Nutrients for the Brain

Antioxidants

Antioxidants are a basic tool to delay or manage dementia because they help reduce free radicals that damage brain cells.¹ Antioxidants include a number of phytochemicals that fight oxidation. They include phytonutrients (bioflavonoids, carotenoids, polyphenols, and indoles), enzymes (glutathione and super oxide dismutase), and vitamins and vitamin-like nutrients (vitamins A, B, C, E, CoQ10, alpha lipoic acid).

Since oxidative stress and inflammation appear to be involved in brain aging and in neurodegenerative diseases,² it is theorized that increased consumption of antioxidants may be effective in preventing or ameliorating these changes. The neuroprotective effects of strawberry, bilberry, black currant, blackberry, blueberry, and mulberry, have been well documented.^{3, 4}

Polyphenols

Polyphenols⁵ are the largest group of phytonutrients and have been reported to have strong antioxidant activities in both in vitro and in vivo.^{6, 7} They are a group of over five-hundred phytochemicals which are naturally occurring micronutrients in plants. These act as powerful antioxidants to protect our health by neutralizing free radicals that occur with pollution, smoking, eating rancid foods, and as a byproduct of normal metabolism. It is also thought that polyphenols support the sympathetic nervous system,⁸ and reduce inflammation⁹ which is in turn linked to a lower risk of several chronic diseases.

The polyphenols are being closely investigated for their ability to prevent and treat neurodegenerative conditions. For example, the polyphenols curcumin, resveratrol, and tea catechins are of great interest to researchers because of their antioxidant capacity, cell signaling support, antiinflammatory action, chelation ability, and neuroprotection – all of which are mechanisms associated with dementia.^{10, 11} Top food sources in the polyphenol category include the spices cloves, star anise, oregano, and celery seed, the fruits black chokeberry and black elderberry, cocoa, dark chocolate, flaxseed meal, and chestnut. In addition, apples, tea, other nuts, artichoke, plum, pomegranate, all berries, black beans, black olives, broccoli, spinach, and red onion.

Carotenoids

Carotenoids are a class of pigments found in plants, where they function as internal sunscreens, protecting the plants from solar radiation. Dark leafy green and brightly colored vegetables are rich in carotenoids, especially lutein and zeaxanthin, which are associated with cognitive function in pre-adolescent children,¹² young adults,¹³ and older adults.¹⁴ They have the ability to limit oxidation and inflammation and therefore improve cognition and reduce the risk of dementias such as Alzheimer’s.¹⁵

Some carotenoids, such as astaxanthin, are as helpful for memory, hippocampus-based neural plasticity, and neurogenesis as exercise, and even more effective when combined with exercise.¹⁶ Lycopene has been shown to exhibit neuroprotective effects by reducing oxidative stress, suppressing production of inflammatory cytokines, and reducing accumulation of amyloid plaques.^{17, 18} It has been shown to attenuate cognitive deficits by improving inflammation in the gut–liver–brain axis as well improving glycolipid (sugar-fat) metabolism,¹⁹ mechanisms by which lycopene provides neurocognitive protection as well as inhibition of nerve cell death and restoration of mitochondrial function.²⁰ Lycopene is found in red fruits and vegetables such as tomatoes.

PD patients have lower levels of carotenoids, with greater deficiencies in advanced PD. Higher blood levels of zeaxanthin specifically are associated with better processing speed as well as enhancing brain blood flow in the specific areas that support that cognitive function. Epidemiological studies have found a decrease in PD risk in individuals who consume foods containing carotenoids and beta-carotene,²¹ as well as cruciferous vegetables such as cauliflower, cabbage, and broccoli (rich in antioxidants with neuroprotective capacity). Dietary sources of xanthophylls include lutein and zeaxanthin in green leafy vegetables and corn, and beta-cryptoxanthin in pumpkins, papayas, and peppers.

Flavonoids

Many epidemiological studies have shown that regular flavonoid-rich fruit intake is associated with delayed Parkinson’s disease, Alzheimer’s disease, ischemic diseases, and aging effects.^{22, 23, 24, 25} There are more than six-thousand types of flavonoids, the largest group of phytonutrients. These plant-based biochemicals often contribute to the color of plant parts.

