#extra-virgin

Researchers found that the fatty acid inhibits the activity of a cell protein called Musashi homolog2, which in turn prevents the protein from stopping the production of a microRNA called miR-7 that suppresses brain tumor formation. In other words, oleic acid empowers miR-7 to do its job of preventing tumors by thwarting its nemesis protein, Musashi homolog2.

That’s the good news. The less good news is we still don’t know if dietary intake of olive oil provides this benefit. The claim may very well be proven out eventually, but testing it was beyond the bounds of this study. What this study does do, however, is provide the lab-tested basis for taking the necessary next steps to find out.

Quoting lead researcher Dr. Gracjan Michlewski, “While we cannot yet say that olive oil in the diet helps prevent brain cancer, our findings do suggest that oleic acid can support the production of tumor-suppressing molecules in cells grown in the lab. Further studies could help determine the role that olive oil might have in brain health."

80,000 cases of brain cancer are diagnosed every year in the U.S., and one third of those cases involve malignant tumors. Nearly 700,000 people in the U.S. are living with a primary brain and central nervous system tumor, according to the American Brain Tumor Foundation. Brain cancer is also the main cause of cancer-related deaths for children under age 14.

So if you’re already using olive oil, there’s ample reason to continue doing so for well-evidenced health benefits, and now possibly another big one. And if you aren’t, consider looking into the many reasons to begin working olive oil into your diet.

Mice in both groups were biologically engineered to develop Alzheimer's. The olive oil group started having extra-virgin olive oil introduced into their diets when they were six months old, before symptoms of the disease would begin appearing. At the nine- and 12-month marks, both groups of mice were given tests designed to assess working memory, spatial memory and learning ability. The olive oil group did significantly better on all of the tests.

The researchers then examined the brain tissue from both groups and found big differences that could only be attributed to diet. Brain cells in the olive oil group were visibly healthier, with stronger connectivity between neurons. Amyloid plaques—the result of toxic proteins accumulating in the brain—were reduced in the olive oil group, as were levels of phosphorylated tau, the substance responsible for neurofibrillary tangles that disrupt brain cell function in Alzheimer’s patients.

The researchers think that olive oil sparks “nerve cell autophagy,” a process that destroys and removes amyloid and phosphorylated tau before either have a chance to accumulate in the brain and cause the onset of Alzheimer’s.

“This is an exciting finding,” said senior study author Domenico Praticò, M.D., in a press statement. “Thanks to the autophagy activation, memory and synaptic integrity were preserved, and the pathological effects in animals otherwise destined to develop Alzheimer’s disease were significantly reduced. This is a very important discovery, since we suspect that a reduction in autophagy marks the beginning of Alzheimer’s disease.”

Bottom line: difference in diet is the only way to explain the effects, and that’s a big win for extra-virgin olive oil—at least in mice. With these studies there’s always the necessary caveat that what works for mice may or may not work as well for humans, and the only way we’ll know for sure is to study the same effect in a human experiment. Since the results of this study were so encouraging, a human study seems likely (although some of the factors will be different for obvious reasons, since we can't know for certain who will or will not develop the disease).

In the meantime, does this study support using extra-virgin olive oil in your diet? Actually, that’s the wrong question. A better one is: do this study and several others pointing to overall health benefits from consuming olive oil support having it in your diet? Given the mounting evidence in olive oil’s favor, it’s difficult to see how the answer could be anything but yes. As part of a Mediterranean diet, olive oil has already been linked to a wealth of health goodness, including lower cholesterol, lower blood pressure and weight loss.

So if you’re already eating extra virgin olive oil, consider this yet another potentially great reason to keep doing so. (Read here for another one.)