Li, T.Y., A.M. Brennan, N.M. Wedick, C. Mantzoros, N. Rifai, F.B. Hu, 2009. Regular Consumption of Nuts Is Associated with a Lower Risk of Cardiovascular Disease in Women with Type 2 Diabetes. J. Nutr.139:1333-1338.
Higher nut consumption has been associated with lower risk of coronary heart disease (CHD) events in several epidemiologic studies. The study examined the association between intake of nuts and incident cardiovascular disease (CVD) in a cohort of women with type 2 diabetes. For the primary analysis, there were 6309 women with type 2 diabetes who completed a validated FFQ every 2-4 y between 1980 and 2002 and were without CVD or cancer at study entry. Major CVD events included incident myocardial infarction (MI), revascularization, and stroke. During 54,656 person-years of follow-up, there were 452 CHD events (including MI and revascularization) and 182 incident stroke cases. Frequent nut and peanut butter consumption was inversely associated with total CVD risk in age-adjusted analyses. After adjustment for conventional CVD risk factors, consumption of at least 5 servings/wk of nuts or peanut butter [serving size, 28 g (1 ounce) for nuts and 16 g (1 tablespoon) for peanut butter] was significantly associated with a lower risk of CVD (relative risk = 0.56; 95% CI: 0.36-0.89). Furthermore, when we evaluated plasma lipid and inflammatory biomarkers, we observed that increasing nut consumption was significantly associated with a more favorable plasma lipid profile, including lower LDL cholesterol, non-HDL cholesterol, total cholesterol, and apolipoprotein-B-100 concentrations. However, we did not observe significant associations for HDL cholesterol or inflammatory markers. These data suggest that frequent nut and peanut butter consumption is associated with a significantly lower CVD risk in women with type 2 diabetes.
Ros, E., 2009. Nuts and novel biomarkers of cardiovascular disease. Am J Clin Nutr. 89(suppl):1649S-56S.
Nuts are energy-dense foods, rich in total fat and unsaturated fatty acids. The favorable fatty acid profile probably contributes to the beneficial effects of nut consumption observed in epidemiologic studies (prevention of coronary heart disease and diabetes) and feeding trials (cholesterol lowering). Besides fat, the complex matrices of nuts contain many bioactive compounds: vegetable protein, fiber, minerals, tocopherols, and phenolic compounds. By virtue of their unique composition, nuts are likely to benefit newer cardiovascular risk biomarkers, such as LDL oxidizability, soluble inflammatory molecules, and endothelial dysfunction. Protection of LDL oxidation by nut intake has been documented in some, but not all, clinical studies. In one study, feeding one daily serving of mixed nuts was associated with lower oxidized LDL concentrations. Regarding inflammation, cross-sectional studies have shown that nut consumption is associated with lower concentrations of circulating inflammatory molecules and higher plasma adiponectin, a potent anti-inflammatory adipokine. Clinical studies with nuts have documented reduced inflammatory cytokine concentrations but no consistent changes of C-reactive protein. Only walnuts have been formally tested for effects on endothelial function. After both walnut diets and single walnut meals, favorable vasoreactivity changes have been observed. Walnut consumption also reduced expression of endothelin 1, a potent endothelial activator, in an animal model of accelerated atherosclerosis. Beneficial effects on vascular reactivity may be ascribed to several constituents of walnuts: L-arginine, the precursor of nitricoxide, a-linolenic acid, and phenolic antioxidants. Although more studies are warranted, the emerging picture is that nut consumption beneficially influences cardiovascular risk beyond cholesterol lowering.
Lopez-Uriarte. P., M. Bullo, P. Casas-Agustench, N. Babio, J. Salas-Salvado, 2009. Nuts and oxidation: a systematic review. Nutrition Reviews. 67(9):497-508.
In recent years, nuts have received special attention because of their potential role in preventing cardiovascular disease. Because nuts are very rich in total fat that can potentially be oxidized and their skins contain several antioxidants, studies have been conducted to evaluate the potential effect of nut consumption on oxidative stress. This review evaluates the in vitro and in vivo studies conducted in animals or humans to analyze the effect of nuts on oxidation.
USDA, ERS, June 2008. Almonds Lead Increase in Tree Nut Consumption. Amber Waves.http://www.ers.usda.gov/AmberWaves/June08/Findings/Almonds.htm
Americans increased their consumption of tree nuts by 45 percent between the mid-1990s and mid-2000s, with almonds being among the favorites. Promotional programs that advertise the nutritional value of nuts, including beneficial levels of vitamin E and omega fatty acids, have likely contributed to the upswing in per capita nut consumption. The trend toward healthier eating has also played a role, along with the increasing popularity of Mediterranean and Middle Eastern foods that contain nuts. Strong domestic and international demand for U.S.-grown tree nuts has helped keep prices up despite increased production.
King, J.C., J. Blumberg, L. Ingwersen, M. Jenab, K.L. Tucker, 2008. Tree nuts and peanuts as components of a healthy diet. J. Nutr. 138: 1736S-1740S.