Flavonoids penetrate and accumulate in the brain regions involved in learning and memory, especially the hippocampus. They have neuroprotective benefits and neuromodulatory proteins that promote neurogenesis, neuronal function, and brain connectivity. They accomplish this through blood-flow improvement and angiogenesis (new blood vessel growth) in the brain and sensory systems. Studies indicate flavonoids offer the brain protective benefits with respect to normal aging, dementia, and stroke.²⁶

Flavonoids are being investigated as an aspect of nutritional interventions for dementia and mild cognitive impairment due to their antioxidant and anti-inflammatory capacity, as well as neuroprotective and metabolic function support,^{27, 28, 29} and neurogenesis in the hippocampus.³⁰

Most vegetables are high in flavonoids, particularly those green and red in color. Foods with the highest levels are all berries, red cabbage, onions, kale, parsley, tea, dark chocolate (we recommend 85% or higher dark chocolate), citrus fruits, and fermented soy such as tofu, or soy sauce.

Phenolic acids

The beneficial effects of phenolic acids are well documented. They may be effective against Alzheimer’s due to their anti-acetylcholinesterase and butyrylcholinesterase inhibiting action, and against amyloid beta peptide fibril formation.^{31, 32, 33} They play a role in reducing depression, neuroinflammation, heart disease, cell death, Parkinson’s, Huntington’s, ALS, and other neurological conditions.³⁴

Foods highest in phenolic acids include tea, coffee, grape seed, blueberries, kiwi, plums, cherries, apples, yellow onion, parsley, capsicum pepper, whole wheat, oats, and brown rice.

Stilbenes

Stilbenes are a small group of plant chemicals. Resveratrol is probably the best-known and the most studied of them. Stilbenes such as resveratrol offer neuroprotective properties with antioxidant, anti-inflammatory, and anti-amyloid effects.³⁵ Resveratrol is “a potent activator of SIRT1, and thus may mimic caloric restriction to prevent disease of aging.”³⁶ It plays a role in decreasing amyloid beta accumulation and toxicity, preventing damage to the hippocampus, depresses microglia activation.³⁷

There are only two stilbenes of note: resveratrol and pterostilbene. Resveratrol is a powerful antioxidant found in red wine, blueberries, cranberries, and peanuts. Consuming these foods has been linked to better heart health, although wine consumption's benefits do not outweigh its detriments.^38a Pterostilbene is found in high amounts in antioxidant-rich foods like blueberries, cranberries, and grapes, and has a higher bioavailability than many of its cousin antioxidants.

Lignans

Lignans are found in legumes, cereals, grains, fruits, algae, and some vegetables. The lignans found in Chinese magnolia (Schisandra chinesis, used in traditional Chinese medicine) have been linked with decreased cognitive impairment and improved learning and memory in AD animals.³⁸ The mechanism may involve regulation of APP, neurotransmitter, and inflammatory metabolism, the antioxidant system, and formation of neurofibrillary tangles.³⁹ In other research, a lignan found in Norway spruce, 7-hydroxymatairesinol, was tested in a rodent model of Parkinson’s, which slowed deterioration of the striatal dopaminergic neuron terminals (but not the cell bodies). Nonetheless motor activity improved.⁴⁰ The best sources of lignans include flax and sesame seeds. Whole flax seed, (rather than milled, which has much less lignan) is helpful in reducing LDL cholesterol⁴¹which is the fatty type of cholesterol that goes on to form plaque. Poor circulation is a risk factor for neurodegenerative conditions, as are high levels of cholesterol in blood.⁴²

Coumarins

Coumarins are found in many plants, such as sweet woodruff, sweet grass, vanilla grass, and sweet clover. One of their bioactivities is their ability to become anti-Alzheimer’s. They are also anti-inflammatory, antioxidant,⁴³ antiviral, antimicrobial and antidepressant.⁴⁴ Their value as a tool for AD is that they inhibit acetylcholinesterase.⁴⁵ Their anti-coagulant capacity makes them a tool where blood thinners and clot-dissolvers are needed.

