Albert, C.M., M. Gaziano, W.C. Willett, J.E. Manson, 2002. Nut consumption and decreased risk of sudden cardiac death in the Physicians’ Health Study. Arch. Intern. Med. 162:1382.
Background: Dietary nut intake has been associated with a reduced risk of coronary heart disease mortality; however, the mechanism is unclear. Since components of nuts may have antiarrhythmic properties, part of the benefit may be due to a reduction in sudden cardiac death. – Methods: We prospectively assessed whether increasing frequency of nut consumption, as ascertained by an abbreviated food frequency questionnaire at 12 months of follow-up, was associated with a lower risk of sudden cardiac death and other coronary heart disease end points among 21454 male participants enrolled in the US Physicians’ Health Study. Participants were followed up for an average of 17 years. Results: Dietary nut intake was associated with a significantly reduced risk of sudden cardiac death after controlling for known cardiac risk factors and other dietary habits (P for trend, .01). Compared with men who rarely or never consumed nuts, those who consumed nuts 2 or more times per week had reduced risks of sudden cardiac death (relative risk, 0.53; 95% confidence interval, 0.30-0.92) and total coronary heart disease death (relative risk, 0.70; 95% confidence interval, 0.50-0.98). In contrast, nut intake was not associated with significantly reduced risks of non-sudden coronary heart disease death or nonfatal myocardial infarction. Conclusion: These prospective data in US male physicians suggest that the inverse association between nut consumption and total coronary heart disease death is primarily due to a reduction in the risk of sudden cardiac death.
Background: A voluntary registry of individuals with peanut and/or tree nut allergy was established in 1997 to learn more about these food allergies. Objective: The purpose of this study was to elucidate a variety of features of peanut and tree nut allergy among the first 5149 registry participants. Methods: The registry was established through use of a structured questionnaire distributed to all members of the Food Allergy and Anaphylaxis Network and to patients by allergists. Parental surrogates completed the forms for children under the age of 18 years. Results: Registrants were primarily children (89% of registrants were younger than 18 years of age; the median age was 5 years), reflecting the membership of the Network. Isolated peanut allergy was reported by 3482 registrants (68%), isolated tree nut allergy by 464 (9%), and allergy to both foods by 1203 (23%). Registrants were more likely to have been born in October, November, or December (odds ratio, 1.2; 95% CI, 1.18-1.23; P < .0001). The median age of reaction to peanut was 14 months, and the median age of reaction to tree nuts was 36 months; these represented the first known exposure for 74% and 68% of registrants, respectively. One half of the reactions involved more than 1 organ system, and more than 75% required treatment, frequently from medical personnel. Registrants with asthma were more likely than those without asthma to have severe reactions (33% vs 21%; P < .0001). In comparison with initial reactions, subsequent reactions due to accidental ingestion were more severe, more common outside the home, and more likely to be treated with epinephrine. Conclusions: Allergic reactions to peanut and tree nut are frequently severe, often occur on the first known exposure, and can become more severe over time.
McManus, K., L. Antinoro, F. Sacks, 2001. A randomized controlled trial of a moderate fat, low energy diet compared with a low fat, low energy diet for weight loss in overweight adults. Int J Obesity.25:1503-11.
