| Low-carb diet can with improve
lipid profiles
NEW YORK (Reuters Health) - A carbohydrate-restricted diet may
be more effective than one emphasizing reduced fat intake in modestly
improving triglyceride and HDL cholesterol levels, according to
reports in the Annals of Internal Medicine. This finding counters
the concern that the increased fat intake of ketogenic diets could
adversely affect lipid levels.
However, results vary widely regardless of which approach is used,
Dr. Walter C. Willett advises in an accompanying editorial, so physicians
should counsel patients to adopt a diet they can stick to, rather
than one emphasizing rapid weight loss.
In a trial at Duke University Medical Center in Durham, North Carolina,
Dr. Eric C. Westman and associates randomly assigned 60 obese but
otherwise healthy individuals with high lipid levels to a conventional
diet that reduced caloric intake by 500 to 1000 calories per day,
with less than 30 percent of calories from fat. The other 60 subjects
were assigned to a diet of less than 20 grams of carbohydrate daily
plus nutritional supplements.
The 45 subjects in the low-carb group who completed the 6-month
study lost an average of 12.9 percent of their body weight. In the
low-fat group, 34 completed the study, and their weight loss averaged
6.7 percent.
The average level of LDL cholesterol, the "bad" cholesterol,
decreased more with restricted carbohydrates. However, 13 of 44
(30 percent) had 10 percent or higher increases in LDL, compared
with 5 of 31 (16%) among those on the conventional weight-reduction
diet.
HDL cholesterol, the "good" cholesterol, increased more
in the low-carb group.
In the other study, Dr. Frederick F. Samaha at Philadelphia Veterans
Affairs Medical Center and colleagues enrolled 132 severely obese
subjects, among whom 64 were placed on a diet with carbohydrate
restriction and 68 on a conventional diet.
After 1 year, 20 in the low-carb group and 25 in the low-fat group
had dropped out.
Those in the low-carb group lost weight faster, but by study end,
weight loss did not differ significantly between the two groups.
Triglyceride levels decreased more in the low-carb group in the
Philadelphia trial, and HDL cholesterol levels decreased less.
Among the 54 subjects with diabetes, glucose levels declined significantly
more in the low-carb group.
In both studies, overall caloric intake decreased more in the low-carbohydrate
diet, but the difference was not statistically significant.
In an accompanying editorial, Willett, of the Harvard School of
Public Health in Boston, points out that in the two papers, some
patients lost more than 20 kilograms and others lost no weight all.
"We can encourage overweight patients to experiment with various
methods for weight control, including reduced carbohydrate diets,"
he writes, "as long as they emphasize healthy sources of fat
and protein and incorporate regular physical activity."
In other words, he adds, "for many patients, the roll will
have little role."
SOURCE: Annals of Internal Medicine, May 18, 2004.
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