People with type 2 diabetes who were advised to follow a diet with a
low glycemic index supplemented with extra canola oil had lower
blood glucose levels and greater reductions in heart risk than those
who ate a diet high in whole grains, researchers found.
"We know that olive oil has a good pedigree among clinicians but
canola oil has a good pedigree too," lead author Dr. David Jenkins,
from the University of Toronto, told Reuters Health.
Canola oil is rich in alpha-linolenic acid, a type of omega-3 fatty
acid also found in walnuts, as well as monounsaturated fatty acids,
which are also in avocados and olives.
A food’s glycemic index refers to how quickly it causes blood sugar
to rise. Starchy foods like white bread and potatoes are considered
to be high glycemic index foods because they can cause blood sugar
levels to spike. Low glycemic index foods, such as lentils,
soybeans, yogurt and many high-fiber grains, create a more gradual
increase in blood sugar.
Sugar builds up in the blood of people with type 2 diabetes because
it can’t be absorbed by cells, ultimately increasing the risk of
other health problems such as heart disease.
"We thought using canola oil might be a good way to hit the heart
disease and the high glucose problem,” said Jenkins.
The researchers recruited 141 people with diabetes, all of whom were
taking medication to help lower their blood sugar levels. None of
the participants reported smoking, drinking excessively or having
other illnesses such as heart disease, liver disease or cancer.
Jenkins and his colleagues randomly assigned the participants to one
of two groups.
People in the test group were asked to supplement their diet with
four and a half slices of canola oil-enriched whole wheat bread each
day and were told to focus on eating foods with a low glycemic
Those in the comparison group were instructed to eat seven and a
half slices of whole wheat bread without the added canola oil each
day - providing an equivalent number of calories - and to avoid
products made with white flour.
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Over the next three months, blood glucose levels dropped in both
groups, but the drop was about one and a half times larger among
those on the canola oil-enriched diet. Improvements in other
measures of heart disease risk generally favored the test diet as
“The thing that really surprised us is that those who seemed to be
most in need benefited the most,” Jenkins said.
He said the participants who had more weight in their mid-region and
those with high blood pressure had the strongest blood sugar
response to the test diet.
While getting extra canola oil allowed people with type 2 diabetes
to improve their glycemic control, whole grains seemed to benefit
blood flow, the team reports in Diabetes Care.
"This is an important incremental finding that supports previous
studies which show that diet may have an effect on cardiovascular
disease," said Dr. Hertzel Gerstein, an endocrinologist at McMaster
University in Hamilton, Ontario, Canada, who was not involved in the
He said that even though the difference was only slight, the
research supports the idea that diet could be an important way of
treating people with diabetes.
“The one message I always tell patients is changing your diet can
help - it won’t be a waste of your time,” Gerstein said.
SOURCE: http://bit.ly/1mn7qVx Diabetes Care, online June 14, 2014.
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