Carnitine, a nutrient that assists the body in turning fat into energy, is produced in the liver and kidneys. Carnitine is stored in muscles, the heart, brain, and sperm. Most often, our bodies make enough carnitine for normal functioning. In rare cases, a person may be deficient in carnitine because of a health condition or due to a medication side effect. Alpha-lipoic acid helps turn glucose into energy because it is an antioxidant that is made in the body and found in every human cell. Always seek the advice of a health care professional before taking any supplement.
When used in combination with conventional medical treatment, carnitine reduces symptoms of stable angina, according to the University of Maryland Medical Center. It can also improve the ability of those with angina to exercise without chest pain. Chest pain should not be self-treated with carnitine; always seek medical attention for acute chest pain.
Peripheral neuropathy is the numbness, tingling and pain felt by diabetics who have nerve damage in their limbs. According to the UMMC, both alpha-lipoic acid and acetyl-L-carnitine help reduce pain and increase normal feeling in affected nerves. In Europe, alpha-lipoic acid has been used for years for this purpose. Intravenous doses of alpha-lipoic acid can help reduce peripheral neuropathy symptoms.
It’s a bit like a scene from a movie: the elderly scientist, working late in the lab, takes a sip of potion from a bubbling flask and undergoes a miraculous transformation as his body regains its youth and vigour. Pure fantasy? Maybe not – because that’s pretty much what happened to elderly laboratory rats when they were fed two dietary supplements in a recent landmark study. According to the professor in charge of the study, ‘the old rats became so full of energy, they got up and did the Macarena’!
Over the last 18 months, scientific interest in alpha lipoic acid (ALA) and acetyl L-carnitine (ALC), the two supplements used in the studies, has exploded and a large number of studies are now under way with humans. Initial results look encouraging, but what are the implications for athletes – and can these nutrients be harnessed to improve performance?
Some readers may be familiar with the amino acid carnitine, which carries fatty acids into the mitochondria (the cellular furnaces), where they are ‘oxidised’ for energy. As its name suggests, acetyl L-carnitine (ALC) is very similar, consisting of the same basic amino acid structure, with an acetyl group attached. In the body, acetyl L-carnitine is synthesised from L-carnitine by the enzyme carnitine acetyltransferase. Although levels tend to decrease after the age of 40, acetyl L-carnitine (ALC) is not normally considered an ‘essential nutrient’ because the body can manufacture all it needs.
One of the main roles of acetyl L-carnitine (ALC) is to carry fatty acids from the cytosol (the main body of the cell) into the mitochondria (the energy-producing furnaces within cells) so that these fats can be oxidised for energy. Although L-carnitine carries out this role too, acetyl L-carnitine (ALC) also provides acetyl groups, from which acetyl-coenzyme A (a key metabolic intermediate) can be regenerated, thereby facilitating the transport of metabolic energy and boosting mitochondrial activity.
The addition of the acetyl group also endows acetyl L-carnitine (ALC) with a greater solubility in water, which enables it not only to diffuse easily across the inner wall of the mitochondria and into the cell cytosol, but also cross cell membranes in general more easily. In plain English, acetyl L-carnitine (ALC) reaches parts of the body that L-carnitine just can’t reach! In addition to its role in mitochondrial activity, acetyl L-carnitine (ALC) is involved in the production of the key brain neurotransmitter acetylcholine and is also able to donate its acetyl group in a number of other biochemical reactions.
Alpha lipoic acid (ALA) is a sulphur-containing antioxidant, which occurs naturally, in small amounts, in such foods as spinach, broccoli, beef, yeast, kidney, and heart. alpha lipoic acid (ALA) is readily soluble in water and fat, enabling it to exert an antioxidant effect in almost any part of the body, including the brain. In the mitochondria, alpha lipoic acid (ALA) can act both as an antioxidant, capable of recycling other antioxidant nutrients such as vitamin C and vitamin E, and as a coenzyme for key metabolic enzymes involved in energy production. In addition to its role as an antioxidant, alpha lipoic acid (ALA) also raises the levels within cells of a substance called glutathione, which is critical for neural function, and aids in glycolysis, the first stages of breaking down carbohydrates for energy.
The initial excitement about ALC/alpha lipoic acid (ALA) supplementation began when a team of researchers in California fed elderly rats both nutrients for a period of seven weeks and then compared them with young rats. They were testing the theory that mitochondrial decline is caused by free radical damage (see panel opposite). There was already evidence that supplementation with acetyl L-carnitine (ALC) could reverse the age-related decline in mitochondrial activity in rats, increase fatty acid oxidation and boost general metabolic activity. However the down side to this increased mitochondrial function was that more oxidative damage occurred, so the researchers decided to add the powerful mitochondrial antioxidant alpha lipoic acid (ALA) to the mix to see if they could get the best of both worlds: increased mitochondrial energy output, with reduced mitochondrial damage.