It's easy to get answers about health and nutrition! Just send your question by email to [email protected] and Dr. Harlan will respond to selected questions of general interest. Answers will be posted in the Ask Dr. Gourmet newsletter (sign up now!) and archived in the Ask Dr. Gourmet section of the website.
I am confused about cooking oil, such as olive oil, canola oil, corn oil, vegetable oil or other kinds of oil. Some said, olive oil is the best, but not good for high temperature cooking; canola oil is an industrial oil and not fit for human consumption... I usually cook at no higher than the boiling point. Compared to their function, would you please tell me which cooking oil is the best?
I love to cook with olive oil, but I use it for lower heat cooking as well as for making salad dressings and such. Oils begin to burn - and thus smoke - at a certain temperature. Even though you are cooking at lower temperatures it is easier to burn olive oil than other kinds. This is partly due to the composition of the oil but is also the result of impurities in the oil. An extra virgin olive oil that has a great fruit flavor will generally have more impurities that will lower the "smoke point" of the oil.
My favorite oil for higher heat cooking is grapeseed oil. The oil itself has a higher smoke point than olive oil and if you look for grapeseed oil that is not labeled "extra virgin" it will likely have fewer impurities.
It also a higher amount of mono-unsaturated fats than many oils with a low amount of trans-fatty acids and, consequently, it may actually help prevent heart disease. In research published in the Journal of Arteriosclerosis there was a remarkably beneficial effect of grapeseed oil on HDL (good) cholesterol. It appears that one ounce per day is enough, with the research showing a 13 to 14 percent increase in HDL cholesterol.
In another study published in Journal of the American College of Cardiology fifty-six participants with low HDL levels substituted up to 1.5 ounces of grapeseed oil for the oil they used in recipes. At the end of the study, the subjects showed no significant change in weight or total cholesterol, but the ratio of LDL to HDL had changed with a 7% reduction in LDL and a 13% increase in HDL levels.
1 tsp. grapeseed oil = 40 calories, 4.5g fat, 0.44g sat fat, 0.73g mono fat, 0g protein, 0g carbohydrates, 0mg sodium, 0mg cholesterol
Both olive oil and grapeseed oil are safe for people who use Coumadin® (warfarin).
I like to use canola oil more in baking or in recipes where I want the properties that come from the oil but don't want added flavor. Canola oil is actually rapeseed oil and before the refining processes used today it was not one that humans could eat. The impurities are now removed and the oil is safe and good for you because, like olive and grapeseed oil, it is very high in mono-unsaturated fats.
Thanks for writing.
Timothy S. Harlan, MD, FACP