Consumption of Nuts at Midlife and Healthy Aging in Women

Diet strategies for promoting healthy aging and longevity: An epidemiological perspective

In recent decades, global life expectancies have risen significantly, accompanied by a marked increase in chronic diseases and population aging. This narrative review aims to summarize recent findings on the dietary factors influencing chronic diseases and longevity, primarily from large cohort studies. First, maintaining a healthy weight throughout life is pivotal for healthy aging and longevity, mirroring the benefits of lifelong, moderate calorie restriction in today's obesogenic food environment. Second, the specific types or food sources of dietary fat, protein, and carbohydrates are more important in influencing chronic disease risk and mortality than their quantity. Third, some traditional diets (e.g., the Mediterranean, Nordic, and Okinawa) and contemporary dietary patterns, such as healthy plant-based diet index, the DASH (dietary approaches to stop hypertension) diet, and alternate healthy eating index, have been associated with lower mortality and healthy longevity. These patterns share many common components (e.g., a predominance of nutrient-rich plant foods; limited red and processed meats; culinary herbs and spices prevalent in global cuisines) while embracing distinct elements from different cultures. Fourth, combining a healthy diet with other lifestyle factors could extend disease-free life expectancies by 8-10 years. While adhering to core principles of healthy diets, it is crucial to adapt dietary recommendations to individual preferences and cultures as well as nutritional needs of aging populations. Public health strategies should aim to create a healthier food environment where nutritious options are readily accessible, especially in public institutions and care facilities for the elderly. Although further mechanistic studies and human trials are needed to better understand molecular effects of diet on aging, there is a pressing need to establish and maintain long-term cohorts studying diet and aging in culturally diverse populations.

Nutritional redundancy in the human diet and its application in phenotype association studies

Studying human dietary intake may help us identify effective measures to treat or prevent many chronic diseases whose natural histories are influenced by nutritional factors. Here, by examining five cohorts with dietary intake data collected on different time scales, we show that the food intake profile varies substantially across individuals and over time, while the nutritional intake profile appears fairly stable. We refer to this phenomenon as 'nutritional redundancy' and attribute it to the nested structure of the food-nutrient network. This network enables us to quantify the level of nutritional redundancy for each diet assessment of any individual. Interestingly, this nutritional redundancy measure does not strongly correlate with any classical healthy diet scores, but its performance in predicting healthy aging shows comparable strength. Moreover, after adjusting for age, we find that a high nutritional redundancy is associated with lower risks of cardiovascular disease and type 2 diabetes.

Long-Term Consumption of Nuts (Including Peanuts, Peanut Butter, Walnuts, and Other Nuts) in Relation to Risk of Frailty in Older Women: Evidence from a Cohort Study

BACKGROUND

Adherence to a healthy diet is inversely associated with frailty. However, the relationship between nuts, a key food group of Mediterranean diet, and frailty is unclear.

OBJECTIVES

This study aimed to evaluate the association between nut consumption and frailty in an aging female population.

METHODS

This population-based observational study included nonfrail women (≥60 y old) in the NHS from 11 states of the United States. Outcome was incident frailty, defined as having ≥3 of the FRAIL components (fatigue, lower strength, reduced aerobic capacity, multiple chronic conditions, and significant weight loss) and assessed every 4 y from 1992 to 2016. From 1990 to 2014, FFQs were used to assess the intakes of peanuts, peanut butter, walnuts (added in 1998), and other nuts at 4-y intervals. Exposure was total nut consumption, calculated as the sum of intakes of peanuts, peanut butter, walnuts, and other nuts and categorized into <1 serving/mo, 1-3 servings/mo, 1 serving/wk, 2-4 servings/wk, and ≥5 servings/wk. The relations of intakes of peanuts, peanut butter, and walnuts with frailty were also investigated separately. Cox proportional hazards models were used to assess the associations between nut consumption and frailty after adjusting for age, smoking, BMI, EI, diet quality, and medication use.

RESULTS

Among 71,704 participants, 14,195 incident frailty cases occurred over 1,165,290 person-years. The adjusted HR (95% CI) for consuming ≥5 servings/wk of nuts was 0.80 (0.73, 0.87), as compared with <1 serving/mo. Higher intakes of peanuts and walnuts, but not peanut butter, were also inversely associated with frailty.

