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Introduction

Nuts and seeds are the vehicle for plant reproduction. Locked inside them is the potential for an entire plant. It is truly amazing to think that a giant oak tree began its life as an acorn. A nut commonly refers to the shell-encased seeds of a tree, however, one of the chief foods that we consider as a nut, the peanut, does not fit the strict definition of a nut as it is actually a legume.

In the United States, peanuts are by far the leading nut crop as they account for greater than 70% of the yearly nut production. Peanuts are followed by almonds, walnuts, and pecans. Unfortunately, most nuts are being consumed after they have been fried in fat and salted or as ingredients in cookies, candies, and confections. I definitely advocate the use of mostly raw or lightly roasted fresh nuts and seeds rather than commercially roasted and salted nuts and seeds.

Health Benefits

As more Americans are seeking healthier food choices, nut and seed consumption is on the rise. Nuts and seeds provide excellent human nutrition, they are especially good sources of essential fatty acids, vitamin E, protein, and minerals. They also provide valuable fiber components, important phytonutrients in nuts and seeds include protease inhibitors, ellagic acid, and other polyphenols.

Because of the high oil content of nuts and seeds, one would suspect that the frequent consumption of nuts would increase the rate of obesity. But, in a large population study of 26,473 Americans it was found that the people who consumed the most nuts were less obese. A possible explanation is that the nuts produced satiety, a feeling of appetite satisfaction. This same study also demonstrated that higher nut consumption was associated with a protective effect against heart attacks (both fatal and nonfatal). Four other large studies, including the Nurses Health Study, the Iowa Health Study, and the Physicians Health Study, all found that nut consumption is linked to a lower risk for heart disease. Researchers who studied data from the Nurses Health Study estimated that substituting nuts for an equivalent amount of carbohydrate in an average diet resulted in a 30% reduction in heart disease risk. Researchers calculated even more impressive risk reduction--45%--when fat from nuts was substituted for saturated fats (found primarily found in meat and dairy products).(1)

Nuts Provide Arginine

Nuts are the best dietary source for arginine - an amino acid that plays an important role in wound healing, detoxification reactions, immune functions, and promoting the secretion of several hormones including insulin and growth hormone. Recently there has been a considerable amount of scientific investigation regarding arginine's role in the formation of nitric oxide. This compound plays a central role in determining the tone of blood vessels. Specifically, it exerts a relaxing effect on blood vessels thereby improving blood flow. Normally, the body makes enough arginine, even when the diet is lacking. However, in some instances the body may not be able to keep up with increased requirements and higher dietary intakes may prove useful.

Arginine supplementation has been shown to boost immune function and be beneficial in a number of cardiovascular diseases including angina pectoris, congestive heart failure, high blood pressure, and peripheral vascular insufficiency (decreased blood flow to the legs or arms). By increasing nitric oxide levels, arginine supplementation improves blood flow, reduces blood clot formation, and improves blood fluidity (the blood becomes less viscous and, therefore, flows through blood vessels more easily). The degree of improvement offered by arginine supplementation in angina and other cardiovascular diseases can be quite significant as a result of improved nitric oxide levels. These benefits may also be attainable by eating foods high in arginine like nuts.(2)

Nut Consumption and Diabetes Risk

Nut consumption has also been shown to lower the risk for diabetes. This benefit may relate to their ability to improve cell membrane structure and function. According to modern pathology, or the study of disease processes, an alteration in cell membrane function is the central factor in the development of virtually every disease. As it relates to diabetes, abnormal cell membrane structure due to eating the wrong types of fats lead to impaired action of insulin.

The type of dietary fat profile linked to type 2 diabetes is an abundance of saturated fat and trans fatty acids (margarine) along with a relative insufficiency of monounsaturated and omega-3 fatty acids. One of the key reasons appears to be the fact that since dietary fat determines cell membrane composition such a dietary pattern leads to reduced membrane fluidity which in turn causes reduced insulin binding to receptors on cellular membranes and/or reduced insulin action. Particularly harmful to cell membrane function are margarine and other foods containing trans fatty acids and partially hydrogenated oils.

