b>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 energyrich food, composed of 45-75% fat depending on the type of nut,that fat is largely unsaturated. Along with the benefits ofhigher fiber, vitamin E, and omega-3 fatty acid consumption,nuts provide other health benefits such as increasing insulinsensitivity, endothelial cell (the cells that line bloodvessels) function, and decreasing blood lipid (cholesterol)levels, thereby decreasing the risk of coronary artery disease(CAD).
Recent studies suggest that consumption of nuts, particularlyalmonds, peanuts, pecan nuts, or walnuts may benefit the heart.Particularly, eating 4-5 servings (50-100 grams/day) each weeklowers blood lipid levels and LDL (bad cholesterol) within a fewshort weeks when it is substituted for traditional, highlysaturated fats (1). Furthermore, 1 ounce of nuts per daydecreases the risk of fatal coronary heart disease by 45% whenthey are substituted for saturated fat and 30% when substitutedfor carbohydrates (2). The lipid lowering affects of nuts wereseen in both lean and obese individuals, with and withouthypercholesterolemia, indicating that consumption of nuts maydecrease cholesterol levels in individuals with preexisting highcholesterol (3). It should be noted here that not all nutsreduced cholesterol levels. Increased consumption of macadamianuts as well as hazelnuts did not alter cholesterol levels,indicating that the health benefits from eating nuts may not begained if those nuts are selected.
There is epidemiological (studies involving the distributionof health-related issues within certain populations) evidencethat areas such as the Mediterranean region that consume a dietrich in nuts have a lower proportion of sudden cardiac death.Furthermore, there is an inverse relationship between nutconsumption and sudden cardiac death as well as obesity, meaningthat a person that consumes more nuts is less likely to die fromCAD or to be obese. Finally, nut consumption is inverselyassociated with the risk of development of type II diabetes,presumably because individuals who consume nuts on a regularbasis 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, andsubstitution of foods containing saturated fat with unsaturatedfat will improve blood lipid levels, thereby decreasing the riskof heart disease. Additionally, nuts are great source of otherheart healthy items, such as vitamin E, fiber, magnesium,potassium and arginine.
Vitamin E has antioxidant properties, making it a greatvitamin in the fight against heart disease. In fact, Vitamin Eis one of the most abundant naturally occurring antioxidantsfound in foods. Antioxidants protect against oxidative damage, aphenomenon that occurs in many diseases including heart diseaseand cancer (5). Vitamin E inhibits the oxidation of LDL (badcholesterol). Oxidation of LDL is one of the initial steps thatoccur during atherosclerosis, leading to endothelial cell damageas well as narrowing of blood vessels. Because nuts contain highamounts of the antioxidant vitamin E, it is thought that thismay be one of many ways which they help lower your risk of CAD.
Omega-3 fatty acids are also found in nuts and haveanti-atherogenic properties. Omega-3 fatty acids inhibitplatelet aggregation (clot formation). Furthermore, omega-3fatty acids improve endothelial function, protecting endothelialcells from damage (2). Endothelial dysfunction occurs early inthe progression of atherosclerosis (narrowing or hardening ofthe arteries). Studies have also reported an inverserelationship between fish oils that contain high amounts ofomega-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 decreasinghypertension (high blood pressure). Because most nuts are highin fiber, it is considered one of the many ways in which nutconsumption leads to reduced risk of CAD. So, a combination oflowering blood cholesterol levels as well as improvingendothelial function culminates in improved heart health withthe consumption of nuts.
Several studies have addressed the question: Does increasednut consumption lead to weight gain? Although the beneficialeffects of nuts on CAD have been well recognized, given theobesity epidemic in the United States physicians were concernedabout possible weight gain induced by nut consumption becausenuts are so high in fat although it is the good, unsaturatedfat. The resounding answer is No, nuts do not increase body massindex (BMI). In fact, there was an inverse relationship betweennut consumption and BMI, indicating that a person eating nuts isless likely to be overweight (8). In the above mentionedstudies, there was no significant change in weight afterincreasing nut consumption. In fact, there was a small tendencytowards while on the nut diet and females with thehighest BMI actually lost weight (8). Foods which are high inprotein and unsaturated fat, such as nuts, may increase restingenergy expenditure by increasing diet-induced thermogenesis.Furthermore, high fiber and protein foods tend to enhancesatiety, or the feeling of being full.
Nuts whether used as food replacement or snacks are anexcellent food choice for the fight against obesity in America.Go nuts!
1.Fraser, G. E. Nut consumption, lipids, and risk of a coronaryevent. 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 foodagainst 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 riskof type 2 diabetes in women. Jama, 288: 2554-2560, 2002.
5.Munteanu, A., Zingg, J. M., and Azzi, A. Anti-atheroscleroticeffects 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 fishoils and cardiovascular disease. Mol Cell Biochem, 263: 217-225,2004.
7.Castro, I. A., Barroso, L. P., and Sinnecker, P. Functionalfoods for coronary heart disease risk reduction: a meta-analysisusing 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.
About the author:Dr. Marjet Heitzer is a biomedical scientist specializedin cancer and endocrine research. She is the founding editor of'Trimming America', the free journal of 'The Plateau-proof DietFoundation'. She is a strong proponent of reversing obesity andsome of its comorbidities, including type II diabetes andhypertension, with a lifestyle change that has healthy dietingat its core.
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