The burgeoning interest in nuts and their impact on human health is fueled by compelling evidence. While nuts are calorie-dense, numerous studies highlight their association with a lowered risk of chronic diseases. This positive outcome is attributed to the rich combination of fatty acids, plant proteins, fibers, vitamins, minerals, carotenoids, and phytosterols found in nuts, offering potential antioxidant benefits.
Nuts, integral to the Mediterranean diet, are globally endorsed for their nutritional prowess. Tree nuts like almonds, hazelnuts, cashews, Brazil nuts, macadamia nuts, walnuts, and pistachios, alongside legumes such as peanuts, stand out as nutrient-rich foods, each boasting a distinctive composition. These offerings encompass beneficial monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acids, proteins, soluble and insoluble fibers, vitamins E and K, folate, thiamine, and an array of minerals like magnesium, copper, potassium, and selenium. Moreover, they house compounds such as xanthophyll carotenoids, antioxidants, and phytosterols, renowned for their positive impact on human health.
Almonds exhibit health benefits whether consumed in modest amounts (10 grams daily) or more substantial portions (100 grams daily). They can prove beneficial in the treatment of individuals averse to or incapable of high statin doses. Furthermore, incorporating almonds into isocaloric diets may contribute to satiety control and enhance cognitive function for those adhering to a low-calorie regimen.
In individuals with type 2 diabetes, incorporating almonds into snacks has shown notable benefits, including reduced postprandial blood glucose levels and increased satiety. This outcome stems from a study involving the consumption of 45 grams of almonds daily over a four-week period, either post meals like breakfast and lunch or as standalone morning or afternoon snacks. Groups opting for almond snacks experienced heightened reductions in hunger and serum glucose concentrations. Remarkably, despite a daily intake of 250 kcal from almonds, no weight gain was observed. The satiety effect appears to counterbalance the energy surplus, with the high fiber content of almonds influencing energy absorption. Interestingly, the metabolizable energy of various almond forms—whole natural, whole roasted, and chopped—was significantly lower than anticipated by Atwater’s factors, highlighting the nuanced impact of almond consumption on calorie absorption.
Over a 10-week period, overweight and obese women who consumed higher amounts of almonds daily (1450 kJ or 345 kcal, equivalent to 60 g) did not experience weight gain. This phenomenon was ascribed to a natural reduction in caloric intake from other food sources, emphasizing the potential role of almonds in moderating overall calorie consumption without inducing weight gain.
Diabetic patients can derive notable benefits from incorporating pistachios into their diet. The inclusion of two snacks, each containing 25 g of pistachios daily, has been shown to reduce glycosylated hemoglobin (HbA1c), fasting blood glucose, systolic blood pressure, body mass index (BMI), and high-sensitivity C-reactive protein (hs-CRP). The pistachio diet demonstrates positive effects on the cardio-metabolic profile, including reductions in waist circumference (WC), LDL cholesterol (LDL-c), free fatty acids, hs-CRP, TNF-alpha, and thiobarbituric acid reactive substances (TBARS), along with an increase in adiponectin concentration.
Consistent intake of 60 grams of pistachios daily has been observed to alter lipoprotein size and particle profile, favoring a less atherogenic pattern. Despite no significant change in total cholesterol (TC), LDL cholesterol (LDL-c), or HDL cholesterol (HDL-c) concentrations, pistachios led to a reduction in the small particle size of LDL-c and HDL-c. This suggests that pistachios may play a beneficial role in cardiovascular health independent of traditional changes in the overall plasma lipid profile.
The assessment of pistachio consumption’s dose-response effect, ranging from 30 to 85 grams per day, either alone or in conjunction with high-carbohydrate bread, demonstrated a gradual decrease in post-meal blood sugar levels, indicative of a reduced glycemic response. Notably, substituting 20% of total energy with pistachios for four weeks improved systemic hemodynamics, enhanced heart rate variability, and effectively managed 24-hour systolic blood pressure in adults with type 2 diabetes. Conversely, daily intake of 42 g or 70 g of pistachios for 12 weeks did not induce changes in BMI or waist-to-hip ratio in Chinese subjects with metabolic syndrome. In summary, there is compelling evidence that pistachio consumption within the range of 25 to 85 g per day can be beneficial for improving lipid profiles, reducing inflammatory markers, and managing blood pressure in affected individuals.
The inclusion of 50 g/day of peanuts and/or peanut butter in the American Diabetes Association (ADA) diet over 24 weeks led to an increased proportion of nutrients with cardioprotective properties (MUFA, PUFA, PUFA/saturation ratio, α-tocopherol, niacin, and magnesium) compared to a peanut-free diet in adults with type 2 diabetes. Importantly, the intervention demonstrated that incorporating peanuts and peanut butter into the ADA diet was not associated with weight gain, as body weight, BMI, and waist circumference decreased, and this trend was consistent even without the inclusion of peanuts in the diet.
The incorporation of high-oleic peanuts into an energy-restricted diet demonstrated notable improvements in fat oxidation and body composition among overweight subjects. Despite similar energy restriction levels between groups with and without peanuts, those consuming peanuts exhibited greater weight loss than expected from energy restriction alone. Particularly, high-oleic peanuts enhanced diet-induced thermogenesis in overweight and obese men, likely by upregulating the gene expression of uncoupling proteins (UCPs). Additionally, these peanuts contributed to reduced hunger through caloric compensation and increased satiety. Moreover, a substantial daily intake of high-oleic peanuts (50–70 g) over 12 weeks without energy restriction did not result in increased body weight or waist circumference.
