Swapping some of your carbs for protein or healthy fats may be just the right
move for a healthier heart, say researchers.
New findings, published in November 2005 in the Journal of the American Medical
Association, show that replacing some carbohydrates, like a bowl of pasta, with
protein or monounsaturated fat, such as a black bean taco, may help to reduce
your overall risk of heart disease.
"[These changes] can lower blood pressure, improve cholesterol levels and reduce
heart disease risk." said Dr. Lawrence Appel, lead author of the study and
professor of medicine at Johns Hopkins University.
To test the heart benefits of different diets, the researchers recruited 164
adults with either high blood pressure or the early signs of this problem. The
participants were divided into three groups, based on diets that emphasized
carbohydrates, protein or unsaturated fats.
In the protein-rich diet, about half of the proteins eaten were derived from
plant sources, like beans, nuts and vegetable-based meat substitutes, which tend
to be lower in fat than animal sources of protein. In the unsaturated-fat-rich
diet, most of the fat was of the monounsaturated kind found in olives, peanuts
and canola oil. This type of fat is considered to be healthy since eating such
foods can lower artery-clogging cholesterol.
For example, a higher-carb lunch would consist of a chicken sandwich with
mayonnaise on whole wheat bread, while the unsaturated-fat-rich dieters would
eat their chicken sandwich with olive-oil margarine and barbeque sauce on white
bread. The protein-rich dieters would eat a veggie burger instead with barbeque
sauce on a hamburger roll.
Snacks for the groups varied, too, with trail mix featured in the carb diet,
cottage cheese for the protein eaters and olive oil potato chips for the
unsaturated fat group.
After staying on the diets for six weeks and maintaining a constant body weight,
researchers found that all of the diets helped to lower the participants’ blood
pressure and bad, or LDL, cholesterol levels. However, those on the high protein
and high unsaturated fat diet showed even lower levels. Overall, these two diets
led to a significantly lower risk of heart disease than the carbohydrate diet.
Previous studies have shown that consuming high amounts of salt and alcohol as
well as being overweight can all affect blood pressure and heart disease risk,
but this is the first study to show that macronutrients, like proteins and fats,
may affect blood pressure in a positive way, say the authors from the OmniHeart
Collaborative Research Group, which conducted the study.
The authors caution, however, that all of the participants were put on meal
plans that are healthier than the typical American diet, possibly explaining why
all three diets helped to improve the participants’ heart health.
"All three diets are good; it’s just that two diets are somewhat better." said
Dr. Frank Sacks from the study center at Brigham & Women’s Hospital at Harvard
Medical School in a press release. "Most of us in public health would be happy
if people were consuming the carbohydrate diet, which is much better than what
most Americans typically eat."
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