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

The metabolizable energy and lipid bioaccessibility of tree nuts and peanuts: A systematic review with narrative synthesis of human and in vitro studies. (Nikodijevic, 2023)
This systematic review, of 21 in vitro and human studies, found the metabolisable energy of nuts (almonds, cashews, hazelnuts, pistachios, walnuts, and peanuts) was consistently lower than that predicted by Atwater factors. Metabolisable energy was influenced by nut type, physical form, heat processing, and dose of consumption. The lower-than-expected metabolisable energy may explain a lack of association between nut intake and body weight, and may have implications for future food composition databases, food labelling and dietary guidelines.

The effect of nuts consumption on circulating oxidized low-density lipoproteins: A systematic review and meta-analysis of randomized controlled trials. (Abbasifard, 2023)
This first-of-its-kind systematic review and meta-analysis, of 15 randomised controlled trials (RCTs) involving 997 people, found nut consumption significantly reduced serum levels of oxidized low-density lipoproteins (ox-LDL). The RCTs included almonds, walnuts, Brazil nuts, pistachios, hazelnuts, pine nuts, and mixed nuts. Subgroup analyses showed pistachios had a particularly strong effect on decreasing ox-LDL. The researchers suggest the reduction in ox-LDL with nut consumption might assist in the prevention and/or progression of cardiovascular disease.

Groundnut and tree nuts: A comprehensive review on their lipid components, phytochemicals, and nutraceutical properties. (Maestri, 2023)
This systematic review analyses the general chemical profile of peanuts and certain tree nuts (almond, walnut, cashew, hazelnut, pistachio, macadamia, pecan), particularly focusing on the bioactive properties of their lipid components and phytochemicals. It also reviews the scientific literature linking consumption of nuts, and/or some of their components, with ameliorative and/or preventive effects on certain diseases, including cancer, and cardiovascular, metabolic, and neurodegenerative diseases.

Composition of nuts and their potential health benefits – An overview. (Goncalves, 2023)
This overview summarises the health benefits of nuts – and particularly the link between nut consumption and reduced risk of certain chronic diseases. It describes nut nutrients with recognised health benefits, including dietary fibre, protein, fatty acids, vitamins and minerals, and bioactive compounds. It also touches on the impact of nut processing on nutrients and phytochemicals, and consumer perceptions of nuts.  

Nuts, energy balance and body weight. (Baer, 2023)
Evidence from randomised controlled trials and observational cohorts consistently shows that higher nut consumption does not cause greater weight gain. Instead, nuts may be beneficial for weight control and prevention of long-term weight gain. This review runs through the findings from research on nut intake and body weight or body mass index. It also outlines the mechanisms that likely contribute to these findings, including aspects of nut composition which affect nutrient and energy availability, as well as satiety signaling.

Effect of nuts on markers of inflammation and oxidative stress: A narrative review. (Rajaram, 2023)
This narrative review summarises the available evidence on how nut intake impacts biomarkers of inflammation and oxidative stress. The researchers say that, overall, it appears some nuts, such as almonds and walnuts, may favourably modify inflammation, and others, such as Brazil nuts, may favourably influence oxidative stress. They say more large-scale randomised controlled trials, which consider different nut types, as well as nut dose and duration, are needed to further explore the antioxidant/anti-inflammatory potential of nuts.

Dried fruits, nuts, and cancer risk and survival: A review of the evidence and future research directions. (Bolling, 2023)
This narrative review summarizes the evidence for dried fruits and nuts and cancer incidence, mortality, and survival and their potential anticancer properties. Among the findings, prospective cohort studies suggest a higher consumption of nuts is linked with a reduced risk of several site-specific cancers (including colon, lung, and pancreas). And a daily handful (28g) of nuts has been associated with a 21% reduction in the rate of cancer mortality. There is also some evidence that frequent nut consumption is linked with improved survival among people with some types of cancer.

