Have you ever felt your brain function faltering after a particularly stressful week at work or wished you could supercharge your cognition so you could forge ahead on a major project? Maybe you’re interested in staving off so-called “normal” age-related cognitive decline. Whatever your underlying motivation, there are many simple, actionable steps you can take to better your brain function. Read on to learn how to optimize your brain for better cognitive performance using evidence-based nutrition and lifestyle strategies.
- The brain–gut connection
- The Standard American Diet’s impact on your brain
- Eight brain superfoods
- Eight micronutrients for your brain health
- Four brain-boosting supplements
- Five lifestyle changes to optimize your brain
Unlikely as it seems, your gut holds the key to better brain health and cognitive performance. A growing body of research is shedding light on the fundamentally important role our gut bacteria play in shaping the health and function of our brains.
Want to supercharge your brain or protect against age-related cognitive decline? Check out these diet and lifestyle tips to optimize your brain health. #nutrition #optimalhealth #chriskresser
The relationship between our gut microbiota and cognitive function is mediated by the gut–brain axis, a biochemical communication network that links the central nervous system, which houses the brain and spinal cord, with the enteric nervous system and bacteria in the gut. Via the gut–brain axis, bacterial metabolites travel from the gut to the brain, where they impact cognitive function.
For example, lipopolysaccharide, a large molecule produced by gram-negative bacteria—which have a unique outer cell membrane—has been found to travel from the gut to the brain, where it accumulates in neurons and impairs their function. Pathogenic and opportunistic bacteria can also produce neurotoxic metabolites such as D-lactic acid and ammonia and neurotransmitters identical to those created by humans, further influencing brain function. Harmful gut microbes may stimulate the production of pro-inflammatory cytokines, altering the integrity of the blood–brain barrier and causing a deterioration in cognitive function.
In humans, abundant evidence demonstrates an intimate relationship between the gut and cognitive function. Intestinal dysbiosis has been identified as an underlying cause of dementia, with dementia patients showing lower levels of beneficial Lactobacillus and Bifidobacteria. Furthermore, modifying the gut microbiota with probiotics is associated with improvements in mood and emotional well-being. (1, 2, 3)
What else does your gut influence?
Your gut health doesn't just impact your brain. Download this free eBook and learn more about the gut–body connection.
The Gut Bacteria–Cognition Connection Is Forged at Birth
The first year of life is a foundational period for microbial colonization of the gut and a period of rapid brain development. Fascinating new research indicates that the microbial composition of the infant gastrointestinal tract influences cognition, as shown in structural MRIs performed at one and two years of age. (4) Infants with high levels of Bacteroides show higher cognitive performance than those with lower levels; interestingly, infants born vaginally have higher levels of Bacteroides than those born via C-section, suggesting that the mode of birth also affects the gut microbiota and cognition. Taking steps to improve the health of a mother’s microbiome and emphasizing the benefits of vaginal delivery over C-section delivery increase the odds of “seeding” the infant gut microbiome with beneficial, cognition-boosting bacteria. Furthermore, encouraging breastfeeding and the avoidance of unnecessary antibiotics may be crucial for optimizing a child’s cognitive development.
Antibiotic Treatment Harms Cognitive Function
Antibiotics may induce cognitive dysfunction by disrupting the gut microbiota. (5) In mice, antibiotic treatment significantly reduces brain-derived neurotrophic factor, or BDNF, a neuron growth factor, ultimately causing cognitive impairment. (6) Whether these adverse effects also occur in humans remains to be seen. In the meantime, I recommend avoiding antibiotics as much as possible if you want to preserve your cognitive health.
What you eat directly affects the structure and function of your brain, and therefore, your cognitive performance. If you want to feed your brain well, the first step is to avoid the Standard American Diet. (7) Abundant research shows that hyperpalatable, sugary, processed foods cause alterations in brain function that promote cognitive impairment.
