The body of evidence about nuts and health continues to grow, with new local and international research papers regularly published.

Key studies: Systematic reviews and meta-analyses

Health benefits related to tree nut consumption and their bioactive compounds. (2021).
This review summarises the research for the impact of nuts on body weight, glucose modulation, cardiovascular risk, inflammation and oxidative stress, cognitive performance and the gut microbiota. It particularly points to a beneficial role of nuts in preventing certain chronic diseases, and protecting against oxidative stress and inflammation. The researchers highlight that the unique combination of nutrients and bioactive compounds nuts contain are responsible.

Food groups and intermediate disease markers: a systematic review and network meta-analysis of randomized trials. (2018).
A recent meta-analysis provides evidence that an increased intake of nuts, legumes and wholegrains is more effective at improving metabolic health (including LDL cholesterol and TAGs) that other food groups.

Tree nut phytochemicals: composition, antioxidant capacity, bioactivity, impact factors. A systematic review of almonds, Brazils, cashews, hazelnuts, macadamias, pecans, pine nuts, pistachios and walnuts. (2011).
The phytochemicals found in tree nuts have been associated with antioxidant, anti-inflammatory, anti-proliferative, antiviral, chemo-preventive and hypocholesterolaemic actions, all of which are known to affect the initiation and progression of several pathogenic processes.

Other evidence

Nuts: Natural pleiotropic nutraceuticals. (2021).
This narrative review paper summarises nut nutrients and the increasing evidence that nuts positively impact a myriad of health outcomes. The macronutrients, micronutrients and phytochemicals of nuts benefit health, particularly a reduced risk of CVD and related metabolic alterations. As nuts are rich in beneficial bioactive compounds and positively impact various health outcomes, the researchers suggest they can be considered ‘natural pleiotropic nutraceuticals’ (that is, having favourable and wide-ranging health benefits). As such, they suggest eating nuts daily should be considered an essential feature of a health-promoting dietary pattern.

Modeling the effect of environmentally sustainable food swaps on nutrient intake in pregnant women. (2021).
This research looked at the impact on nutrient intakes of replacing commonly-consumed foods in pregnancy with environmentally-sustainable alternatives. With the highest gashouse gas emissions (GHG), beef was selected as the reference food. The most pronounced reductions in CO2 emissions were from replacing beef with tofu, legumes, and nuts. For instance, replacing 1 serve/week of beef with an isocaloric serve of nuts (18g) during pregnancy could reduce GHG emissions by 383kg CO2 equivalents, and increase folate (+10.2µg/serve) and fiber (+1.1g/serve) – with a small decrease in iron intake (-1.1mg/serve). The researchers say simple dietary swaps can noticeably reduce environmental impact, without compromising nutrient intake in pregnancy.

Small targeted dietary changes can yield substantial gains for human and environmental health. (2021)
US-based researchers evaluated 5,853 foods to identify environmentally sustainable foods that promote health. They quantified whether the foods either added or took minutes away from a ‘healthy life’. Results suggested that substituting just 10% of daily calorie intake from beef or processed meat in favour of fruit, vegetables, nuts, legumes and ‘selected seafood’ adds 48 minutes of healthy life every day and cuts our carbon footprint by a third (33%). Eating a 30g serve of nuts and seeds provides a gain of 25 minutes of healthy life per day.

Associations of total nut and peanut intakes with all-cause and cause-specific mortality in a Japanese community: The Takayama study. (2021)
This Japanese-based cohort study tracked >31,000 adults over 16 years, to investigate the link between total nut and peanut intakes with all-cause and cause-specific mortality. The mean intakes of total nuts were 1.8 and 1.4g/day in men and women, respectively. It found tree nut and peanut intakes, even in low amounts, were linked with a reduced risk of mortality, particularly in men. This is one of the few studies to have looked at this association in non-white, non-Western populations.

