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

Tree nut and peanut consumption and risk of cardiovascular disease: A systematic review and meta-analysis of randomised controlled trials. (Houston et al, 2023).
A total of 153 articles, describing 139 randomised controlled trials, were included in this systematic review, with 129 studies in the meta-analysis. It found a significant decrease in total cholesterol, LDL cholesterol, triglycerides, total cholesterol: HDL cholesterol, LDL cholesterol: HDL cholesterol, and Apolipoprotein B, following nut consumption. The researchers say this review provides evidence into a combined effect of tree nuts and peanuts on a range of cardiovascular risk biomarkers. And this, in turn, creates an overall cardiovascular disease risk reduction.

Effects of mixed nut consumption on LDL cholesterol, lipoprotein(a), and other cardiometabolic risk factors in overweight and obese adults. (Nora et al, 2023).
This 16-week randomised control trial investigated the effects of consuming 42.5g/day of mixed nuts (cashews, almonds, macadamia nuts, Brazil nuts, pecans, pistachios, walnuts, and peanuts) on LDL-cholesterol, lipoprotein (a), and inflammatory markers, compared to a control. Mixed nut consumption significantly lowered body fat percentage (without significantly changing body weight or BMI) and diastolic blood pressure, and increased adiponectin, but did not significantly affect LDL-cholesterol or lipoprotein (a).

Nut and seed consumption is inversely associated with metabolic syndrome in females but not males: Findings from the 2005–2018 NHANES data. (Wong et al, 2023).
This cross-sectional analysis used data from 22,687 adults involved in the National Health and Nutrition Examination Survey (NHANES). Compared to non-consumers, female (but not male), habitual consumers of either nuts or seeds had lower odds of having metabolic syndrome (OR: 0.83, 95% CI 0.71, 0.97). Combined consumption of nuts and seeds up to 15g/day, but not in higher intake levels, was inversely associated with metabolic syndrome, high fasting glucose, central obesity, and low HDL-cholesterol in females. Nut consumption seemed to be the main driver of these relationships.

Macadamia nut effects on cardiometabolic risk factors: A randomised trial. (Jones et al, 2023).
The randomised cross-over trial involved 35 people aged 40-75 years-old, who had abdominal obesity plus one extra cardiometabolic risk factor. Compared to control, consumption of macadamias (making up ~15% of daily kilojoules, or between 35-59g/day) over 8 weeks led to reductions in total cholesterol, LDL-cholesterol and apolipoprotein B. Macadamia intake did not impact waist circumference, body weight or percentage of body fat, or glycaemic parameters. Macadamia consumption increased total fat and mono-unsaturated fatty acid intake.

Comparing the effects of consuming almonds or biscuits on body weight in habitual snackers: A one-year randomized controlled trial. (Brown et al, 2023).
This randomised controlled trial found snacking on almonds can improve diet quality, without changing body weight. The researchers randomly assigned 136 non-obese habitual discretionary snackers to receive either (isocaloric) almonds or biscuits daily for 12 months. There were no significant differences in body weight or body composition (from baseline to 12 months), in either group. But intake of many nutrients, including protein, fibre, vitamin E and zinc, significantly increased from baseline in the almond group, compared with the biscuit group.

A pecan-enriched diet reduced postprandial appetite intensity and enhanced peptide YY secretion: A randomized control trial. (Cogan et al, 2023).
This 4-week randomised controlled trial looked at the impact of a pecan-enriched diet (68g pecans/day) on appetite in older adults (50-75 years). It found enhanced satiety hormone secretion and dampened appetite intensity with the pecan-enriched diet. Specifically, there was an increase in fasting and postprandial peptide YY for the pecan group, compared with control (but cholecystokinin and ghrelin did not differ). Body weight and body fat remained stable over the 4-week study period, in both groups, suggesting pecans may be beneficial to appetite control and weight maintenance.

Effect of walnut consumption on neuropsychological development in healthy adolescents: A multi-school randomised controlled trial. (Pinar-Marti et al, 2023).
In this randomised controlled trial, 771 healthy teenagers (aged 11–16 years) were randomised into two groups (intervention and control). The intervention group received 30g/day of raw walnuts – to be incorporated into their diet for 6 months. Being prescribed to eat walnuts for 6 months did not improve the neuropsychological function of healthy adolescents. However, participants who adhered to the intervention the most had improved sustained attention, fluid intelligence, and ADHD symptoms.

Antioxidant and anti-inflammatory properties of walnut constituents: Focus on personalized cancer prevention and the microbiome. (Fan et al, 2023).
This review, of 33 studies, summarises the current evidence for the effect of walnut bioactives on health, and particularly colorectal health. It outlines the growing body of evidence that walnuts may contribute in a positive way to the gut microbiome, and outlines their potential anti-cancer and antioxidant properties. The researchers suggest that incorporating walnuts into the diet may offer a simple, cost-effective strategy towards wide-ranging health benefits.

MIND diet and cognitive function and its decline: A prospective study and meta-analysis of prospective cohort studies. (Huang et al, 2023).
This research found higher adherence to the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) was associated with better cognitive function and potentially slower cognitive decline among middle-aged and older adults. Participants with higher MIND diet scores had a significantly better global cognitive function. And consumption of nuts, fish, red meats, and tea showed independent positive associations with cognitive function, and fried food consumption exhibited negative associations.