En kost med rött kött och fettdepåer i artärerna

[King Grub]

TMAO är en metabolit som är kopplad till förfettning av artärerna. Rött kött, men inte vitt kött eller andra proteinkällor, ökar nivåerna av TMAO.

Aims

Carnitine and choline are major nutrient precursors for gut microbiota-dependent generation of the atherogenic metabolite, trimethylamine N-oxide (TMAO). We performed randomized-controlled dietary intervention studies to explore the impact of chronic dietary patterns on TMAO levels, metabolism and renal excretion.

Methods and results

Volunteers (N = 113) were enrolled in a randomized 2-arm (high- or low-saturated fat) crossover design study. Within each arm, three 4-week isocaloric diets (with washout period between each) were evaluated (all meals prepared in metabolic kitchen with 25% calories from protein) to examine the effects of red meat, white meat, or non-meat protein on TMAO metabolism. Trimethylamine N-oxide and other trimethylamine (TMA) related metabolites were quantified at the end of each diet period. A random subset (N = 13) of subjects also participated in heavy isotope tracer studies. Chronic red meat, but not white meat or non-meat ingestion, increased plasma and urine TMAO (each >two-fold; P < 0.0001). Red meat ingestion also significantly reduced fractional renal excretion of TMAO (P < 0.05), but conversely, increased fractional renal excretion of carnitine, and two alternative gut microbiota-generated metabolites of carnitine, γ-butyrobetaine, and crotonobetaine (P < 0.05). Oral isotope challenge revealed red meat or white meat (vs. non-meat) increased TMA and TMAO production from carnitine (P < 0.05 each) but not choline. Dietary-saturated fat failed to impact TMAO or its metabolites.

Conclusion

Chronic dietary red meat increases systemic TMAO levels through: (i) enhanced dietary precursors; (ii) increased microbial TMA/TMAO production from carnitine, but not choline; and (iii) reduced renal TMAO excretion. Discontinuation of dietary red meat reduces plasma TMAO within 4 weeks.

Impact of chronic dietary red meat, white meat, or non-meat protein on trimethylamine N-oxide metabolism and renal excretion in healthy men and women. European Heart Journal, 10 December 2018.

https://academic.oup.com/eurheartj/a...dFrom=fulltext