The TMAO thing is probably BS

The most abundant source of TMAO is fish that has demostrated benefit for CVD. There are hundreds of studies of the benefit of carnitine(meat amino acid) in patients with CVD.

CONCLUSION:

These findings suggest that TMAO slows aortic lesion formation in this mouse model and may have a protective effect against atherosclerosis development in humans.

https://www.ncbi.nlm.nih.gov/pubmed/26584136

Oral L-carnitine supplementation increases trimethylamine-N-oxide but reduces markers of vascular injury in hemodialysis patients.

https://www.ncbi.nlm.nih.gov/pubmed/25636076

Propionyl-L-carnitine prevents the progression of atherosclerotic lesions in aged hyperlipemic rabbits.

https://www.ncbi.nlm.nih.gov/pubmed/7605374

The influence of chronic L-carnitine supplementation on the formation of preneoplastic and atherosclerotic lesions in the colon and aorta of male F344 rats.

https://www.ncbi.nlm.nih.gov/pubmed/25164827

Malcolm Kendrick has been discussing L-carnitine. I suspect the rest may be just more vegan propaganda "it's in meat so it must be bad!" Er, wrong as usual!