Nuts – nutrition and health benefits of daily use
Charlene Rainey
When you are considering what to include in a balanced healthy diet, there are more than just a few reasons to choose nuts. Frequent nut consumption has been shown to reduce the risk factors for some chronic diseases, such as heart disease. Yet a recent survey of Americans reported nut consumption to be on the decline. Because nuts offer protection from chronic diseases, we may be avoiding the very thing that is needed in the American diet. So what is it about nuts that accounts for these health benefits? It just may be the synergistic effect of several nut nutrients and components.
TRADITIONAL USES
Thoughout history and around the world, nuts have been cherished, and their uses have varied. From recipe ingredients to travelers’ snacks and from winter staples to imported delicacies, nuts have been enjoyed around the world throughout time.
Pistachios date back as far as the Stone Age of 7000 BC. Romans thickened dishes with ground nuts, as did the Persians and Arabs. In 10th century Baghdad, a dish named Harisa was almond-thickened for a creamy sauce over stew. Nearly 400 years later, it had become popular in Europe. In the sixth century BC, Solon forbid the exporting of produce from Greece during a time when nut trees flourished in the Attic landscape. The Greek Empire needed to meet the urgent needs for the basics of life. Hais is a travelers’ dish made from a variety of pounded nuts and dried fruit rolled into balls and dusted with powdered sugar. Nuts made their way from Persia to China to be considered an imported delicacy. Yet, in Scandinavia, nuts were grown as a staple that could be dried and stored for the long, harsh winters.[1]
DISPELLING THE MYTHS
Because nuts have been a natural selection as food for humans since the beginning of time, why, in this day and age, are these natural whole foods being avoided? Surveys tell us that American consumers have some misconceptions about nuts (in other words, some nutty ideas about nuts.)
Myth: A surprising number of Americans believe that nuts contain cholesterol.
Fact: Nuts, as plant food, contain no cholesterol; the fact is that no plants have cholesterol. Found in every cell of every animal, cholesterol is what makes up part of the cell membrane. In plants, fiber makes up the cell walls. This is one of the main differences between plant and animal foods. All plants have fiber, and all animals have cholesterol.
Much nutrition education is needed about this simple fact. FDA rules for making nutrient content claims on food labels emphasize that plant foods, like nuts, have never contained cholesterol and should be called “Cholesterol Free Foods” so that consumers will not confuse plant foods with foods that have been reformulated to remove cholesterol. Nutritionists have long known these facts, but it is important to remember the prevailing misconceptions of the consuming public. They still need the facts about plant foods and, most especially, about nuts because daily nut consumption has been shown to lower blood cholesterol.[2]
Myth: Amount of nuts consumed per eating occasion may be too high.
Fact: National consumption survey data confirms that the amount consumed per eating occasion is typically small, at 1 oz.[3] This amount fits easily into a balanced diet. In setting dietary recommendations, the World Health Organization has recommended a daily consumption of 400 g of fruits and vegetables, which is to include a 30-g serving of nuts and seeds (about 1 oz) on a daily basis.[4] Because nuts vary in size, household measures, such as cups and tablespoons, are inconsistent. One ounce of nuts is usually less than one-quarter cup, or [tilde]15-25 nuts — a small handful.
Myth: You cannot lose weight eating nuts.
Fact: Clinical trials have shown weight loss success with a snack of nuts before lunch and one before dinner. Two groups of dieters were kept on a 1300-kcal/d weight-loss diet. One group snacked on peanuts before meals, and the control group snacked on the same number of calories but ate other popular snacks, such as pretzels or potato chips. Both the nut snackers and the control group lost about 3 pounds in 2 weeks.[5] This is not surprising because both groups had the same calorie intake, and snacks before meals have long been shown to suppress the appetite and help maintain low caloric intakes. Consumption of nuts in moderation is compatible with a weight reduction diet.
