L-carnitine is made in the body from the amino
acidslysine and methionine, and is needed to release energy from fat. It transports fatty acids into mitochondria,
the powerhouses of cells. In infancy, and in situations of high energy needs, such as pregnancy and breast-feeding, the need for L-carnitine
can exceed production by the body. Therefore, L-carnitine is considered a "conditionally
essential" nutrient.1
Where is it found?
Dairy and red meat contain the greatest amounts of carnitine.
Therefore, people who have a limited intake of meat and dairy products tend to have lower
L-carnitine intakes.
L-carnitine has been used
in connection with the following conditions (refer to the individual
health concern for complete information):
Reliable
and relatively consistent scientific data showing a substantial health benefit. Contradictory, insufficient, or preliminary studies
suggesting a health benefit or minimal health benefit. For an herb, supported by traditional use but minimal
or no scientific evidence. For a supplement, little scientific support and/or minimal health
benefit.
Who is likely to be deficient?
Carnitine deficiencies are rare, even in strict vegetarians, because the body produces carnitine
relatively easily.
Rare genetic diseases can cause a carnitine deficiency. Also, deficiencies are occasionally
associated with other diseases, such as
diabetes and cirrhosis.2
3 Among people with diabetes, carnitine deficiency is more likely to be found in persons
experiencing complications of diabetes (such as
retinopathy, hyperlipidemia, or neuropathy), suggesting that carnitine deficiency may play
a role in the development of these complications.4 A carnitine deficiency can also
result from oxygen deprivation which can occur in some heart conditions. In Italy, L-carnitine is prescribed
for heart failure, heart arrhythmias, angina, and lack of oxygen to the
heart.5
How much is usually taken?
Most people do not need carnitine supplements. For therapeutic use, typical amounts are
1–3 grams per day.
It remains unclear whether the propionyl-L-carnitine form of carnitine used in congestive heart failure research has greater benefits
than the L-carnitine form, since limited research in both animals and humans with the more
common L-carnitine has also shown very promising effects.6
Are there any side effects or interactions?
L-carnitine has not been consistently linked with any toxicity.
The information presented in Healthnotes is for informational purposes
only. It is based on scientific studies (human, animal, or in vitro), clinical
experience, or traditional usage as cited in each article. The results reported may not
necessarily occur in all individuals. For many of the conditions discussed, treatment with
prescription or over the counter medication is also available. Consult your doctor,
practitioner, and/or pharmacist for any health problem and before using any supplements or
before making any changes in prescribed medications. Information expires June 2009.
