Overview
- Penn State’s randomized crossover controlled feeding trial (n=30) found that 0.5 or 2.5 ounces of lean beef daily within a Mediterranean-style diet did not increase the blood marker TMAO compared with an American diet phase.
- TMAO levels were not different when participants ate a Mediterranean diet with 5.5 ounces of lean beef or an American diet with 2.5 ounces of non‑lean beef.
- All three Mediterranean diet phases increased gut microbiome diversity relative to the American diet, based on blood, fecal, and urine analyses.
- Each participant completed four four‑week diet periods with all meals provided, reducing between‑person confounding and isolating dietary pattern effects.
- Researchers cautioned the results do not extend to processed or non‑lean meats or to large, infrequent servings, and disclosed funding from the National Cattlemen’s Beef Association and Penn State.