Is there a "HEALTHY" oil? We've heard the term used so often that most of us believe there is such a thing. But which is it? Some tout olive oil because of its ancient Mediterranean roots. Others point to the long tradition of using soy products in Asia to prove the benefit of soybean oil. Still others recommend tropical oils because they have been used for centuries by Pacific Islanders. Can we rely on history to tell us which oils are best? What does science say about oil and health?

Here's a study that attempts to answer the question, "Do all oils affect us the same way?" Conducted in Colombia on ten healthy, young volunteers, the study compared the effects of olive, soybean, and palm oils, either fresh or after they'd been used for frying 10 or 20 times. The subjects were randomly fed potato soup that had 60ml of one of the types of oil added. The effects of the different oils were measured by performing flow-mediated vasodilation (FMD) while fasting and again three hours after eating the oil-rich meal. Blood samples were also taken at these stages to determine lipid profiles and plasma glucose determinations. What happened? Endothelial function--the ability of the arteries to expand in response to nitric oxide--decreased 32% and triglyceride levels in the blood went up 27%. This acute adverse effect happened regardless of the type of oil used or whether the oil was fresh or had been used for frying. All oils caused the subjects' arteries to vasoconstrict temporarily while simultaneously raising their triglycerides.

This study is just one of many studies featured in the newly-created science section of community. This section provides medical studies that will enable you to read for yourself what science teaches us about the relationship between diet and health. While I do believe that history has health lessons for us, I think that science helps us understand and apply the lessons from history. As an example, Jeff Novick, MS, RD, does a great job showing us the relationship between history, science, olive oil, and the Mediterranean Diet in the excerpt below taken from one of his lectures.

For myself and my patients, I've already looked at the science and made up my mind. Which oil is best? The oil that stays in the bottle on the grocery store shelf and away from my food is the best one for me! Oil is not a health food, no matter where its origin. Being of Italian descent, it took a lot for me to give up olive oil. But once my cholesterol started lowering and my asthma disappeared, I've never again considered adding olive oil back into my diet. (Well, except for that one time when I caved to family pressure and started wheezing within hours of that meal!) It takes courage to look at history honestly. It takes courage to face our cherished family comfort foods and examine them in the light of science. But improved health is available for those with the courage to read and apply the science.

For additional information, you might like:

(1) From Oil to Nuts

(2) Does Coconut Oil Lower Cholesterol?

(3) Show Me the Science: Endothelial Function

(4) Is Olive Oil Really Heart Healthy?

(5) Olive Oil not "Heart Healthy"