Nuts have been part of the diet for thousands of years. In 2003, a Qualified Health Claim was approved, stating that eating 1.5 oz (42 g) of nuts per day may reduce the risk of heart disease. Usual intakes fall short of this recommendation. About one-third of Americans report consuming nuts (tree nuts or peanuts) on any one day. Seven percent of Europeans report eating nuts, but the amount eaten by European nut consumers (31 g/d) is larger than that of Americans (21 g/d). Nuts are an excellent source of vitamin E and magnesium. Individuals consuming nuts also have higher intakes of folate, β-carotene, vitamin K, lutein+zeaxanthin, phosphorus, copper, selenium, potassium, and zinc per 1000 kcal. Regular nut consumption increases total energy intake by 250 kcal/d (1.05 MJ/d), but the body weight of nut consumers is not greater than that of nonconsumers. Nuts are an excellent source of phytochemicals (phytosterols, phenolic acids, flavonoids, stilbenes, and carotenoids). The total phenolic constituents probably contribute to the total antioxidant capacity of nuts, which is comparable to broccoli and tomatoes. To improve guidance on the use of nuts in the diet, the position of nuts in typical food patterns needs to be addressed. The 2005 MyPyramid includes nuts in the meat and beans group. Yet, nuts are rarely consumed as meat substitutes. Because 60% of the nuts consumed in the U.S. are eaten as snacks, emphasizing their use as a healthy snack may be more effective than inclusion within a food group.
Aranceta, J., C.P. Rodrigo, A. Naska, V.R. Vadillo, A. Trichopoulou, 2006. Nut consumption in Spain and other countries. British Journal of Nutrition. 96, Suppl. 2, S3-S11
In countries of the Mediterranean region, nuts have been consumed in moderate quantities since ancient times. Epidemiological studies show lower risk of cardiovascular diseases in populations with frequent nut consumption, independent from other dietary components. This article assesses nut consumption in Spain and other countries using different sources of data collected at the country, household or individual levels. The per capita consumption of nuts in Spain in 2001 was 7.9 g/person/d. The varieties most widely consumed are walnuts, almonds, hazelnuts and peanuts. Results of the eVe study estimate an average nut consumption in the Spanish population aged 25-60 years of 3.3 g/person/d. No significant statistical differences were observed between men and women. Consumption is higher in men aged between 35 and 44 years (4.5 g/d) and in women aged between 45 and 54 years (3.5 g/d). In the population of 2-24 years, according to the enKid study, nut consumption is estimated at 4.9±18.5 g/person per d. The age group with the highest consumption is teenagers between 14 and 17 years. The northeastern, northern and eastern regions of Spain show the highest consumption. According to FAO balance sheets, in 2001, Lebanon (16.5 kg/person per year) and Greece (11.9 kg/person per year) were the countries in the Mediterranean region with the highest consumption of nuts, followed by Spain (7.3 kg/person per year), Israel and Italy.
Jenkins, D.J.A., F.B. Hu, L.C. Tapsell, A.R. Josse, C.W.C. Kendall, 2008. Possible Benefit of Nuts in Type 2 Diabetes. J. Nutr. 138: 1752S-1756S.
Nuts, including peanuts, are now recognized as having the potential to improve the blood lipid profile and, in cohort studies, nut consumption has been associated with a reduced risk of coronary heart disease (CHD). More recently, interest has grown in the potential value of including nuts in the diets of individuals with diabetes. Data from the Nurses Health Study indicates that frequent nut consumption is associated with a reduced risk of developing diabetes and cardiovascular disease. Randomized controlled trials of patients with type 2 diabetes have confirmed the beneficial effects of nuts on blood lipids also seen in nondiabetic subjects, but the trials have not reported improvement in A1c or other glycated proteins. Acute feeding studies, however, have demonstrated the ability of nuts, when eaten with carbohydrate (bread), to depress postprandial glycemia. Furthermore, there was evidence of reduced postprandial oxidative stress associated with nut consumption. In terms of dietary composition, nuts have a good nutritional profile, are high in monounsaturated fatty acids (MUFA) and PUFA, and are good sources of vegetable protein. Incorporation of nuts in the diet may therefore improve the overall nutritional quality of the diet. We conclude that there is justification to consider the inclusion of nuts in the diets of individuals with diabetes in view of their potential to reduce CHD risk, even though their ability to influence overall glycemic control remains to be established.
Griel, A.E., Y. Cao, D.D. Bagshaw, A.M. Cifelli, B. Holub, P.M. Kris-Etherton, 2008. A Macadamia nut-rich diet reduces total and LDL-cholesterol in mildly hypercholesterolemic men and women. J. Nutr.138:761-767.
