The body of evidence about nuts and health continues to grow. These local and international research papers, published around September 2024, corroborate decades of research about the importance of a regular handful of nuts within a healthy diet.

The effect of consuming nuts on cognitive function: A systematic review and meta-analysis of randomized clinical trials. (Moabedi et al, 2024).
This meta-analysis, of five randomised clinical trials (RCTs), involving 928 adults in total, studied the effect of nuts on cognition scores. The systematic review revealed that, of the five studies, two showed a significant beneficial effect of nuts on cognition status. The meta-analysis found an elevation in cognitive function scores with the consumption of nuts, compared with control. However, this result was not statistically significant. Future high-quality RCTs, with larger sample sizes, are needed to shed light on the impact of nuts on cognition.

Relevance of Mediterranean diet as a nutritional strategy in diminishing COVID-19 risk: A systematic review. (Halim et al, 2024).
This systematic review explored the relationship between the Mediterranean diet and COVID-19. It included six observational studies, with a total of 55,489 participants. A higher intake of olive oil, reduced consumption of red meat and cereals, moderate alcohol intake, and an increased intake of nuts and fruits were associated with a lower risk of COVID-19. And greater consumption of fruits, vegetables, nuts, legumes, fish, and whole grains was linked to reduced severity of the disease. The study suggests that higher adherence to the Mediterranean diet may offer protection against developing COVID-19.

The correlation between nuts consumption and severity and symptoms of COVID-19. (Almasi et al, 2024).
This cross-sectional study involved 684 adults who had recently recovered from COVID-19. It assessed participant’s dietary intake, using a food frequency questionnaire, along with other measures, including severity of COVID-19 and serum levels of C-reactive protein (CRP). It found that higher intake of nuts was correlated with a lower likelihood of severe COVID-19 infection, hospitalisation, and duration of illness, along with improvements in COVID-19 symptoms, such as fever, headache, and weakness.

Planetary health diet and cardiovascular disease: Results from three large prospective cohort studies in the USA. (Sawicki et al, 2024).
This study used data from three large cohorts of men and women in the US, who were free of cardiovascular disease at baseline. It found that eating more in line with the Planetary Health Diet (PHD), as measured by a higher PHD index score, was associated with a lower risk of cardiovascular disease. Similarly, a higher score was associated with a lower risk of coronary heart disease, overall stroke, and ischaemic stroke. The findings support the PHD as a promising strategy to promote both human and planetary health.

Association between planetary health diet and cardiovascular disease: A prospective study from the UK Biobank. (Sotos-Prieto et al, 2024).
This large prospective cohort study involved 118,469 middle-aged and older British adults (aged 40–69 years), who were free of cardiovascular disease (CVD) at the start of the study. They were tracked over a median of 9.4 years. It found higher adherence to the Planetary Health Diet (PHD) was linked with a lower risk of CVD. Specifically, the highest PHD index score (that is, the best adherence to the diet) was associated with a 14% lower risk of CVD, a 12% lower risk of myocardial infarction, and a 18% lower risk of stroke, compared with the lowest quintile of adherence.

Associations of the planetary health diet index (PHDI) with asthma: The mediating role of body mass index. (Huang et al, 2024).
This study analysed data from 32,388 participants in the National Health and Nutrition Examination Survey (NHANES), spanning from 2005 to 2018. Amongst the findings, there was a significant negative association between the Planetary Health Diet Index (PHDI) and asthma, and after adjusting for covariates, for every 10-point increase in the PHDI, there was a 4% decrease in the prevalence of asthma. In addition, BMI was significantly positively associated with asthma, and BMI decreased as the PHDI increased.  BMI mediated the relationship between the PHDI and the prevalence of asthma.

Association between substituting macronutrients and all-cause mortality: A network meta-analysis of prospective observational studies. (Wallerer et al, 2024).
This network meta-analysis, of 39 studies, examined the association of isocaloric substitution of dietary (macro)nutrients with all-cause mortality. It found beneficial associations with increasing PUFA (both n-3 and n-6) and (plant-) MUFA intake while reducing carbohydrates, SFA and TFA, along with replacing animal protein and animal-MUFA with plant-based sources of protein and fat (MUFA) on the all-cause mortality risk. This highlights the value of plant-based dietary recommendations.

Regulation of intestinal inflammation by walnut-derived bioactive compounds. (Dei et al, 2024).
This review sums up the evidence to date on the potential of walnuts to help manage inflammatory bowel disease (IBD). It outlines the bioactive compounds in walnuts, such as polyunsaturated fatty acids and tocopherols, with anti-inflammatory properties, and how these could benefit intestinal inflammation. This includes regulating inflammatory pathways and modulating the gut microbiota. The researchers point out that the current research in this area is largely from in vivo or animal studies, with limited clinical studies.