Association of major dietary protein sources with all‐cause and cause‐specific mortality: Prospective cohort study. (2021).
This prospective cohort study followed more than 102,000 post-menopausal women (aged 50 to 79 years old at the start of the study) for an average of 18 years. The women were enrolled in the well-regarded Women’s Health Initiative. It found eating more plant protein, and substituting animal protein with plant protein, was linked with a lower risk of all-cause mortality, cardiovascular disease (CVD) and dementia. Among the key findings was that substituting total red meat, eggs and dairy products with nuts was associated with a lower risk of death from all causes.

Socioeconomic and lifestyle factors modifies the association between nut consumption and metabolic syndrome incidence. (2021).
This prospective cohort study found an association between consuming nuts and a reduced risk of metabolic syndrome (MetS), particularly among more physically active study participants. The researchers tracked 1,915 adults, who were part of the Tehran Lipid and Glucose study, for around nine years. Consuming nuts higher than the median and having moderate to high physical activity levels resulted a 26% and 37% reduction in Mets, respectively. Participants who did not smoke had lower risk of MetS, regardless of the amount of nuts they consumed. And the risk reduction with nuts was seen in both educated and non-educated groups. 

Nut and legume consumption and human health: An umbrella review of observational studies. (2021).
This study reviewed previously-published meta-analyses of observational studies on nut and legume intake and disease, and assessed the level of evidence. Out of the six meta-analyses focussed on legume intake, and 15 on nut intake, a possible association with decreased risk of colorectal adenoma and coronary heart disease was found for higher legume consumption, and a decreased risk of cardiovascular and cancer mortality, colon cancer, hypertension and ischaemic stroke for higher nut consumption.

Metabolic syndrome features and excess weight were inversely associated with nut consumption after 1-year follow-up in the PREDIMED-Plus Study. (2020).
The aim of this study was to assess whether changes in nut consumption over a one-year follow-up were associated with changes in features of metabolic syndrome in a middle-aged and older Spanish population at high cardiovascular disease risk. It found that features of metabolic syndrome and excess weight were inversely associated with nut consumption after one-year follow-up. As nut consumption increased, between each tertile, there was a significant decrease in waist circumference, triglycerides, systolic blood pressure, weight, and BMI, and a significant increase in HDL cholesterol in women.

In vitro anti-HSV-1 activity of polyphenol-rich extracts and pure polyphenol compounds derived from pistachio kernels. (2020).
Mussarra-Pizzo M. et al. This study examined the activity of polyphenol-rich extracts of natural shelled pistachio kernels on herpes simplex virus type 1 (HSV-1) replication. The results indicate that polyphenols from pistachios are effective against herpes simplex virus type 1. This study concluded that the antiviral effects of pistachio extracts are the result of a balance of the individual polyphenolic components (antioxidants) that in combination exert the anti-viral activity.

First Course DASH, Second Course Mediterranean: Comparing Renal Outcomes for Two ‘Heart-Healthy’ Diets (2020).
What do the DASH and Mediterranean diets have in common? According to the authors of this new review, renal health benefits – including reduced risk for chronic kidney disease, nephrolithiasis, and mortality due to all renal causes. They put the benefits of both eating patterns largely down to their common focus on whole, plant-based foods, such as nuts, fruits, vegetables, legumes and whole grains.

Does ‘activating’ nuts affect nutrient bioavailability? (2020)
This study assessed the effects of different soaking regimes on phytate and mineral concentrations of whole and chopped almonds, hazelnuts, peanuts, and walnuts. The treatments were: 1. Raw; 2. soaked for 12 h in salt solution; 3. soaked for 4 h in salt solution; 4. soaked for 12 h in water. Although there were some statistically significant differences in phytate concentrations between treatments, no soaking treatment reduced phytate concentrations to a level that would result in clinically meaningful improvements in the bioavailability of minerals. In summary, the authors found no evidence that soaking is an effective strategy to reduce phytate concentrations and improve the nutrient bioavailability of almonds, hazelnuts, peanuts and walnuts.