HEALTH BENEFITS
Protection Against Heart Disease. Several studies have looked at the effect of frequent nut consumption on the risk of first coronary death from coronary, and risk of ischemic heart disease. The Adventist Health Study looked at a group of 31,000 people and showed the risk of death from coronary was reduced significantly by consuming nuts more than five times a week. In men, the risk of first coronary was delayed by 5 years with frequent nut consumption.[6-8] The risk of ischemic heart disease was also reduced with frequent nut consumption, and an analysis of the Iowa Women’s Health study produced similar results.[9]
Diabetes. New guidelines for diabetics suggest that diets should be individualized and have more of an emphasis on monounsaturated fats. Clinical trials have shown that diets high in monounsaturated fats and low in carbohydrates produce more desirable plasma glucose, lipid, and insulin profiles. Nuts fit perfectly into this diabetic diet and are a suitable evening snack with a low carbohydrate, high protein, and high monounsaturated fat profile.[10-12]
Nutrient Density. The nutrient composition of some common nuts is given in Table 1. Although nutrient levels vary for different nut types, among them you will find good sources — about 10% of the Daily Value (DV) — of fiber, thiamin, niacin, folate, phosphorus, and zinc and excellent sources — about 20% or more of the DV — of vitamin E, magnesium, selenium, copper, and manganese.
Table 1
Nutrient Content of Selected Nuts(a) per 1-ounce (28-g) Serving
Nutrient Units Peanut Almond Cashew Brazil nut
Calories kcal 158.8 164.9 160.7 183.7
Total fat g 13.8 14.6 13.0 18.5
Saturated fat g 1.9 1.4 2.6 4.5
Polyunsaturated fat g 4.4 3.1 2.2 6.8
Monounsaturated fat g 6.8 9.5 7.6 6.4
Cholesterol mg 0.0 0.0 0.0 0.0
Sodium mg 5.0 3.1 4.5 0.6
Potassium mg 197.4 205.0 158.2 168.0
Carbohydrate g 4.5 5.7 9.2 3.6
Dietary fiber g 2.0 3.1 1.7 1.6
Sugars g 1.0 1.6 1.7 0.7
Protein g 7.2 5.6 4.3 4.0
Vitamin A DV(b) 0 0 0 0
Vitamin C DV 0 0 0 0
Calcium DV 3 7 1 5
Iron DV 7 6 9 5
Vitamin E DV 12 33 1 11
Thiamin DV 12 4 4 19
Riboflavin DV 2 13 3 2
Niacin DV 17 5 2 2
Vitamin B6 DV 5 2 4 4
Folate DV 17 4 5 0
Pantothenic acid DV 5 1 3 1
Phosphorus DV 11 15 14 17
Magnesium DV 12 21 18 16
Zinc DV 6 5 10 9
Selenium DV 3 2 8 920
Copper DV 16 13 31 25
Manganese DV 27 32 12 11
Nutrient Pecan Walnut
Calories 186.8 179.8
Total fat 18.9 17.3
Saturated fat 1.5 1.6
Polyunsaturated fat 4.7 11.0
Monounsaturated fat 11.8 4.0
Cholesterol 0.0 0.0
Sodium 0.3 2.8
Potassium 109.8 140.6
Carbohydrate 5.1 5.1
Dietary fiber 1.8 1.2
Sugars 1.1 0.6
Protein 2.2 4.0
Vitamin A 1 1
Vitamin C 1 1
Calcium 1 3
Iron 3 4
Vitamin E 4 4
Thiamin 16 7
Riboflavin 2 2
Niacin 1 1
Vitamin B6 3 8
Folate 3 5
Pantothenic acid 5 2
Phosphorus 8 9
Magnesium 9 12
Zinc 10 5
Selenium 5 3
Copper 17 19
Manganese 63 41
Manganese is essential as both an activator and a component of several enzymes. The progress of manganese research has been hampered by the lack of a practical method to assess its status, function, and intake requirements in humans. However, manganese has been shown to be essential in every animal species, and deficiency signs in humans include reproductive problems, retarded growth, congenital birth defects, abnormal bone and cartilage formation, and impaired glucose tolerance.[25,26]
Zinc is an essential component of a large number of enzymes needed in most major metabolic pathways. It is involved in the synthesis and breakdown of carbohydrates, fats, proteins, and nucleic acids and also acts to stabilize the structure of subcellular components and membranes. The body does not store very much readily-available zinc, so a regular intake is important. Deficiency signs, such as loss of appetite, retarded growth, skin changes, and immunity problems, appear rapidly when a low-zinc diet is introduced.[25,26]
