Mediterranean Diet Beats Low-Fat Diet for Kidney Function in Type 2

BY QUINN PHILLIPS | APRIL 11, 2022

For people with both type 2 diabetes and coronary artery disease (CAD) — a common and dangerous form of heart disease — a Mediterranean diet may be a better option than a low-fat diet when it comes to preserving kidney function, according to a new study published in the journal Clinical Nutrition.

Following a Mediterranean-style diet has been linked to numerous health benefits in many different studies, which is why this eating pattern often comes in first in rankings of diets for people with diabetes. This pattern of eating involves consuming plenty of fruits and vegetables, whole grains, beans and other legumes, and olive oil, and limiting your intake of sugar and other refined carbohydrates, red and processed meats, and animal fat. There are variations on the Mediterranean diet, as well, such as a “green” Mediterranean diet — which has a special emphasis on green leafy vegetables and green tea. Studies have shown that following a “green” Mediterranean diet is linked to improved metabolic health, reduced liver fat, and less brain shrinkage with age. Following a Mediterranean diet more broadly is also linked to benefits ranging from improved erectile performance in men to better memory in older age.

For the latest study, 1,002 participants with coronary artery disease — some of whom also had diabetes — were randomly assigned to follow either a Mediterranean diet or a low-fat diet, and provided guidance about how to do so. The Mediterranean diet consisted of 35% fat, including 22% monounsaturated fat (the main type of fat found in olive oil and most nuts), and less than 50% carbohydrate. The low-fat diet consisted of 28% fat, including 12% monounsaturated fat, and greater than 55% carbohydrate. Both at the beginning of the study and after a five-year follow-up period, participants had their kidney function measured — in the form of estimated glomerular filtration rate (eGFR).

Smaller decline in kidney function linked to Mediterranean diet in those with type 2

Overall, participants in both diet groups saw a decline in kidney function over the follow-up period. But among participants with type 2 diabetes, there was a smaller decline in kidney function in the Mediterranean diet group. In contrast, participants without type 2 diabetes tended to experience about the same amount of kidney function loss in both diet groups. For participants with type 2 diabetes, those who started out with mildly impaired kidney function experienced the greatest benefit from following a Mediterranean diet when it came to less decline in kidney function, compared with following a low-fat diet.

“The long-term consumption of a Mediterranean diet rich in [extra-virgin olive oil], when compared to a low-fat diet, may preserve kidney function, as shown by a reduced decline in eGFR in [coronary artery disease] patients with [type 2 diabetes],” the researchers concluded. “These findings reinforce the clinical benefits of the Mediterranean diet in the context of secondary cardiovascular disease prevention.”