Chronic consumption of SAD foods reduces synaptic plasticity, a crucial process that mediates cognitive function, while also impairing learning and memory. (8, 9) Importantly, these effects occur independently of obesity, meaning you can be a thin SAD eater and still suffer the cognitive consequences of such a diet. The good news, however, is that changing your diet will likely boost your brain health, even if you’ve been eating poorly for years! In animal research, switching adolescent mice to a healthier control diet restores neurocognitive dysfunction, suggesting that diet changes can benefit cognitive function well beyond the formative years for brain development. (10)
Eat Nutrient-Dense, Whole Foods to Support Cognitive Performance
A recent study conducted at the University of Illinois looked at patterns of nutrient biomarkers in the blood of healthy adults to examine the association between nutrition and cognition. The researchers found that study participants with patterns of nutrient biomarkers associated with a plant-rich, whole-foods diet demonstrated better “network efficiency,” a subjective measure of cognition, and better performance on cognitive function tests compared to those with nutrient biomarker patterns indicative of an unhealthy diet. (11)
Find a Macronutrient Ratio That Works for You
Rebalancing macronutrients can also benefit cognitive performance. For some individuals, a high-fat ketogenic diet significantly enhances cognitive function. These anecdotal reports are supported by research demonstrating that a ketogenic diet improves memory and mild cognitive impairment. (12, 13) Conversely, if you’ve been low carb or keto for a while and have noticed a decline in your memory, focus, or mood, it may be time to add more carbs to your diet. Nutrient-dense carbohydrates provide the brain with glucose for energy production and can help boost critical thinking, learning, and memory capacities.
Whatever macronutrient ratio you choose, the most important thing is to eat a diet that keeps your blood sugar stable. Frequent blood sugar swings are a risk factor for cognitive impairment, but they can be well managed through diet. (14)
Once you’ve determined the macronutrient intakes that work best for your brain, it’s time to get down to the details and add specific foods and micronutrients that optimize cognitive performance.
Eating berries has been found to improve cognition in children, boost episodic and working memory in adults, and prevent cognitive decline. (15, 16, 17) These brain-boosting benefits are attributed to berries’ polyphenol content. In humans, polyphenols cross the blood–brain barrier and accumulate in brain regions important for learning and memory; once in the brain, these polyphenols may combat oxidative stress and neuroinflammation. However, berries also benefit brain health by promoting the growth of gut microbes with neuroprotective properties. (18) Try a mix of berries—blueberries seem to lead the pack for brain benefits—as well as sweet cherries, which have lots of polyphenols.
2. Dietary Fiber
Simply increasing the amount of fiber in your diet may boost your cognitive function. Prebiotic fiber, a type of dietary fiber fermented for fuel by beneficial gut bacteria, also boosts cognition. (19) In animal and human trials, eating prebiotic fiber improves synaptic plasticity, learning, memory, and executive functioning. (20, 21) Prebiotic fiber appears to positively impact cognition by elevating neurotrophic factors such as BDNF, modulating the gut–brain axis, and regulating blood glucose levels and insulin sensitivity. (22, 23, 24)
Prebiotic fiber is found in:
- Chicory root
- Jerusalem artichoke
3. Green Leafy Vegetables
“Eat your greens” is advice you should take to heart if you want to boost your cognitive performance! Research indicates that nutrients in green leafy vegetables such as folate, phylloquinone, and lutein protect against cognitive impairment by reducing oxidative stress and neuroinflammation and enhancing mitochondrial function. (25) Aim for at least one serving per day of dark leafy greens such as spinach, Swiss chard, collard greens, and lettuce.
Numerous studies demonstrate a relationship between nut intake and cognitive function. A high nut intake has been linked to better cognition in old age and strengthens brainwave functions associated with learning and memory. (26, 27) Nuts may boost cognition by improving insulin sensitivity and endothelial function, two important mediators of brain function, and by reducing inflammation. Walnuts in particular have been the focus of some of this research because they are especially high in the essential fatty acid alpha-linolenic acid (ALA), which is positively associated with brain function.
To reap the brain benefits of nuts, you don’t need to eat very much; a recent study found that eating just one handful of walnuts per day had a significant neuroprotective, memory-boosting effect. (28)
5. Dark Chocolate
Chocolate lovers, rejoice! We know from research that cocoa flavonoids enhance human cognition, making dark chocolate one food you’ll want to include in your diet. (29) The consumption of flavanol-rich cocoa improves cognitive performance in both older adults with memory impairment and those who are cognitively intact. It also improves processing speed, executive function, working memory, and verbal fluency. (30) Cocoa flavonoids boost cognitive performance by increasing BDNF, enhancing cerebrovascular blood flow, and improving insulin sensitivity. (31) You can get the benefits of dark chocolate by eating about one to two ounces per day. Note that chocolate should have a cocoa content of at least 70 to 75 percent to be considered dark. Be aware that “Dutch processing,” done to improve flavor, can also lower flavonoid content; choose “non-alkalized” or “natural” dark chocolate for maximum flavanols.
