Carnitine (vitamin Bt) review

• Basics: a non-essential amino acid, responsible for the transport of long-chain fatty acids into the energy-producing centers of the cells.

• Benefits: helps maintain blood lipid profile and promote fatty acid utilization within heart muscle, helps the body convert fatty acids into energy.

• Dosage: 500 milligrams (MG) to 4,000 mg per day for general health.

• Sources: red meat, fish, poultry, tempeh (fermented soybeans), wheat, asparagus, avocados, and peanut butter.

• Deficiency: deficiency occurs as a primary genetic defect of carnitine transport and secondary to a variety of genetic and acquired disorders.

• Overdose: toxicity from l-carnitine overdosage is rare.

Editor's choice: Acetyl L-Carnitine

Carnitine aids in converting fatty acids into energy used by the muscles throughout the body. It is stored in the skeletal muscles, heart, brain and sperm. An inadequate carnitine level may present itself in symptoms including confusion, heart pain, muscle weakness and obesity. Acetyl L-Carnitine by Vitabase is manuafactured according to the highest pharmaceutical standards and uses only the best quality raw ingredients. Click here for more information.

Carnitine (vitamin Bt)

Carnitine is a non-essential amino acid produced in the liver, brain and the kidneys from the essential amino acids methionine

and lysine. Carnitine is the generic term for a number of compounds that include L-carnitine, L-acetylcarnitine, acetyl-L-carnitine, and L-propionyl carnitine. Carnitine can be synthesised within the body from lysine or methionine. As with all amino acids used directly in the metabolism, carnitine exists in the left-handed form. This isomer is expressed as L-carnitine, as it is usually marketed. Carnitine is eaten in the diet in red meats and dairy products, including breast milk, and is also made in the body from breaking down muscle protein and converting it to carnitine.

Carnitine is a nutrient responsible for the transport of long-chain fatty acids into the energy-producing centers of the cells (known as the mitochondria). Carnitine plays a critical role in metabolizing a number of other important substances as well, which helps to explain why it holds promise for so many disorders. Carnitine transports fats into the mitochondria, the cellular powerhouse, where these fats are converted into an energy source for the body. Our heart and skeletal muscle tissue rely on fat utilization as a source of energy, and also to spare glycogen. Carnitine helps the body convert fatty acids into energy, which is used primarily for muscular activities throughout the body. The body produces carnitine in the liver and kidneys and stores it in the skeletal muscles, heart, brain, and sperm. Carnitine can also act as an antioxidant and appears to play a role in maintaining the health of nerves and protecting the liver and kidneys from the toxicity of drugs.

Carnitine (vitamin Bt) functions, uses, and health benefits

Carnitine helps transport fatty acids to the powerhouse of the cell. Fatty acids are the main fuel source for heart and skeletal muscle. Long-chain fatty acids require l-carnitine to transport them across the inner membranes of the mitochondria, wherein their metabolism produces bioenergy. L-carnitine can remove short-chain and medium-chain fatty acids from the mitochondria

in order to maintain coenzyme A levels in these organelles. L-Carnitine also facilitates the metabolism of carbohydrates and enhances the rate of oxidative phosphorylation. L-Carnitine works synergistically with CO-Q10, an antioxidant and energy co-factor that is found in the inner membrane of the mitochondria.

Carnitine plays a critical role in metabolizing a number of other important substances as well, which helps to explain why it holds promise for so many disorders. Carnitine mediates the transport of medium/long-chain fatty acids across mitochondrial membranes, facilitating their oxidation with subsequent energy production. Carnitine may have neuroprotective effects. This means that the strong antioxidant properties of acetyl-L-carnitine may help to prevent oxidative damage to nerve cells that are important for brain functioning.

The strongest evidence for the use of supplemental L-carnitine may be in the management of cardiac ischemia and peripheral arterial disease. It may also more generally be indicated for cardioprotection. It lowers triglyceride levels and increases levels of HDL-cholesterol in some. It is used with some benefit in those with primary and secondary carnitine deficiency syndromes. There is less evidence to support arguments that carnitine is indicated in liver, kidney and immune disorders or in diabetes and Alzheimer's disease.