CONCLUSIONS

This large prospective cohort study showed a strong and consistent inverse association between regular nut consumption and incident frailty. This suggests that nut consumption should be further tested as a convenient public health intervention for the preservation of health and well-being in older adults.

Walnut consumption and health outcomes with public health relevance-a systematic review of cohort studies and randomized controlled trials published from 2017 to present

CONTEXT

Considering the accumulation of recent studies investigating the health effects of walnut consumption, both including and beyond cardiovascular health effects, a systematic review of this literature to investigate the strength of the evidence is warranted.

OBJECTIVE

To investigate associations between walnut consumption and outcomes with public health relevance (specifically all-cause mortality, type 2 diabetes, CVD, metabolic syndrome, obesity, cancer, neurological and mental health, musculoskeletal, gastrointestinal, and maternal disorders) and the effect on associated disease risk markers, reported in studies published from 2017 to present.

DATA SOURCES

MEDLINE, FSTA, CENTRAL, and Scopus were searched from 1 January 2017 to 5 May 2021.

DATA EXTRACTION

Human studies (cohort studies and RCTs) ≥3 weeks in duration comparing consumption of walnuts (whole, pieces, or 100% butter) to a control and measuring associations with relevant public health outcomes and disease risk markers were assessed. Key study characteristics were extracted independently by 2 investigators using a standardized table. The quality of the studies was assessed using the Cochrane Risk-of-Bias tool 2.0 and the Newcastle-Ottawa Scale.

DATA ANALYSIS

Only 1 RCT was considered to be at low risk of bias for any of its outcomes. The cohort studies were considered to be of moderate or high quality. The results were synthesized using vote counting, based on the direction of effect. Thirty-three articles, 23 describing RCTs (walnut dose ∼10-99 g/day, 1,948 subjects) and 10 describing cohort studies (∼675,928 subjects), were included. Vote counting could be performed for the blood lipids, cardiovascular function, inflammation- and hemostatic-related factors, markers of glucose metabolism, and body weight and composition outcome groupings. The results are presented in effect direction plots. With respect to blood lipids, results from 8/8 RCTs favoured walnuts, in accordance with associations with a reduced risk of CVD suggested by cohort studies; results from 6/6 RCTs favoured control with respect to body weight and composition, although most of these effects were small. This was contrary to cohort study results suggesting small benefits of walnut consumption on body weight. There was no overall consistent direction of effect for cardiovascular function, markers of glucose metabolism, or inflammation- and hemostatic-related factors.

CONCLUSIONS

Evidence published since 2017 is consistent with previous research suggesting that walnut consumption improves lipid profiles and is associated with reduced CVD risk. Evidence is accumulating in other areas, such as cognitive health, although more research is needed to draw firm conclusions.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD4202122.

Nuts: Natural Pleiotropic Nutraceuticals

Common nuts (tree nuts and peanuts) are energy-dense foods that nature has gifted with a complex matrix of beneficial nutrients and bioactives, including monounsaturated and polyunsaturated fatty acids, high-quality protein, fiber, non-sodium minerals, tocopherols, phytosterols, and antioxidant phenolics. These nut components synergize to favorably influence metabolic and vascular physiology pathways, ameliorate cardiovascular risk factors and improve cardiovascular prognosis. There is increasing evidence that nuts positively impact myriad other health outcomes as well. Nut consumption is correlated with lower cancer incidence and cancer mortality, and decreased all-cause mortality. Favorable effects on cognitive function and depression have also been reported. Randomized controlled trials consistently show nuts have a cholesterol-lowering effect. Nut consumption also confers modest improvements on glycemic control, blood pressure (BP), endothelial function, and inflammation. Although nuts are energy-dense foods, they do not predispose to obesity, and in fact may even help in weight loss. Tree nuts and peanuts, but not peanut butter, generally produce similar positive effects on outcomes. First level evidence from the PREDIMED trial shows that, in the context of a Mediterranean diet, consumption of 30 g/d of nuts (walnuts, almonds, and hazelnuts) significantly lowered the risk of a composite endpoint of major adverse cardiovascular events (myocardial infarction, stroke, and death from cardiovascular disease) by ≈30% after intervention for 5 y. Impressively, the nut-supplemented diet reduced stroke risk by 45%. As they are rich in salutary bioactive compounds and beneficially impact various health outcomes, nuts can be considered natural pleiotropic nutraceuticals.