The results associated high blood levels of omega-3 alpha-linolenic acid (ALA) from plant sources such as walnuts with a better use of brain glucose.

Walnuts are one of the main plant sources of omega-3 and the only tree nut rich in these fatty acids, which are essential for health and the body cannot produce.

This study supports the scientific evidence linking walnut consumption with cognitive health benefits

A new Spanish study published in Alzheimers and Dementia: Diagnosis, Assessment & Disease Monitoring, found an association between high blood levels of omega-3 alpha-linolenic acid (ALA) from plant sources such as walnuts and better brain glucose utilization. This suggests a brain more resistant to the development of Alzheimers disease. In India, an estimated 5.3 million people have dementia, with Alzheimers being the most common cause. According to the Dementia in India Report 2020 by the Alzheimers and Related Disorders Society of India (ARDSI), this number is projected to rise to 7.6 million by 2030. The research results are encouraging, as they suggest a simple and affordable prevention alternative, through dietary habits.

California Walnuts

Researchers analyzed omega-3 blood levels in 320 participants in the Alzheimer’s and Families+(ALFA) cohort in Spain, who were at high genetic risk for AD, but did not have cognitive impairment. Volunteers were injected with tagged glucose to check how it was metabolized in different brain areas and parallel, erythrocyte fatty acids were quantified, reflecting the consumption of fatty acid-rich foods during the last weeks.

Results showed that those with higher blood levels of omega-3 alpha-linolenic acid (ALA), which comes from plant-based sources such as walnuts, showed a better use of brain glucose in critical areas of the brain, which are first affected when the disease begins to manifest. This was observed in the entire study population, but especially in participants with a higher genetic risk of Alzheimer’s.

Conversely, omega-3 docosahexaenoic (DHA), coming from marine sources, was more beneficial in those who, despite not presenting symptoms of Alzheimer’s, were already beginning to have the accumulation of proteins (amyloid and tau) that are characteristic of the disease.

Dr. Aleix Sala-Vila, lead investigator of the study and member of the Hospital del Mar Medical Research Institute (IMIM), “Reinforces the idea that foods rich in omega-3, such as walnuts, could be useful in making the brain more resistant to the changes that precede the appearance of the disease.”

In conditions like AD, signs and symptoms may not show until much later in life. So, adopting simple, nourishing habits early in life and doing them often, like incorporating foods rich in omega-3s (such as walnuts and fatty fish) could be a promising action that may benefit cognitive function and neurodegenerative conditions (2).

Ms. Naaznin Husein, renowned Nutritionist, and Founder of Freedom Wellness Management, emphasizes the importance of omega-3-rich walnuts in supporting brain health: “Incorporating walnuts into the diet may be an easy and delicious way to help support brain health throughout the lifespan, as a growing body of research has examined how walnuts could support cognition and prevent risk factors for neurodegenerative diseases such as Alzheimers, as well as cardiovascular diseases such as diabetes or high blood pressure, and reduce the risk of cancer. In addition to their health benefits, walnuts are a versatile food with many possibilities when it comes to introducing them into the daily diet“.

Additional research is needed to extrapolate these results to other populations and understand the effect of walnuts alone on dietary ALA levels and brain glucose metabolism.

Walnuts and Brain Health

California Walnuts and Cognitive Health

Walnuts are the only nut with a significant amount of alpha-linolenic acid (ALA)., the plant-based omega-3 fatty acids (2.8 grams of ALA per serving) that the body needs but cannot produce. These fatty acids are mentioned in the new study for their ability to reduce the risk of degenerative diseases and dementia.

Another recent Spanish study led by the Institut dInvestigaci Sanitria Pere Virgili (IISPV) and published in the journal eClinicalMedicine(3), also revealed that walnuts and their omega-3 content could have a positive impact on the cognitive development and psychological maturation of adolescents, playing a key role in brain development, especially in the human development stage.

Walnuts also contain bioactive compounds, such as polyphenols, which contribute to maintaining health and preventing disease(4) and have been the subject of scientific research concerning brain function.

Additionally, as corroborated by multiple scientific studies published during the last decade, walnuts contribute to preventing risk factors for cardiovascular diseases, such as diabetes or high blood pressure, as well as to reduce the risk of cancer and neurodegenerative diseases such as Alzheimers disease.

Bibliographic Reference:

New study: Falcn, Carles; Gispert, Juan-Domingo; Sala-Vila, Aleix, et al. Omega-3 blood biomarkers relate to brain glucose uptake in individuals at risk of Alzheimer’s disease dementia. Alzheimers Dement (Amst). 2024 Jul-Sep. doi: 10.1002/dad2.12596

Other references:

(1) Alzheimer’s Association. Alzheimer’s Disease Facts and Figures (2017)

Arab L, Ang A. A cross sectional study of the association between walnut consumption and cognitive function among adult US populations represented in NHANES. J Nutr Health Aging. 2015;19(3):284-290.

Barbaresko J, Lellmann AW, Schmidt A, et al. Dietary factors and neurodegenerative disorders: An umbrella review of meta-analyses of prospective studies. Adv Nutr. 2020;11(5):1161-1173.

(2) Chauhan A, Chauhan V. Beneficial effects of walnuts on cognition and brain health. Nutrients. 2020;12(2):550.

(4) Ciudad, Carlos J., Izquierdo-Pulido, Mara; No Vronique; Snchez-Gonzlez, Claudia. Health benefits of walnut polyphenols: An exploration beyond their lipid profile. Crit Rev Food Sci Nutr. 2017 Nov 2;57(16):3373-3383. doi: 10.1080/10408398.2015.1126218.

(3) Fernndez-Barrs, Silvia; Pinar-Mart, Ariadna; Sala-Vila, Aleix; et al. Effect of walnut consumption on neuropsychological development in healthy adolescents: a multi-school randomised controlled trial. April 2023, https://doi.org/10.1016/j.eclinm.2023.101954

Gutierrez L, et al. Effects of nutrition on cognitive function in adults with or without cognitive impairment: A systematic review of randomized controlled clinical trials. Nutrients. 2021;13:3728.

Organizacin Mundial de la Salud (OMS). Global action plan on the public health response to dementia 2017 – 2025

Pribis P, Shukitt-Hale B. Cognition: the new frontier for nuts and berries. Am J Clin Nutr. 2014;100 Suppl 1:347S-52S.

Sala-Vila A, et al. Effect of a 2-year diet intervention with walnuts on cognitive decline. The Walnuts And Healthy Aging (WAHA) study: A randomized controlled trial. Am. J. Clin. Nutr. 2020;111:590-600.

Theodore LE, Kellow NJ, McNeil EA, Close EO, Coad EG, Cardoso BR. Nut consumption for cognitive performance: A Systematic review. Adv Nutr. 2021;12(3):777-792.

Valls-Pedret C, Sala-Vila A, Serra-Mir M, et al. Mediterranean diet and age-related cognitive decline: A randomized clinical trial [published correction appears in JAMA Intern Med. 2018 Dec 1;178(12):1731-1732]. JAMA Intern Med. 2015;175(7):1094-1103.