This is a story that starts with some negative publicity for meat, fish, and eggs, but has a better ending, although much controversy remains and science is still working out pathways. Fortunately for us, all sides agree that wine and high-quality olive oil, as well as other high polyphenol foods, emerge as “fixers” of this newly discovered risk factor.
In 2013 there was renewed interest in the compound TMAO (trimethylamine N-oxide), which our bodies (specifically our gut bacteria and liver) make from dietary choline, carnitine, and lecithin. Those primary ingredients are enriched in meat, fish, and eggs in particular. Fish contain the highest amount of preformed TMAO of any food group. Several papers found associations between higher plasma levels of TMAO and increased risk for cardiovascular disease (heart attack or stroke) between 2013 and 2019. The papers caused a small panic in the paleo and carnivore camps, which had been advocating avoidance of grains, beans, and fruit due to the potential inflammatory effects of lectins, sugars, and processing. Also, it was difficult to square this new TMAO effect (risk) with the consistent and strong protective effects of frequent fish consumption. Other studies were published that did not always confirm the connection. The dietary ingredients (or sometimes they were given as supplements) were carnitine, choline, and lecithin. They were converted by the microbes to TMA and then by the liver to TMAO.
We have since learned, once again, that we are all slightly different. There are several genes where certain “variants” predict for lower or higher conversion of choline to TMA. The microbiome, once again, emerges as an important player, with some microbes helping to get us into trouble, ramping up TMAO production, and antibiotics sometimes being helpful, knocking these “troublemaking” bacteria down a little bit. There is intense interest in developing a specific probiotic that could assist with this specific task, sort of a “cardiovascular yogurt”.
The science is definitely not settled. Certain people have gene variants that predict even more inflammation with lectins, wheat, and grains, and carbohydrates in general. Once the whole picture is analyzed, they might best be advised to include fish, eggs, and grass-fed meat in small portions. What we do know for sure: we can measure TMAO easily, at any laboratory. We can obtain very detailed information about our gut flora and our gene variants (particularly PEMT, FMO3, MTHFR1) so we know more about our terrain. But the best news, for all of us, is that high polyphenol foods can reduce or eliminate this compound, through a mechanism that has to do with its beneficial effects on gut health and microbiome. This means red wine and a very high-quality olive oil can be an adjunct in preventing heart disease. Just a tasting note- the olive oils with the very highest polyphenol content are the ones we want, and they can have a sharp or pungent taste. They also have a darker color, and sometimes some sediment. So, don’t heat them, but use them generously for salads, pesto, in smoothies, or drizzled onto appetizers. And definitely connect with the “olive oil expert” Ersilia Moreno at www.oliveoiloftheworld.com.