The body of evidence about nuts and health continues to grow. These local and international papers, outlining new nut research, corroborate decades of research about the importance of a regular handful of nuts in a healthy diet.

Mixed tree nut snacks compared to refined carbohydrate snacks resulted in weight loss and increased satiety during both weight loss and weight maintenance: A 24-week randomized controlled trial. (2021).

This 24-week randomised controlled trial involved 95 healthy adults, aged 30-68 years, with overweight/obesity. Study participants added either 1.5 oz (around 40g) of mixed nuts, or a kilojoule-equivalent amount of pretzels, to their weight loss diet (-500kJ/day) for 12 weeks. This was followed by a weight maintenance program for another 12 weeks. Both groups lost weight: 1.6kg over 12 weeks for the nut group, and 1.9kg for the pretzel group. But at 24 weeks, only the nut group maintained this weight loss. And at 24 weeks, compared to baseline, satiety was increased significantly in the nut group, compared with the pretzel group.

A higher-protein nut-based snack product suppresses glycaemia and decreases glycaemic response to co-ingested carbohydrate in an overweight prediabetic Asian Chinese cohort: the Tū Ora postprandial RCT. (2021).

This randomised cross-over trial, involving 10 overweight prediabetic Chinese adults, assessed the postprandial glycaemic response of a higher-protein, nut-based snack bar (containing 1,009kJ), compared with a higher-carbohydrate, cereal-based bar with the same number of kilojoules. The nut bar induced a significantly lower 30–120 minutes glucose response, and a 10-fold lower incremental area under the glucose curve. The nut bar also reduced the glucose response, by around 25%, when co-ingested with white bread. The researchers conclude that a nut-based snack product may be a healthier alternative, even in high-risk, overweight, pre-diabetic adults.

Associations between nut intake, cognitive function and non‐alcoholic fatty liver disease (NAFLD) in older adults in the United States: NHANES 2011-14. (2021).

This study by Australian-based researchers found nut intake may increase cognitive performance in healthy older adults. It found cognitive scores were higher in people with a moderate intake of nuts, equivalent to 15-30g nuts daily, compared with those who didn’t eat nuts. The study involved 1,814 US-based adults aged 60 years or older, from the National Health and Nutrition Examination Surveys (NHANES) 2011-2012 and 2013-2014 cohorts. Eating more than 30g nuts/day did not lead to higher cognitive performance, compared to the moderate intake group. But higher nutrient intake and better diet quality were seen with higher nut intake.

Almond consumption decreases android fat mass percentage in adults with high android subcutaneous adiposity but does not change HbA1c in a randomized controlled trial. (2021).

This 6-month randomised controlled trial, involving 134 adults, found almond consumption reduced fat mass in adults with an ‘apple-shaped’ body. That is, participants with high android subcutaneous adiposity (or high ‘fat stores’ around the abdominal region) who consumed around 42g of almonds daily had a greater percentage loss of android fat mass, compared to a control group. Participants consuming almonds ingested 195±87 kcals/day more than those in the control group, but this did not result in any differences in body weight. At six-months, there were no differences in HbA1c between the two groups.

Investigating walnut consumption and cognitive trajectories in a representative sample of older US adults. (2021).

Daily walnut consumption was linked with cognitive function at baseline in this observational study, involving 3,632 US-based adults aged 65 years and older. But walnut consumption was not associated with protection against age-related cognitive decline over time. It was, however, linked with a higher intake of nutrients identified to have neuroprotective benefits. This was a secondary analysis of the Health and Retirement Study and Health Care and Nutrition Study.

Mediterranean diet, Alzheimer disease biomarkers and brain atrophy in old age. (2021).

This study found that higher adherence to a Mediterranean diet may help prevent the build-up of amyloid protein and tau protein, which are linked with Alzheimer’s disease. It may also result in larger grey matter volume and better memory. The researchers say their findings corroborate the view of a Mediterranean diet as a protective factor against memory decline and mediotemporal atrophy. They propose that the risk of developing Alzheimer’s may be reduced by incorporating more elements of the Mediterranean diet into daily diets. The study involved 512 older adults (mean age: 69.5±5.9 years) – some at a higher risk of developing Alzheimer’s disease, while others were classed as ‘cognitively normal’. 

Post-diagnostic reliance on plant-compared with animal-based foods and all-cause mortality in omnivorous long-term colorectal cancer survivors. (2021).

A plant-based diet was inversely associated with all-cause mortality in long-term colorectal cancer survivors, according to this German prospective cohort study. Diet was assessed with food frequency questionnaires, at a median of 6 years after diagnosis, in 1,404 colorectal cancer survivors. Overall, a plant-based diet displayed a significant, inverse association with all-cause mortality (HR per 10-point increase in diet index, 0.72; 95% CI, 0.57–0.91). More research is needed to further disentangle the impacts of different qualities of plant-based diets (healthful versus unhealthful plant-based diet) on cancer survivors’ health.

Impact of diet on CVD and diabetes mortality in Latin America and the Caribbean: A comparative risk assessment analysis. (2021).

This research quantified diet-related burdens of cardiometabolic diseases in adults, across 32 Latin American and Caribbean countries. In 2010, an estimated 513,371 cardiometabolic deaths were related to suboptimal intakes of commonly-consumed foods. The largest diet-related cardiometabolic diseases burdens were low intake of nuts/seeds, low fruit intake, and high processed meat consumption. These findings were consistent across countries. 

Plant-based diets and risk of disease mortality: A systematic review and meta-analysis of cohort studies. (2021).

This research explored the association between adherence to plant-based diets and the risk of mortality. Twelve prospective cohort studies, with 42,697 deaths among 508,861 participants were included. It found a potential protective role of PBDs against chronic disease mortality. Risk of all-cause mortality was 10% lower in the highest category of adherence to plant-based diets, compared to the lowest, and risk of coronary heart disease mortality was 23% lower.

Minimal changes in telomere length after a 12-week dietary intervention with almonds in mid-age to older, overweight, and obese Australians: Results of a randomised clinical trial. (2021).

The study investigated the link between an almond-enriched diet and telomere length in overweight or obese Australians, aged 50-80 years. Participants were randomised to either an almond-enriched diet (n=62) or iso-caloric nut-free diet (n=62) for 12 weeks. The study found that including almonds in the diet improved diet quality, but had no impact on telomere length in this group of mid- to older-age adults. The researchers say future studies should investigate the impact of more substantial dietary changes over longer periods of time.

Effects of supplementing a healthy diet with pecan nuts or extra-virgin olive oil on inflammatory profile of patients with stable coronary artery disease: A randomized clinical trial. (2021).

This randomised clinical trial involved 204 people with stable coronary artery disease. It investigated whether adding pecans or extra-virgin olive oil to a healthy diet, over 12 weeks, impacted inflammatory markers. Study participants were randomised to either a control group (healthy diet), a pecan nuts group (30g/day of pecans + healthy diet) and an olive oil group (30mL/day of extra-virgin olive oil + healthy diet). Including pecans or extra-virgin olive oil in an already-healthy diet had no significant effect on inflammatory markers.