In a groundbreaking study published in 2011 researchers showed that breakdown of dietary choline by bacteria in the gut was linked to atherosclerosis in mice. In a later study it was shown that the gut microbiome similarly breaks down dietary L-carnitine to a compound that increases atherosclerosis.
Choline is a nutrient, typically grouped with the B vitamins, that is found primarily in liver, meat, and eggs. A large proportion of fats in our bodies carry a choline group as part of their molecular structure. L-carnitine is chemically very similar to choline and is, like choline, also found primarily in red meat. The main function of L-carnitine in the body is to transport fats into the mitochondria, the power stations of the cell, to produce energy.
Choline and L-carnitine are broken down by microbes in the gut to a compound known as TMA. This TMA is adsorbed in the body and gets oxidized by the liver to form TMAO. When mice are fed choline or L-carnitine the blood levels of TMA and TMAO increase and the mice develop artherosclerotic heart disease. In contrast, mice that have been made germ-free do not convert choline and L-carnitine in TMA and consequently these mice are protected from heart disease.
In their latest study published in Cell these researchers describe a compound that inhibits the formation of TMAO and reduces atherosclerosis in mice. The compound known as DMB or 3,3-dimethyl-1-butanol is found in some cold-pressed extra virgin olive oils and grapeseed oils. It is important to note that DMB is not an antibiotic, hence bypassing all the concerns on chronic antibiotic use in humans. DMB does not kill bacteria but only inhibits their ability to produce TMA.
The role of the gut microbiome in human disease is currently a field of intensive study and likely many more revelations will be made on the role of these tiny bacteria in human health.
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