Gut Bacteria

Trimethylamine N-Oxide (TMAO) – Another link to the progression of cardiovascular disease

Recent research has shown that gut bacteria plays a role in the development of cardiovascular disease. Some of our gut bacteria digest meat, seafood, poultry, eggs, dairy products, and certain sports/soft drinks and supplements that can increase the risk of developing cardiovascular disease. Due to our inability to control our gut bacteria researchers have found that limiting certain foods decrease our risk of developing cardiovascular disease while increasing these same foods can increase the risk of developing cardiovascular disease. To decrease the risk of developing cardiovascular disease avoidance of animal-based foods, certain supplements, and certain sports/soft drinks is recommended. Until research can definitively recommend a safe amount of phosphatidylcholine, choline, lecithin, and L-carnitine that can be consumed, it is best to avoid animal-based foods, supplements and sports drinks which contain higher amounts of these nutrients.

TMAO in 60 seconds

Why does TMAO matter?

TMAO enables cholesterol to create cholesterol plaques on the inside of the arterial wall and prevents the body from excreting excess cholesterol which may lead to heart attack, stroke, and death (Tang et al. 2013; Koeth et al. 2013; Koeth et al. 2014).

Do we need carnitine in our diet?

According to the subcommittee on the Tenth Edition of the Recommended Dietary Allowances, Food and Nutrition Board, Commission on Life Sciences, National Research council report (1989) “Carnitine is synthesized in the liver and kidney” and therefore no Recommended Daily Allowance can be established (p. 265).

Gut bacteria and red meat – Trimethylamine N-oxide (TMAO)

Who is at risk for having higher levels of TMAO?

Researchers have found that high levels of TMAO are predominantly found in individuals consuming meat centered diets, carnitine (found in eggs, liver, beef & pork) and choline (found in chicken, fish, dairy and even plants) (Tang et al. 2013; Koeth et al. 2013). According to Zeisel, Mar, Howe, & Holden, (2003) eggs, milk, liver, red meat, poultry, shellfish, and fish are main sources of choline (p. 1303-1305). Research conducted by Wang et al., (2011) found these same foods “eggs, milk, liver, red meat, poultry, shellfish, and fish are believed to be the major dietary sources for choline, and hence TMAO production” (p. 3). While most associate red meat with TMAO, eggs and other animal products also increase TMAO levels within individuals (Tang et al. 2013, p. 1581).

Current research demonstrates that, given their similar structures, carnitine and choline are metabolized by our gut microbiota and form trimethylamine (TMA) which is further converted to TMAO by the liver (Tang et al. 2013; Koeth et al. 2013). More recent research into Carnitine metabolism by gut microbiota has discovered another metabolic pathway carnitine follows. Research conducted by Koeth et al. (2014), demonstrates that carnitine metabolism within the microbiome produces y-butyrobetaine which is a precursor to the formation of TMA which leads to the production of TMAO within the liver, the production of y-butrobetaine is produced “at a rate ~1000 Fold higher that the formation of TMA” (p. 1).

TMAO Assay Biomarkers for Biome: 2014 Medical Innovation No. 9

Do high TMAO levels put me at risk for developing a heart attack?

High levels of TMAO in the blood mean an individual is at increased risk of having a heart attack. According to Tang et al. (2013), “Plasma TMAO levels predict the risk of incident major adverse cardiovascular events independently of traditional cardiovascular risk factors” (1582).

What is in your Gut Can Determine Heart Attack And Stroke Risk (1 of 2)

How do researchers know gut microbiota aid in the development of heart disease?

Researchers were able to determine that our gut microbiota were the cause of TMA production during the study by providing antibiotics to individuals which suppressed the gut microbiota that produced TMA. After suppressing the microbiota that produced TMA individuals no longer created TMAO in the liver, until the gut bacteria grew back and began producing TMA which than lead to the production of TMAO (Koeth et al. 2013, P. 4). Interestingly enough those who do not eat animal flesh or animal by products, vegans, produce almost no TMAO which indicate that gut microbiota in vegans do not exist in large enough quantities to produce TMAO (Koeth et al., 2013; Koeth et al., 2014).

