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.
Ros, E., 2008. Nuts: consumption, composition, health benefits and safety. CAB Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources 3, No. 070
Nuts are nutrient-dense foods rich in unsaturated fatty acids; most nuts contain monounsaturated fatty acids, whereas walnuts are rich in both n-6 (linoleic acid) and n-3 (a-linolenic acid) polyunsaturated fatty acids. The complex matrices of nuts contain many bioactive compounds: vegetable protein (including L-arginine, the amino acid precursor of nitric oxide the endogenous vasodilator), fiber, minerals, tocopherols and phytochemicals, such as phytosterols and phenolic compounds. By virtue of their unique composition, nuts are likely to beneficially impact health outcomes. Epidemiological studies have consistently associated frequent nut intake with a reduced incidence of coronary heart disease. Decreased rates of sudden cardiac death and diabetes development in association with nut consumption have also been reported. Many small feeding trials have clearly demonstrated that intake of all kinds of nuts has a cholesterol-lowering effect, even in the context of healthy diets. There are emerging evidences that nut consumption has a positive effect on oxidative stress, inflammation and vascular reactivity. Blood pressure, visceral adiposity and the metabolic syndrome also appear to be positively influenced by nut consumption. Thus, it is clear that nuts beneficially impact cardiovascular risk factors beyond cholesterol lowering. Contrary to expectations, epidemiological studies and clinical trials suggest that regular consumption of nuts is unlikely to contribute to obesity or increase the risk of diabetes. Safety concerns are limited to the infrequent occurrence of nut allergy in children. In conclusion, nuts are densely packaged nutrients with wide-ranging cardiovascular and metabolic benefits, which can be readily incorporated into healthy diets.
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.
Davis, P.A., M. Jenab, J.P. Vanden Heuvel, T. Furlong, S. Taylor, 2008. Tree nut and peanut consumption in relation to chronic and metabolic diseases including allergy. J. Nutr. 138: 1757S-1762S.
The New and Emerging Research session highlighted the emerging understanding of both the positive and negative effects of nuts consumption on health. The limited nature of both experimental and epidemiological evidence for positive relationship(s) between nut intake and health were noted. Study inconsistency and limitations, particularly survey methodology, were explored. Recent results from epidemiologic studies indicating a potential negative association between nut and seed intake and cancer risk were reviewed. The ability of walnuts to reduce endothelin suggests an interesting biochemical mechanism of nut action that may affect other endothelin-associated diseases, which should be further explored. The effects of nuts and their constituents on a nuclear receptor screen (PPAR, β/, , LXR, β, RXR, β, , PXR, and FXR) have been explored. Nut allergenicity and approaches necessary to minimize this effect were also described. In contrast to the positive effects, nut allergies present tree nut-allergic consumers with health challenges. The Food Allergy and Anaphylaxis Network stressed the importance of ensuring that consumers with food allergies have legible, accurate food labels. The Food Allergen Labeling and Consumer Protection Act has engendered precautionary, worst-case allergen scenario labeling statements with unknown benefits to consumer health. Issues of cross-contamination due to shared equipment and shared facilities highlighted the need to rely on allergen control programs that use ELISA technology and have increased understanding of nut allergens. Ultimately, to maximize the positive benefits of nuts, the consumer must be provided with all the information required to make an informed choice.
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.
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.
