Pesticide and Environmental Update
Walnuts
and Heart Health
By Marcia Wood
Walnuts, already shown in some studies to reduce "bad" (LDL)
cholesterol, may have yet another way of enhancing cardiovascular health.
University of California-Davis (UC-Davis) scientists and their
Agricultural Research Service (ARS) and University of Padova (Italy)
co-investigators have found that laboratory hamsters that ate feed
containing walnuts had significantly lower levels of a natural chemical
called endothelin. The compound causes inflammation of arteries and growth
of sticky deposits—called plaque—on blood vessels. These conditions
contribute to heart disease, the leading cause of death in the United
States.
In this six-and-one-half-month study of about 100 hamsters, walnuts
apparently suppressed heart artery endothelin. Walnuts had that effect at
all levels tested, which were the equivalent of a human eating from three
to eight handfuls of walnuts a day.
For the study, scientists used English walnuts, the kind sold in
supermarkets nationwide, adding them to the hamsters' meals as a finely
ground powder.
Research chemist Wallace H. Yokoyama, with the ARS Western Regional
Research Center in Albany, Calif., collaborated in the study, which was
led by research nutritionist Paul A. Davis at UC-Davis.
The study, reported earlier this year in the Journal of Nutrition,
builds upon observations by researchers elsewhere that eating walnuts may
affect blood vessels directly. The California study is the first to
demonstrate this by showing walnuts' ability to suppress artery endothelin
in lab animals. Additional studies are needed to determine if this
beneficial effect occurs in people who eat a moderate amount of walnuts.
Walnuts are a good source of fiber, healthful fatty acids and minerals.
They can be sprinkled on breakfast cereal, tossed with crisp greens for a
lunch or dinner salad, or simply eaten out of hand as a snack.
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