Effect of walnut supplementation on dietary polyphenol intake and urinary polyphenol excretion in the walnuts and healthy aging study. (Amen, 2023)
In this prospective, randomized intervention trial, over two years, dietary polyphenol intake of elderly participants (aged 63-79 years) who added daily walnuts to their diets (at 15% of daily energy, or 30-60g/day) were compared to those in a control group, that did not consume walnuts. Those in the walnut group had a higher intake of total polyphenols, flavonoids, flavanols, and phenolic acids. Walnuts made a significant contribution to the total polyphenols in the diet, suggesting that a single food added to a habitual diet can increase polyphenol intake, in a Western population.

Urinary phenolic metabolites associated with peanut consumption may have a beneficial impact on vascular health biomarkers. (Parilli-Moser, 2023)
This study investigated the association of urinary phenolic metabolites with vascular biomarkers, after peanut product consumption. A three-arm, parallel-group randomized controlled trial was conducted in 63 healthy young adults who consumed 25g/day of skin roasted peanuts, 32g/day of peanut butter, or 32g/day of a control butter, over six months. It found that certain urinary phenolic metabolites, especially hydroxycinnamic acids, increased after regular peanut and peanut butter consumption, and this could have a positive impact on vascular biomarkers.

Differences in all-cause mortality risk associated with animal and plant dietary protein sources consumption. (Haghighatdoost, 2023)
This prospective cohort study examined the associations of dietary protein sources with all-cause mortality risk. A total of 5,431 participants, aged ≥ 35 years, were followed for a median of 11.3 years. It found higher intakes of plant proteins and animal proteins were associated with a decreased and increased risk of mortality, respectively. Among specific major protein sources, higher intakes of nuts and fish were associated with a 27% and 21% lower risk of all-cause mortality, respectively.

Primary prevention of cardiovascular disease in women with a Mediterranean diet: Systematic review and meta-analysis. (Pant, 2023)
This systematic review and meta-analysis focused on the association between a Mediterranean diet and incident cardiovascular disease (CVD) and death, specific to women. Sixteen prospective cohort studies were included in the meta-analysis, with a total of 722,495 female participants. It found that a Mediterranean diet was beneficial in women, with a 24% lower risk of CVD, 25% lower risk of coronary heart disease, and a 23% lower risk of total mortality. Stroke incidence was lower in women with higher Mediterranean diet adherence, but this result was not statistically significant.

Determination of the level of evidence for the association between different food groups/items and dietary fiber intake and the risk of cardiovascular diseases and hypertension: An umbrella review. (Jabbari, 2023)
This review considered the evidence, from 58 articles, for the association between the consumption of different food groups/items and dietary fibre and the incidence risk of cardiovascular disease (CVD), hypertension, and atrial fibrillation from meta-analyses and pooled analyses of observational studies. Among the findings was a suggestive inverse association between higher consumption of fruits, whole grains, fish, legumes, nuts, and dietary fibers with the incidence risk of hypertension and different types of CVD.

Changes in quantity plant-based protein intake on type 2 diabetes remission in coronary heart disease patients: from the CORDIOPREV study. (Gutierrez-Mariscal, 2023)
In this study, people with newly-diagnosed type 2 diabetes, without glucose-lowering treatment, were randomised to consume a Mediterranean or a low-fat diet. Type 2 diabetes remission was assessed with a median follow-up of 60 months. Among the findings, those who increased plant protein intake were more likely to remit from diabetes, than those who decreased its intake. The researchers say their results support the need to increase plant protein intake as dietary therapy to reverse type 2 diabetes in the context of healthy diets without weight loss.

A healthful plant-based eating pattern is longitudinally associated with higher insulin sensitivity in Australian adults. (Goode, 2023)
This study examined the longitudinal relationship between a healthful plant-based eating pattern and insulin sensitivity in 667 young to middle-aged Australian adults, with a median follow-up duration of 13 years. It found a healthful plant-based eating pattern (determined using healthful plant-based diet index (hPDI) scores) was associated with higher insulin sensitivity, and therefore, potentially lower type 2 diabetes risk later in life.