Mann, J.I., 2000. Optimizing the plant-based diet. Asia Pacific J Clin Nutr. 9(suppl):S60-4.
Any attempt to optimize a plant-based diet necessitates an identification of the features of the diet which confer benefit as well as any which may be associated with detrimental effects. The former task is more difficult than might be assumed as there is no doubt that some of the apparent health benefits observed amongst vegetarians are a consequence of environmental determinants of health which characterize groups of people who choose vegetarian diets, rather than dietary practices. This review will consider the major health benefits of plant-based diets, the specific foods or nutrients which confer the benefits as far as can be ascertained from present knowledge, potential nutrient deficiencies associated with a plant-based diet and nutritional strategies that can be employed to prevent any such deficiencies.
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.
Colquhoun, D.M., 2000. Food for prevention of coronary heart disease: Beyond the low fat, low cholesterol diet. Asia Pacific J Clin Nutr. 9(suppl):S86-90.
The single major cause of death throughout the world is coronary heart disease. Prevalence is stable or decreasing in North America, Australasia and most of Europe, while rapidly increasing in eastern Europe, Asia and Africa. Atherosclerosis is the underlying pathology. This is one of the classic lifestyle diseases on the background of genetic susceptibility. Diet plays a key role in the initiation and progression of coronary heart disease. A low total fat diet is almost universally recommended throughout the world. However, the most successful secondary prevention diet trials have used modification of fat, rather than decrease in total fat per se. Successful diet trials suggest that diet modification is as effective as accepted drug therapy to prevent recurrent coronary events, and importantly is very cost effective. Marine lipid supplementation has been demonstrated beyond reasonable doubt to decrease total mortality and in particular sudden death in patients who have survived their first myocardial infarction. Large-scale diet intervention trials are indicated to improve the scientific basis for dietary recommendations to prevent initial and recurrent coronary heart disease.
Bruce, B., G.A. Spiller, L.M. Klevay, S.K. Gallagher, 2000. A diet high in whole and unrefined foods favorably alters lipids, antioxidant defenses and colon function. J Clin Nutr. 19(1): 61-7.
OBJECTIVE: Diets rich in whole and unrefined foods, like whole grains, dark green and yellow/orange-fleshed vegetables and fruits, legumes, nuts and seeds, contain high concentrations of antioxidant phenolics, fibers and numerous other phytochemicals that may be protective against chronic diseases. This study compared the effects of a phytochemical-rich diet versus a refined-food diet on lipoproteins, antioxidant defenses and colon function. METHODS: Twelve hyperlipidemic women followed two diets for four weeks starting with a refined-food diet. Subjects then directly crossed over to the phytochemical-rich diet. Duplicate, fasting serum lipids and single, fasting antioxidant enzymes were measured at the end of the four-week refined-food diet period (baseline) and again at the end of the phytochemical-rich diet period. RESULTS: Total energy and total fat intake were similar during both diet periods, but there was a decrease in saturated fat (SFA) of 61% in the phytochemical-rich diet group. Dietary fiber, vitamin E, vitamin C and carotene intakes were 160%, 145%, 160% and 500% more, respectively, than during the refined-food diet period. The phytochemical-rich diet induced a drop of 13% in total cholesterol (TC) (p < 0.05) and 16% (p < 0.001) in low density lipoprotein-cholesterol (LDL-C). Erythrocyte superoxide dismutase decreased 69% (p < 0.01) and glutathione peroxidase dropped 35% (p < 0.01). Colon function was improved on the phytochemical-rich diet. CONCLUSIONS: A diet abundant in phytochemically-rich foods beneficially affected lipoproteins, decreased need for oxidative defense mechanisms and improved colon function.
Sicherer SH, A. Muñoz-Furlong, A.W. Burks, H.A. Sampson, 1999. J Allergy Clin Immunol. 103(4):559-562.
