Formation of methylamines from ingested choline and lecithin

Area of Science:

• Biochemistry
• Human Physiology
• Microbiology

Background:

• Choline and lecithin are common dietary components.
• Physicians are increasingly using high-dose choline and lecithin for neurological conditions.
• Gut bacteria metabolize choline into trimethylamine (TMA), dimethylamine (DMA), and monomethylamine (MMA).

Purpose of the Study:

• To investigate the impact of oral choline and lecithin administration on methylamine excretion in humans and rats.
• To assess the potential health risks, including nitrosamine formation, linked to choline metabolism.

Main Methods:

• Healthy human subjects and rats were administered choline chloride, choline stearate, or lecithin.
• Urinary excretion of TMA, DMA, and MMA was measured.
• Methylamine contamination in tested compounds was analyzed.

Main Results:

• Choline chloride, choline stearate, and lecithin significantly increased urinary TMA, DMA, and MMA excretion in humans, with choline chloride showing the most pronounced effect.
• Choline chloride administration increased urinary TMA excretion in rats but did not affect DMA or MMA levels.
• Commercial lecithins and choline stearate were found to be contaminated with methylamines.

Conclusions:

• Oral administration of choline and lecithin leads to increased urinary methylamine excretion, primarily due to gut bacterial metabolism.
• Choline chloride exhibits the strongest effect on methylamine excretion.
• Contamination of supplements with methylamines can influence excretion levels, highlighting the importance of compound purity.