Tackling Obesity in America – Go Nuts!

Marjet D. Heitzer, Ph.D.

The Plateau-proof Diet Foundation

http://www.plateauproofdiet.com

Email: [email protected]

Nuts are an excellent source of protein as well as fiber,
vitamin E, and omega-3 fatty acids. Although nuts are an energy
rich food, composed of 45-75% fat depending on the type of nut,
that fat is largely unsaturated. Along with the benefits of
higher fiber, vitamin E, and omega-3 fatty acid consumption,
nuts provide other health benefits such as increasing insulin
sensitivity, endothelial cell (the cells that line blood
vessels) function, and decreasing blood lipid (cholesterol)
levels, thereby decreasing the risk of coronary artery disease
(CAD).

Recent studies suggest that consumption of nuts, particularly
almonds, peanuts, pecan nuts, or walnuts may benefit the heart.
Particularly, eating 4-5 servings (50-100 grams/day) each week
lowers blood lipid levels and LDL (bad cholesterol) within a few
short weeks when it is substituted for traditional, highly
saturated fats (1). Furthermore, 1 ounce of nuts per day
decreases the risk of fatal coronary heart disease by 45% when
they are substituted for saturated fat and 30% when substituted
for carbohydrates (2). The lipid lowering affects of nuts were
seen in both lean and obese individuals, with and without
hypercholesterolemia, indicating that consumption of nuts may
decrease cholesterol levels in individuals with preexisting high
cholesterol (3). It should be noted here that not all nuts
reduced cholesterol levels. Increased consumption of macadamia
nuts as well as hazelnuts did not alter cholesterol levels,
indicating that the health benefits from eating nuts may not be
gained if those nuts are selected.

There is epidemiological (studies involving the distribution
of health-related issues within certain populations) evidence
that areas such as the Mediterranean region that consume a diet
rich in nuts have a lower proportion of sudden cardiac death.
Furthermore, there is an inverse relationship between nut
consumption and sudden cardiac death as well as obesity, meaning
that a person that consumes more nuts is less likely to die from
CAD or to be obese. Finally, nut consumption is inversely
associated with the risk of development of type II diabetes,
presumably because individuals who consume nuts on a regular
basis are less likely to be obese (4).

How do nuts decrease the risk of coronary heart disease? First,
nuts are composed mainly of monounsaturated fats, and
substitution of foods containing saturated fat with unsaturated
fat will improve blood lipid levels, thereby decreasing the risk
of heart disease. Additionally, nuts are great source of other
heart healthy items, such as vitamin E, fiber, magnesium,
potassium and arginine.

Vitamin E has antioxidant properties, making it a great
vitamin in the fight against heart disease. In fact, Vitamin E
is one of the most abundant naturally occurring antioxidants
found in foods. Antioxidants protect against oxidative damage, a
phenomenon that occurs in many diseases including heart disease
and cancer (5). Vitamin E inhibits the oxidation of LDL (bad
cholesterol). Oxidation of LDL is one of the initial steps that
occur during atherosclerosis, leading to endothelial cell damage
as well as narrowing of blood vessels. Because nuts contain high
amounts of the antioxidant vitamin E, it is thought that this
may be one of many ways which they help lower your risk of CAD.

Omega-3 fatty acids are also found in nuts and have
anti-atherogenic properties. Omega-3 fatty acids inhibit
platelet aggregation (clot formation). Furthermore, omega-3
fatty acids improve endothelial function, protecting endothelial
cells from damage (2). Endothelial dysfunction occurs early in
the progression of atherosclerosis (narrowing or hardening of
the arteries). Studies have also reported an inverse
relationship between fish oils that contain high amounts of
omega-3 fatty acids and mortality from coronary artery disease
(6).

Fiber has also been shown have beneficial health benefits (7).
Fiber lowers blood cholesterol as well as decreasing
hypertension (high blood pressure). Because most nuts are high
in fiber, it is considered one of the many ways in which nut
consumption leads to reduced risk of CAD. So, a combination of
lowering blood cholesterol levels as well as improving
endothelial function culminates in improved heart health with
the consumption of nuts.

Several studies have addressed the question: Does increased
nut consumption lead to weight gain? Although the beneficial
effects of nuts on CAD have been well recognized, given the
obesity epidemic in the United States physicians were concerned
about possible weight gain induced by nut consumption because
nuts are so high in fat although it is the good, unsaturated
fat. The resounding answer is No, nuts do not increase body mass
index (BMI). In fact, there was an inverse relationship between
nut consumption and BMI, indicating that a person eating nuts is
less likely to be overweight (8). In the above mentioned
studies, there was no significant change in weight after
increasing nut consumption. In fact, there was a small tendency
towards weight loss while on the nut diet and females with the
highest BMI actually lost weight (8). Foods which are high in
protein and unsaturated fat, such as nuts, may increase resting
energy expenditure by increasing diet-induced thermogenesis.
Furthermore, high fiber and protein foods tend to enhance
satiety, or the feeling of being full.

Nuts whether used as food replacement or snacks are an
excellent food choice for the fight against obesity in America.
Go nuts!

1. Fraser, G. E. Nut consumption, lipids, and risk of a coronary
event. Clin Cardiol, 22: III11-15, 1999.

2. Nash, S. D. and Westpfal, M. Cardiovascular benefits of nuts.
Am J Cardiol, 95: 963-965, 2005.

3. Sabate, J. and Fraser, G. E. Nuts: a new protective food
against coronary heart disease. Curr Opin Lipidol, 5: 11-16,
1994.

4. Jiang, R., Manson, J. E., Stampfer, M. J., Liu, S., Willett,
W. C., and Hu, F. B. Nut and peanut butter consumption and risk
of type 2 diabetes in women. Jama, 288: 2554-2560, 2002.

5. Munteanu, A., Zingg, J. M., and Azzi, A. Anti-atherosclerotic
effects of vitamin E–myth or reality? J Cell Mol Med, 8: 59-76,
2004.

6. Holub, D. J. and Holub, B. J. Omega-3 fatty acids from fish
oils and cardiovascular disease. Mol Cell Biochem, 263: 217-225,
2004.

7. Castro, I. A., Barroso, L. P., and Sinnecker, P. Functional
foods for coronary heart disease risk reduction: a meta-analysis
using a multivariate approach. Am J Clin Nutr, 82: 32-40, 2005.

8. Sabate, J. Nut consumption and body weight. Am J Clin Nutr,
78: 647S-650S, 2003.

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