Nut consumption in a representative survey of Australians: a secondary analysis of the 2011-2012 National Nutrition and Physical Activity Survey. (2020).
Exploration of nut consumption in a representative sample of Australians identified that nut intake does not meet recommendations. Mean nut intake was 4·61g/d, with only 5.6 % of nut consumers consuming the target of 30 g of nuts per day. Higher nut consumption was not adversely associated with higher body weight, aligning with the current evidence base. Given the current levels of nut consumption in Australia, strategies to increase nut intake to recommended levels are required.

Tree nut snack consumption is associated with better diet quality and CVD risk in the UK adult population: National Diet and Nutrition Survey (NDNS) 2008–2014. (2020).
Researchers examined the association of tree nut snack consumption with diet quality and cardiovascular disease (CVD) risk in UK adults from the National diet and nutrition survey. Tree nut snack consumers report better dietary quality and consumption was associated with lower CVD risk factors. Encouraging replacement of less healthy snacks with tree nuts should be encouraged as part of general dietary guidelines.

Consumption of Nuts at Midlife and Healthy Aging in Women. (2020).
Results of this research showed a significant association between the consumption of nuts and healthy aging at midlife, and a greater likelihood of overall health and well-being at older ages. Walnuts appeared to have the strongest relation to healthy aging. The findings support the notion that long-term nut consumption merits as a strategy contributing to a healthier lifespan.

Bio-actives and health benefits of nuts and dried fruits. (2020).
This review summarizes recent findings on bioactive constituents, health claims, and health benefits of nuts and dried fruits and also discusses their great potential as healthy foods to benefit a number of diseases afflicting human beings.

Hazelnut consumption improves testicular antioxidant function and semen quality in young and old male rats. (2019).
Hazelnut supplementation in the diets of young and old rats significantly improved testicular function and semen quality.

Metabolizable energy from cashew nuts is less than that predicted by Atwater Factors. (2019).
The average available energy content of a 30g handful of cashews is 137kcal – 16% lower than what is found on food labels. These results are in line with previous studies suggesting that the Atwater factors over-estimate the calories in nuts.

The health burden of preventable disease in Australia: a systematic review. (2019).
An Australian systematic review determined the health burden of preventable disease and found that of the 15 dietary risk factors, diets low in nuts and seeds, low in fruit, low in vegetables and low in wholegrains attributed to the greatest number of deaths.

Prospective association between nut consumption and physical function in older men and women. (2019).
Men consuming >11.5g nuts per day had half the risk of impaired agility and mobility; whilst women consuming >11.5g nuts per day had reduced overall physical function impairment, compared to those consuming no nuts.

Association between nut consumption and non-alcoholic fatty liver disease in adults. (2019).
A recent cohort study of more than 20,000 healthy adults showed that consuming nuts more than 4x/week resulted in a 20% lower prevalence of NAFLD, which remained significant after adjusting for variables.

Development of a database for estimation of the nut content of Australian single-ingredient and multi-ingredient foods. (2019).
Nuts were found in a wide range of foods, highlighting the importance of developing specific databases to facilitate estimation of core food intake. This database can be used to estimate nut intake in the Australian population and explore associations between nut intake and health outcomes.

The health burden of preventable disease in Australia: a systematic review. (2019).
Although the methods used to estimate preventable health burden varied greatly between studies, all found that a substantial amount of death and disability was attributable to lifestyle-related risk factors. Implications for public health: There is a large health burden in Australia caused by modifiable risk factors and further action is warranted to address this burden.

Food in the Anthropocene: the EAT–Lancet Commission on healthy diets from sustainable food systems. (2019).
Transforming to healthy diets by 2050 requires global substantial shifts – including more than doubling consumption of healthy foods like nuts, fruit and veg, and legumes.

Prospective association between nut consumption and physical function in older men and women. (2019).
An average nut intake of ~15g/day was associated with a 50% reduction in the risk of impaired agility and mobility in men, and with lower risk of overall physical function impairment in women.

Anti-aging potential of tree nuts with a focus on the phytochemical composition, molecular mechanisms and thermal stability of major bioactive compounds. (2018).
Tree nuts, complete functional foods, contain macro- and micronutrients of high biological value. These bioactive compounds have a synergistic effect in preventing and delaying many age-related pathologies (e.g. cardiovascular diseases, stroke, type 2 diabetes mellitus, certain types of cancer, and several neurodegenerative diseases). The consumption of tree nuts has been scientifically proven to improve lifespan and health span and should be a part of a healthy diet in the elderly.