Selenium is an essential component of an enzyme that, along with vitamin E and other enzymes, makes up one of the body’s antioxidant defense systems.[26] Its interrelationship with vitamin E is so close that many diseases caused by simultaneous deficiencies in selenium and vitamin E can be treated with either substance. Brazil nuts are one of very few foods that are exceptionally high in selenium, which has been shown to significantly reduce tumor incidence in cancer prevention studies. The selenium in Brazil nuts was found to be just as bioactive in these studies as the supplement form, sodium selenite.[29]
Nuts are also one of the best dietary sources of the trace element boron, a probable essential mineral.[25,26] The boron levels of nuts are naturally high: about 640 [Mu]g/oz of almonds; 480 [Mu]g/oz of peanuts; and 200 [Mu]g/oz of pecans. Boron has been shown to increase concentrations of plasma estrogen and to assist with bone development.[31] Boron is also an antiinflammatory, which may help to decrease the risk of cardiovascular disease and arthritis.[20,32]
FOLATE AND OTHER B VITAMINS
Peanuts are a good source of folate, containing 9%-17% of the DV per serving. Folate is an essential coenzyme involved in many metabolic pathways, including the formation of nucleic acids, DNA and RNA.[25,33] Because it is necessary for cell division, folate is especially important for pregnant women and children. Neural tube birth defects (defects of brain or spinal cord) can occur if folate intake is insufficient before or during early pregnancy, but this risk is reduced by one-half when adequate folate levels are maintained prior to conception.[34-36]
Folate, and to a lesser extent, vitamin B6 intakes have been shown to decrease serum levels of homocysteine, a risk factor for cardiovascular disease (vitamin B6 generally ranges from 2% to 8% of the DV in nuts.) Researchers at the University of Washington recently estimated that perhaps 50,000 deaths per year could be prevented if People increased their intake of folate.[37] National data indicate that 88% of adults in the United States are not consuming enough.[38]
In addition to folate, peanuts are a good source of the B vitamins thiamin and niacin. Pecans are also a good source and Brazil nuts an excellent source of thiamin, and almonds are a good source of riboflavin. These B vitamins play many essential roles in the conversion of carbohydrates, proteins, and fats into energy.[25]
VITAMIN E, THE ANTIOXIDANT VITAMIN
It has been reported that many people do not consume the recommended daily intakes of vitamin E.[39] The need for this vitamin is even greater when the diet is rich in polyunsaturated fats. A single serving of nuts can provide up to 33% of the DV for vitamin E, which, as an antioxidant, is the body’s primary defense against oxidative cell damage. Vitamin E acts to trap free radicals in cell membranes, preventing oxidization of the unsaturated lipids vital to the cell’s integrity.[25] This protective effect is important to the health of all cells and helps to prevent a number of diseases, including cancer and heart disease.[40-42]
DIETARY FIBER
Per serving, nuts provide between 5% and 12% of the DV of 25 g of fiber in a 2000-kcal/d diet (Table 4). Dietary fiber is beneficial to the functioning of the digestive tract. It absorbs water, softening the stool and preventing constipation. In this way, it can help prevent hemorrhoids, varicose veins, hiatal hernias, and diverticulosis, Clinical trials have shown that dietary fiber can help to control diabetes, lower serum cholesterol, and possibly reduce the risk of some types of cancer.[25] Consumption studies have shown that dietary fiber intake is low in the typical American diet and should be increased from 12 g/d to 20 or 30 g/d.[43,44]
Table 4 Dietary Fiber Content (g) of Selected Nuts” per 1-oz 28-g) Serving
Total Soluble Insoluble
Peanut 2.0 0.5 1.4
Almond 3.1 0.3 2.8
Cashew 1.7 0.1 1.6
Brazil nut 1.6 0.2 1.4
Pecan 1.8 0.4 1.4
Walnut 1.2 0.4 0.8
