-6s, but most do not get enough omega-3s to support healthy brain function in the short and long term. Referring to earlier discussions of depression and mood, he says a wealth of literature indicates that at least one, two or even three grams per day of the EPA form can improve mood and well-being, with effects "at least on par with some of the major antidepressant treatments out there," but without similar side effects. He adds that for people already taking antidepressants, supplementing one to three grams of EPA can allow a lower antidepressant dose that is still effective. No specific studies, doses or trial details are cited in this part of the conversation, so these statements rest on his summary of the literature.

Beyond depression, he says EPA and omega-3s seem to play a very important role in maintaining normal cognitive function in people who are not depressed. For supplements, he lists liquid or capsule fish oil, krill oil for people who avoid fish because of allergy or ethics, and algae and other EPA forms for those who don't want krill oil. He maintains that a lot of EPA can come from food, and that those foods also contain other things beneficial for the brain.