Allergy to peanuts and tree nuts (TNs) is one of the leading causes of fatal and near-fatal food-induced allergic reactions. These allergies can be lifelong and appear to be increasing in prevalence. Despite the seriousness of these allergies, the prevalence of peanut and TN allergy in the general population is unknown. OBJECTIVE: We sought to determine the prevalence of peanut and TN allergy among the general population of the United States. METHODS: We used a nationwide, cross-sectional, random digit dial telephone survey with a standardized questionnaire. RESULTS: A total of 4374 households contacted by telephone participated (participation rate, 67%), representing 12,032 individuals. Peanut or TN allergy was self-reported in 164 individuals (1.4%; 95% confidence interval [CI], 1.2%-1.6%) in 151 households (3.5%; 95% CI, 2.9%-4.0%). The prevalence of reported allergy in adults (1.6%) was higher than that found in children under 18 years of age (0.6%). In 131 individuals, details of the reactions were obtained. When applying criteria requiring reactions to be typical of IgE-mediated reactions (hives, angioedema, wheezing, throat tightness, vomiting, and diarrhea) within an hour of ingestion, 10% of these subjects were excluded. Among the remaining 118 subjects, allergic reactions involved 1 organ system (skin, respiratory, or gastrointestinal systems) in 50 subjects, 2 in 45 subjects, and all 3 in 23 subjects. Forty-five percent of these 118 respondents reported more than 5 lifetime reactions. Only 53% of these 118 subjects ever saw a physician for the allergic reaction, and only 7% had self-injectable epinephrine available at the time of the interview. The prevalence of peanut and TN allergy was adjusted by assuming that 10% of the remaining 33 subjects without a description of their reactions would also be excluded and correcting for a 7% false-positive rate for the survey instrument. A final “corrected” prevalence estimate of 1.1% (95% CI, 1.0%-1.4%) was obtained. CONCLUSIONS: Peanut and/or TN allergy affects approximately 1.1% of the general population, or about 3 million Americans, representing a significant health concern. Despite the severity of reactions, about half of the subjects never sought an evaluation by a physician, and only a few had epinephrine available for emergency use.
Sampson, H.A., 1999. Food allergy. Part 1: Immunopathogenesis and clinical disorders. J Allergy Clin Immunol. 103:717-728.
Up to 8% of children less than 3 years of age and approximately 2% of the adult population experience food-induced allergic disorders. A limited number of foods are responsible for the vast majority of food-induced allergic reactions: milk, egg, peanuts, fish, and tree nuts in children and peanuts, tree nuts, fish, and shellfish in adults. Food-induced allergic reactions are responsible for a variety of symptoms involving the skin, gastrointestinal tract, and respiratory tract and may be caused by IgE-mediated and non-IgE-mediated mechanisms. In part 1 of this series, immunopathogenic mechanisms and clinical disorders of food allergy are described.
Eggesbø, M., R. Halvorsen, K. Tambs, G. Botten, 1999. Prevalence of parentally perceived adverse reactions to food in young children. Pediatr Allergy Immunol. 10:122-132.
A substantial number of parents perceive that their children have adverse reactions to food, but it is well documented that objective assessments agree with only one-quarter to one-half of parentally reported reactions. In order to prevent wrong diagnoses and curtail unnecessary or inadequate diets, primary health care providers need to deal with the parental perception of adverse reactions to food. A description of the prevalence and pattern of parentally perceived adverse reactions to food in children is needed to meet this challenge. The aim of the present study was to estimate the prevalence, incidence and cumulative incidences of parentally perceived adverse reactions to food in children younger than 2 years of age, and to study the duration of the reactions. A population-based cohort of 3623 children born in Norway was followed from birth until the age of two. At 6-month intervals, the parents completed questionnaires regarding the occurrence and type of any reaction to food. Information was available on the outcome measure at all age points for 77.4% of the families and these were used in the analyses; 3.8% of the cohort were entirely lost to follow-up. The cumulative incidence of adverse reactions to food was 35% by age two. Fruits, milk and vegetables accounted for nearly two-thirds of all reported reactions. Milk was the single food item most commonly incriminated, the cumulative incidence being 11.6%. The cumulative incidences of reported reactions to fruits and vegetables were 20.4% and 7.3%, respectively, with citrus fruits, strawberry and tomatoes as the most common food items in these groups. The cumulative incidences were less for food reactions associated with eggs (4.4%), fish (3%), nuts (2.1%) and cereals (1.4%). The duration of the reactions was short ± approximately two-thirds of the reactions were not reported again 6 months later. However, the probability of remission depended on the food item concerned, the age at onset of reactions, and whether the reaction had been reported previously or not. Adverse reactions to food are reported by the parents of one-third of children in Norway before the age of two. The most striking feature of this study is the short duration of the food reactions, as approximately two-thirds of the reactions are not reported again 6 months later. Nevertheless, the high frequency of reactions attributable to milk is of concern. Milk is an important part of the Norwegian diet for children, and if removed from the diet its nutritional value is not easily replaced. Further studies are needed to assess the degree to which parents alter the diet of their children based upon perceived reactions to food.