Beneficial effects of walnut consumption on human health: role of micronutrients. (2018).
Walnuts are optimal healthful foods, containing a number of bioactive nutrients, which helps to explain their health promoting effects.

A comparison of perceptions of nuts between the general public, dietitians, general practitioners, and nurses. (2018).
Significant differences exist between health care professional groups, and between health care professionals and the general public in terms of beliefs, attitudes and perceptions of nuts. Results indicate that a greater understanding of the health benefits of, as well as addressing the barriers to nut consumption, is important to increasing nut intake throughout the population.

Can nuts mitigate malnutrition in older adults? A conceptual framework. (2018).
Nuts are nutrient dense, typically rich in healthy fats, fibre and protein together with a range of essential vitamins and minerals. The review explores the role of different forms of nuts (such as pastes), timing, sensory monotony and variety as methods in need of further investigation to help determine the feasibility of nuts in preventing and reversing malnutrition in the elderly.

Nutrition across the life stages: AIHW. (2018).
Across all the life stages, Australians are not faring well, with up to 41% of total energy coming from discretionary foods. Australians are eating too much sugar, saturated fat and sodium, and not eating enough of the foods from the five food groups. It’s clear that changes are needed to improve the nutritional quality of Australians’ diets and that multiple areas require improvement, rather than a single food group, food type or nutrient.

The economic burden of not meeting food recommendations in Canada: The cost of doing nothing. (2018).
Nuts and seeds and whole grains were the top cost contributors rather than vegetables and fruit. Our findings suggest that unhealthy eating constitutes a tremendous economic burden to Canada that is similar in magnitude to the burden of smoking and larger than that of physical inactivity which were estimated using similar approaches. A status quo in promotion of healthy eating will allow this burden to continue. Interventions to reduce the health and economic burden of unhealthy eating in Canada may be more effective if they are broad in focus and include promotion of nuts and seeds and whole grains along with vegetables and fruit rather than have a narrow focus such as primarily on vegetables and fruit.

Can nuts mitigate malnutrition in older adults? A conceptual framework. (2018).
Several properties of whole nuts, some of which appear important for addressing overnutrition, (e.g., hardness, lower-than-expected nutrient availability, satiety-enhancing effects) may limit their effectiveness as a food to combat undernutrition. However, we propose that modifications such as transforming the physical form of nuts, addressing the timing of nut ingestion, and introducing variety may overcome these barriers. This review also discusses the feasibility of using nuts to prevent and reverse undernutrition among older adults.

Walnut consumption for two years and leukocyte telomere attrition in Mediterranean elders: results of a randomized controlled trial. (2018).
The inclusion of 30-60g walnuts/day for 2 years delayed telomere attrition (a possible hallmark for ageing) in older adults, suggesting that walnuts might impact ageing in older adults.

The effects of ‘activating’ almonds on consumer acceptance and gastrointestinal tolerance. (2018).
According to a study published in the European Journal of Nutrition, soaking (or activating) almonds did not reduce phytates, nor did it improve GI tolerance when compared to un-soaked nuts.

Associations between nut consumption and health vary between omnivores, vegetarians, and vegans. (2017).
Higher nut consumption appeared overall to be associated with greater benefits amongst omnivores compared to vegetarians and vegans. Findings support existing literature around beneficial effects of nut consumption and suggest that benefits may be larger among omnivores. Nut promotion strategies may have the highest population impact by specifically targeting this group.

Review of nut phytochemicals, fat-soluble bio-actives, antioxidant components and health effects. (2015).
Nuts, which contain phytochemicals, fat-soluble bio-actives, minor components as well as nutrient and non-nutrient anti-oxidants beyond their basic nutritional functions, offer an excellent choice for heart-healthy snack food and food additive. Nuts should be consumed with their skin (pellicles), whenever possible, because of their high phytochemical content as well as antioxidant activity.


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