CONTEXT: Long-term success in weight loss with dietary treatment has been elusive. OBJECTIVE: To evaluate a diet moderate in fat based on the Mediterranean diet compared to a standard low-fat diet for weight loss when both were controlled for energy. DESIGN: A randomized, prospective 18 month trial in a free-living population. PATIENTS: A total of 101 overweight men and women (26.5 – 46 kg/m2). INTERVENTION: (1) Moderate-fat diet (35% of energy); (2) low-fat diet (20% of energy). MAIN OUTCOME MEASUREMENTS: Change in body weight. RESULTS: After 18 months, 31/50 subjects in the moderate-fat group, and 30/51 in the low fat group were available for measurements. In the moderate-fat group, there were mean decreases in body weight of 4.1 kg, body mass index of 1.6 kg/m2, and waist circumference of 6.9 cm, compared to increases in the low-fat group of 2.9 kg, 1.4 kg/m2 and 2.6 cm, respectively; P ≤ 0.001 between the groups. The difference in weight change between the groups was 7.0 kg. (95% CI 5.3, 8.7). Only 20% (10/51) of those in the low-fat group were actively participating in the weight loss program after 18 months compared to 54% (27/50) in the moderate-fat group, (P <0.002). The moderate-fat diet group was continued for an additional year. The mean weight loss after 30 months compared to baseline was 3.5 kg (n=19, P=0.03). CONCLUSIONS: A moderate-fat, Mediterranean-style diet, controlled in energy, offers an alternative to a low-fat diet with superior long-term participation and adherence, with consequent improvements in weight loss.
Noah, A., A.S. Truswell, 2001. There are many Mediterranean diets. Asia Pacific J Clin Nutr. 10(1):2-9.
Interest in Mediterranean diet began 30 years ago, when Ancel Keys published the results of the famous Seven Countries Study. Since 1945, almost 1.3 million people have come to Australia from Mediterranean countries as new settlers. There are 18 countries with coasts on the Mediterranean sea: Spain, southern France, Italy, Malta, Croatia, Bosnia, Albania, Greece, Cyprus, Turkey, Syria, Lebanon, Egypt, Libya, Malta, Tunisia, Algeria and Morocco. This study from which this report derives aims to investigate the influence of the food habits of immigrants from Mediterranean countries on Australian food intake. Here we look at the ‘traditional’ food habits of the above Mediterranean countries as told by 102 people we interviewed in Sydney, who came from 18 Mediterranean countries to Sydney. Most of the informants were women, their age ranged from 35 to 55 years. The interview was open-ended and held in the informant’s home. It usually lasted around 11/2 hours. The interview had three parts. Personal information was obtained, questions relating to the food habits of these people back in their original Mediterranean countries and how their food intake and habits have changed in Australia were also asked. From the interviews, we have obtained a broad picture of ‘traditional’ food habits in different Mediterranean countries. The interview data was checked with books of recipes for the different countries. While there were similarities between the countries, there are also important differences in the food habits of the Mediterranean countries. Neighboring countries’ food habits are closer than those on opposite sides of the Mediterranean Sea. We suggest that these food habits can be put into four groups. The data here refer to food habits in Mediterranean countries 20 or 30 years ago, as they were recovering from the Second World War. There is no single ideal Mediterranean diet. Nutritionists who use the concept should qualify the individual country and the time in history of their model Mediterranean diet.
Lin, B.H., E. Frazao, J. Allhouse, 2001. U.S. consumption patterns of tree nuts. Food Review 24(2):54-8.
Americans are more than a little nutty when it comes to their diets. Recent USDA food consumption data show that about 1 in every 10 consumers eats tree nuts (almonds, walnuts, pecans, pistachios, cashews, and others) on any given day, and the amount eaten is fairly small. On average, slightly more than 1 gram of tree nuts are eaten per person per day. Tree nut consumption is higher among wealthier consumers and Whites in the United States. More adults age 40 and above eat tree nuts than younger consumers. A smaller proportion of consumers living in the South and in rural areas consume tree nuts than other consumers.
Munoz, S., M. Merlos, D. Zambon, C. Rodriguez, J. Sabaté, E. Ros, J.C. Laguna, 2001. Walnut-enriched diet increases the association of LDL from hypercholesterolemic men with human HepG2 cells. J Lipid Res. 42(12):2069-76.
