Strate, L.L., Y.L. Liu, S. Syngal, W.H. Aldoori, E.L. Giovannucci, 2008. Nut, corn, and popcorn consumption and the incidence of diverticular disease. JAMA. 300(8):907-914.
Context Patients with diverticular disease are frequently advised to avoid eating nuts, corn, popcorn, and seeds to reduce the risk of complications. However, there is little evidence to support this recommendation. Objective To determine whether nut, corn, or popcorn consumption is associated with diverticulitis and diverticular bleeding. Design and Setting The Health Professionals Follow-up Study is a cohort of US men followed up prospectively from 1986 to 2004 via self-administered questionnaires about medical (biennial) and dietary (every 4 years) information. Men reporting newly diagnosed diverticulosis or diverticulitis were mailed supplemental questionnaires. Participants The study included 47,228 men, aged 40 to 75 years who at baseline were free of diverticulosis or its complications, cancer, and inflammatory bowel disease and returned a food-frequency questionnaire. Main Outcome Measure Incident diverticulitis and diverticular bleeding. Results During 18 years of follow-up, there were 801 incident cases of diverticulitis and 383 incident cases of diverticular bleeding. We found inverse associations between nut and popcorn consumption and the risk of diverticulitis. The multivariate hazard ratios for men with the highest intake of each food (at least twice per week) compared with men with the lowest intake (less than once per month) were 0.80 (95% confidence interval, 0.63-1.01; P for trend = .04) for nuts and 0.72 (95% confidence interval, 0.56-0.92; P for trend = .007) for popcorn. No associations were seen between corn consumption and diverticulitis or between nut, corn, or popcorn consumption and diverticular bleeding or uncomplicated diverticulosis. Conclusions In this large, prospective study of men without known diverticular disease, nut, corn, and popcorn consumption did not increase the risk of diverticulosis or diverticular complications. The recommendation to avoid these foods to prevent diverticular complications should be reconsidered.
Salas-Salvado’, J., J. Ferna’ ndez-Ballart, E. Ros, M-A. Martı’nez-Gonza’ lez, M. Fito’, R. Estruch, D. Corella, M. Fiol, E. Go’mez-Gracia, F. Aro’s, G. Flores, J. Lapetra, R. Lamuela-Ravento’s, V. Ruiz-Gutie’rrez, M. Bullo’, J. Basora, M-I. Covas for the PREDIMED Study Investigators, 2008. Effect of a Mediterranean diet supplemented with nuts on metabolic syndrome status one-year results of the PREDIMED randomized trial. Arch Intern Med. 168(22):2449-2458.
Background: Epidemiological studies suggest that the Mediterranean diet (MedDiet) may reduce the risk of developing the metabolic syndrome (MetS). We compared the 1-year effect of 2 behavioral interventions to implement the MedDiet vs advice on a low-fat diet on MetS status. Methods: A total of 1224 participants were recruited from the PREDIMED (Prevencio’n con Dieta Mediterra’nea) Study, a multicenter, 3-arm, randomized clinical trial to determine the efficacy of the MedDiet on the primary prevention of cardiovascular disease. Participants were older subjects at high risk for cardiovascular disease. Interventions were quarterly education about the MedDiet plus provision of either 1 L/wk of virgin olive oil (MedDiet + VOO) or 30 g/d of mixed nuts (MedDiet + nuts), and advice on a low-fat diet (control diet). All diets were ad libitum, and there was no increase in physical activity for any of the interventions. Lifestyle variables and MetS features as defined by the National Cholesterol Education Program Adult Treatment Panel III criteria were assessed. Results: At baseline, 61.4% of participants met criteria for the MetS. One-year prevalence was reduced by 6.7%, 13.7%, and 2.0% in the MedDiet + VOO, MedDiet + nuts, and control diet groups, respectively (MedDiet + nuts vs control groups, P=.01; MedDiet + VOO vs control group, P =.18). Incident rates of the MetS were not significantly different among groups (22.9%, 17.9%, and 23.4%, respectively). After adjustment for sex, age, baseline obesity status, and weight changes, the odds ratios for reversion of MetS were 1.3 (95% confidence interval, 0.8-2.1) for the MedDiet + VOO group and 1.7 (1.1-2.6) for the MedDiet + nuts group compared with the control diet group. Conclusion: A traditional MedDiet enriched with nuts could be a useful tool in the management of the MetS.