For years, health authorities advised people to avoid eating whole eggs if they wanted to preserve their brain health. This misguided recommendation was based on the false premise that dietary cholesterol, which is abundant in eggs, raises blood cholesterol and the risk of chronic diseases such as heart disease and dementia. However, the diet–lipid hypothesis has since been disproven, and new research indicates that eggs are actually beneficial for brain health!
Eating eggs early in life improves biomarkers of infant brain development. (32) In adults, egg intake is associated with better performance on cognitive tests. (33) Eggs support optimal cognitive function by supplying the brain with choline and DHA, two crucial brain-supportive nutrients that I will discuss in more detail shortly. Eggs also contain the carotenoid lutein, which evidence suggests plays a vital role in neurological development. (34)
Millions of people around the world rely on coffee to keep themselves energetic, focused, and productive throughout the day. Coffee’s primary ingredient, caffeine, dramatically enhances cognitive performance. (35) Caffeine enhances hippocampal neurotransmission and memory consolidation, making it a powerful tool for optimizing cognitive performance. (36, 37) However, decaffeinated coffee also increases alertness, suggesting that coffee has cognition-enhancing activity beyond its caffeine content.
If you’re not a coffee drinker, then consider adding tea to your brain-boosting diet plan. Drinking green and black tea, which both come from the Camellia sinensis plant, is inversely associated with cognitive dysfunction. (38, 39)
Some of the compounds in tea that may be responsible for its cognitive benefits include theanine and caffeine. (40) The caffeine in tea improves alertness and performance on long-duration cognitive tasks, while theanine promotes relaxation and calmness, creating a balanced state of focus for tackling cognitively demanding tasks.
Several micronutrients perform crucial functions in your brain—and, sadly, many of us are deficient in one or more of these. Try increasing your intake of these nutrients for better cognitive performance—either by eating whole, nutrient-dense food or through strategic supplementation.
In animal studies, mice who are exposed to threats from predators naturally suppress neurogenesis (brain cell growth)—perhaps because they are conserving energy while they’re under stress. However, when they are given vitamin B1 (thiamine), this response goes away. Neurogenesis is no longer suppressed, suggesting a role for the vitamin in protecting cognitive function during times of stress. (41) Thiamine is also a cofactor in brain glucose metabolism, and therefore affects energy availability in the brain. While thiamine deficiency is associated with dementia, thiamine supplementation reverses cognitive dysfunction and brain pathology in Alzheimer’s disease. (42, 43, 44) Whole-food sources of thiamine include white and brown rice, pork, trout, black beans, mussels, tuna, acorn squash, beef steak, yogurt, and milk.
Vitamin B6 helps regulate the metabolism of homocysteine, an amino acid that, when elevated, increases the risk of cognitive decline, dementia, and Alzheimer’s disease. (45) B6 is also a crucial component of the process to create multiple neurotransmitters, and it regulates brain glucose metabolism. Food sources of vitamin B6 include poultry, fish, dark leafy greens, and legumes.
A surprising number of people are deficient in vitamin B12, a nutrient essential for cognition. According to a study out of Tufts University, 40 percent of people between the ages of 26 and 83 have plasma B12 levels in the low normal range—a range at which many experience neurological symptoms. Nine percent had a glaring deficiency, and 16 percent exhibited “near deficiency.” Perhaps most surprisingly, low B12 levels were as common in younger people as they were in the elderly. (46)
B12 regulates multiple processes involved in cognition, including homocysteine metabolism, neurogenesis, neurotransmission, and the production of the myelin sheath that insulates neurons. B12 deficiency causes nerve damage, memory loss, and a host of other cognitive problems. If you’re looking to optimize your cognitive performance, then your B12 level is something you won’t want to overlook.
To learn more about the importance of vitamin B12 for cognitive function, see my previous blog post on B12 deficiency and listen to my podcast “RHR: Why B12 Deficiency Is Significantly Underdiagnosed.”