In a randomized, cross-over feeding trial involving 10 men with polygenic hypercholesterolemia, a control, Mediterranean-type cholesterol-lowering diet, and a diet of similar composition in which walnuts replaced approximately 35% of energy from unsaturated fat, were given for 6 weeks each. Compared with the control diet, the walnut diet reduced serum total and LDL cholesterol by 4.2% (P = 0.176), and 6.0% (P = 0.087), respectively. No changes were observed in HDL cholesterol, triglycerides, and apolipoprotein A-I levels or in the relative proportion of protein, triglycerides, phospholipids, and cholesteryl esters in LDL particles. The apolipoprotein B level declined in parallel with LDL cholesterol (6.0% reduction). Whole LDL, particularly the triglyceride fraction, was enriched in polyunsaturated fatty acids from walnuts (linoleic and alpha-linolenic acids). In comparison with LDL obtained during the control diet, LDL obtained during the walnut diet showed a 50% increase in association rates to the LDL receptor in human hepatoma HepG2 cells. LDL uptake by HepG2 cells was correlated with alpha-linolenic acid content of the triglyceride plus cholesteryl ester fractions of LDL particles (r(2) = 0.42, P < 0.05). Changes in the quantity and quality of LDL lipid fatty acids after a walnut-enriched diet facilitate receptor-mediated LDL clearance and may contribute to the cholesterol-lowering effect of walnut consumption.
Anderson et al, 2001. Walnut polyphenolics inhibit in vitro human plasma and LDL oxidation. J Nutr. 0022-3166
Recent epidemiologic studies have associated nut consumption with a reduced incidence of cardiovascular mortality. However, little is known about the contribution of nut polyphenols to antioxidant and cardiovascular protection. In this investigation, polyphenol-rich extracts from English walnuts (Juglans regia) were studied and compared with ellagic acid for their ability to inhibit in vitro plasma and LDL oxidation, as well as their effects on LDL ý-tocopherol during oxidative stress. In addition, the Trolox equivalent antioxidant activity (TEAC) was determined and liquid chromatography electrospray detection mass spectrometry (LC-ELSD/MS) analyses of the walnut extracts were performed. 2,2′-Azobis'(2-amidino propane) hydrochloride (AAPH)-induced LDL oxidation was significantly inhibited by 87 and 38% with the highest concentration (1.0 ýmol/L) of ellagic acid and walnut extract, respectively. In addition, copper-mediated LDL oxidation was inhibited by 14 and 84% in the presence of ellagic acid and walnut extract, respectively, with a modest, significant LDL ý-tocopherol sparing effect observed. Plasma thiobarbituric acid reacting substance (TBARS) formation was significantly inhibited by walnut extracts and ellagic acid in a dose-dependent manner, and the extracts exhibited a TEAC value greater than that of ý-tocopherol. LC-ELSD/MS analysis of the walnut extracts identified ellagic acid monomers, polymeric ellagitannins and other phenolics, principally nonflavonoid compounds. These results demonstrate that walnut polyphenolics are effective inhibitors of in vitro plasma and LDL oxidation. The polyphenolic content of walnuts should be considered when evaluating their antiatherogenic potential.
Almario, R.U., V. Vonghavaravat, R. Wong, S.E. Kasim-Karakas, 2001. Effects of walnut consumption on plasma fatty acids and lipoproteins in combined hyperlipidemia. Am J Clin Nutr. 74:72-9
BACKGROUND: Epidemiologic studies show an inverse relation between nut consumption and coronary heart disease. OBJECTIVE: We determined the effects of walnut intake on plasma fatty acids, lipoproteins, and lipoprotein subclasses in patients with combined hyperlipidemia. DESIGN: Participants sequentially adhered to the following diets: 1) a habitual diet (HD), 2) a habitual diet plus walnuts (HD+W), 3) a low-fat diet (LFD), and 4) a low-fat diet plus walnuts (LFD+W). RESULTS: In 13 postmenopausal women and 5 men (x ± SD age 60 ± 8 y), walnut supplementation did not increase body weight despite increased energy intake and the LFD caused weight loss (1.3 ± 0.5 kg; P < 0.01). When comparing the HD with the HD+W, linoleic acid concentrations increased from 29.94 ± 1.14% to 36.85 ±1.13% and ?-linolenic acid concentrations increased from 0.78 ± 0.04% to 1.56 ± 0.11%. During the LFD+W, plasma total cholesterol concentrations decreased by 0.58± 0.16 mmol/L when compared with the HD and by 0.46 ± 0.14 mmol/L when compared with the LFD. LDL-cholesterol concentrations decreased by 0.46 ± 0.15 mmol/L when compared with the LFD. Measurements of lipoprotein subclasses and particle size suggested that walnut supplementation lowered cholesterol preferentially in small LDL (46.1 ± 1.9% compared with 33.4 ± 4.3%, HD compared with HD+W, respectively; P < 0.01). HDL-cholesterol concentrations decreased from 1.27 ± 0.07 mmol/L during the HD to 1.14 ± 0.07 mmol/L during the HD+W and to 1.11 ± 0.08 mmol/L during the LFD. The decrease was seen primarily in the large HDL particles. Conclusions: Walnut supplementation may beneficially alter lipid distribution among various lipoprotein subclasses even when total plasma lipids do not change. This may be an additional mechanism underlying the anti-atherogenic properties of nut intake.
