Crazy for snacks, go nuts, walnuts to be
exact.
Medical
researchers from the Yale-Griffin Prevention Research Center in Connecticut
have found evidence suggestive that adding walnuts to one's diet can protect
against diabetes and heart disease in at-risk individuals.
The
research found that daily intake of 56g* of walnuts improves endothelial
function in overweight adults with visceral adiposity. The addition of walnuts
to the diet does not lead to weight gain.
Walnuts
are a uniquely rich source of a-linolenic acid (ALA), and epidemiological
studies suggest that plant-derived ALA may confer particular cardiovascular
benefits. A meta-analysis investigating the impact of walnut consumption on
blood lipids showed that walnut-enriched diets significantly decreased total
cholesterol and low-density lipoprotein cholesterol (LDL-C) when compared with
control diets for the duration of the short-term trials. Furthermore, walnuts
are also rich in tocopherol, phenolic antioxidants, folic acid, and magnesium,
nutrients that have been shown to impact endothelial function favourably.
For
the study, a sample of 46 adults aged 30-75 were selected. Participants had a
Body Mass Index larger than 25, and a waist circumference exceeding 40 inches
for men and 35 inches for women. They were also required to be non-smokers, and
all exhibited one or more additional risk factors for metabolic syndrome, a
precursor of diabetes and cardiovascular disease. The group was randomly
assigned to two 8-week sequences of either a walnut-enriched ad libitum diet or
an ad libitum diet without walnuts. Those chosen for the walnut diet were
instructed to consume 56g of shelled, unroasted English walnuts per day as a
snack or with a meal.
FMD
or flow-mediated vasodilatation of the brachial artery improved significantly
from baseline in subjects on the walnut-enriched diet as compared with
the control diet. Beneficial trends in systolic blood pressure reduction were
seen, and maintenance of the baseline anthropometric values was also observed.
Secondary measures included serum lipid panel, fasting glucose and insulin, were
unaltered.
"We
know that improving diets tends to be hard, but adding a single food is
easy," explained Dr. David Katz, Director of the Yale-Griffin Prevention
Research Center and lead author of the research team. "Our theory is that
if a highly nutritious, satiating food like walnuts is added to the diet, there
are dual benefits: the benefits of that nutrient rich addition and removal of
the less nutritious foods."
###
The
above story is based on materials provided by Taylor & Francis, via
AlphaGalileo.
The
original research article is now available online in the Journal of the
American College of Nutrition:
Katz
DL, Davidhi A, Ma Y, Kavak Y, Bifulco L, Njike VY. Effects of walnuts on endothelial function in overweight adults with
visceral obesity: a randomized, controlled, crossover trial. J Am Coll Nutr. 2012 Dec;31(6):415-23.
* AUD1.30 (RM3.90) for 56g of Walnuts at Coles
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