Nutrition and Cognition

We know more now about the effects of micro and macronutrients on the body than at any point in history, let alone the effects of nutrition on the brain.

This month we're going to take a deep dive into the foods that enhance (and inhibit) cognitive function and performance, and those that prevent decline.

Nutrition is a powerful lever to pull to have a healthy body, engage in clear thinking, have plenty of energy to live a full life, and be proactive in preventing disease and neural decline.

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Food For Thought - Eat to Think Better guide

Before exploring nutrients that are indicated to be helpful in cognitive function, it’s necessary to understand the problem that many Americans face today regarding diet. In an article titled “Food for Thought: How Nutrition Impacts Cognition and Emotion”, authors Spenser and colleagues describe an increased burden on society in the form of compromised cognitive and emotional dysfunction. There is a strong correlation between poor dietary patterns and/or metabolic disorders which lead to a variety of illnesses on top of compromised cognitive and emotional function. We now live in a time when many people are overfed but undernourished, as is evident in the statistic from the aforementioned article that just under 60% of the global population is considered overweight or obese.

Alarmingly, research demonstrates that neuroinflammation can be triggered by as little as one to seven days of a diet high in saturated fat and/or sugar. Additionally, research from the University of Oxford demonstrated significantly inhibited retrieval speed and focused attention of information from episodic (ex: recalling what you had for breakfast or where you parked your car) and working memory (ex: following instructions or participating in conversation) after only five days of consuming a diet high in saturated fat in healthy men between the age of 19 and 28 years old. This was in comparison to participants who consumed a standard diet.

Data analysis from the experiment found participants’ ability to retrieve information from working and episodic memory deteriorated in addition to the deterioration of their focused concentration. The speed of visual information processing was also substantially impaired (Holloway et al., 2011).

Fortunately, there are three main food groups that can contribute to protecting cognitive function and reducing cognitive decline. Essential fatty acids, fruits and vegetables rich in color, and lean proteins.

Polyunsaturated Fatty Acids

The first of the three is polyunsaturated fatty acids (PUFA), also called essential fatty acids, such as omega-3 and omega-6 PUFA. These must be provided by one’s dietary intake, meaning that humans are not able to naturally produce these essential fatty acids within their own body. This is why the word “essential” is used to describe omega-3 and omega-6 fatty acids. Western diet is typically rich with omega-6 PUFA whereas omega-3s are substantially less common. An imbalance in these essential fatty acids can lead to brain health compromises and cardiovascular impairments.

The standard western diet is high in inflammatory foods, fortunately omegas can help counter inflammation, specifically omega-3 fatty acids have a potent anti-inflammatory effect. It has been shown that nerve inflammation is strongly associated with mood disorders, most studied is depression. It logically follows that a brain free of inflammation, or experiencing reduced inflammation, functions better.

These essential fatty acids form long chain poly PUFA found in the brain and are found to play a pivotal role in regulating neurobiological processes, specifically those participating in mood and cognition. Omega-6 fatty acids can be sourced from most plants, palm, and coconut; while omega-3 can be found in green leafy vegetables, walnuts, and flax. Omega-3 can also be added to one’s diet in the form of oily fish (Kitson et al., 2010).

Insufficient amounts of omega-3 PUFA has been found in both the brain and peripheral tissues (this is a term used to describe any tissue that is not directly related to the area of concern, in this case, the brain) of patients with cognitive decline and mood disorders (Bazinet & Layé, 2014).  

Polyphenols

Polyphenolic compounds are found in colorful fruits and vegetables, they have potent anti-inflammatory and antioxidant properties. Research suggests that berry fruit specifically, can equip the brain against age-related oxidative stress and neuroinflammatory deficits by adjusting the neural environment. Epidemiological studies further indicate that a fruit and vegetable forward diet can prevent cognitive decline; this is in contrast with evidence showing those with inadequate consumption of fruits and vegetables have increased rates of cognitive decline (Miller et al., 2017).

Polyphenolic compounds are often found in fruits and vegetables with dark coloring, such as blueberries, blackberries, plums, cherries, currants, black olives, strawberries, and apples. Pecans, hazelnuts, and dark chocolate also bear these compounds, the benefit of which is that they have anti-inflammatory and antioxidant properties (Spencer et al., 2017).

