Nuts consumption protects cognitive functions in over-55s. Study

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Dried fruit consumption

Frequent consumption of nuts improves cognitive functions and slows down their deterioration in over-55s. Yet another confirmation of the beneficial properties of nuts comes from a Spanish study (Ni et al., 2023) published in The American Journal of Clinical Nutrition. (1)

1) Cognitive functions at risk

Researchers evaluated the relationship between the consumption of nuts and cognitive functions on 6.630 individuals aged between 55 and 75 years (average age 65 years, 48,4% women), overweight or obese, with at least three conditions attributable to the syndrome metabolic. A set of risk factors that increases the possibility of developing cerebrovascular and cardiovascular diseases and diabetes.

The metabolic syndrome is in fact diagnosed in the presence of at least three risk factors including:

– abdominal obesity (abdominal circumference over 94 cm in men and 80 cm in women),

– obesity, i.e. Body Mass Index greater than 30. A person’s BMI is calculated by dividing weight (in kg) by height squared (m2), (2)

– low levels of HDL cholesterol (‘good cholesterol’), less than 40 mg/dl in men and 50 mg/dl in women,

– triglyceride values ​​above 250 mg/dl,

– high blood pressure. It is considered as such when the maximum pressure (systolic) is always over 140 mmHg and/or the minimum pressure (diastolic) is greater than 90 mmHg,

– high blood sugar levels (above 100 mg/dl fasting).

2) The study

Participants to the study were framed in light of the two aspects under investigation:

– the habitual consumption of nuts, such as walnuts, almonds, hazelnuts, pistachios, peanuts and macadamias,

– the cognitive conditions, examined by administering 8 neuropsychological tests, at the start of the study and at its conclusion two years later.

3) The results

The results of the research showed in people who consumed nuts frequently – at least three portions of 30 g each each week – clear improvements in cognitive function and a slowing of cognitive deterioration.

The biggest benefits emerged in participants with pre-existing depressive symptoms at the start of the research.

Frequent intake of nuts may help delay cognitive decline in older adults with overweight/obesity, metabolic syndrome, and at risk for cognitive decline, even in a relatively short period of 2 years‘, the researchers conclude.

4) The properties of nuts

The neurological and cardiometabolic neurological and cardiometabolic effects of nuts can be explained by their nutrient-rich profile and high content of bioactive compounds‘, the researchers conclude.

Walnuts, almonds and hazelnuts – so long as natural, without salt, sugar icing and/or fats – are healthy ingredients, because:

– they are rich in micronutrients (i.e. vitamin E, folic acid, selenium) and bioactive compounds (e.g. carotenoids, phenolic compounds) with antioxidant and anti-inflammatory properties,

– contain many unsaturated fatty acids (in particular linoleic and α-linolenic acid) with vasculo-protective and anti-inflammatory actions, as well as playing an indispensable role in maintaining neuronal structure and function,

– provide high quality plant proteins and amino acids, such as L-arginine, which have neuroprotective effects,

– are characterized by an optimal mineral composition. Rich in calcium, magnesium and potassium but free of sodium, they have beneficial effects on blood pressure and insulin sensitivity.

5) Microbiota-friendly nuts

Additional feature beneficial of nuts is the high content of dietary fibre.

These, together with unsaturated fats and polyphenols, can modulate the intestinal microbiota and, consequently, support cognitive function through the gut-brain axis. (3)

Marta Strinati

Footnotes

(1) Ni J, Nishi SK, Babio N, Ros E, Basterra-Gortari FJ, Corella D, O C, Martínez JA, Alonso-Gómez ÁM, Wärnberg J, Vioque J, Romaguera D, López-Miranda J, Estruch R, Tinahones FJ, Santos-Lozano JM, Serra-Majem L, Cano-Ibáñez N, Tur JA, Fernández-García JM, Pintó Aranda F, Ruiz-Canela M, Mestres Solà C, Portolés O, Sala-Vila A, Garcia-Rios A, Compañ-Gabucio LM, Gómez-Gracia E, Zulet MA, Chaplin A, Casas R, Martínez-Diz S, Tojal -Sierra L, Gómez-Pérez AM, Toledo E, Rios S, Ortega-Azorín C, de la Torre R, Peña-Orihuela PJ, Garcia-de la Hera M, Sayón-Orea C, Malcampo M, Salas-Salvadó J; PREDIMED-Plus investigations. Higher versus lower nut consumption and changes in cognitive performance over two years in a population at risk of cognitive decline: a cohort study. Am J Clin Nutr. 2023 Aug;118(2):360-368. https://doi.org/10.1016/j.ajcnut.2023.05.032

(2) Marta Strinati. Prevent and treat obesity and overweight for cardiovascular health. GIFT (Great Italian Food Trade).

(3) Paola Palestini, Dario Dongo. Microbiome and intestine, the second brain. GIFT (Great Italian Food Trade).

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Professional journalist since January 1995, he has worked for newspapers (Il Messaggero, Paese Sera, La Stampa) and periodicals (NumeroUno, Il Salvagente). She is the author of journalistic surveys on food, she has published the book "Reading labels to know what we eat".