Study summary · research use only
Levocarnitine
Plain-language summary
Paraphrased from the published abstract below — not a verdict on whether anything works.
This review/monograph (human, lactation context) describes levocarnitine and acetyl-l-carnitine as normal components of human milk required for fat metabolism, noting the body can use only levocarnitine, dextrocarnitine can act as an antagonist of levocarnitine, and acetyl-l-carnitine and propionyl-l-carnitine can be converted to levocarnitine by the body. Levocarnitine bioavailability is stated as less than 20%, while acetylcarnitine and propionylcarnitine bioavailability may be higher; women with carnitine deficiency may secrete insufficient carnitine into breastmilk, and preterm infants are often deficient in levocarnitine and require supplementation. The authors note no data exist on levocarnitine supplementation in nursing mothers or infants without carnitine deficiency, and that levocarnitine is generally tolerated in adults, with occasional gastrointestinal upset, restlessness, and a fishy breath/sweat/urine odor reported.
Abstract
Levocarnitine and acetyl-l-carnitine (acetlycarnitine) are normal components of human milk that are required for fat metabolism. The body can use only levocarnitine; dextrocarnitine can be an antagonist of levocarnitine. Acetyl-l-carnitine, and propionyl-l-carnitine can be converted to levocarnitine by the body. The bioavailability of levocarnitine is less than 20%, but acetlycarnitine and propionlycarnitine may be higher. These substances have no specific lactation-related uses. Within the normal range of dietary intake, excretion of levocarnitine into breastmilk is relatively constant. Women with carnitine deficiency appear to secrete insufficient amounts of carnitine into their breastmilk for their breastfed infants, who may require levocarnitine supplementation.[1] Preterm infants are often deficient in levocarnitine and require supplementation.[2] No data exist on the safety and efficacy levocarnitine supplementation in nursing mothers or infants without carnitine deficiency. Levocarnitine and its derivatives are generally well tolerated in adults with occasional gastrointestinal upset and restlessness. A fishy odor to the breath, sweat and urine has been reported. Although data are very limited, poor bioavailability might limit absorption by the breastfed infant. It appears unlikely that maternal levocarnitine supplements during nursing would be harmful to the infant, but until more data are available, it is probably best to avoid levocarnitine supplementation unless a healthcare professional prescribes it.
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