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.
Spaccarotella, K.J., Kris-Etherton P.M., Stone, W.L., Bagshaw, D.M., Fishell V.K., West S.G., Lawrence F.R., and Hartman T.J., 2008. The Effect of Walnut Intake on Factors Related to Prostate and Vascular Health in Older Men. Nutrition Journal. 7:13.
Background: Tocopherols may protect against prostate cancer and cardiovascular disease (CVD). Methods: We assessed the effect of walnuts, which are rich in tocopherols, on markers of prostate and vascular health in men at risk for prostate cancer. We conducted an 8-week walnut supplement study to examine effects of walnuts on serum tocopherols and prostate specific antigen (PSA). Subjects (n = 21) consumed (in random order) their usual diet +/- a walnut supplement (75 g/d) that was isocalorically incorporated in their habitual diets. Prior to the supplement study, 5 fasted subjects participated in an acute time course experiment and had blood taken at baseline and 1, 2, 4, and 8 h after consuming walnuts (75 g). Results: During the time course experiment, triglycerides peaked at 4 h, and gamma-tocopherol (γ-T) increased from 4 to 8 h. Triglyceride – normalized γ-T was two-fold higher (P = 0.01) after 8 versus 4 h. In the supplement study, change from baseline was +0.83 ± 0.52 μmol/L for γ-T, -2.65 ± 1.30 μmol/L for alpha-tocopherol (α-T) and -3.49 ± 1.99 for the tocopherol ratio (α-T: γ-T). A linear mixed model showed that, although PSA did not change, the ratio of free PSA:total PSA increased and approached significance (P = 0.07). The α-T: γ-T ratio decreased significantly (P = 0.01), partly reflecting an increase in serum γ-T, which approached significance (P = 0.08). Conclusion: The significant decrease in the α-T: γ-T ratio with an increase in serum γ-T and a trend towards an increase in the ratio of free PSA:total PSA following the 8-week supplement study suggest that walnuts may improve biomarkers of prostate and vascular statu
O’Keefe, J.H., N.M. Gheewala, J.O. O’Keefe, 2008. Dietary Strategies for Improving Post-Prandial Glucose, Lipids, Inflammation, and Cardiovascular Health. J Am Coll Cardiol. 51:249-55
The highly processed, calorie-dense, nutrient-depleted diet favored in the current American culture frequently leads to exaggerated supraphysiological post-prandial spikes in blood glucose and lipids. This state, called postprandial dysmetabolism, induces immediate oxidant stress, which increases in direct proportion to the increases in glucose and triglycerides after a meal. The transient increase in free radicals acutely triggers atherogenic changes including inflammation, endothelial dysfunction, hypercoagulability, and sympathetic hyperactivity. Post-prandial dysmetabolism is an independent predictor of future cardiovascular events even in nondiabetic individuals. Improvements in diet exert profound and immediate favorable changes in the post-prandial dysmetabolism. Specifically, a diet high in minimally processed, high-fiber, plant-based foods such as vegetables and fruits, whole grains, legumes, and nuts will markedly blunt the post-meal increase in glucose, triglycerides, and inflammation. Additionally, lean protein, vinegar, fish oil, tea, cinnamon, calorie restriction, weight loss, exercise, and low-dose to moderate-dose alcohol each positively impact post-prandial dysmetabolism. Experimental and epidemiological studies indicate that eating patterns, such as the traditional Mediterranean or Okinawan diets, that incorporate these types of foods and beverages reduce inflammation and cardiovascular risk. This anti-inflammatory diet should be considered for the primary and secondary prevention of coronary artery disease and diabetes.
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.
Natoli, S., P. McCoy, 2007. A review of the evidence: nuts and body weight. Asia Pac J Clin Nutr. 16 (4):588-597 588.
