(Reuters Health) - Among rice lovers, people who eat brown
rice or other whole grains seem to have a lower risk of developing
diabetes than those who eat white rice, Boston-based researchers
said on Monday.
HEALTH
Among more than 197,000 US adults followed for up to 22 years, they
found that eating more refined white rice was associated with a
higher risk of type 2 diabetes, while eating more brown rice was
associated with a lower risk of the disease.
Type 2 diabetes is characterized by high blood sugar levels caused
by the body's inability to process sugar properly. The illness can
sometimes be controlled through diet and exercise but may also
require drugs.
"In general, the public should pay special attention to their
carbohydrate intake and try to replace refined carbohydrates,
including white rice, with whole grains," Dr. Qi Sun, of Harvard
School of Public Health and Brigham and Women's Hospital, told
Reuters Health by email. Current US dietary guidelines recommend
that at least half of carbohydrates in the diet come from whole
grains.
More Americans are eating rice, Sun and colleagues note in their
report. According to the U.S. Department of Agriculture, rice
consumption has shot up more than threefold since the 1930s.
However, most of the rice eaten by Americans is refined white rice,
which is stripped of its fiber, vitamins and minerals in the
refining process and is more likely to fuel an increase in blood
sugar after eating than its healthier whole grain cousin, brown
rice.
The Boston team assessed rice intake and diabetes risk among nearly
40,000 men and more than 157,000 women in three long-running
studies of doctors and nurses. Altogether, 10,507 of them developed
type 2 diabetes during follow up.
Across all three studies, having more white rice in the diet was
associated with an elevated risk of type 2 diabetes, the
researchers report in the Archives of Internal Medicine.
When they pooled the data and took into account various diet and
lifestyle factors that might influence the results, the doctors and
nurses who ate the most white rice (at least 5 servings per week)
had a significant 17 percent higher risk of developing diabetes
than those who ate the least white rice (less than 1 serving a
month).
In contrast, eating 2 or more servings of brown rice each week, as
opposed to less than 1 serving a month, was associated with an 11
percent reduced risk of developing type 2 diabetes. Again, this was
after accounting for other diet and lifestyle factors that might
influence the results. The protective effect seen for higher brown
rice consumption was "not dramatic, albeit significant," Sun
said.
The researchers estimate that replacing one third of a serving of
white rice daily (about 50 grams) with the same amount of brown
rice could lower a person's risk of getting type 2 diabetes by 16
percent. They further estimate that replacing white rice with whole
grains as a group could be associated with a risk reduction as
great as 36 percent.
It's important to note that white rice contributed less than 2
percent of total calories for study subjects; brown rice less than
1 percent. Given that rice was not a significant part of the diet,
there could be other reasons for the findings, the researchers
acknowledge. But Sun pointed out that they adjusted for numerous
factors that might influence the results and the findings still
held up.
It's also possible that eating more brown rice is a marker for a
healthier lifestyle. And, in fact, the brown rice eaters in the
study did have a more health-conscious lifestyle and diet.
However, Sun said, "we adjusted for these factors including body
adiposity (fat), smoking, physical activity, and other dietary
factors, and the significant associations remained. This suggests
that what we observed is unlikely the result of other factors."
The consistency of the results across all 3 studies also suggests
that the findings are unlikely to be due to chance, Sun and
colleagues note in their report.
Type 2 diabetes, which is closely linked to being overweight as
well as poor diet and lack of exercise, is reaching epidemic
levels. An estimated 8 percent of the U.S. population, and 180
million people around the world, now suffer from diabetes.
"From a public health point of view, replacing refined grains such
as white rice by whole grains, including brown rice, should be
recommended to facilitate the prevention of type 2 diabetes," Sun
and colleagues conclude.
In addition to the study's funding by the U.S. National Institutes
of Health, Sun is supported by a postdoctoral fellowship from
Unilever Corporate Research. Unilever owns a number of food product
brands