Should you trade your extra virgin olive oil for corn oil? Not so fast, says Nutrition Diva.
Q. Can you comment on the recent study that found that corn oil reduced cholesterol better than olive oil? Is olive oil not all it's cracked up to be?
A. At a recent meeting of the American Society of Nutrition, researchers presented results of a study comparing the effects of corn oil and olive oil on LDL (or "bad") cholesterol levels. After 3 weeks on a diet rich in corn oil, subjects saw an 11% reduction in their LDL cholesterol levels. Three weeks on a diet rich in olive oil lowered cholesterol levels by 3.5%.
This study (which is, so far, unpublished) was funded by companies that sell corn oil and conducted by a company that does nutritional research for hire. That doesn't mean that the results are invalid -- but it should be noted.
See also: Can We Trust Industry Funded Research?
This result is not surprising. Corn oil is naturally rich in phytosterols, compounds that block the absorption of cholesterol. (See also: What Are Phytosterols?) Olive oil is not as high in phytosterols.
Nonetheless, I'm not trading in my olive oil for corn oil just yet.
For one thing, corn oil is very high in polyunsaturated fats, a type of fat that forms harmful compounds when heated. Olive oil, on the other hand, is rich in monounsaturated fats, which are more stable and less likely to form these compounds. (See also: Which Oils Are Best for Cooking? )
Secondly, in addition to its modest effect on cholesterol levels, olive oil contains polyphenols and other antioxidants that protect the heart in other ways.
And finally, there are a lot of other delicious ways to get phytosterols into your diet. Nuts, seeds, legumes, and avocado are all good sources. (See also: Eat More of These Foods to Lower Your Cholesterol)
So, while I think the results of this study may be valid, I don't think they necessarily support the conclusion that corn oil is a better choice than olive oil. A diet featuring olive oil as well as phytosterol-rich foods seems to me to be the best (and tastiest) way to go!
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