|
 When people in the study added 56 grams of walnuts (2 ounces, or
about 14 walnuts) to their daily diet for six months, they had
improvements in blood vessel function and reductions in “bad” LDL
cholesterol, which builds up in blood vessels and can lead to blood
clots and heart attacks.
Blood vessel dysfunction and high LDL cholesterol are both risk
factors for type 2 diabetes, which is associated with obesity and
aging and occurs when the body can’t make or process enough of the
hormone insulin.
Walnuts, which are rich in fatty acids and other nutrients like
folate and vitamin E, weren’t linked to weight gain in the study
even though they are a high-calorie food.
“Adding walnuts to your diet will improve your diet quality and
health – cardiometabolic health specifically – and you can add
walnuts without fear of weight gain because they are very satiating
and appear to bump out other calories quite reliably and make room
for themselves,” said study author Dr. David L. Katz of the Yale
University Prevention Research Center in Derby, Connecticut.
The nuts didn’t seem to improve high blood pressure and high blood
sugar, two other risk factors for diabetes, Katz and colleagues
reported in BMJ Open Diabetes Research and Care.
For the study, the researchers randomly assigned 31 men and 81 women
at high risk for diabetes to follow a reduced calorie diet with or
without nutrition counseling.
Within these groups, half of the participants were assigned at
random to add walnuts to their diet for six months. After a
three-month break from the experiment, researchers then switched the
groups and assigned walnuts to the participants who were previously
asked to abstain from eating them.
Participants ranged in age from 25 to 75. All had multiple risk
factors for diabetes, such as being overweight, or having high blood
sugar, blood pressure or cholesterol, or having excess fat around
the midsection.
After taking into account factors such as age, exercise habits,
calorie consumption and fatty acid intake, the study found walnuts
were linked to improved diet quality regardless of whether people
received nutrition counseling.
The California Walnut Commission funded the study and has
compensated Katz for speaking engagements.
[to top of second column] |
One limitation of the research is that participants weren’t given
specific foods to consume and diets were assessed based on
self-reported surveys asking people at several points to recall what
they ate in the previous 24 hours, the authors acknowledge. The
study also wasn’t designed to show whether walnuts could prevent
diabetes, which makes the results less reliable.
Even though the data from the study suggest that adding walnuts to
the diet can help maintain overall healthy eating habits, more
research from larger and longer-term studies is still needed to
fully understand the potential benefits of walnuts, said Roberta
Holt, a nutrition researcher at the University of California, Davis,
who wasn’t involved in the study.
Results from the periodic diet surveys aren’t enough to prove
walnuts caused the changes in LDL cholesterol or blood vessel
function, Holt added by email.
“While the intake of walnuts improved LDL cholesterol and vascular
function from baseline, the control (no walnuts) also improved,”
Holt noted.
Even so, there is plenty of previous research linking consumption of
walnuts to improved markers of heart health and lower risks of
diabetes and heart disease, noted Deirdre Tobias, an epidemiologist
at Brigham and Women’s Hospital and Harvard Medical School in
Boston.
“Walnuts and other tree nuts are a healthful source of plant-based
protein and fat,” Tobias, who wasn’t involved in the study, said by
email. “They are a food that (is) consistent with overall dietary
recommendations and can easily be incorporated into a patient’s
diet, if they like walnuts and are not allergic.”
SOURCE: http://bit.ly/1NG8vvI BMJ Open Diabetes Research and Care,
online November 23, 2015.
[© 2015 Thomson Reuters. All rights
reserved.] Copyright 2015 Reuters. All rights reserved. This material may not be published,
broadcast, rewritten or redistributed. |
