Nutrients for Neuroprotection

by Jordan Taffet, Dietetic Intern, M.S. Candidate

Neuroprotection refers to the mechanisms used to protect the brain against nerve injury and degeneration, as well as to protect the central nervous system. Nutrition can be used as a powerful tool to promote neuroprotection within the body. Nutrition is easily adjustable, cost effective, and critical for promoting a neuroprotective and anti-inflammatory state. Focusing on the power of nutraceuticals is important, especially because chemical drugs which are sometimes prescribed to protect the brain or delay neurodegeneration are known to possess serious side effects. Nutraceutical antioxidants in fruits, vegetables and minerals can be neuroprotective and possess innate disease-fighting abilities (1). By focusing on nutrition, one can utilize dietary agents to target radical oxygen species and to promote apoptosis (programmed cell death). Outlined below are some of the best nutrients that you can consume to protect your brain.

One of the most important nutrient groups known to be neuroprotective is fatty acids. These are found in sources such as: fish, nuts, seeds, and vegetables. One study found that almonds, hazelnuts and walnuts are recommended for brain-protective activity, as well as for preventing brain atrophy in patients with Alzheimer’s Disease (2). This is because these nuts have been shown to effect amyloidogenesis (the production of amyloid- the sticky protein that creates plaques commonly seen in those with Alzheimer’s), tau phosphorylation (the accumulation of neurofibrils commonly seen in Alzheimer’s Disease), and oxidative stress levels, by inhibiting these processes and by promoting a state of anti-inflammation and neurogenesis. Fatty acids, particularly omega-3 fatty acids, are also important, as they play a structural role in the brain and are key for neuronal activity and overall health. Omega-3 and other fatty acids have been shown to stimulate immune function and regulate inflammatory responses (3). These results have promising implications for those with cognitive decline and/or disease states, such as Alzheimer’s Disease. Studies have found that treating Alzheimer’s patients over the age of 55 with docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA) and lipoic acid has improved cognitive decline in these patients (3). DHA has been shown to be especially neuroprotective, as it undergoes enzymatic and non-enzymatic reactions in the brain, leading to the synthesis of potent lipid mediators that promote a neuroprotective state (4).

Several studies also indicate the importance of maintaining cardiovascular health for the purposes of neuroprotection through physical activity. Health conditions such as cardiovascular disease, diabetes and obesity are all closely related to cognition and have dietary implications and targets that can be utilized to promote healthy brain aging and to target brain health (5). In addition, research indicates that caloric restriction can be beneficial for neuroprotection, as excess nutrient availability has been linked to a decline in cognitive functioning (6). This is due to the fact that caloric restriction promotes lower insulin levels and is anti-inflammatory. This creates an environment within the body in which mitochondrial workload can be reduced and the signaling of mammalian target of rapamycin (mTOR) is inhibited, extending longevity. Caloric restriction also activates cellular and neuronal adaptation, which have been shown to induce acetylation changes in the histone lysine, producing a neuroprotective effect (6). Because of these findings, it is important that the aging population, those at risk for cognitive decline, and the general population focus on a Mediterranean diet, high in antioxidants and omega-3 fatty acids, in addition to regular physical activity, in order to promote an optimal state of neuroprotection.

Another important nutrient group for neuroprotection is probiotics and prebiotics, which help to feed beneficial gut bacteria. Research shows that prebiotics can have a proliferative action on indigenous gut bacteria, which is directly correlated to our neurobiology (7). Prebiotics have been shown to change the expression of brain receptors and circulating hormones, which may play a role in achieving a healthy microbiome and gut-brain connection. Probiotics, which are found in fermented foods, have also been shown to be neuroprotective in the elderly. Fermented foods such as: soybeans and roots have been shown to reduce radical oxygen species through the modification of chemical constituents, improving the overall activity and bioavailability of the nutrients in the food (8). The process of fermentation leads to an increase in phytochemical content, enhancing neuroprotection by increasing the bioavailability and intestinal absorption, and therefore utilization of nutrients within the foods that we eat. Research shows that this relationship lies in the hypothalamic-pituitary adrenal (HPA) axis, which is involved in the neurobiology of the stress response (8). Thus, consuming both probiotic and prebiotic foods can be beneficial for boosting the gut microbiome, leading to a healthier gut-brain connection.

Lastly, antioxidant intake has been directly correlated with neuroprotection. Because antioxidants are the first target of radical oxygen species under periods of high stress, antioxidant intake is very important for overall cognition. Research has shown that both endogenous and dietary antioxidants, such as those from vegetables and fruits, are important for maintaining redox states and for controlling neuroglial signaling pathways during periods of stress (9). Some studies show that specific antioxidants, such as resveratrol, help to induce autophagy in order to protect against neurodegenerative diseases (10). This has beneficial effects in individuals with Alzheimer’s, as resveratrol could counteract the cognitive decline that occurs in Alzheimer’s through modulating specific signaling pathways that control neuroinflammation within the brain and the body.

Overall, it is generally accepted that a Mediterranean diet is neuroprotective. Research indicates that following a Mediterranean diet can be beneficial for protecting against brain diseases and for lowering the frequency of cognitive decline (11). This is due to the beneficial components that a Mediterranean diet provides, which promote a natural change in gut microbiota and cognitive functioning, promoting an overall better state of mental health. Aiming to consume a Mediterranean-based diet with an emphasis on fatty acids, probiotics/prebiotics, and antioxidant intake will promote an overall neuroprotective environment within the body. This can simply be achieved by focusing on whole, plant-based foods with high nutrient bioavailability, while limiting animal-based products (except for fish). Focusing on nutrition can be a promising tool for those wanting to combat cognitive decline or disease as well as for those simply wanting to achieve a more neuroprotective state in order to promote longevity and health.

References:

  1. Mao X. et al., 2018. doi: 10.1016/j.pharmthera.2017.10.012.
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