Low-carbohydrate diets that protect your heart

For years, the low carbohydrate diets or in fats have been presented as the key to lose weight and maintain a healthy heart. However, recent findings show that not all “low-carb or low-fat” plans offer the same benefits: the way we choose foods could be more important than the amount of macronutrients.

Researchers of harvard analyzed the eating habits of almost 200,000 people over decades, looking for patterns that influenced heart health. Their discoveries reveal that the foods that make up our diet can tip the balance towards a stronger heart…or towards a higher risk of coronary heart disease.

Not all carbohydrates and fats are the same

Diets low in carbohydrates and fats, rich in High-quality plant foods low in animal products and refined carbohydrates, are linked to a lower risk of heart disease, according to a new study led by researchers at the Harvard TH Chan School of Public Health (USA).

The same diets high in refined carbohydrates and high in animal fats and proteins were associated with an increased risk of heart disease. The study suggests that it is the quality of the macronutrients that make up these diets that makes the difference in heart health, rather than the quantity. The study is published in ‘JACC’.

“Low-carbohydrate, low-fat diets have been widely promoted in the United States over the past two decades for weight control and metabolic health, but their effects on heart disease risk remain uncertain,” notes the first author. Zhiyuan Wupostdoctoral researcher at the Department of Nutrition.

“Our findings help debunk the myth that simply regulating carbohydrate or fat intake is inherently beneficial and clearly demonstrate that the quality of the foods that make up low-carb, low-fat diets is critical to protecting heart health,” he says.

Clear benefits for the heart

Previous studies have shown that diets that emphasize healthy sources of carbohydrates and fats (such as whole grains, fruits, vegetables, nuts, legumes, and olive oil) are associated with a lower risk of coronary heart disease.

The researchers sought to examine this evidence specifically in the context of low-carbohydrate, low-fat diets. To do this, they used diet and health data from almost 200,000 men and women who participated in the Health Professionals Follow-up Study, the Nurses’ Health Study and the Nurses’ Health Study II. The researchers analyzed the participants’ diets and scored them to distinguish diets low in carbohydrates and healthy and unhealthy fats. They evaluated the scores in the context of whether participants developed coronary heart disease, controlling for several health and lifestyle confounders. The researchers also analyzed blood samples from the participants and measured levels of cardiovascular risk biomarkers.

The study revealed that low-carbohydrate, low-fat diets, with an emphasis on high-quality carbohydrates and plant sources of protein and fat, were associated with a risk approximately 15% less coronary heart disease. Instead, the same two diets, rich in refined carbohydrates and animal proteins and fats, were associated with an increased risk of coronary heart disease.

In analyzing the blood samples, the researchers also found that healthy versions of low-carbohydrate, low-fat diets were associated with an improvement in cardiovascular biomarkers, such as higher levels of HDL (good) cholesterol and lower levels of triglycerides.

“For physicians, dieticians and patients, our study suggests that promoting an overall healthy eating pattern, rather than strict macronutrient restriction, should be a central strategy for the primary prevention of heart disease,” concludes the corresponding author. Qi Sunassociate professor in the Departments of Nutrition and Epidemiology.