Sabaté, J., 1999. Nut consumption, vegetarian diets, ischemic heart disease risk, and all-cause mortality: evidence from epidemiologic studies. Am J Clin Nutr. 70(suppl):500S.
Perhaps one of the most unexpected and novel findings in nutritional epidemiology in the past 5 y has been that nut consumption seems to protect against ischemic heart disease (IHD). Frequency and quantity of nut consumption have been documented to be higher in vegetarian than in nonvegetarian populations. Nuts also constitute an important part of other plant-based diets, such as Mediterranean and Asian diets. In a large, prospective epidemiologic study of Seventh day Adventists in California, we found that frequency of nut consumption had a substantial and highly significant inverse association with risk of myocardial infarction and death from IHD. The Iowa Women’s Health Study also documented an association between nut consumption and decreased risk of IHD. The protective effect of nuts on IHD has been found in men and women and in the elderly. Importantly, nuts have similar associations in both vegetarians and nonvegetarians. The protective effect of nut consumption on IHD is not offset by increased mortality from other causes. Moreover, frequency of nut consumption has been found to be inversely related to all-cause mortality in several population groups such as whites, blacks, and the elderly. Thus, nut consumption may not only offer protection against IHD, but also increase longevity.
Kris-Etherton, P.M., S. Yu-Poth, J. Sabaté, H.E. Ratcliffe, G. Zhao, T.D. Etherton, 1999. Nuts and their bioactive constituents: effects on serum lipids and other factors that affect disease risk. Am J Clin Nutr.70 (suppl.):504S-11S.
Because nuts have favorable fatty acid and nutrient profiles, there is growing interest in evaluating their role in a heart-healthy diet. Nuts are low in saturated fatty acids and high in monounsaturated and polyunsaturated fatty acids. In addition, emerging evidence indicates that there are other bioactive molecules in nuts that elicit cardioprotective effects. These include plant protein, dietary fiber, micronutrients such as copper and magnesium, plant sterols, and phytochemicals. Few feeding studies have been conducted that have incorporated different nuts into the test diets to determine the effects on plasma lipids and lipoproteins. The total- and lipoprotein-cholesterol responses to these diets are summarized in this article. In addition, the actual cholesterol response was compared with the predicted response derived from the most current predictive equations for blood cholesterol. Results from this comparison showed that when subjects consumed test diets including nuts, there was a ~25% greater cholesterol-lowering response than that predicted by the equations. These results suggest that there are non-fatty acid constituents in nuts that have additional cholesterol-lowering effects. Further studies are needed to identify these constituents and establish their relative cholesterol lowering potency.
Hu, F.B., M.J. Stampfer, 1999. Nut consumption and risk of coronary heart disease: a review of epidemiologic evidence. Current Atherosclerosis Reports. (1):205-10.
Traditionally nuts have been perceived as an unhealthy food because of their high fat content. However, recent accumulative evidence suggests that frequent consumption of nuts may be protective against coronary heart disease (CHD). So far, five large prospective cohort studies (the Adventist Health Study, the Iowa Women Health Study, the Nurses’ Health Study, the Physicians’ Health Study, and the CARE Study) have examined the relation between nut consumption and the risk of CHD and all have found an inverse association. In addition, several clinical studies have observed beneficial effects of diets high in nuts (including walnuts, peanuts, almonds, and other nuts) on blood lipids. The beneficial effects of nut consumption observed in clinical and epidemiologic studies underscore the importance of distinguishing different types of fat. Most fats in nuts are mono- and polyunsaturated fats that lower low-density lipoprotein cholesterol level. Based on the data from the Nurses’ Health Study, we estimated that substitution of the fat from 1 ounce of nuts for equivalent energy from carbohydrate in an average diet was associated with a 30% reduction in CHD risk and the substitution of nut fat for saturated fat was associated with 45% reduction in risk. Given the strong scientific evidence for the beneficial effects of nuts, it seems justifiable to move nuts to a more prominent place in the United States Department of Agriculture Food Guide Pyramid. Regular nut consumption can be recommended in the context of a healthy and balanced diet.
