L-carnitine and dietary intake

The human body contains a total of 20-25 gm of L-carnitine, about 98% of which is in the skeletal and heart muscles. This shows the importance of carnitine in muscle function. The dietary intake is estimated to about 100-300 mg per day on a Western diet. Meat and dairy products are the major dietary sources of carnitine (Rebouche and Engel, 1984). Carnitine is readily absorbed from the gastrointestinal tract by both active and passive transport mechanisms. Adult carnitine requirements are generally satisfied by dietary intake and endogenous synthesis. Vegetarians face a shortfall in their daily carnitine intake and therefore are at risk for carnitine insufficiency. Since infants are unable to synthesize adequate amounts of carnitine, infant formulas are often fortified with L-carnitine.