Dr. Perricone's No. 8 Superfood: Nuts and Seeds
- When thoughts turn to food between meals, enjoy a handful of raw, unsalted nuts. They're extremely filling and satisfying—and healthful.
- Add some nuts to regular meals—a tablespoon of chopped almonds on your oatmeal, a tablespoon of walnuts in your lunchtime salad or a hazelnut-encrusted grilled salmon fillet. Nuts are so versatile they can take the place of flour and breadcrumbs—with a lot more flavor and health benefits. Just remember, as with all things, to use moderation.
Learn more about the benefits of nuts and seeds:
- Nuts, seeds and heart health
- Nutty, seedy cancer foes
- Nuts and diabetes
- In a nutshell: a rich but slimming snack
- Nuts and seeds in your diet
Studies involving more than 220,000 people show that "nutty" diets help reduce the risk of heart disease, the leading killer of both men and women in the United States. This should come as no surprise, as nuts contain powerful antioxidants and anti-inflammatories and like so many other diseases, heart disease is an inflammatory condition.
For example, consider these findings:
- The famous Seventh Day Adventists study followed more than 30,000 church members over a 12-year period. The results showed that even in this healthy-living, largely vegetarian group, those who ate nuts at least five times per week cut their risk of dying from coronary heart disease (CHD) by 48 percent, compared with those who ate nuts less than once weekly. They also cut their risk of a nonfatal heart attack by 51 percent.
- In a study involving more than 3,000 African-American men and women, those who consumed nuts at least five times a week cut their risk of dying from CHD by 44 percent, compared with those who ate nuts less than once weekly.
- The results of the 14-year Nurses' Health Study—which involved more than 86,000 women—indicate that women who consume more than five ounces of nuts weekly will cut their risk of CHD by 35 percent, compared with those who eat less than one ounce per month. (Similar reductions seen in the risk of death from CHD and non-fatal heart attacks.) And, the 17-year Physicians' Health Study involving more than 21,000 men found that those who consumed nuts at least twice a week cut their risk of sudden cardiac death by 53 percent, compared with those who rarely ate nuts. (There was no significant decrease in the risk of nonfatal heart attack or nonsudden CHD death.)
- Heart-healthy protein: Most nuts are high in arginine, an amino acid that reduces cholesterol levels and, as a precursor to nitric oxide, dilates blood vessels, thus reducing blood pressure and the risk of angina, congestive heart failure and heart attack.
- Heart-healthy fats: Most of the fat in nuts consists of the polyunsaturated omega-3 and omega-6 varieties that reduce blood cholesterol levels. Numerous clinical studies have found that almonds, hazelnuts, macadamia nuts, peanuts, pecans, pistachio nuts and walnuts all reduce total cholesterol and LDL-cholesterol in people with normal-to-high cholesterol levels. And, the fatty compounds in nuts' phytosterols inhibit accumulation of fats in artery walls, which promotes angina, strokes and heart attacks.
- Heart-healthy vitamins: Vitamin E—an antioxidant in which almonds are especially rich—helps prevent the oxidation of cholesterol that leads to fatty buildup in the arteries. The B vitamin folate, found in many nuts, lowers high blood levels of homocysteine, a strong predictor of heart disease.
- Heart-healthy minerals: Nuts and seeds are generally rich in calcium, magnesium and potassium, all of which serve to reduce blood pressure.
- Heart-healthy phytochemicals: The coatings of all nuts and seeds—such as the thin brown papery layer coating almonds and peanuts—are rich in the antioxidant polyphenols associated with reduced risk of heart disease. (Processed nuts and seeds possess fewer of these antioxidants: choose raw nuts in the shell when possible.) Walnuts in particular are high in alpha-linolenic acid, an essential fatty acid that is protective to the heart and circulation.
The particular fats, antioxidant polyphenols and proteins that make nuts heart-healthy also help prevent cancer:
- Phytic acid is a natural plant antioxidant found in nuts and seeds. It serves as a potent antioxidant to help preserve seeds and may reduce the rate of colon cancer and other inflammatory bowel diseases via the same mechanism.
- The coatings of all nuts and seeds are rich in the antioxidant polyphenols associated with reduced risk of cancer. (This is another reason to choose raw nuts and seeds in the shell, versus processed nuts and seeds.)
- Beta-sistosterol and campesterol—two of the phytosterols in most nuts—appear to suppress breast and prostate tumors.
- The amino acid arginine abundant in most nuts—especially almonds—also inhibits tumor growth and boosts immunity.
- Walnuts are especially helpful because they contain ellagic acid—the cancer-fighting polyphenol antioxidant also found in pomegranates and red raspberries.
- Selenium, another key antioxidant factor and cancer-preventive mineral, is especially abundant in Brazil nuts.