Protein

In a review of research, Puri and colleagues explore the association between macro and micronutrients on cognitive health and slowing cognitive deterioration in their article titled, “Nutrition and Cognitive Health: A Life Course Approach”. Their research highlights an association between high-protein diets and improved cognitive function. There are positive correlations with diets low in saturated and trans fats, like the Mediterranean diet. Whole food diets are associated with a strong gut microbiome which connects with brain function through the gut-brain axis (Puri et al., 2023). Logically, the Mediterranean diet is highlighted since it primarily consists of whole foods, a plant-forward approach, and low to minimally processed foods.

In an article by Li and co-authors, dietary protein intake in adults over 60 was studied. 2,937 adults over 60 years and older participated in the study between 2011 and 2014, all of whom completed cognitive testing. They found that there was a positive association with protein intake and cognitive function. These results were seen with protein intake from meat, eggs, and legumes. However, a negative association was found in proteins from milk and milk products which demonstrated an adverse association in cognitive function. The study highlights the possibility of addressing sufficient protein intake as a cost-effective way to offer dietary interventions to reduce the social and increasing economic burden related to cognitive decline in aging adults (Li et al., 2020).  

In summary, the necessity to consider the cognitive impact of food choices is becoming increasingly important as more highly processed foods with high fat and sugar contents enter the Western diet resulting in neuroinflammation and decreased cognitive performance. Through intentional fueling of the human body, cognitive function can be protected and supported by having a diet rich in omega-6 and omega-3 essential fatty acids, fruits and vegetables, particularly dark leafy greens and darkly pigmented berries, and proteins including meat, eggs, and legumes. Not only is there great potential for individuals to take an active role in their own physical and cognitive health but there is also the possibility to reduce social economic burden by supporting all people, especially vulnerable populations, in access to nutrient-rich meals.

If you learned something or have tried using any sort of oral cognitive enhancement and it worked (or didn't) let me know! Reply to this email to keep me in the loop

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Heather Benek
Nutrition Director
Pittsburgh FIT

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References  
Bazinet, R. P., & Layé, S. (2014). Polyunsaturated fatty acids and their metabolites in brain function and disease. Nature reviews. Neuroscience, 15(12), 771–785. https://doi.org/10.1038/nrn3820

Holloway, C. J., Cochlin, L. E., Emmanuel, Y., Murray, A., Codreanu, I., Edwards, L. M., Szmigielski, C., Tyler, D. J., Knight, N. S., Saxby, B. K., Lambert, B., Thompson, C., Neubauer, S., & Clarke, K. (2011). A high-fat diet impairs cardiac high-energy phosphate metabolism and cognitive function in healthy human subjects. The American journal of clinical nutrition, 93(4), 748–755. ttps://doi.org/10.3945/ajcn.110.002758 

Kitson, A. P., Stroud, C. K., & Stark, K. D. (2010). Elevated production of docosahexaenoic acid in females: potential molecular mechanisms. Lipids, 45(3), 209–224. https://doi.org/10.1007/s11745-010-3391-6

Li, Y., Li, S., Wang, W., & Zhang, D. (2020). Association between Dietary Protein Intake and Cognitive Function in Adults Aged 60 Years and Older. The journal of nutrition, health & aging, 24(2), 223–229. https://doi.org/10.1007/s12603-020-1317-4 

Miller, M. G., Thangthaeng, N., Poulose, S. M., & Shukitt-Hale, B. (2017). Role of fruits, nuts, and vegetables in maintaining cognitive health. Experimental gerontology, 94, 24–28. https://doi.org/10.1016/j.exger.2016.12.014 

Puri S, Shaheen M, Grover B. (2023). Nutrition and cognitive health: A life course approach. Front Public Health. 2023 Mar 27;11:1023907. doi: 10.3389/fpubh.2023.1023907  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10083484/  

Spencer, S. J., Korosi, A., Layé, S., Shukitt-Hale, B., & Barrientos, R. M. (2017). Food for thought: how nutrition impacts cognition and emotion. NPJ science of food, 1, 7. https://doi.org/10.1038/s41538-017-0008-y

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