Folate works synergistically with B12 to regulate homocysteine metabolism and methylation. Folate deficiency decreases DNA stability, impairs neuronal differentiation and repair, and causes atrophy of the hippocampus, a region of the brain involved in memory and learning. Folate is also needed for synthesis and regeneration of BH4, a cofactor for enzymes that produce neurotransmitters.
Natural folate is found in dark leafy greens, legumes, cauliflower, beets, and chicken liver. I recommend avoiding foods fortified with folic acid, the synthetic form of folate, because high levels of folic acid may remain unmetabolized in the body and impair normal folate metabolism.
If you supplement with folate, choose methylfolate and check out your B12 status ahead of time; supplementing with large amounts of folate can mask B12 deficiency and actually worsen cognitive impairment, so it is crucial to keep these two B vitamins in balance.
Choline is an essential but overlooked nutrient required for healthy cognitive function. It’s needed for the cellular integrity of neurons and glial cells—which help support and insulate the neurons. Choline deficiency harms the structure of the neurons and hampers neurotransmission, leading to impaired cognition.
Choline optimizes cognition throughout the lifespan. Robust data from animal and human studies indicate that a high choline intake during pregnancy promotes better cognition in offspring. (48, 49) Choline intake is also associated with better cognitive performance in adults. (50) For more on choline intake and pregnancy, check out my article “Choline, SIBO, and Pregnancy: What’s the Deal?”
The top whole-food sources of choline are beef liver, whole eggs, red meat, and poultry. Cruciferous vegetables are another good source of choline, with one cup of cooked broccoli and one cup of collard greens offering 63 mg and 73 mg of choline, respectively.
Docosahexaenoic acid (DHA) makes up over 90 percent of the omega-3 fatty acids found in the brain. It modulates neurotransmitter release, neurogenesis, neuron myelination, membrane receptor function, synaptic plasticity, neuroinflammation, and gene expression in the brain. (51) In fact, DHA intake is so crucial for brain function that some researchers believe it was the primary factor responsible for the increase in brain size that occurred in our hominid ancestors two million years ago.
The importance of DHA for cognition begins early in life. During gestation and infancy, DHA rapidly accumulates in the brain; in fact, research strongly suggests that maternal DHA status during these periods significantly influences an infant’s cognitive abilities during the first few years of life. (52, 53)
The cognitive benefits of DHA also extend beyond the formative years. In adults, DHA boosts memory and slows cognitive decline. (54, 55) Importantly, the plant-derived alpha-linoleic acid, a type of omega-3 fatty acid, does not have the same effect as DHA on cognition; this finding indicates that DHA-rich seafood is a requisite part of a cognition-supporting diet.
To maximize the beneficial effects of DHA on the brain, avoid a simultaneously high intake of industrial seed oils. Industrial seed oils are high in omega-6 fatty acids, which compete with omega-3s and can reduce DHA bioavailability in the body.
Iron deficiency is a well-known cause of impaired cognition. (56) However, too much iron—a condition referred to as iron overload—impairs brain function. (57, 58) By eating a well-balanced diet that contains animal foods, the only sources of highly bioavailable heme iron, along with plant foods, which contain phytochemicals that inhibit the absorption of excessive iron, you can keep your iron levels in check and your brain functioning optimally.
8. Vitamin D
Vitamin D doesn’t just build healthy bones—it also creates a healthy brain. Low vitamin D is linked to poor cognition, whereas vitamin D sufficiency promotes normal neurogenesis and cognitive function. (59, 60) Boost your vitamin D level by getting a safe amount of sun exposure and by eating vitamin D-rich foods such as cod liver oil, wild salmon and mackerel, pastured egg yolks, and lard from pastured pigs.
Curcumin, the bright yellow pigment found in turmeric root, has been traditionally used in Asian countries for its anti-inflammatory and antioxidant properties for thousands of years. Emerging research indicates that curcumin supports brain health; daily curcumin supplementation improves memory and attention in healthy adults, while also slowing age-associated cognitive decline. (61, 62) While the bioavailability of isolated curcumin is relatively low, it is enhanced when taken in a liposomal form. For cognitive support, I recommend 400 to 600 mg of curcumin daily.