In a randomized study focusing on obese women at high risk of type 2 diabetes, acute consumption of 43 g/day of whole, unshelled peanuts and peanut butter added to a 75 g carbohydrate-matched breakfast meal yielded promising results. Both breakfast variations, featuring whole peanuts or peanut butter, led to reduced glycemic responses at the initial and subsequent meals. Furthermore, they elevated peptide YY concentration, correlating with a decreased desire to eat. This underscores the potential of incorporating peanuts and peanut butter into breakfast to modulate glycemic responses and influence satiety in individuals at risk of type 2 diabetes.
Daily consumption of 65 grams of roasted peanuts at breakfast has been associated with reduced carbohydrate intake and a diminished postprandial glycemic response, potentially contributing to enhanced blood sugar control and a lowered risk of diabetes. Over a three-week period, peanut consumption in the range of 43-75 g per day has shown benefits in blood sugar control, satiety induction, and reduction in non-esterified fatty acid (NEFA) concentrations, independent of changes in body composition. Including peanuts in the diet not only enhances dietary quality but also promotes satiety, boosts fat oxidation and thermogenesis, and mitigates glycemic response. Notably, consuming large portions of peanuts, such as 70 grams, does not result in weight gain.
Brazil nuts, recognized for their antioxidant properties due to selenium content, have demonstrated positive effects. Incorporating Brazil nuts into the diet can enhance glutathione peroxidase activity. In obese women, Brazil nut consumption effectively increased selenium status and glutathione peroxidase activity, irrespective of Pro198Leu genotype-related polymorphism. Additionally, in hypertensive and dyslipidemic individuals, daily consumption of 13 g of partially defatted Brazil nuts led to reduced oxidative stress, oxidized LDL cholesterol, blood pressure, and increased antioxidant status.
The nutritional composition divergence between nuts and peanuts is crucial for understanding their distinct impacts on human health. In terms of lipids, almonds, hazelnuts, and cashews exhibit a high ratio of monounsaturated fatty acids (MUFA) to saturated fatty acids (SFAs), with hazelnuts leading with a ratio of 10:1. Brazil nuts display the lowest MUFA/SFA ratio, while macadamia nuts boast the highest MUFA/polyunsaturated fatty acids (PUFA) ratio. Walnuts stand out with the highest level of PUFA, particularly α-linolenic acid. Almonds take the lead in fiber content among tree nuts at 13g/100g. Conversely, peanuts have a higher protein and fiber content compared to tree nuts. Beyond fatty acids, these foods differ in micronutrients and bioactive substances, such as alpha-tocopherol in almonds and hazelnuts, selenium in Brazil nuts, phenolic compounds in walnuts, carotenoids in pistachios, and phytosterols in peanuts. These nutritional distinctions can influence health effects and guide selection for preventive or adjunct treatments.
While a limitation of recommending larger servings is the energy density of nuts, evidence suggests that almond consumption does not induce weight gain and may positively impact health by reducing glycemic peaks and enhancing satiety. Including walnuts in a regular diet, whether in smaller (21 g) or larger (75 g) portions, is a strategic approach to improving diet quality with potential cardiovascular risk reduction and improved endothelial function.
Indeed, consuming 40 grams of pistachios has demonstrated effectiveness in reducing fasting glucose and LDL cholesterol, increasing HDL cholesterol, and improving vascular function. Notably, larger portions of pistachios (70 grams) have not been linked to weight gain.
Peanuts, recommended for their health benefits, show positive outcomes across intervention portions ranging from 43 to 75 grams per day. Despite their energy density, there is no observed positive association between peanut consumption and body fat, even at amounts as high as 70 grams per day. Peanuts offer health benefits by reducing postprandial blood glucose, enhancing micronutrient intake, and promoting increased fat oxidation and satiety.
Brazil nuts exhibit varying impacts on health depending on portion size. A single nut (approximately 0.5 grams) can elevate serum selenium concentration and glutathione peroxidase enzyme activity in obese women. Larger amounts have shown benefits in reducing oxidative stress, LDL cholesterol oxidation, and blood pressure in individuals with high blood pressure and dyslipidemia.
In contrast, a daily consumption of 30 grams of hazelnuts did not reduce certain inflammatory markers. While tree nuts and peanuts have been extensively studied in cardiovascular diseases, there’s a scarcity of research on their consumption in patients with cancer and other conditions characterized by high oxidative and metabolic stress. However, one study has confirmed the beneficial effects of nuts in cancer, attributing the advantages, especially in almonds, to their antioxidant properties.
The allergenic potential of nuts is an important consideration, with studies revealing increased immunological sensitivity, measured by immunoglobulin E (IgE), associated with hazelnut consumption. This suggests a heightened sensitivity and allergic potential, particularly in children. Walnuts and peanuts have also been linked to allergic effects, although thermal processing, such as roasting, has been shown to improve digestibility and reduce the activity of allergenic proteins.
Despite initial concerns about the high energy density of nuts and seeds contributing to weight gain, it’s evident that consumption within reasonable amounts does not lead to increased weight. Instead, these foods contribute to satiety control and increased thermogenesis. Moreover, the introduction of nuts and seeds into the diet enhances its quality, as they are rich in monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), protein, fiber, vitamins, minerals, and bioactive compounds with antioxidant potential. Their nutritional properties can be beneficial for human health, particularly in the prevention and treatment of diseases.