Zambón, D., J. Sabate´, S. Muñoz, B. Campero, E. Casals, M. Merlos, J.C. Laguna, E. Ros, MD, 2000. Substituting walnuts for monounsaturated fat improves the serum lipid profile of hypercholesterolemic men and women a randomized crossover trial. Ann Intern Med. 132:538-546.
Background: It has been reported that walnuts reduce serum cholesterol levels in normal young men. Objective: To assess the acceptability of walnuts and their effects on serum lipid levels and low-density lipoprotein (LDL) oxidizability in free-living hypercholesterolemic persons. Design: Randomized, crossover feeding trial. Setting: Lipid clinic at a university hospital. Patients: 55 men and women (mean age, 56 years) with polygenic hypercholesterolemia. Intervention: A cholesterol-lowering Mediterranean diet and a diet of similar energy and fat content in which walnuts replaced approximately 35% of the energy obtained from monounsaturated fat. Patients followed each diet for 6 weeks. Measurements: Low-density lipoprotein fatty acids (to assess compliance), serum lipid levels, lipoprotein (a) levels, and LDL resistance to in vitro oxidative stress. Results: 49 persons completed the trial. The walnut diet was well tolerated. Planned and observed diets were closely matched. Compared with the Mediterranean diet, the walnut diet produced mean changes of -4.1% in total cholesterol level, -5.9% in LDL cholesterol level, and -6.2% in lipoprotein(a) level. The mean differences in the changes in serum lipid levels were 20.28 mmol/L (95% CI, 20.43 to 20.12 mmol/L) (-10.8 mg/dL [0-16.8 to -4.8 mg/dL]) (P< 0.001) for total cholesterol level, -0.29 mmol/L (CI, -0.41 to -0.15 mmol/L) (-11.2 mg/dL [-16.3 to -6.1 mg/dL]) (P< 0.001) for LDL cholesterol level, and -0.021 g/L (CI, -0.042 to -0.001 g/L) (P = 0.042) for lipoprotein ( a) level. Lipid changes were similar in men and women except for lipoprotein (a) levels, which decreased only in men. Low-density lipoprotein particles were enriched with polyunsaturated fatty acids from walnuts, but their resistance to oxidation was preserved. Conclusion: Substituting walnuts for part of the monounsaturated fat in a cholesterol-lowering Mediterranean diet further reduced total and LDL cholesterol levels in men and women with hypercholesterolemia.
Lino, M., K. Marcoe, J.M. Dinkins, H. Hiza, R. Anand, 2000. USDA Center for Nutrition Policy and Promotion. The role of nuts in a healthy diet. Insight 23, December.
While not a staple in the American diet, nuts are consumed by many Americans. This Nutrition Insight examines the contribution nuts can make to a diet, consumption of nuts, characteristics of people who eat nuts, and the association of nut consumption with diet quality.