Tannins

One group of tannins, proanthocyanidins that are found in lentils, grape seed, apples, and cocoa seeds. This beneficial actions reduces oxidation of LDL cholesterol, protecting against chromosomal damage,⁴⁶ and is a powerful antioxidant.⁴⁷ These are functions that help reduce the risk of dementia and related conditions.

Amino Acids

Amino acids are the building blocks of life, the biochemical compounds that combine to create proteins. When proteins break down through digestion or other processes, they separate out into amino acids again. There are a number of ways of classifying amino acids. One way is to identify them by whether the body can produce them or whether they must come from food; these are the essential amino acids that cannot be made by the body.

Two groups of essential amino acids, aromatic and acidic, are needed for proper brain function. The aromatic amino acids include tryptophan, tyrosine, phenylalanine that are biosynthetic precursors for the neurotransmitters, serotonin, dopamine, and norepinephrine. Single meals, depending on their protein content, can rapidly influence uptake of aromatic amino acid into the brain, directly modifying their conversion to neurotransmitters. If these amino acids are not available in required amounts, this will directly affect the release of neurotransmitters from neurons, resulting in reduction in brain function.

Nonessential amino acids are produced by the body. Seven of them are used by the brain and enter the brain at varying rates: glycine, proline, serine, alanine, cysteine, aspartate, and glutamate. Serine and alanine are essential for the brain. Serine makes glycine, alanine makes glutamate and aspartate. Of these the acidic amino acids, glutamate, and aspartate, are themselves brain neurotransmitters. Glutamate, for example is required, but excess glutamate (as from adding monosodium glutamate (MSG) to food) becomes toxic to nerve cells.

Essential Fatty Acids

Of the omega-3s, EPA and DHA are essential for both brain health and general well-being. DHA is especially important for brain health. It is needed for cognitive functioning and memory.⁴⁸ Although omega-6 fats are essential (GLA provides the healthy, anti-inflammatory type of omega6) the modern Western diet contains far more omega-6 fatty acids than necessary.

The recommended ratio of omega-6 to omega-3 fatty acids in the diet is 4:1 or less. However, the Western diet has a ratio between 10:1 and 50:1 due primarily to the excess carbohydrates and sugars in the common diet, particularly white starches and sugars, vegetable oils and foods containing transfatty acids. Omega-7s are an overlooked, lesser known essential fatty acid which are helpful against the metabolic disorders that underlie diabetes, cardiovascular disease, obesity, and cancer. Omega-7 found in salmon, anchovies and olive oil is important as an anti-inflammatory agent.

Vitamins and Minerals

When we think of good nutrition, we most commonly think of vitamins and minerals, and with good reason. Acting together, they perform hundreds, perhaps thousands of roles in the body. In good supply, they build and protect bones, provide immune support, repair damage on both the macro and cellular level, and they convert food into energy. Thirteen vitamins are considered essential. These are vitamins A, C, D, E, K and eight B vitamins: thiamine (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), pyroxidine (B6), biotin (B7), folate (B9) and cobalamin (B12). Four of them (A, D, E, and K) are fat-soluble and are stored in fatty tissue. And the body produces some of them naturally: D from sunlight, and K produced by bacteria in the intestinal system.

Essential minerals for the body and the brain fall into two main groups, those that comprise much of the body’s mineral supply, and those that are present only in trace amounts, but which are essential for healthy functioning. The balance of minerals, enzymes, and various neurobiological compounds form the basis of the health brain.

Herbs and Whole Foods

A wide variety of both medicinal and culinary herbs and whole foods are important sources of antioxidants, amino acids, essential fatty acids, minerals, vitamins and vitamin-like biochemicals found in plants. Some are traditionally used, with knowledge of their specific capacities going back thousands of years. Many of these traditional medicinal herbs as well as more common phytonutrients are being researched extensively for both their value in addressing neurodegenerative conditions, and for their value in the process of exploring why neurodegenerative conditions occur.

Next: Exercise for Brain Health

Footnotes

Note: additional sources of the above information are available in our guide to brain care, Natural Brain Care, or upon request.

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47. Ibid. Shahidi. (2018).
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