Updated: Mar 10, 2021
Diet can significantly affect our cognition; our ability for higher mental functions such as memory, learning and attention (1). Research has found that even in adulthood, our brains have the ability to form new neurons, called neurogenesis. It has been found that diet is a big predictor of how much neurogenesis we undergo, and this can not only affect learning and memory, but can also potentially prevent diseases such as dementia in the elderly (2).
‘Healthy’ Versus ‘Unhealthy’ diets
A study on 987 school children aged 8-10 years looked at the difference in academic performance of those who ate a ‘healthy’ diet high in fruits vegetables, milk and water, compared to those students who consumed an ‘unhealthy’ diet, high in sugar sweetened beverages, sweet snacks and salty snacks (1).
The study found that unhealthy diets were associated with lower Math and English test scores, and a 28% decreased chance of scoring in the ‘advanced’ category in English. This study was done on a large, ethnically diverse group of children, although some bias could have occurred as the children self-reported their dietary intake. These results were consistent with those of a systematic review (3), which found that better academic achievement is associated with breakfast consumption and diets high in nutritional quality.
Low Protein, ‘Fasting Diet’
A study on mice tested the effects of a low protein, high fat diet (10% protein, 56% fat, 34% carbohydrates) consisting of vegetable soups, energy bars, energy drinks, chip snacks and chamomile flower tea on cognitive performance (4). This diet aims to mimic the effects of prolonged fasting, known to improve lifespan. The results showed that after just 72 hours, adult neurogenesis increased, improving spatial memory. They also found that the mechanism by which cognitive performance increased was similar to that found to reduce memory deficits in a mouse model of Alzheimer’s disease.
Omega-3 Fatty Acids
Research shows that a diet high in oily fish and omega-3 fatty acids promotes brain health in adolescents through an increase in new neurons in the brain, improving memory and learning, and has even shown to reverse damage in the brain caused by stress (5). In the elderly, a diet low in omega-3 fatty acids is associated with cognitive decline, while a diet rich in it is associated with preventing cognitive decline, and potentially diseases such as dementia and Alzheimer’s (6).
Blueberries are enriched with flavonoids, and have been found to increase the production of neurons in the adult brain of chronically stressed rats (6). Flavonoids have also shown to increase spatial working memory in aged rats, which indicates there is potential for therapeutic use in humans.
Human studies have found that blueberry supplementation improves memory in older adults (7). A study on older adults with memory impairment found that after 12 weeks of around 500ml of blueberry juice a day, the participants had significantly better learning scores and word list recall performance. This was confirmed in 7-10 year olds who consumed 15 - 30g freeze-dried blueberry powder and had significant improvement in cognitive performance after just 6 hours (8).
Beetroot is thought to increase cerebral blood flow in the brain as it is rich in nitrates. A study on older adults around the age of 75 were split into two groups, and either given a diet of beetroot juice or a nitrate depleted diet (9). It was found that the beetroot juice group had better frontal cortex blood flow, a region in the brain which determines working memory and task-switching.
Another study found that after a single serving of 500ml beetroot juice in young adults around the age of 21 years, cerebral blood flow increased significantly (10). Although the results from this study need to be confirmed in a larger scale study and are only applicable to young healthy adults, the combined results from both these studies seem to indicate beetroot juice could be a useful addition to your diet.
Overall, it is a combination between meal texture, meal frequency and meal content that affect our brain performance (6). There are many more foods that can improve our memory, cognitive alertness, and learning capacity. Not only what we eat, but what we combine those foods with, and our eating patterns largely determine our focus and cognitive ability. Finding a balance between what you enjoy, and what benefits you could be the key to the door to a more fulfilling, and mentally stimulating life.
For a full dietary analysis and to find out how you can boost your brain performance through a personalised diet plan to fit your lifestyle and needs, book an appointment with Nutritionist, Ishika Sharma
Ishika Sharma (ANutr)
Ishika Sharma is a registered associate nutritionist from London, specialising in weight loss, gut health and healthy ageing. She graduated from King's College London in Nutrition BSc, and has had clinical dietetic training in the NHS in weight loss, malnutrition, paediatrics and gut issues such as irritable bowel syndrome. She keeps up to date with nutrition research and critically appraises scientific literature to ensure all nutrition advice is current, and evidence-based.
Ishika sees patients who wish to lose weight and want a personalised approach, with regular guidance and check ins. She also gives nutrition advice for gut issues, skin problems, optimal ageing through nutrition and fatigue issues.
1. Bleiweiss-Sande R, Chui K, Wright C, Amin S, Anzman-Frasca S, Sacheck JM. Associations between Food Group Intake, Cognition, and Academic Achievement in Elementary Schoolchildren. Nutrients [Internet]. 2019 Nov 9 [cited 2021 Mar 8];11(11). Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6893423/
2. Scarmeas N, Anastasiou CA, Yannakoulia M. Nutrition and prevention of cognitive impairment. The Lancet Neurology. 2018 Nov 1;17(11):1006–15.
3. Burrows T, Goldman S, Pursey K, Lim R. Is there an association between dietary intake and academic achievement: a systematic review. Journal of Human Nutrition and Dietetics. 2017;30(2):117–40.
4. Brandhorst S, Choi IY, Wei M, Cheng CW, Sedrakyan S, Navarrete G, et al. A periodic diet that mimics fasting promotes multi-system regeneration, enhanced cognitive performance and healthspan. Cell Metab. 2015 Jul 7;22(1):86–99.
5. Hueston CM, Cryan JF, Nolan YM. Stress and adolescent hippocampal neurogenesis: diet and exercise as cognitive modulators. Translational Psychiatry. 2017 Apr;7(4):e1081.
6. Stangl D, Thuret S. Impact of diet on adult hippocampal neurogenesis. Genes Nutr. 2009 Dec;4(4):271–82.
7. KRIKORIAN R, SHIDLER MD, NASH TA, KALT W, VINQVIST-TYMCHUK MR, SHUKITT-HALE B, et al. Blueberry Supplementation Improves Memory in Older Adults. J Agric Food Chem. 2010 Apr 14;58(7):3996–4000.
8. Whyte AR, Schafer G, Williams CM. Cognitive effects following acute wild blueberry supplementation in 7- to 10-year-old children. Eur J Nutr. 2016 Sep 1;55(6):2151–62.
9. Presley TD, Morgan AR, Bechtold E, Clodfelter W, Dove RW, Jennings JM, et al. Acute effect of a high nitrate diet on brain perfusion in older adults. Nitric Oxide. 2011 Jan 1;24(1):34–42.
10. Bond V, Curry BH, Adams RG, Asadi MS, Millis RM, Haddad GE. Effects of Dietary Nitrates on Systemic and Cerebrovascular Hemodynamics. Cardiol Res Pract [Internet]. 2013 [cited 2021 Mar 8];2013. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3886243/