Tackling Obesity in America - Go Nuts!

Marjet D. Heitzer, Ph.D. The Plateau-proof Diet Foundation http://www.plateauproofdiet.com Email: info@plateauproofdiet.com Nuts are an excellent source of protein as well as fiber, vitamin E, and omega-3 fatty acids. Although nuts are an energy rich food, composed of 45-75% fat depending on the type of nut, that fat is largely unsaturated. Along with the benefits of higher fiber, vitamin E, and omega-3 fatty acid consumption, nuts provide other health benefits such as increasing insulin sensitivity, endothelial cell (the cells that line blood vessels) function, and decreasing blood lipid (cholesterol) levels, thereby decreasing the risk of coronary artery disease (CAD). Recent studies suggest that consumption of nuts, particularly almonds, peanuts, pecan nuts, or walnuts may benefit the heart. Particularly, eating 4-5 servings (50-100 grams/day) each week lowers blood lipid levels and LDL (bad cholesterol) within a few short weeks when it is substituted for traditional, highly saturated fats (1). Furthermore, 1 ounce of nuts per day decreases the risk of fatal coronary heart disease by 45% when they are substituted for saturated fat and 30% when substituted for carbohydrates (2). The lipid lowering affects of nuts were seen in both lean and obese individuals, with and without hypercholesterolemia, indicating that consumption of nuts may decrease cholesterol levels in individuals with preexisting high cholesterol (3). It should be noted here that not all nuts reduced cholesterol levels. Increased consumption of macadamia nuts as well as hazelnuts did not alter cholesterol levels, indicating that the health benefits from eating nuts may not be gained if those nuts are selected. There is epidemiological (studies involving the distribution of health-related issues within certain populations) evidence that areas such as the Mediterranean region that consume a diet rich in nuts have a lower proportion of sudden cardiac death. Furthermore, there is an inverse relationship between nut consumption and sudden cardiac death as well as obesity, meaning that a person that consumes more nuts is less likely to die from CAD or to be obese. Finally, nut consumption is inversely associated with the risk of development of type II diabetes, presumably because individuals who consume nuts on a regular basis are less likely to be obese (4). How do nuts decrease the risk of coronary heart disease? First, nuts are composed mainly of monounsaturated fats, and substitution of foods containing saturated fat with unsaturated fat will improve blood lipid levels, thereby decreasing the risk of heart disease. Additionally, nuts are great source of other heart healthy items, such as vitamin E, fiber, magnesium, potassium and arginine. Vitamin E has antioxidant properties, making it a great vitamin in the fight against heart disease. In fact, Vitamin E is one of the most abundant naturally occurring antioxidants found in foods. Antioxidants protect against oxidative damage, a phenomenon that occurs in many diseases including heart disease and cancer (5). Vitamin E inhibits the oxidation of LDL (bad cholesterol). Oxidation of LDL is one of the initial steps that occur during atherosclerosis, leading to endothelial cell damage as well as narrowing of blood vessels. Because nuts contain high amounts of the antioxidant vitamin E, it is thought that this may be one of many ways which they help lower your risk of CAD. Omega-3 fatty acids are also found in nuts and have anti-atherogenic properties. Omega-3 fatty acids inhibit platelet aggregation (clot formation). Furthermore, omega-3 fatty acids improve endothelial function, protecting endothelial cells from damage (2). Endothelial dysfunction occurs early in the progression of atherosclerosis (narrowing or hardening of the arteries). Studies have also reported an inverse relationship between fish oils that contain high amounts of omega-3 fatty acids and mortality from coronary artery disease (6). Fiber has also been shown have beneficial health benefits (7). Fiber lowers blood cholesterol as well as decreasing hypertension (high blood pressure). Because most nuts are high in fiber, it is considered one of the many ways in which nut consumption leads to reduced risk of CAD. So, a combination of lowering blood cholesterol levels as well as improving endothelial function culminates in improved heart health with the consumption of nuts. Several studies have addressed the question: Does increased nut consumption lead to weight gain? Although the beneficial effects of nuts on CAD have been well recognized, given the obesity epidemic in the United States physicians were concerned about possible weight gain induced by nut consumption because nuts are so high in fat although it is the good, unsaturated fat. The resounding answer is No, nuts do not increase body mass index (BMI). In fact, there was an inverse relationship between nut consumption and BMI, indicating that a person eating nuts is less likely to be overweight (8). In the above mentioned studies, there was no significant change in weight after increasing nut consumption. In fact, there was a small tendency towards weight loss while on the nut diet and females with the highest BMI actually lost weight (8). Foods which are high in protein and unsaturated fat, such as nuts, may increase resting energy expenditure by increasing diet-induced thermogenesis. Furthermore, high fiber and protein foods tend to enhance satiety, or the feeling of being full. Nuts whether used as food replacement or snacks are an excellent food choice for the fight against obesity in America. Go nuts! 1. Fraser, G. E. Nut consumption, lipids, and risk of a coronary event. Clin Cardiol, 22: III11-15, 1999. 2. Nash, S. D. and Westpfal, M. Cardiovascular benefits of nuts. Am J Cardiol, 95: 963-965, 2005. 3. Sabate, J. and Fraser, G. E. Nuts: a new protective food against coronary heart disease. Curr Opin Lipidol, 5: 11-16, 1994. 4. Jiang, R., Manson, J. E., Stampfer, M. J., Liu, S., Willett, W. C., and Hu, F. B. Nut and peanut butter consumption and risk of type 2 diabetes in women. Jama, 288: 2554-2560, 2002. 5. Munteanu, A., Zingg, J. M., and Azzi, A. Anti-atherosclerotic effects of vitamin E--myth or reality? J Cell Mol Med, 8: 59-76, 2004. 6. Holub, D. J. and Holub, B. J. Omega-3 fatty acids from fish oils and cardiovascular disease. Mol Cell Biochem, 263: 217-225, 2004. 7. Castro, I. A., Barroso, L. P., and Sinnecker, P. Functional foods for coronary heart disease risk reduction: a meta-analysis using a multivariate approach. Am J Clin Nutr, 82: 32-40, 2005. 8. Sabate, J. Nut consumption and body weight. Am J Clin Nutr, 78: 647S-650S, 2003.