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:
- 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
- Flynn NE, Meininger CJ, Haynes TE, Wu G. The metabolic basis
of arginine nutrition and pharmacotherapy. Biomed Pharmacother
2002;56(9):427-38.
- Rivellese AA, De Natale C, Lilli S. Type of dietary fat and
insulin resistance. Ann N Y Acad Sci 2002;967:329-35.
- 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.
Michael T. Murray, N.D., is widely regarded as one of world's leading authorities on natural medicine. A prolific author, Dr. Murray has written over 20 books on health and nutrition including the best-selling Encyclopedia of Natural Medicine and his latest book The Encyclopedia of Healing Foods. Dr. Murray is also Director of Product Development and Education for Natural Factors one of the leading manufacturers of natural products.
