The body of evidence about nuts and health continues to grow. These local and international research papers, published around June 2023, corroborate decades of research about the importance of a regular handful of nuts within a healthy diet.

Higher versus lower nut consumption and changes in cognitive performance over two years in a population at risk of cognitive decline: A cohort study. (Ni et al, 2023).
This prospective cohort study, involving 6,630 participants aged 55-75 years with overweight/obesity and metabolic syndrome (placing them at risk of cognitive decline), found frequent nut consumption was linked with smaller decline in general cognitive performance over a 2-year period. It suggests a potential dose-response relationship between nut consumption and a delay in cognitive decline. Randomised clinical trials are needed in this area to verify the findings.

Longer-term mixed nut consumption improves brain vascular function and memory: A randomized, controlled crossover trial in older adults. (Nijssen et al, 2023).
This randomised, single-blinded, cross-over trial consisted of 28 healthy participants, with a mean age of 65 years +/- 3 years. The intervention (60g/day of mixed nuts) and control periods (no nuts) were both across 16 weeks, and separated by an 8-week washout period. After nut consumption, cerebral blood flow, a marker of brain vascular function, was higher in certain regions of the brain. Nut consumption also improved endothelial function, and benefitted arterial stiffness and retinal microvasculature. Some aspects of cognitive performance (visuospatial memory, and verbal memory) also improved.

Nut consumption and depression: Cross-sectional and longitudinal analyses in two cohorts of older adults. (Fernández-Rodríguez et al, 2023).
This observational research, investigating two cohorts of older Spanish adults (≥65 years), found nut consumption to be linked with a lower risk of depression. In the meta-analysis of cross-sectional results from the two studies, compared to consuming <1 serving (30g) of nuts/week, the odds ratio for depression was 0.90 (0.64, 1.16) for consuming 1 to <3 servings/week and 0.92 (0.70, 1.13) for consuming ≥3 servings/week. The corresponding figures for the longitudinal results were 0.90 (0.41, 1.38) and 0.66 (0.35, 0.97).

Effect of nut consumption on non-alcoholic fatty liver disease: A systematic review and meta-analysis. (Pan et al, 2023).
This first-of-its-kind meta-analysis, of observational studies, found nut consumption may help protect against non-alcoholic fatty liver disease (NAFLD) – the main cause of chronic liver disease. A total of 11 articles were included. Results showed that the odds ratio (OR) of NAFLD was 0.90 (95% CI: 0.81–0.99, p < 0.001) when comparing the highest and lowest total nut intake, indicating a significant negative correlation. Subgroup analysis revealed that the protective effect of nuts on NAFLD was more significant in females.

Mediterranean diet lowers all-cause and cardiovascular mortality for patients with metabolic syndrome. (Fan et al, 2023).
This prospective cohort study, using data from NHANES database, found that, in people with metabolic syndrome, adhering to a healthy Mediterranean-style diet (MED diet) was significantly associated with lower all-cause and cardiovascular mortality. It also found a MED diet may even offset the adverse effects of sedentary behavior and depression. Among the findings, greater intakes of vegetables, legumes, nuts and high MUFA/SFA ratio were all linked with lower all-cause mortality.

Olive oil and nuts in rheumatoid arthritis disease activity. (Cavelli et al, 2023).
In this cross-sectional study, involving 365 Italian adults (median age of around 58 years), with rheumatoid arthritis, higher consumption of olive oil and nuts generally led to an improvement of disease activity. But in most cases, this was not statistically significant. However, the beneficial effect of olive oil and nuts (representing vegetable sources of fatty acids) was stronger in the more severe or long-standing forms of rheumatoid arthritis.

Analysis of dietary patterns on cardiovascular risks in children: From a cross-sectional and a longitudinal study. (Ren et al, 2023).
This research, which tracked 4,351 children, aged 6-12 years old, explored the link between dietary patterns (DPs) and cardiovascular disease risk in children. Four major DPs were identified: (1) low intake of nuts and algae pattern, (2) low-energy intake pattern, (3) high-energy intake pattern, and (4) regular DP. Compared with the regular DP, the low intake of nuts and algae pattern was associated with an increased risk of hypertension, dyslipidemia, and obesity.

Folate retention in nuts and seeds – Effects of household cooking. (Loznjak et al, 2023).
This research evaluated the stability of the water-soluble vitamin, folate, or vitamin B9, in three types of nuts (almonds, hazelnuts and peanuts) and seeds (pumpkin, sesame, and sunflower seeds), during exposure to light and household cooking. It found that light (daylight or UVB light) had no significant effect on folate stability. And on average, total folate retention was 81% (±7%) after household cooking (boiling at 100°C, for 5-60 minutes, and/or roasting at 175°C for 2-15 minutes).

Acute effect of a beverage containing Brazil and cashew nuts on oxidative stress, lipemia, and blood pressure of women with cardiometabolic risk (Brazilian Nuts Study): A randomized clinical trial. (Bonifacio et al, 2023).
This randomised controlled trial, involving women, aged 20-55 years, with cardiometabolic risk, investigated the acute effect of a beverage containing cashew and Brazil nuts. The women received either a beverage containing nuts (30g Brazil nuts + 15g cashews) or one without nuts. Postprandially, there was a greater reduction in malondialdehyde levels (a lipid peroxidation marker) in the intervention group, compared to the control group. The remaining oxidative stress markers showed similar changes between groups.

Hazelnut-enriched diet effectively increases lipoproteins’ resistance to oxidation in hypercholesterolemic subjects. (Akcan et al, 2023).
This clinical trial involved 15 participants with elevated cholesterol (but not receiving drug treatment). Compared to control, it found that a hazelnut-enriched diet (making up 18-20% of total daily energy intake, or 49-86g hazelnuts/day), over 30 days, had a protective effect against lipoprotein (mostly LDL) oxidation. The researchers concluded that hazelnut consumption could lead to changes in the structure of HDL and LDL cholesterol, increasing the resistance of lipoproteins to oxidation, which may play an important role in protecting against atherosclerosis.