Eating a high fat diet causes a chain reaction in the gut, starting with the cells of the gut wall causing metabolic regulation of commensal bacteria, leading more bacteria to breakdown choline, and causing higher levels of TMAO in the bloodstream.
It is already known that a poor quality, high fat diet leads to atherosclerosis and cardiovascular disease. Dr Myriam Byndloss and her team at Vanderbilt University Medical Center, in Nashville, set out to find out how.
The research (1) with mice showed the foods eaten can have an immediate effect on your health.
The researchers found that eating a diet high in fried food, fast food and fatty foods causes three problems:
- A high fat diet promotes an increase in anaerobic bacteria (ones that don’t use oxygen) around the intestinal epithelium, actually causing damage to the mitochondria of the colonocytes (the colon wall cells).
- In turn, these mitochondrial changes influence the bacteria in the gut, turning on or off their metabolic pathways.
- This results in more gut bacteria breaking down choline leading to an increase of trimethylamine N-oxide, or TMAO, in the bloodstream. TMAO is known to cause chronic inflammation and heart disease.
The whole process is a chain reaction and comes about because high fat diets cause an increase in anaerobic bacteria leading to a reduction in oxygen uptake by the gut wall cells and their power stations, causing metabolic changes and more nitrate in the mucous lining. This weakens the healthy gut bacteria, leading pathogens, like E. coli, to become dominant, causing more choline metabolism.
Chris Woollams, former Oxford University Biochemist added, “This is certainly not the first study to link gut bacteria to TMAO production. We have summarised most of these steps before (2). The Cleveland Clinic showed that gut bacteria could feed on red meat and full cream milk to make more choline and then TMAO. They used Extra Virgin Olive oil to block this.
The University of Louisville also showed that a high fat diet led to a change in gut bacteria which produced more TMAO.
And we know how exactly how bad TMAO is for the body, not just for atherosclerosis and cardiovascular disease, but for chronic inflammation and even cancer spread. This latest research confirms the knowledge and gives us more clues on how it occurs, by telling us the gut wall mitochondria are involved.”
- Science – Woongjae Yoo et al; 12 Aug 2021; vol 373(6556) 813-818 https://science.sciencemag.org/content/373/6556/813
- How high fat diets are dangerous to your health, especially heart health.