Epidemiologic studies and clinical trials have demonstrated that the unique fatty acid profile of nuts beneficially affects serum lipids/lipoproteins, reducing cardiovascular disease (CVD) risk. Nuts are low in SFA and high in PUFA and monounsaturated fatty acids (MUFA). Macadamia nuts are a rich source of MUFA. A randomized, crossover, controlled feeding study (5-wk diet periods) compared a Macadamia nut-rich diet [42.5g (1.5 ounces)/8.79 MJ (2100 kcal)] [MAC; 33% total fat (7% SFA, 18% MUFA, 5% PUFA)] vs. an average American diet [AAD; 33% total fat (13% SFA, 11% MUFA, 5% PUFA)] on the lipid/lipoprotein profile of mildly hypercholesterolemic (n = 25; 15 female, 10 male) subjects. Serum concentrations of total cholesterol (TC) and LDL cholesterol (LDL-C) following the MAC (4.94 ± 0.17 mmol/L, 3.14 ± 0.14 mmol/L) were lower than the AAD (5.45 ± 0.17 mmol/L, 3.44 ± 0.14 mmol/L; P < 0.05). The serum non-HDL cholesterol (HDL-C) concentration and the ratios of TC:HDL-C and LDL-C:HDL-C were reduced following consumption of the MAC diet (3.83 ± 0.17, 4.60 ± 0.24, and 2.91 ± 0.17, respectively) compared with the AAD (4.26 ± 0.17, 4.89 ± 0.24, and 3.09 ± 0.18, respectively; P < 0.05). There was no change in serum triglyceride concentration. Thus, macadamia nuts can be included in a heart-healthy dietary pattern that reduces lipid/lipoprotein CVD risk factors. Nuts as an isocaloric substitute for high SFA foods increase the proportion of unsaturated fatty acids and decrease SFA, thereby lowering CVD risk.
Kris-Etherton, P.M., F.B. Hu, E. Ros, J. Sabaté, 2008. The role of tree nuts and peanuts in the prevention of coronary heart disease: multiple potential mechanisms. J Nutr. 138, 1746S-1751.
Epidemiologic and clinical trial evidence has demonstrated consistent benefits of nut and peanut consumption on coronary heart disease (CHD) risk and associated risk factors. The epidemiologic studies have reported various endpoints, including fatal CHD, total CHD death, total CHD, and nonfatal myocardial infarct. A pooled analysis of 4 U.S. epidemiologic studies showed that subjects in the highest intake group for nut consumption had a 35% reduced risk of CHD incidence. The reduction in total CHD death was due primarily to a decrease in sudden cardiac death. Clinical studies have evaluated the effects of many different nuts and peanuts on lipids, lipoproteins, and various CHD risk factors, including oxidation, inflammation, and vascular reactivity. Evidence from these studies consistently shows a beneficial effect on these CHD risk factors. The LDL cholesterol-lowering response of nut and peanut studies is greater than expected on the basis of blood cholesterol-lowering equations that are derived from changes in the fatty acid profile of the diet. Thus, in addition to a favorable fatty acid profile, nuts and peanuts contain other bioactive compounds that explain their multiple cardiovascular benefits. Other macronutrients include plant protein and fiber; micronutrients including potassium, calcium, magnesium, and tocopherols; and phytochemicals such as phytosterols, phenolic compounds, resveratrol, and arginine. Nuts and peanuts are food sources that are a composite of numerous cardioprotective nutrients and if routinely incorporated in a healthy diet, population risk of CHD would therefore be expected to decrease markedly.
Djoussé, L., T. Rudich, J.M. Gaziano, 2008. Nut consumption and risk of heart failure in the Physicians’ Health Study I. Am J Clin Nutr. 88:930 -3.
Background: Heart failure is highly prevalent among older adults and is associated with high cost and societal burden. Although previous studies have reported beneficial effects of dietary factors on heart failure predictors, no previous study has examined whether frequent consumption of nuts is associated with a lower risk of heart failure in a large prospective cohort. Objective: We examined the association between nut consumption and incident heart failure to determine whether such a relation is modified by overweight or obesity. Design: This was a prospective cohort study of 20 976 participants from the Physicians’ Health Study I. Nut consumption was assessed with a simple abbreviated food questionnaire, and self-reported heart failure was ascertained by follow-up questionnaires. We used Cox regression to estimate relative risks of heart failure. Results: After an average follow-up of 19.6 y, 1093 new cases of heart failure occurred. Nut consumption was not associated with the risk of developing heart failure in this cohort: multivariable adjusted hazard ratios were 1.0 (reference), 0.98 (95% CI: 0.83, 1.15), 1.06 (95% CI: 0.89, 1.27), and 1.01 (95% CI: 0.84, 1.22) for nut consumption of <1, 1, and ≥2 servings/wk, respectively (P for linear trend: 0.64). The lack of a meaningful relation between nut intake and incident heart failure was seen in both lean and overweight or obese participants (P for interaction: 0.96). Conclusion: Our data do not provide evidence for an association between nut consumption and incident heart failure in US male physicians. However, our data cannot rule out possible benefits of nut consumption on subtypes of heart failure not prevalent in this cohort.
