Weekly olive oil intake reduces blood clotting in obese adults, study says

11 Mar 2019 --- Consuming olive oil at least once a week could help reduce the risk of blood clotting and blocked blood flow in obese adults. This is according to research from New York University’s School of Medicine which found that olive oil consumption decreases platelet activity in the blood. The study, however, does have some limitations as it involved only obese adults, but the researchers remain positive that its effects may be widely applicable.

The researchers followed “morbidly obese patients” and found that “a potential benefit of olive oil holds even in people who are severely obese and also produces a very clinically important message – that even in the setting of severe obesity and cardiovascular risk, that adhering to a ‘healthy diet,’ perhaps the Mediterranean diet, or one that contains olive oil, may still provide risk reduction,” Dr. Sean P. Heffron, Assistant Professor of Medicine, NYU School of Medicine, tells NutritionInsight.

The research was presented at the American Heart Association’s (AHA) Epidemiology and Prevention, Lifestyle and Cardiometabolic Health Scientific Sessions 2019, a global exchange of the latest advances in population-based cardiovascular science for researchers and clinicians.

The research process
The study followed 63 obese, non-smoking, non-diabetic participants who consumed olive oil. The participants’ average age was 32 years old and their average body mass index (BMI) was 44. A BMI of over 30 translates into obesity.

“We hypothesized that olive oil consumption might influence platelet activity based on epidemiologic evidence of a reduction in thrombotic events, in association with greater olive oil consumption, as well as some older experimental evidence suggesting an impact on platelets,” Dr. Heffron explains.

Platelets are blood cell fragments that stick together and form clumps and clots when they are activated. They contribute to the build-up of artery-clogging plaque, known as atherosclerosis, a condition which increases risk of heart attack and stroke, according to Dr. Heffron. 

Using food frequency surveys, the researchers found that those who ate olive oil at least once per week had lower platelet activation than those who ate oil less and the lowest platelet activation was seen in those who ate oil more frequently.

“People who are obese are at increased risk of having a heart attack, stroke or other cardiovascular events, even if they don’t have diabetes or other obesity-associated conditions. Our study suggests that choosing to eat olive oil may have the potential to help modify that risk, potentially lowering an obese person’s threat of having a heart attack or stroke,” Dr. Heffron says.

“To our knowledge, this is the first study to assess the effects of dietary composition, olive oil specifically, on platelet function in obese patients,” says co-author Ruina Zhang, B.S. and NYU Medical student.

How much oil is good for you?
Some limitations of the study are that it relied on questionnaires completed by the participants. It measured frequency of consumption but not volume and because it was observational the study could not prove that eating olive oil will reduce platelet activation in obese adults. So how much olive oil is enough?

“The granularity of our data was not sufficient for us to determine a ‘minimum amount necessary,’ although there was a trend toward lower platelet activation with more frequent consumption up to a daily basis. Consuming olive oil on a daily basis, if possible, is what I would recommend,” Dr. Heffron suggests. 

“I suppose that one could over consume it, although I wouldn’t worry about toxicity. I’d be more concerned potentially about excess calories being consumed, especially since I treat and study obese persons who are trying to lose weight. For my patients, I recommend that they try substituting olive oil for other types of less healthy fats that they might be consuming so that there isn’t an overall increase in caloric consumption in their diets,” he adds.

Since the study only involved obese adults, “we can’t know whether its effects apply to everyone. I would say that olive oil has been suggested to be beneficial in a number of studies involving persons with or at risk for cardiovascular disease, so potential benefit in a large population is certainly there. It may be that we were able to detect a benefit in our subjects because their obesity predisposed them to have platelets prone to becoming activated,” Dr. Heffron notes.

Dr. Heffron and his team are now in the process of conducting lab experiments, in an attempt to narrow down the active component(s) in olive oil that are responsible for their findings. “I hope to use this data to support applications for funding and to conduct more definitive mechanistic studies of the effects of dietary fats on platelet characteristics and function,” he concludes.

The benefits of olive oil for health, due to its monounsaturated fats, a class of nutrients found in olive oils, nuts and avocados, have long been a topic of interest in research. A study by University of Illinois researchers found that monounsaturated fatty acids are linked to general intelligence and that this relationship is driven by the correlation between MUFAs and the organization of the brain's attention network. 

Moreover, olive oil makes for a basic component of the Mediterranean diet, which is touted as holding many health benefits. According to recent research from The University of South Australia, a dairy-enhanced Mediterranean diet will significantly increase health outcomes for those at risk of cardiovascular disease, even proving more effective than a low-fat diet. 

According to another study presented at The International Liver Congress 2018 in Paris, which enrolled almost 300 individuals in the US and Turkey, following a Mediterranean diet, with a good amount of vegetables and fermented milk products such as yogurt, along with coffee and tea, is linked to greater gut microbial diversity and a lower risk of hospitalization in patients with liver cirrhosis.

By Kristiana Lalou