Though health-conscious eaters often shun whole milk, a new study
suggests that adults who favor full-fat dairy gain less weight over
time.
Swedish researchers found that among more than 19,000
middle-aged women, those who had at least one serving of whole milk
or cheese each day put on less weight over the next 9 years than
women who consumed these foods less often.
The potential role of dairy foods in weight control won much
attention after some recent studies suggested that milk, yogurt and
other dairy foods might help regulate body fat. However, the
picture is far from clear, as other research has failed to find
that dairy products benefit the waistline.
The new findings, published in the American Journal of
Clinical Nutrition, are unlikely to clear up the
confusion.
For one thing, only whole milk, and not low-fat milk, seemed to
offer protection against weight gain. For another, the benefit was
seen only among women who were normal-weight at the start of the
study.
It's always possible that the associations between dairy intake
and weight gain do not reflect a direct action of dairy foods at
all, according to Doctor Magdalena Rosell, a researcher at the
Karolinska Institute in Stockholm and the study's lead author.
Eating habits can be seen as a marker of overall lifestyle, and
women who favored whole milk might have had other habits that aided
their weight control, Rosell said.
It's also possible that women who had already been gaining
weight opted to drink low-fat milk making the milk a "marker," but
not a cause, of weight gain, according to Rosell.
The findings are based on data from 19,352 women ages 40 to 55
who were surveyed about their diets, weight and other health
factors at the study's outset and again 9 years later.
Women who said they had whole milk or cheese at least once a day
throughout the study period were less likely to report a
significant weight gain defined as 1 kilogram or more per year.
One theory on why dairy products have been linked to lower body
weight is that the calcium aids in fat regulation, but a number of
studies have refuted that notion. The new findings cast further
doubt, since low-fat milk showed no positive weight effects.
It's possible, according to Rosell, that a type of fat found in
dairy foods called conjugated linoleic acid, or CLA, aids in weight
control.
However, she added, there's not enough evidence yet to support
that idea. At this point, there's no reason, Rosell said, for
people to eschew the general advice to choose low-fat dairy
products, which are lower in artery-clogging saturated fats.
"From what we know today, I do not see any reasons to change
that recommendation," she said.
(China Daily January 8, 2007)
