Going Nuts About NutritionGoing Nuts About Nutrition
January 1, 2003
January 2003 Going Nuts About Nutrition By Angela M. Miraglio, M.S., R.D.Contributing Editor Nuts have been a global dietary staple throughout the ages, but recent emphasis on low-fat eating has sullied their nutritional reputation. Now health authorities recommend including nuts in a well-balanced, energy-appropriate diet, based on new research of their disease-prevention qualities. Nut nutrition factsNuts include a variety of tree nuts, plus peanuts, a legume. Nuts contain similar nutrients — carbohydrate, protein, fat, some vitamins and minerals, plant sterols, antioxidants, and other phytonutrients — but the nutritional profile of each type differs. Their protein content and quality varies — only almonds, peanuts and pistachios provide approximately the same amount of protein as meat. However, the Protein Quality Score for most nuts ranges from 46% to 61%, with lysine as the limiting amino acid. Pistachio nuts come close to a 100% score, but fall short in lysine (97%) and threonine (96%). In a varied diet, other protein sources easily provide the lacking amino acids. Nuts also supply arginine, a nonessential amino acid that is a precursor for nitric oxide, which may play a role in reducing cardiovascular disease (CVD) risk, especially when not competing with lysine for transport. Nuts contain 46% to 76% total fat, much of which is unsaturated. Macadamia nuts have the highest percentage of saturated fat (SFA) at 12%, and monounsaturated fat (MUFA) at 59%. Hazelnuts, pecans and almonds also have considerable amounts of MUFA in the range of 34% to 46%. Walnuts have the highest amount of polyunsaturated fat (PUFA) at 47%, the lowest amount of MUFA, at 9% and are the only nut with a significant amount of omega-3 fatty acid (9%). In fact, 1 oz. of walnuts meets the 2002 dietary recommendation of the Food and Nutrition Board of the National Academies’ Institute of Medicine for omega-3 fatty acids. Nuts to your healthNuts may have a positive impact on reducing disease risk, most likely due to their unsaturated fat, fiber and antioxidants. A number of epidemiological studies provide evidence of nuts’ protective effect in prostate cancer and CVD. Clinical intervention trials using mixed nuts demonstrated significant reduction in total cholesterol by 7% to 25% and LDL cholesterol by 10% to 33%, with no significant effect on HDL cholesterol. Some studies also showed a significant decrease in triglycerides (TG). Concerns that increasing consumption of nutrient-dense, calorific nuts will lead to weight gain and exacerbate a growing obesity problem are not corroborated by research findings from most nut-consumption studies. In 2001, researchers at Brigham and Women’s Hospital and the Harvard School of Public Health in Boston reported on a study comparing a calorie-controlled, low-fat diet (20% of calories) with a moderate-fat Mediterranean-style diet (35% of calories), which included a high amount of unsaturated fat from tree nuts, peanuts, and canola and olive oils. After six months, both groups showed comparable weight loss, but after 18 months, a larger percentage of the moderate-fat group was still participating in the study, and at 30 months, maintaining a significant weight loss. The researchers attributed this better long-term compliance to increased palatability and greater variety of food choices. A study from Purdue University, West Lafayette, IN, looked at the effects of chronic peanut consumption on energy balance and hedonics in healthy, normal-weight individuals. Subjects showed little change in energy balance due to dietary compensation attributed to peanuts’ high-satiety value. Additionally, the enjoyment ratings of peanuts remained high throughout the five-month study. Recently, numerous studies have confirmed that almonds, hazelnuts, macadamia nuts, peanuts, pecans, pistachios and walnuts significantly reduce CVD risk factors. One study on almond-enriched diets reported no change in insulin sensitivity and an improved serum-lipid profile in healthy adults, as well as no change in glycemia and serum lipid changes similar to high MUFA oils in individuals with type 2 diabetes. Some studies compared nut consumption to the Dallas-based American Heart Association’s Step I or Step II diets, or to a Mediterranean or Asian diet, and in all cases, the nut diets had an advantage: • Macadamia nuts lowered TG while the Step I diet raised it.• A diet high in MUFAs from olive or peanut oil and peanuts and peanut butter improved plasma cholesterol and TG concentrations better than a Step II diet without affecting HDL-cholesterol.• A pecan-enriched Step I diet (20% isoengeretic replacement) outperformed the Step I diet.• Walnuts added to cholesterol-lowering Step I, Mediterranean and Asian diets, while maintaining fat and energy levels, improved lipid profiles. The Asian-diet data indicated that the omega-3 fatty acid (alpha-linoleic) played a role in lowering the LDL-cholesterol in women. Incorporating nuts into foodsA word of caution — peanuts and tree nuts are leading causes of severe allergic reactions. Highly sensitive individuals can react to traces of an allergen and, therefore, it is imperative that the presence of peanuts and tree nuts, or even the possibility of their presence, be identified on product labels. Most individuals who have a known allergy to peanuts or a specific tree nut are advised to avoid peanuts and all tree nuts. Nuts serve as an opportunity to create nutrient-dense, tasty foods that add beneficial MUFAs to the diet. As a substitute for high-fat foods with fewer nutrients, they may satisfy the desire for fatty foods and increase satiety without increasing weight. Each type of nut offers a unique taste profile and mix of important nutrients and phytochemicals. Since no one nut is a “magic potion” for health, consumers are encouraged to eat a variety of nuts, and manufacturers have many options for incorporating nuts into foods. Angela M. Miraglio ([email protected]) is a registered dietitian and Fellow of the American Dietetic Association from Des Plaines, IL. Her firm, AMM Food & Nutrition Consulting, provides communications and technical support to food and beverage companies and associations. 3400 Dundee Rd. Suite #100Northbrook, IL 60062Phone: 847-559-0385Fax: 847-559-0389E-Mail: [email protected]Website: www.foodproductdesign.com |
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