Low-carb diets may trump low-fat in lowering blood pressure

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Need more low-carb diet versus something else comparisons? You’re in luck. A new study found that following a low-carb diet may be better for lowering blood pressure than taking an over-the-counter weight loss medication and sticking to a low-fat diet.

Both plans showed similar drops in weight and improvements in other health factors, but the low-carb diet came out ahead in lowering blood pressure. Researchers placed participants in two groups -- one consisted of 57 people who ate a low-carbohydrate diet and were allowed to consume unlimited amounts of meat and eggs, but initially only 20 grams per day of carbohydrates (they could add a few extra grams if the cravings got too bad).

The other 65-person group was limited in the intake of fat per day -- 30% or less of total calories, as well as restricted consumption of saturated fat (10% or less) and cholesterol (300 mg. or less). In addition the group took the over-the-counter weight loss drug orlistat. The study lasted for 48 weeks.

The low-carb group dropped an average of 5.9 points of systolic blood pressure (the top number that measures the heart’s contractions) and 4.5 points on diastolic blood pressure (the bottom number measuring the heart at rest, between heartbeats). The other group dropped 1.5 points on systolic and 0.4 points on diastolic. More people in the low-carb group decreased their blood pressure medication.

On most other results the two groups were similar -- the low-carb set lost about 9.5% of body weight while the medication/low-fat diet group lost about 8.5%, and cholesterol and trigylceride levels improved.

In the study, researchers said they thought the two groups would show similar drops in blood pressure since both lost about the same amount of weight, and because orlistat has been shown to slightly lower blood pressure. They speculate that the low-carb diet may have a diuretic effect, or that the lower serum insulin levels that occur with a low-carb diet could have an effect on sodium retention.

The study was published in the January 25th issue of the Archives of Internal Medicine.

-- Jeannine Stein