Acetyl-L-carnitine is a nutrient that supports energy production in the mitochondria of neurons. In animal studies, acetyl-L-carnitine supplementation increases the proliferation of healthy mitochondria, a process linked to improved brain function. (63) It also boosts learning capacity by enhancing synaptic neurotransmission and has dramatic antidepressant effects. (64, 65) In clinical trials, acetyl-L-carnitine has been found to increase attention and reduce fatigue at a dosage of 2,000 mg per day. (66)
Phosphatidylserine is a phospholipid that naturally occurs in the body and is required for healthy nerve cell membranes and neurotransmission. Research indicates that phosphatidylserine supports the formation of short-term memory, the consolidation of long-term memory, the ability to learn and recall information, attention and concentration, problem-solving, math skills, and language skills. (67, 68) The recommended dosage of phosphatidylserine for improving attention and cognitive function is between 200 and 400 mg per day. (69, 70, 71)
Bacopa, also known as brahmi, has been used in Ayurvedic medicine for centuries to promote longevity and cognitive enhancement. Current research strongly supports the traditional use of Bacopa for brain function. In a recent randomized, placebo-controlled trial, Bacopa was found to significantly improve cognitive function in medical students. (72) It also enhances attention, cognitive processing, and working memory in the elderly. (73, 74) The standard dose of Bacopa, taken in the form of powdered leaves, is 300 mg per day. Traditionally, Bacopa was consumed with ghee because its constituents are fat soluble. To enhance the bioavailability of a Bacopa supplement, take it with a meal that contains fat.
1. Try Fasting
When you eat (or don’t eat) may be just as important as what you eat when it comes to cognitive performance. Recent research indicates that fasting may improve cognitive function by reducing the activity of inflammatory signaling pathways that adversely impact learning and memory. (75, 76) The form of fasting used in these animal studies was intermittent fasting, an umbrella term for various eating protocols that cycle between periods of fasting and non-fasting over a defined period of time—typically 24 hours. While clinical trials are needed to determine the cognitive effects of fasting in humans, this research offers tantalizing evidence that intermittent fasting may be a simple, free way for people to augment their cognitive performance.
2. Sleep More
Aim for eight to nine hours of high-quality sleep per night. By high quality, I mean uninterrupted sleep in a completely dark room (use blackout shades in your bedroom, if necessary). To optimize your sleep quality, what you do before bed also matters; wear blue light-blocking glasses at night to maximize your melatonin production, stick to a regular sleep/wake schedule, and keep all electronic devices out of your bedroom.
3. Reduce Your Screen Time
If you want to optimize your cognitive function, reducing your “screen time” is essential. A troubling amount of evidence suggests that excessive screen time—defined as time spent on smartphones, laptops, tablets, and other electronic devices, shortens attention span, causes gray matter to atrophy in the brain, and impairs our ability to conduct “deep work,” defined by computer scientist Cal Newport as “the ability to focus without distraction on a cognitively demanding task.” (79, 80, 81, 82) In fact, scientists have gone so far as to state that:
… habitual involvement with these devices [smartphones, computers, tablets, etc.] may have a negative and lasting impact on users’ ability to think, remember, pay attention, and regulate emotion. (83)
While turning off notifications on your phone to reduce distractions is all well and good, to make a significant dent in your screen time, I recommend first reading Cal Newport’s fantastic book, Digital Minimalism. Once you’ve read the book, figure out which apps, social media platforms, and digital devices are most beneficial in your life and which ones you should eliminate for good.
If you’ve ever felt cognitively “stuck” and experienced a surge of inspiration upon moving your body, then you’ve discovered the cognitive benefits of exercise! Exercise boosts BDNF, a neuron growth factor, and synaptic plasticity; these effects improve executive function and creativity. (84, 85)
In addition to incorporating a regular exercise routine into your schedule, be sure to take “movement breaks” throughout the day. Alternate between sitting and working at a standing desk, take a walk at lunch, and don’t be shy about taking water cooler breaks; these short bouts of exercise reduce chronic disease risk factors and keep your brain healthy.
5. Reduce Your Stress
Last but not least, reducing stress is crucial for optimizing cognitive performance. Whereas mental and emotional stress drains our cognitive reserves, mindfulness practices make our brain networks more efficient, improve attention, and prevent cognitive decline. (86, 87, 88) Try a mindfulness app such as Headspace, Calm, or 10 Percent Happier; join a yoga or tai chi class; meditate; take a walk in nature; or immerse yourself in a favorite hobby to reduce your stress and optimize your cognitive function.