In contrast, to the dampening of insulin sensitivity caused by margarine and saturated fats, clinical studies have shown that monounsaturated fats and omega-3 oils improve insulin action.(3) Adding further support is that fact that population studies have also indicated that frequent consumption of monounsaturated fats such as olive oil, nuts, and nut oils and omega-3 fatty acids from fish protect against the development of type 2 diabetes. For example, one recent study showed that that consumption of nuts was inversely associated with risk of type 2 diabetes, independent of known risk factors for type 2 diabetes, including age, obesity, family history of diabetes, physical activity, smoking, and other dietary factors. What the term inversely associated means is that the higher the intake of nuts, the less likely a woman would develop type 2 diabetes. What was really amazing was that this relationship was seen even in woman who were obese.(4)

In addition to nut consumption, in order to improve cell membrane structure and function, I recommend using RxOmega-3 Factors - a pharmaceutical grade fish oil supplement from Natural Factors. The benefits of the omega-3 oils from fish oils well known. Adding a fish oil supplement to your daily routine provides extra insurance that you are getting sufficient levels of these important oils. Using a high quality fish oil supplement is the perfect solution to people wanting the health benefits of fish oils without the mercury and other contaminants often found in fish. Each capsule of RxOmega-3 Factors provides 600 mg of long-chain omega-3 fatty acids (400 mg EPA/200 mg DHA). We recommend one capsule daily for general health, if greater support is needed the dosage increases to two to three capsules daily.

Cooking with Nut Oils

The best oils to cook with in baking recipes, stir fries, and sautés, are the monounsaturated oils. While olive oil and canola oil are by far the most popular monounsaturated fats in use, nut oils may prove superior to both. In particular, macadamia nut oil is superior to cook with because of lower level of polyunsaturated oil (3% for macadamia nut oil vs. 8% for olive and 23% for canola). As a result, while olive oil and canola oil can form lipid peroxides at relatively low cooking temperatures, macadamia nut oil is stable at much higher temperatures (over twice that of olive oil and four times more stable than canola). Macadamia oil, like olive oil is also very high in natural anti-oxidants. In fact it contains over 4.5 times the amount of vitamin E as olive oil. For more information on macadamia nut oil, visit www.macnutoil.com.

Selecting and Storing Nuts and Seeds

In general, nuts and seeds, due to their high oil content, are best purchased and stored in their shells. The shell is a natural protector against free radical damage caused by light and air. Make sure the shells are free from splits, cracks, stains, holes, or other surface imperfections. Do not eat or use moldy nuts or seeds as this may not be safe. Also avoid limp, rubbery, dark, or shriveled nut meats. Store nuts and seeds with shells in a cool, dry environment. If whole nuts and seeds with their shells are not available, make sure they are stored in air-tight containers in the refrigerator or freezer. Crushed, slivered, and nut pieces are most often rancid. Prepare your own from the whole nut if a recipe calls for these.

In addition to simply eating nuts and seeds as snacks, they can be added to many foods for the unique flavor. With the aid of a food processor, nut and seed butters can be prepared. Most nuts and seeds have enough natural oils, but occasionally you may need to add some additional oil. Keep nut butters in air-tight containers in the refrigerator.

Practical Application

Try to have at least one serving of nuts or seeds (one serving equals 1/4 cup) and 3 tablespoons of the healthy oils daily. Use olive, macadamia, or canola oil to replace the butter, margarine, and shortening that you use for cooking. Use flaxseed or olive oil in homemade salad dressings. Avoid using safflower, sunflower, soy and corn oil because they contain too much omega 6 fatty acid.

My last recommendation is to try to mix it up a bit, by eating a variety of nuts and seeds such as almonds, brazil nuts, walnuts, pecans, flaxseeds, sunflower seeds, and pumpkin seeds.


Key References:

1. Hu FB, Stampfer MJ. Nut consumption and risk of coronary heart disease: a review of epidemiologic evidence. Curr Atheroscler Rep 1999;1(3):204-9, 1999
2. Flynn NE, Meininger CJ, Haynes TE, Wu G. The metabolic basis of arginine nutrition and pharmacotherapy. Biomed Pharmacother 2002;56(9):427-38.
3. Rivellese AA, De Natale C, Lilli S. Type of dietary fat and insulin resistance. Ann N Y Acad Sci 2002;967:329-35.
4. Jiang R, Manson JE, Stampfer MJ, et al. Nut and peanut butter consumption and risk of type 2 diabetes in women. JAMA 2002;288(20):2554-60.