New Study Shows Walnuts Lower Cholesterol More Than Fish
LOMA LINDA, CA--(Marketwire - April 13, 2009) -
Loma Linda University research just
published in the American Journal of Clinical Nutrition compares the
effects of walnuts and fatty fish in the fight against heart disease,
demonstrating that in healthy individuals, walnuts lower cholesterol more
than fish, while fatty fish lower triglycerides. Both can reduce the
overall risk of coronary heart disease.
"The practical significance of the study is that eating an
easy-to-incorporate amount of walnuts and fatty fish can cause meaningful
decreases in blood cholesterol and triglycerides even in healthy
individuals," says lead author Sujatha Rajaram, PhD, associate professor in
the department of nutrition at Loma Linda University School of Public
Following the qualified health claim issued by the Food and Drug
Administration, researchers found that incorporating approximately 1.5
ounces of walnuts (42 grams, a handful of whole nuts or about three
tablespoons of chopped nuts) into the daily diet lowered serum total
cholesterol by 5.4 percent and LDL (bad) cholesterol by 9.3 percent
compared to a control diet based on USDA recommendations.
Using American Heart Association guidelines, the researchers also found
that a diet including two servings of fatty fish per week (roughly four
ounces each as recommended by the AHA for individuals without heart
disease) decreased triglyceride levels by 11.4 percent. Additionally, it
increased HDL (good) cholesterol by 4 percent, but also slightly increased
LDL (bad) cholesterol compared to the control diet. The fish used in this
study was salmon.
"Both plant- and marine-derived omega-3 fats are cardioprotective, and
since they seem to be effective for lowering different risk factors, it
would be prudent to include both in the diet," says Dr. Joan Sabaté, MD,
DrPH, one of the authors of the study and chair of the department of
Dr. Rajaram adds, "Individuals should strive to include a plant source of
omega-3 fat in their diet, like walnuts, and also a marine source of
omega-3 fat. If fatty fish is not a preferred option for marine-derived
omega-3 fat, other options include microalgae oil or DHA-enriched eggs."
The department of nutrition has significant experience conducting tightly
controlled feeding studies among varying populations. This one, conducted
with a healthy population, is the fifth study testing the health and
nutrition properties of walnuts. This study differs from the previous
studies in that it compared a plant source of the omega-3 fatty acid with a
marine source, the first study to make this comparison. Subjects were
randomly assigned to each of the three diets for eight weeks over a 24-week
feeding schedule. This gave the researchers a chance to compare the effect
of each diet on each participant.
Loma Linda University is a health-science university in Southern California
known for its nutrition and lifestyle research in relation to chronic
diseases. For more information about the University please visit the
website (www.llu.edu). To access the American Journal of Clinical Nutrition
manuscript reference doi: 10.3945/ajcn.2009.26736S on the Internet.
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