[22.] Bhargava UC, Westfall BA, Siehr DJ. Preliminary pharmacology of ellagic acid from Juglans nigra (black wainut). J Pharmacol Sci 1968;57:1728-1732.[23.] Stoner GD, Mukhtar H. Polyphenols as cancer chemopreventive agents. J Cell Biochem 1995;Suppl 22:169S-S80.[24.] Pace-Asciak CR, Rounova O, Hahn SE, Diamandis EP, Goldberg DM. Wines and grape juices as modulators of platelet aggregation in healthy human subjects. Clin Chim Acta 1996;246:16%-182.[25.] National Research Council. Recommended Dietary Allowances. 10th ed. Washington DC: National Academy Press; 1989.[26.] World Health Organization. Trace elements in human nutrition and health. Geneva: World Health Organization; 1996.[27.] Klevay LM. Copper in nuts may lower heart disease risk. Arch Intern Med 1993;153:401-402.[28.] Ip C, Lisk DJ. Bioactivity of selenium from Brazil nut for cancer prevention and selenoenzyme maintenance. Nutr Cancer 1994;21:203-212.[29.] Varo P, Lahelma O, Nuurtamo M, Saari E, Koivistoinen P. Mineral element composition of Finnish foods: VII. Potato, vegetables, fruits, berries, nuts, and mushrooms. Acta Agric Scand 1980;22(Suppl):90S — 113S.[30.] Gormican A. Inorganic elements in foods used in hospital menus. I Am Diet Assoc 1970;56:397-403.[31.] Hunt CD. Metabolic responses of postmenopausal women to supplemental dietary boron and aluminum during usual and low magnesium intake: Boron, calcium, and magnesium absorption and retention and blood mineral concentrations. Am J Clin Nutr 1997;65:803-813.[32.] Hunt CD, Herbel JL, Idso JP. Dietary boron modifies the effects of vitamin [D.sub.3] nutriture on indices of energy substrate utilization and mineral metabolism in the chick. J Bone Miner Res 1994;9:171-181.[33.] Appling DR. Compartmentation of folate-mediated one-carbon metabolism in eukaryotes. FASEB J 1991;5:2645-2651.[34.] CDC. Recommendations for the use of folic acid to reduce the number of cases of spina bifida and other neural tube defects. MMWR Morb Mortal Wkly Rep 1992;41:1-7.[35.] Wald N. Prevention of neural tube defects: Results of the Medical Research Council Vitamin Study. Lancet 1991;338:153-154.[36.] Czeizel AE, Dudas I. Prevention of the first occurrence of neural-tube defects by periconceptual vitamin supplementation. N Engl J Med 1992;327:1832-1835.[37.] Boushey CJ, Beresford SAA, Omenn GS, Motulsky AG. A quantitative assessment of plasma homocysteine as a risk factor for vascular disease, probable benefits of increasing folic acid intakes. JAMA 1995;274:1049-1057.[38.] Subar AF, Block G, Janes LD. Folate intake and food sources in the U.S. population. Am J Clin Nutr 1989;50:508-516.[39.] Murphy SP, Subar AF, Block G. Vitamin E intakes and sources in the United States. Am J Clin Nutr 1990;52:361-367.[40.] Diplock AT. Antioxidant nutrients and disease prevention: An overview. Am I Clin Nutr 1991;53:189S-193S.[41.] Buiatti E, Palli D, Decarli A, et al. A case-control study of gastric cancer and diet in Italy: II. Association with nutrients. Int J Cancer 1990;45:896-901.[42.] Esterbauer H, Dieber-Rotheneder M, Striegl G, Waeg G. Role of vitamin E in preventing the oxidation of low-density lipoprotein. Am J Clin Nutr 1991;53:314S-321S.[43.] Lanza E, Jones Y, Block G, Kessler L. Dietary fiber intake in the U.S. population. Am J Clin Nutr 1987;46:790-797.[44.] Butrum RR, Clifford CK, Lanza E. NCI dietary guidelines: Rationale. Am J Clin Nutr 1988;48:888-895.[45.] United States Department of Agriculture. Nutrient Database for Standard Reference [machine-readable data set, Accession No. PB93-502771]. Release 10. Springfield (VA): National Technical Information Service; 1993.[46.] University of Minnesota School of Public Health, Nutrition Coordinating Center. Nutrition Data System. Version 2.5/7A/22. Minneapolis: University of Minnesota; 1995.[47.] Pennington JAT. Food Values of Portions Commonly Used. 15th ed. New York: Harper and Row; 1989.[48.] ESHA Research. Genesis R & D. Version 4.14. Salem (OR): ESHA Research; 1993.Here are just a few reasons to eat nuts daily:
Taste great Are a traditional whole food Lower the risk of heart
disease Fit into a weight
maintenance diet Provide a daily source of
antioxidants Are nutrient dense in up to
nine nutrients Provide a wide variety of
protective phytochemicals Compare well with other
popular snacks Provide naturally
monounsaturated and
polyunsaturated fatty acids
with no trans fatty acids Add much-needed dietary
fiber to your diet Are a unique source of
essential minerals As always nuts are
cholesterol-free
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