Olive Oil Diet and Aging Arteries: A Cordoba Trial
A small crossover trial from the Reina Sofia University Hospital in Cordoba put 20 healthy older volunteers on three different diets for four weeks each and found that the Mediterranean diet rich in olive oil left the fewest signs of damage in the lining of their arteries. The paper is in the American Journal of Clinical Nutrition. Here is what was measured, why researchers bother with markers like these, and how far a study of 20 people can reasonably be pushed.
What was done
Ten men and ten women, all healthy and elderly, ate each of three diets in a randomized order: one high in saturated fat, one low in fat and high in carbohydrate, and one Mediterranean pattern enriched with monounsaturated fat, which in Cordoba means virgin olive oil. Each period lasted four weeks, and each subject served as his or her own comparison, which is the strength of a crossover design.
The researchers were not looking at heart attacks. They were counting particles. When the cells lining a blood vessel are stressed or dying they shed fragments called endothelial microparticles, and the body sends out endothelial progenitor cells to patch the lining. Counting both gives you a snapshot of wear and repair.
What they found
After the olive oil diet the volunteers had fewer microparticles of both kinds, from activated cells and from dying ones, and more progenitor cells than after either of the other two diets. Measures of oxidative stress were lower, plasma beta carotene was higher, and blood flow response in a standard test of vessel function was better.
Javier Delgado, one of the authors, put it as the endothelium being less affected by the wear associated with age when the diet is based on olive oil. The team links that to protection against future cardiovascular events, which is a reasonable hypothesis and not a finding of this study.
| Marker | After the olive oil diet |
|---|---|
| Total and endothelial microparticles | Lower than after the other two diets |
| Endothelial progenitor cells | Higher |
| Oxidative stress markers | Lower |
| Blood flow response | Better |
How far it goes
Twenty people, four weeks, surrogate markers. That is the size of a pilot, and the authors present it as a first result of its kind rather than a verdict. Marker studies like this one are how nutrition research gets a signal cheaply, and they are also how a modest result becomes a slogan by the time it reaches a label.
What makes this one worth reading is the comparison. The olive oil diet was not tested against junk, it was tested against a low fat high carbohydrate diet, which is the standard medical advice a lot of older people have been given for decades, and it came out ahead on these measures. That is the argument Spanish researchers have been building for twenty years, and it has moved a long way.
It still does not tell you to drink olive oil. It tells you that when the fat in an ordinary diet comes mainly from olive oil rather than from saturated fat or from bread and rice, some markers of vascular aging look better after a month.
This is general information, not medical advice. If you have heart disease or are being treated for cholesterol, ask your doctor before making changes.
Nobody in the trade sells oil on microparticle counts, and there is a reason. Health research has never moved a bottle on its own: it moves the category. When olive oil is in the news as a healthy fat, the whole shelf lifts, including the cheapest refined blend with a picture of a Tuscan hill on it, which carries almost none of the phenolic compounds that the research is interested in. The studies are done on virgin oil. The sales go to whatever is nearest.
Sources
- Marin et al., Mediterranean diet reduces endothelial damage and improves the regenerative capacity of endothelium, American Journal of Clinical Nutrition, February 2011
- Olive Oil Times, Olive Oil Keeps the Heart Young