(28-10-10) Mediterranean diet may trim diabetes risk

By Amy Norton
Thu Oct 14, 1:15 pm ET

NEW YORK (Reuters Health) ? Older adults who stick with a traditional
Mediterranean diet rich in plant-based fats may help lower their risk of type 2
diabetes -- even without counting calories or shedding weight, new research
hints.
In a study of 418 older Spanish adults, researchers found that those
instructed to follow a Mediterranean diet were less likely to develop diabetes
over four years than those instructed to follow a low-fat diet -- about 10
percent developed the disease, versus 18 percent in the low-fat group. And
weight loss did not appear necessary to gain the benefit.
The findings, reported in the journal Diabetes Care, may sound too good to be
true.
But they back up previous work by the same researchers showing that the
Mediterranean diet, even without weight loss, appeared to curb the risk of
metabolic syndrome -- a collection of risk factors for diabetes that includes
abdominal obesity, high blood pressure and elevated blood sugar and
triglycerides.
However, even if the eating pattern brings benefits in the absence of weight
loss, that does not negate the importance of regular exercise or calorie-
consciousness, a spokesperson for the American Dietetic Association told
Reuters Health.
Instead, the findings support existing dietary advice for people with diabetes
and those at risk of the disease, said Constance Brown-Riggs, a registered
dietitian and certified diabetes educator based in Massapequa, New York.
"This pretty much backs up what we've been recommending," Brown-Riggs said.
The traditional Mediterranean diet is generally high in vegetables, fiber-rich
grains, legumes, fish and plant-based sources of unsaturated fat --
particularly olive oil and nuts -- while being low in red meat and high-fat
dairy, prime sources of saturated fat.
All of those features are healthy choices for anyone, Brown-Riggs pointed out.
But the study, she added, "does not, by any means, say that you don't have to
exercise." Nor does it mean that calories are unimportant, she said.
For the study, researchers led by Dr. Jordi Salas-Salvado of the University of
Rovira i Virgili in Reus, Spain, followed 418 initially diabetes-free adults
between the ages of 55 and 80. Each had at least three risk factors for heart
disease, such as high blood pressure, smoking or excess weight.
At the outset, the men and women were randomly assigned to follow one of three
diets: a traditional Mediterranean diet with added emphasis on boosting
consumption of olive oil, a rich source of monounsaturated fat; the same diet,
with a focus on getting polyunsaturated fats from nuts; or a low-fat diet that
encouraged cutting down on all types of fat.
In addition, participants in the olive-oil group were given a free allotment
of the oil (a liter per week), and those in the nut group were given enough
mixed nuts to have about an ounce per day.
None of the groups were told to limit calories or get more exercise.
Over the next four years, the researchers found, 10 percent to 11 percent of
participants in the two Mediterranean groups developed diabetes. That compared
with 18 percent of those in the low-fat diet group.
When the researchers accounted for a number of other factors -- such as
participants' weight, smoking history and reported exercise levels -- the
Mediterranean diet itself was linked to 52 percent reduction in diabetes risk
compared with the low-fat diet.
Moreover, both Mediterranean diet groups showed a lower diabetes risk over
time without evidence that weight loss was the reason, according to Salas-
Salvado's team. When comparing participants who did or did not develop
diabetes, the researchers found that average weight and exercise levels were
the same in the two groups at the end of the study.
In contrast, participants in the low-fat group who remained diabetes-free did
lose a few pounds, on average. But those who eventually developed diabetes
gained a few pounds, on average.
The findings support the idea that components of the Mediterranean diet have
health benefits independent of any effects on weight. Past research in this
same study group found that participants on the diet had improvements in blood
sugar levels and sensitivity to blood-sugar-regulating hormone insulin -- in
the absence of weight loss.
In addition, the researchers note, the unsaturated fats in the Mediterranean
diet are thought to have anti-inflammatory effects. Researchers believe that
chronic, low-level inflammation in the body may have a role in a number of
disease processes, including those underlying diabetes.
Brown-Riggs agreed that the diet's anti-inflammatory effects may help explain
its health benefits. But she also pointed out that for overweight individuals,
shedding excess pounds can curb inflammation as well. Exercise, meanwhile, can
have numerous health benefits, including a reduced risk of heart disease.
So calorie control and regular exercise should remain goals, according to
Brown-Riggs.
She also cautioned against seeing olive oil, or any single component of the
Mediterranean diet, as a magic bullet.
"Sometimes individuals can get hung up on one item, like olive oil," she said,
"But what we're talking about here is an overall eating pattern, and an overall
lifestyle."

SOURCE: http://link.reuters.com/qam58p Diabetes Care, online October 7, 2010.

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