Egg Industry Response to Choline & TMAO

How to decrease the production of TMAO and decrease the risk of developing heart disease?

Removing animal-based foods from the diet can significantly alter gut bacteria which feed on choline and L-Carnitine, and lethicin. According to Rak, and Rader, (2011) while this research poses many new ideas as to the treatment of atherosclerosis “The most obvious is to limit dietary choline intake” (p. 40). Simply reducing and to a greater extent eliminating these foods from the diet will alter gut bacteria. Diet rich in animal based foods are very different than diets low in fat and high in plant-based foods. According to Rak & Rader (2011) “what’s more, our diet comparisons shows that a very low carbohydrate diet (Atkins) diet contains roughly 2.5 times more choline than a typical very low fat (ornish) diet” (p. 40).

In fact, in august 2010, after years of peer reviewed published scientific literature, two programs proven to have beneficial effects on stopping the progression and even reversing the progression of heart disease, both the Pritikin program and Ornish diets, consisting of 15% of calories from fat or less are now covered by the Centers for Medicare and Medicaid Services (Horrigan, 2010, p. 346).

Can we change our gut Microbiota so that we do not produce TMAO and can decrease our risk of developing heart disease?

Yes. In fact changing the foods we eat can quickly change our gut microbiota within as little as one or two days as noted by Lawrence et al., (2014) (p. 559). Removing animal products, animal flesh and animal by products from the diet can quickly change the amount of TMAO our body produces. Those who do not eat animal flesh or animal by products, vegans, produce almost no TMAO which indicate that gut microbiota in vegans do not exist in large enough quantities to produce TMAO (Koeth et al., 2013; Koeth et al., 2014).

Avoiding all animal foods and sports drinks containing carnitine, choline, and lethicin while simultaneously adopting a whole foods plant-based diet which incorporates fruits, vegetables, whole grains, along with beans, peas and legumes, can greatly reduce and possible even diminish the production of TMAO in individuals.

What Is In Your Gut Determine Heart Attack And Stroke Risk (2 of 2)

Do lean meats and low fat dairy products, improve cardiovascular health?

Current data suggests that lean meats and low fat dairy products still contain cholesterol, saturated fat, and trans fat which increase the risk of developing cardiovascular disease. According to the Institute of Medicine (IOM) there is no safe level of ingestion of cholesterol, saturated fat and trans fat and Americans should eat as little as possible (IOM, 2002, p.835-836). While, the new 2015-2020 United States dietary guidelines also recognize there is no need for the consumption of cholesterol. The United States Dietary Guidelines stated that the human body has the ability to produce all of the cholesterol and saturated fat it needs and therefore has no need for cholesterol, saturated fat, or trans fat as these substance increase the risk of cardiovascular disease. (U.S. Department of Health and Human Services [DHH] and U. S. Department of Agriculture [USDA]. (2015), P. 31, 32, 90). However, new evidence suggests that there may be other potential health risks beyond the ingestion of cholesterol, saturated fat and trans fats found naturally in animal flesh and animal by products that increase the risk of developing cardiovascular disease. This new evidence points to the intestinal microbiota metabolism of phospholipid phosphatidylcholine, choline or lecithin (found in chicken, fish, dairy and even plants) and L-carnitine (found in eggs, liver, beef, and pork) and its ability to produce trimethylamine-N-oxide (TMAO) which significantly increases the risk of atherosclerosis (Tang et al. 2013; Koeth et al. 2013).

Are there other foods that contain lecithin and carnitine that do not contain animal flesh and animal byproducts that can still increase the risk of developing cardiovascular disease?

Yes, be sure to read labels very closely. Some supplements contain lecithin and carnitine and many energy drinks also contain carnitine which can still contribute to the production of TMAO, leading to heart disease (Rak and Rader, 2011, p. 40).