Healthy carbs benefit from protein, olive oil

Tweaking a healthy, high-carb diet to include a little more protein or healthy oils can further curb the risk of heart disease, say researchers who had volunteers try three variations of the same diet.

The findings do not mean you should gorge on meat or that carbs should be shunned.

The study – involving 159 adults with borderline or mild high blood pressure – found the best results, however, with diets that replaced some carbohydrates with protein such as nuts and dairy, or with healthy fats, such as olive oil.

All three diets were low in saturated fats and required plenty of fruits and vegetables, and all improved blood pressure and cholesterol readings.


Adopting any of them would be beneficial – and a big change for most North Americans, said lead researcher Dr. Lawrence Appel of Johns Hopkins School of Medicine.

“Most people aren't following anything close to any of these,” he said, adding that the bottom line is: “You can eat healthy in three different ways, and two of them are a bit better than the other.”

All participants tried each of the diets for six weeks, eating meals prepared in a research kitchen and taking a few weeks' break before starting the next diet.

The volunteers' average blood pressure was borderline high – 131 over 77 before starting the study. It fell by an average of about 8 points while they were on the carbohydrate diet, 9.5 points on the protein diet and 9.3 points on the healthy fats diet.

Levels of LDL cholesterol, the bad kind, measured 129 on average at the start; 100 is considered optimal. LDL levels fell an average of almost 12 points on the carb diet, about 14 points on the protein diet and about 13 points on the healthy fats diet.

Those reductions most likely would translate into less heart disease if the diets were widely adopted, the researchers said.

They estimated that for every 100 people with mild high blood pressure, there would be one less heart attack over 10 years for those on the protein or healthy fats diet, compared with the more carb-friendly diet.

The study, funded by the U.S. National Institutes of Health, was prepared for presentation Tuesday at an American Heart Association conference in Dallas and is published in Wednesday's Journal of the American Medical Association.

A JAMA editorial about Dr. Appel's research questioned whether people in the real world would stick to the diets, since they would have to buy and prepare their own meals.

“Longer trials examining actual cardiovascular event outcomes will be needed to convince a skeptical public of the benefit of yet another unique and difficult-to-achieve dietary regimen,” editorial author Dr. Myron Weinberger of Indiana University said.

Dr. Eva Obarzanek, a co-author and researcher at the National Heart, Lung and Blood Institute, said the results show people “don't have to be restricted. If they have a certain preference, they should know that they can follow any of these.

“None of these diets are extreme,” she said. “These are well-rounded studies.”

Rachel Johnson, a University of Vermont nutrition professor, said the results refine “what we already know. It's not a huge about-face.”

In the same edition of the Journal, a study found that high doses of the cholesterol-lowering drug Lipitor were no better at preventing recurrent heart attacks and heart-related deaths than regular doses of the competing drug Zocor. The study was funded and conducted by Lipitor's maker Pfizer Inc.

By Lindsay Tanner

Posted in the Globe and Mail