Numerous studies show that nuts reduce the risk for diabetes: a benefit likely related to their fatty acids' ability to enhance cell membrane structure and function. Degradation in cell membrane function promotes development of virtually every disease and promotes chronic inflammation. The wrong types of fats in our diets precipitate an abnormal cell membrane structure, leading to impaired action of insulin.
Type 2 (adult onset) diabetes is associated with an excess of saturated fats and trans-fatty acids in the diet and a relative insufficiency of monounsaturated and omega-3 fatty acids. Margarine, supermarket brands of peanut butter and the vast majority of pre-packaged baked goods, including cakes, pies and cookies as well as any other foods containing partially hydrogenated oils, are high in trans-fatty acids, which are especially harmful to cell membrane function.
In contrast, monounsaturated fats and omega-3 fatty acids improve the efficiency of insulin. For example, among the more than 86,000 women followed over 16 years in the Nurses' Health Study, those who consumed an ounce of nuts at least five times a week cut their risk of developing type 2 diabetes by 27 percent, compared with those who rarely or never consumed nuts.
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While it may seem odd, diets that include moderate amounts of nuts—which are inherently high in fat and calories—help prevent obesity and even reduce weight. One study found that dieters on a calorie-controlled, "moderate-fat" (35 percent of calories) plan that included nuts and other good fats lost as much weight as dieters on a 20-percent-fat calorie-controlled plan. The moderate-fat group also maintained their weight loss better than the low-fat group over the 18-month test period and beyond—likely because the "moderate-fat, nuts-allowed" group reported fewer problems with sensations of hunger than the low-fat diet group did.
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Nuts and seeds add texture and flavor to salads and many recipes. Of course, they also make great snacks. Many people like to snack on nut butters, spread on crackers or fruit. I do not recommend buying nut butters prepared on site in stores because you can't know whether the grinder is clean and because the fresh nut butter is exposed to air and light as it emerges from the grinder. Frankly, you are better off buying pre-made nut butters from reputable natural food brands that do not add hydrogenated oils. It is fairly easy to make your own nut and seed butters in a food processor; just add additional oil as needed. As with nuts and seeds, keep homemade nut butters and open, store-bought nut butters in airtight containers in the refrigerator.
I recommend eating one serving of nuts or seeds (1/4 cup) every day. And, in addition to olive oil, it is healthy to cook with macadamia, peanut, sesame or canola oil instead of butter, margarine or shortening. Needless to say, you need to consider the distinct flavor of each nut oil: Peanut oil is ideal for many Asian meals. Never cook with fragile flax, hemp or walnut oils, as their delicate omega-3 fatty acids will oxidize under the exposure to heat and air and light. Use flaxseed, walnut, hemp seed or olive oil in homemade salad dressings. When possible, always buy organic nuts, seeds and oils.
All nuts and seeds are healthful in moderation. The key is to eat a variety. However, certain ones stand out for their exceptionally healthful fatty acid composition. I recommend the following nuts and seeds because they are the highest in either omega-3 or omega-9 (monounsaturated) fatty acids. Both fatty acids are heart-healthy; omega-3s are powerful anti-inflammatory agents as well. The fatty acid content of each nut or seed is expressed here as a percent of its total fat content (note: The percentage figures provided are averages, as the fatty acid content of nuts and seeds varies considerably among data sources):
- Highest in omega-9 monounsaturated fatty acids: Macadamia (50 percent), pecans (45 percent), almonds (42 percent), filberts (38%), pistachios (35 percent), Brazil nuts (32 percent), peanuts (23 percent), sesame seeds (21 percent). Note: Unlike most nuts, pistachios are high in antioxidant carotenoids.
- Highest in omega-3 polyunsaturated fatty acids: Flaxseed (50 percent), walnuts (8 percent), pumpkin seed (7 percent).
The appetite-suppressing and health benefits of nuts and seeds are lost when they are salted, oiled, roasted, stale or rancid. And, the fats in nuts and seeds are susceptible to oxidation after they are shelled and exposed to light and air—a process that destroys their nutritional value and degrades their taste.
Accordingly, nuts and seeds should be bought in small quantities and stored in their shells, which shield them against oxidation, in a cool, dry place. Discard any shells with cracks and any nuts or seeds that are discolored, limp, rubbery, moldy or shriveled or that have an "off" smell or taste. Store any shelled nuts or seeds in an airtight container in your refrigerator (one week or less) or freezer. Last, prepare your own crushed or slivered nuts, to ensure maximum freshness.
The enzyme inhibitors and phytates in nuts limit the availability of their nutrients. To maximize the nutritional value of nuts, soak nuts in salted water for six to eight hours, drain out the water and oven-dry the nuts on a cookie sheet on low heat. (Cashews become slimy after six hours.)
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