We all know that the Mediterranean diet is excellent for heart health. It’s been proven time and again to be one of the best diets around. As well as being healthy, it’s also widely considered to be pretty tasty and easier to follow than many health regimes. However, as surprising as it might sound, for people with cholesterol concerns, olive oil might not be the best oil to use.

Replacing saturated fats (like butter) with unsaturated (like olive oil) can help heart health. Olive oil’s main fat is monounsaturated fatty acids, which helps lower total cholesterol and LDL cholesterol. Now, in a massive study, using meta-analysis to crunch enormous amounts of data, researchers have found olive oil isn’t the best.

Dr. Lukas Schwingshackl, a researcher at the German Institute of Human Nutrition, who lead the study said, “Some people from Mediterranean countries probably are not so happy with this result, because they would prefer to see olive oil at the top. But this is not the case.”

The researchers looked at 55 studies, dating back to the ’80s to gather information about the impacts different types of oil consumed in the same amounts has on people. For the study included in their pool of data, it had to look at how multiple types of oil impacted a person’s LDL, HDL, triglycerides and overall cholesterol.

“The beauty of this method,” explained Schwingshackl, “is that you can compare a lot of different interventions simultaneously... and, in the end, you get a ranking. You can say, ‘this is the best oil for this specific outcome.’”

The meta-analysis looked at 13 oils: flaxseed oil, olive oil, safflower oil, sunflower oil, rapeseed oil, hempseed oil, coconut oil, corn oil, soybean oil, palm oil, beef fat, butter and lard. In the end, they found that four seed oils — sunflower, flaxseed, rapeseed and safflower — were the healthiest for cholesterol. And that, unsurprisingly, butter and lard were the worst. The meta-analysis isn’t a clinical trial, so these findings are not etched in stone. However, it would be nigh on impossible to have a human study that required people to have only one type of fat for years. Those criteria would be necessary to say that the results were definitive. So, in the absence of that, we have to settle for these results.

A different study thinks that the winner is cottonseed oil. The Univ. of Georgia research, led by Dr. Jamie Cooper, saw that cottonseed oil dramatically improved the cholesterol of participants. It was being compared to olive oil, which had a minimal amount of impact. However, the study was five days long, with 15 young men. More information would be needed to confirm the results, but it does backup Schwingshackl’s team’s find that seed oils beat olive oil.

While we don’t know the very best oil, you may be interested in adding a seed oil to your pantry.