There is currently no single dietary or lifestyle intervention that is effective in long-term weight loss. Traditional weight loss diets tend to be low in total fat and therefore often restrict nut consumption. However, nuts are an important source of many vitamins, minerals, monounsaturated and polyunsaturated fatty acids. This paper reviewed all the available evidence from the literature in relation to nut consumption and body weight. The findings show that the role of nut consumption in body weight management is varied. Nuts, when included as part of an energy-controlled diet, were found in some instances to assist with weight loss. However, when nuts were added to an existing diet without controlling for energy intake, body weight increased, although to a lesser extent than theoretically predicted. There is limited evidence on the effect nut consumption has on type 2 diabetes, although available evidence indicates that nuts as part of a healthy diet do not cause weight gain and can have a positive influence on the fatty acid profile of a person with diabetes. This review shows there is a lack of evidence to support the restriction of nut consumption in weight management, indicating that further research is needed to assess the role of nuts in weight management.
Fleischer, D.M., 2007. The natural history of peanut and tree nut allergy. Current Allergy and Asthma Reports. 7:175–181.
Peanut and tree nut allergies were once thought to be permanent. Recent studies have shown that about 20% and 10%, respectively, of young patients may outgrow peanut and tree nut allergies. For the majority of patients, however, the natural history is not favorable. In addition, approximately 8% of patients who outgrow peanut allergy may suffer a recurrence. The rising prevalence of these allergies, coupled with the knowledge that allergic reactions to these foods have the potential to be severe or fatal and that accidental exposures are common, makes developing effective treatments to alter the natural history of peanut and tree nut allergies even more crucial for those who will not outgrow them. At this time, avoidance of the offending foods and being prepared to treat a potential reaction after accidental ingestion is the only treatment, but many promising therapeutic interventions are being investigated.
Zhao, G., T.D. Etherton, K.R. Martin, P.J. Gillies, S.G. West, P.M. Kris-Etherton, 2007. Dietary α-linolenic acid inhibits proinflammatory cytokine production by peripheral blood mononuclear cells in hypercholesterolemic subjects. Am J Clin Nutr. 85:385-91.
Background: Atherosclerosis is a chronic inflammatory disease. We previously reported that a diet high in α-linolenic acid (ALA) reduces lipid and inflammatory cardiovascular disease risk factors in hypercholesterolemic subjects. Objective: The objective was to evaluate the effects of a diet high in ALA on serum proinflammatory cytokine concentrations and cytokine production by cultured peripheral blood mononuclear cells (PBMCs) from subjects fed the experimental diets. Design: A randomized, controlled, 3-diet, 3-period crossover study design was used. Hypercholesterolemic subjects (n = 23) were assigned to 3 experimental diets: a diet high in ALA (ALA diet; 6.5% of energy), a diet high in linoleic acid (LA diet; 12.6% of energy), and an average American diet (AAD) for 6 wk. Serum interleukin (IL)-6, IL-1β, and tumor necrosis factor-α (TNF-α) concentrations and the production of IL-6, IL-1β, and TNF-α by PBMCs were measured. Results: IL-6, IL-1β, and TNF-α production by PBMCs and serum TNF-α concentrations were lower (P < 0.05 and P < 0.08, respectively) with the ALA diet than with the LA diet or AAD. PBMC production of TNF-α was inversely correlated with ALA (r = – 0.402, P = 0.07) and with eicosapentaenoic acid (r = – 0.476, P = 0.03) concentrations in PBMC lipids with the ALA diet. Changes in serum ALA were inversely correlated with changes in TNF-α produced by PBMCs (r = – 0.423, P < 0.05). Conclusions: Increased intakes of dietary ALA elicit anti-inflammatory effects by inhibiting IL-6, IL-1β, and TNF-α production in cultured PBMCs. Changes in PBMC ALA and eicosapentaenoic acid (derived from dietary ALA) are associated with beneficial changes in TNF-α release. Thus, the cardioprotective effects of ALA are mediated in part by a reduction in the production of inflammatory cytokines.
