Plant-based diets like vegetarian, vegan and Mediterranean diets benefit cardiometabolic health. Diets that reduce saturated fats and increase fruits, vegetables and whole grains can boost heart health. These diets often get a lot of their fat from plant oils. The Mediterranean diet heavily features olive oil — up to 40 percent of calories sometimes come from vegetable oils when people follow the Mediterranean diet.
Extra virgin olive oil (EVOO) is pressed from olives and processed without high heat or chemicals. That process protects the beneficial compounds in the oil called phenols. Phenols act as an antioxidant. However, no definitive studies prove EVOO is healthier than other olive oils. And being healthier than butter doesn’t necessarily mean a fat is healthy.
Researchers wanted to test how heart-healthy EVOO really is. They designed a randomized controlled, crossover trial and called it “The Recipe for Heart Health Trial.” In a crossover trial, the groups experience the same tests in different orders to ensure the researchers get precise results. There is no control group.
The test used 40 adults with a five percent or higher risk of heart disease. They were split into two groups following a healthy plant-based diet for four weeks. One group’s diet included four tablespoons of EVOO per day. The other had less than a teaspoon a day. After four weeks, the two groups swapped diets, with a “washout period” of one week, wherein they ate normally.
After each four-week period, both groups had better LDL cholesterol levels. There was no significant difference between the two groups. Following a plant-based diet, no matter how much EVOO a person ate, helped LDL cholesterol. But, if a person went from eating very little EVOO to a lot, they didn’t see any further reduction in LDL cholesterol. People also lost more weight and had better blood sugar levels when eating very little EVOO.
“Olive oil is better than chicken fat, beef fat, cheese fat, dairy fat. … Chicken fat is 30 percent saturated fat. Beef is 50 percent saturated fat. But for olive oil it’s all the way down to 14 percent. That’s good,” said Dr. Neal Barnard, president of the Physicians Committee for Responsible Medicine. “But what if instead I get a nonstick pan and I don’t use any fat at all? That’s best of all because every gram of fat, no matter where it’s from, has nine calories, and our research has shown that when people get away from these fats in general they do best of all.”
Dr. Matthew Lederman said he hopes this study will help people see olive oil for what it is. Olive oil has a “health halo,” instead of being an oil.
“This study is not saying you can’t ever have oil, but don’t try and kid yourself that it’s a health food,” said Dr. Lederman.
