A large new Harvard study suggests that a small daily dose of olive oil can substantially reduce the risk of premature death. That raises questions among whole-food, plant-based consumers, since avoiding added oil is a cornerstone of the WFPB diet.
The new studypublished in January in Journal of the American College of Cardiology, examined olive oil consumption and mortality using data collected from more than 90,000 health workers over 28 years: 60,582 women in the Nurses’ Health Study and 31,801 men in the Health Professionals Follow-up Study.
The participants completed health assessment questionnaires every two years. Every four years they answered detailed food frequency questionnaires that asked how often, on average, they had eaten specific foods in the previous year, including the types and brands of fats and oils used in cooking and added at the table. During the 28-year follow-up period, 36,856 participants died.
After adjusting for known risk factors and other dietary factors, the researchers found that participants who consumed more than half a tablespoon of olive oil daily were 19 percent less likely to die from cardiovascular disease and other causes. They were 29% less likely to die from neurodegenerative diseases such as Alzheimer’s, 17% less likely to die from cancer, and 18% less likely to die from respiratory diseases compared to those who never or rarely consumed olive oil olive.
“Our findings confirm current dietary recommendations to replace animal fats with vegetable oils for the prevention of chronic diseases and premature death,” said study lead author Marta. Guasch-Ferrésenior research scientist in the Department of Nutrition at the Harvard Chan School of Public Health.
So is oil healthy now?
An important takeaway for WFPB consumers is that the Harvard study looked at mortality rates based on different types of added fats in the diet. They did not examine the benefits of a diet with little or no added oil. Neal Barnard, MD, addressed the question on the January 20 episode of the exam room by the Medical Committee podcast.
“Olive oil is better than chicken fat, beef fat, cheese fat, and milk fat. It’s better than all of this,” said Barnard, chairman of the Physicians Committee for Responsible Medicine. the exam room host Chuck Carroll. “Chicken fat is 30 percent saturated fat. Beef is 50 percent saturated fat. But for olive oil it’s all the way up to 14 [percent]. That is good.”
Then Barnard had a big caveat: “But what if I buy a nonstick pan instead and don’t use any fat? That’s best of all because every gram of fat, no matter where it’s from, has 9 calories, and our research has shown that when people steer clear of these fats, they generally do better. So olive oil: better than animal fats, absolutely. Slam dunk. But learning to really minimize even oils, even olive oil, is probably the best way to go,” he said.
“Researchers have tried to show that there is something magical about olive oil. And there are various plant components, just like in broccoli and sweet potatoes. The big problem, however, seems to be that you’re not eating animal fat anymore,” added Barnard.
In fact, while the new study found that replacing butter, mayonnaise, or butterfat with olive oil was associated with a lower risk of total and cause-specific mortality, they did not find a significant risk reduction when substituting olive oil. olive for other vegetable oils.
The study authors also noted that participants with higher olive oil intake tended to be more active than other participants and less likely to smoke. They also consumed more fruits and vegetables than those who ate less or no olive oil.
The case of the WFPB against oil
“There is no question that when you get rid of all those other fats, olive oil, which is monounsaturated, is less harmful. But the point is this: It’s not about getting an 18 or 19 percent risk reduction when you’re really trying to get rid of cardiovascular disease,” said lifestyle medicine pioneer Caldwell Esselstyn, MD, author of Prevent and reverse heart disease.
“When has Harvard done an oil study where you take patients who are seriously ill with heart disease and stop and reverse them? That’s what we were able to achieve, along with [Dr. Dean] Ornish and others who follow this kind of approach,” Esselstyn said.
in a 2014 study published in the Journal of family medicine, Esselstyn and colleagues tested a whole food, plant-based diet in 198 patient volunteers with established cardiovascular disease. Of the 177 patients (89 percent) who responded to intensive counseling and stayed on the diet for a median of 3.7 years, only one patient had a major cardiovascular event — a stroke. Meanwhile, 13 of the 21 patients who did not follow the diet experienced adverse cardiac events.
In 2019, Esselstyn wrote a editorial for the International journal of disease prevention and reversal outline a variety of studies showing that oil consumption promotes vascular injury, including research published in 2000 which examined the post-meal impact of olive oil on the endothelium, a membrane that lines the heart and blood vessels and helps control vascular relaxation and contraction. The study found that meals prepared with olive oil reduced flow-mediated dilation, a measure of arterial blood flow, by 31 percent.
Another concern with added oil is its high caloric density and its ability to promote overeating and weight gain.
At 4,000 calories per pound, “the oil essentially follows the same pattern as processed sugar, which is also extracted from plants,” explain Alona Pulde, MD, and Matthew Lederman, MD, in The Forks Over Knives Plan. “Think about what oil is: fat, and nothing but fat. … Oil of any kind has more calories per gram than any other food we know of. And without fiber or water, oil lacks the bulk to convey to your senses how many calories you’ve consumed; this practically guarantees that you will consume more calories in the food than you need.”
To learn more about a whole foods, plant-based diet, visit our plant-based primer. For help with meal planning, see forks meal plannerFOK’s simple weekly meal planning tool to keep you on a healthy, plant-based path.
