In a new study, researchers found healthy foods, not diet types, are important for reducing people’s heart disease risk.
The research was conducted by a team from Beth Israel Deaconess Medical Center.
Everyone knows that achieving or maintaining healthy body weight is one key to preventing heart disease.
But even experts don’t agree on the best way to achieve that goal, with some recommending eliminating carbohydrates and others emphasizing reducing fats to lose weight.
So far few studies have tested the effects of these specific macronutrients on heart health.
In this study, the team examined the effects of three healthy diets emphasizing different macronutrients—carbohydrates, proteins, or unsaturated fats—on a biomarker that directly reflects heart injury.
They analyzed stored blood samples from 150 participants. The average age among the study participants was 53.6 years.
The participants had elevated blood pressure but were not yet taking medications to control hypertension or cholesterol.
They were fed each of three diets for six weeks with feeding periods separated by a washout period.
The diets were: a carbohydrate-rich diet similar to the well-known DASH diet, with sugars, grains, and starches accounting for more than half of its calories;
a protein-rich diet with 10 percent of calories from carbohydrates replaced by protein;
and an unsaturated fat-rich diet with 10 percent of calories from carbohydrates replaced by the healthy fats found in avocados, fish, and nuts.
All three diets were low in unhealthy saturated fat, cholesterol, and sodium while providing other nutrients at recommended dietary levels.
Using highly specific tests, the team found that all three diets reduced heart cell damage and inflammation, consistent with improved heart health.
All three healthy diets reduced heart injury and inflammation and acted quickly within a 6-week period.
However, changing the macronutrients of the diet did not provide extra benefits.
This is important for two reasons: First, the effects of diet on heart injury are rapid and cardiac injury can be reduced soon after adopting a healthy diet.
Second, it is not the type of diet that matters for cardiac injury (high or low fat, high or low carb), but rather the overall healthfulness of the diet.
The findings support flexibility in food selection for people attempting to eat a healthier diet and should make it easier.
The team says the message from our data is clear: eating a balanced diet rich in fruits and vegetables, lean meats, and high in fiber that is restricted in red meats, sugary beverages, and sweets, will not only improve heart risk factors but also reduce direct injury to the heart.
One author of the study is Stephen Juraschek, MD, Ph.D., Assistant Professor of Medicine at BIDMC and Harvard Medical School.
The study is published in the International Journal of Cardiology.
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