Several new studies presented at an ongoing Alzheimer’s conference found that otherwise healthy adults who followed either a Mediterranean diet or close modifications to it had a substantially reduced risk for dementia, Alzheimer’s disease, and other cognitive decline. These diets are generally heavy on fruits, vegetables, lean protein such as chicken and fish, olive oil, whole grains, and legumes while veering away from red meats and saturated fats like butter. Oh, and (moderate) servings of red wine are encouraged, too. Seriously.

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“Eating a healthy plant-based diet is associated with better cognitive function and around 30% to 35% lower risk of cognitive impairment during aging,” said University of California, San Francisco School of Medicine’s Claire McEvoy, a lead author of one of the studies, according to CNN.

Those are some pretty impressive numbers. But to be clear, these are so-called observational studies, where much of the data is self-reported. And, as always, correlation isn’t the same thing as causation.

But without an actual “randomized control trial” where a bunch of people are placed on a non-Mediterranean diet and another group on a Mediterranean diet for huge swaths of their lives (similar to the processes used for drug approvals), large-scale observational studies may be the best available resource, especially if they account for confounding factors. And there’s now an impressive amount of medical literature suggesting high-protein, low-fat, whole grain, and veggie-filled diets are, at least for those who are otherwise healthy, associated with real health gains.