Why Nutrition Is Critical to Cognition

As life expectancy lengthens around the world, the incidence of dementia and cognitive decline is also increasing. The number of people affected by dementia is growing exponentially, with an estimated 46.8 million people diagnosed worldwide.¹ By 2030, that number is predicted to grow to 74.7 million. Nutrition-based interventions are making a big difference for patients with cognitive decline, including Alzheimer’s disease (AD).^2,3

Multi-pronged lifestyle interventions offer the greatest hope for prevention and delay of cognitive decline.⁴ To this end, researchers are evaluating the neuroprotective effects of plants and their impacts on disease-related neural dysfunctions.² Plants contain flavonoids with antioxidant and anti-inflammatory properties that affect both phosphatidylinositol 3-kinase (P13K)/AKT and mitogen-activated protein kinase (MAPK). Most notably, they modulate signaling pathways. Flavonoids may be important for both neural rehabilitation and recovery of cognitive performance.² For patients at risk of or diagnosed with Alzheimer’s disease, a high-flavonoid diet may be especially beneficial.

Before considering specific lab tests, it may be more useful to evaluate patients’ everyday diet. Overall nutrition may be more important than single nutrient measurements. For instance, one population-based sample with longitudinal follow-up offers evidence that a nutrient-dense diet is an important factor in retaining cognitive health after AD diagnosis.⁵ The study found that patients with dementia often have declining nutrition scores over time. It may be no surprise that cognitive decline patients struggle to maintain a nutritious diet. Lower nutrition scores predicted a faster rate of cognitive decline. Higher nutrition scores had the opposite effect. This suggests that nutrition status could be a key predictor for dementia progression, as well as key for prevention.⁵

In addition to affecting cognitive scores, nutrition affects underlying brain structures. As one example, polyphenols in foods have anti-inflammatory effects on microglia.⁶ Poor nutrition, such as consuming a Western diet, is correlated with reduced hippocampal volume.⁷ As research continues to develop, the underlying mechanisms and protective effects of nutrition will continue to influence clinical care.⁸

REFERENCES

1. Prince M, Wimo A, Guerchet M, et al. World Alzheimer Report 2015—The Global Impact of Dementia. London: Alzheimer’s Disease International; 2015. https://www.alz.co.uk/research/world-report-2015.
2. Bakhtiari M, Panahi Y, Ameli J, Darvishi B. Protective effects of flavonoids against Alzheimer’s disease-related neural dysfunctions. Biomed Pharmacother. 2017;93:218-29. doi: 10.1016/j.biopha.2017.06.010.
3. Morris MC. Nutrition and risk of dementia: overview and methodological issues. Ann N Y Acad Sci. 2016;1367(1):31-37. doi: 10.1111/nyas.13047.
4. Livingston G, Sommerlad A, Orgeta V, et al. Dementia prevention, intervention, and care. Lancet. 2017 July 19. doi: 10.1016/S0140-6736(17)31363-6.
5. Sanders C, Behrens S, Schwartz S, et al. Nutritional status is associated with faster cognitive decline and worse functional impairment in the progression of dementia: the Cache County Dementia Progression Study. J Alzheimers Dis. 2016;52(1):33-42. doi: 10.3233/JAD-150528.
6. Peña-Altamira E, Petralla S, Massenzio F, Virgili M, Bolognesi ML, Monti B. Nutritional and pharmacological strategies to regulate microglial polarization in cognitive aging and Alzheimer’s disease. Front Aging Neurosci. 2017;9:175. doi: 10.3389/fnagi.2017.00175.
7. Jacka FN, Cherbuin N, Anstey KJ, Sachdev P, Butterworth P. Western diet is associated with a smaller hippocampus: a longitudinal investigation. BMC Med. 2015;13:215. doi: 10.1186/s12916-015-0461-x.
8. Dauncey MJ. Nutrition, the brain and cognitive decline: insights from epigenetics. Eur J Clin Nutr. 2014;68(11):1179-85. doi: 10.1038/ejcn.2014.173.