Popular product has unexpected impact on heart health

People with heart disease found at risk due to olive oil

Switching from an omnivorous diet to one with a variety of nuts, fruits and vegetables in light dressing is a surefire way to reduce body fat for people at risk of heart disease, according to nutritionists. But now it is indicated that adding extra virgin olive oil may compromise a healthy lifestyle.

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A team of researchers from the University of Florida and the National Institute of Diabetes and Digestive and Kidney Diseases have taken a closer look at the health benefits of a plant-based diet in people at risk for developing atherosclerotic cardiovascular disease.

The recent boom in vegan diets and Mediterranean-style eating has touted the benefits of extra virgin olive oil as a way to lower dangerous cholesterol levels.

To be clear, the Mediterranean diet includes animal fats, and adding the often-recommended amount of olive oil to the diet means that fat intake can account for nearly half of the body's energy output.

Studies have shown conflicting results about the benefits of the different components of the Mediterranean diet, and there is little evidence that olive oil combined with low-calorie whole plant foods actually benefits people with risk factors for heart disease.

To find out, the researchers asked 40 adults aged 18 to 79 to follow a carefully tailored vegan diet for eight weeks: four weeks of adding four extra teaspoons of olive oil per day to their diet, followed by four weeks of eating a diet without it, with a week off in between.

Both the low- and high-oil diets led to improvements in cardiometabolic markers (including cholesterol, blood sugar, and inflammation) compared to before they started the diets. Interestingly, the order in which the diets were followed affected how much cholesterol changed from baseline at the start of the study.

When the volunteers started on a relatively moderate olive oil diet and then switched to a diet with virtually no olive oil, their levels of low-density lipoprotein (LDL), or «bad,» cholesterol, dropped.

The team believes that the small amounts of saturated fat found in extra virgin olive oil may interfere with how the liver processes LDL, causing it to rise in the blood, which could increase the risk of stroke and heart attack.

«Reducing extra virgin olive oil consumption may result in greater lipid reductions than relatively higher consumption,» the researchers explain.

There are a few caveats: Although the researchers accounted for differences in sex and body weight in their calculations, all of the participants were considered to be at high risk for atherosclerotic cardiovascular disease (CVD), which can develop when too much LDL cholesterol clogs your arteries.

“Although both diets improved the metabolic phenotype, eating less oil may provide superior LDL-C reduction in those at highest risk for the disease,” the researchers noted.

Thus, according to the researchers, people with elevated risk of heart disease, you should consider giving up extra servings of olive oil. Future studies could show how this link might play out in larger groups of participants and over a longer period of time.

Adding extra virgin olive oil after eating small amounts of whole, plant-based foods may counteract the decline, researchers say.

“The choice of optimal sources of dietary fat, as well as the amount of extra virgin olive oil, as part of a risk-reducing vegan diet may vary depending on the dietary context and level of risk,” the experts conclude.< /p>