Carnitine is used for a small percentage of people who are at risk of liver damage from AEDs and is used for children with multiple seizure types who are taking multiple AEDs. Carnitine is used in emergency situations where there is liver damage caused by valproate, or in cases of valproate overdose. It is used in rare diseases involving problems of the transport of carnitine into the mitochondria.

L-carnitine has been marketed as a weight loss supplement, because the primary function of carnitine in human cells is to burn fat as a source of energy. Carnitine supplementation may actually help increase energy, burn fat more efficiently and may improve heart and liver health all at the same time.

Carnitine is recommended as a daily supplement to help maintain blood lipid profile and promote fatty acid utilization within heart muscle. People who take l-carnitine supplements soon after suffering a heart attack may be less likely to suffer a subsequent heart attack, die of heart disease, experience chest pain and abnormal heart rhythms, or develop congestive heart failure. Some studies have shown Carnitine may reduce the pain and complications of lack of oxygen to the heart and improve exercise tolerance in people with existing heart disease.

The function of carnitine is to help the body use stored fat as fuel. Carnitine is helpful for improving exercise performance. Supplementation with carnitine has been said to enhance lipid oxidation, increase VO2max and decrease the accumulation of lactic acid during exercise.

Carnitine reduces the incidence of angina and cardiac arrythmias as well as reduces the need for anti-angina and anti-arrythmic medications.

Acetyl-L-carnitine may be indicated for use in cases of mild Alzheimer's disease, dementia, Down's syndrome, recovery from stroke and for the management of various neuropathies.

Carnitine (vitamin Bt) dosage, intake, recommended daily allowance (RDA)

Carnitine is not an essential amino acid and, since it is not a vitamin or a mineral, no RDA or dietary reference intake (DRI) values have been established. The L-isomer of carnitine (L-carnitine) is the only physiologically useful form of carnitine. Recommended doses of l-carnitine supplements vary depending on the health condition being treated. The normal recommended dose appears to be 500 milligrams (MG) to 1,000 mg per day. Then gradually work up to 2 to 4 grams (2,000 to 4,000 mg) per day. Typical doses of supplemental acetyl-L-carnitine are between 500 mgs to 2 gms daily in divided doses. Doses of 2 to 6 grams per day are typically recommended for cardiovascular, sports performance and weight loss benefits. Infant formulas (including total parenteral nutrition solutions) that do not contain carnitine should be supplemented with carnitine to the levels found in human milk, 11.3 mg/L (70 mmol/L).

Sources of carnitine

Dietary sources of carnitine include foods of animal origin, such as meat and dairy products. Red meat (particularly lamb) and dairy products are the primary sources of carnitine. Carnitine can also be found in fish, poultry, tempeh (fermented soybeans), wheat, asparagus, avocados, and peanut butter. Cereals, fruits, and vegetables contain little or no carnitine. Carnitine can be manufactured in the body provided the requisite vitamins and minerals are also present. A typical Western diet supplies about 100mg of carnitine per day. It is found mostly in red meats and dairy products. Plant foods are not good sources of carnitine. In general, healthy adults do not require dietary carnitine as carnitine stores are replenished through endogenous synthesis from lysine and methionine in the liver and kidneys.

Carnitine deficiency

There are two types of carnitine deficiency, primary and secondary. In both primary and secondary carnintine deficiencies, increased dietary intake and supplements of carnitine can be beneficial. Although the exact mechanism is unknown, it is thought that flooding the body with high concentrations of carnitine assures that some carnitine are able to get into the cells. Carnitine deficiency occurs as a primary genetic defect of carnitine transport and secondary to a variety of genetic and acquired disorders. A person with primary carnitine deficiency has very low levels of carnitine in the blood due to a faulty carnitine transporter which prevents carnitine from getting into the cells where it is needed. The secondary form of carntine deficiency can arise secondary to metalobic disorders in the mitochondria. Blockage of metabolic pathways in the mitochondria leads to a build-up of acyl compounds. Infants are particularly susceptible to carnitine depletion, because the demands of tissue accretion associated with rapid growth exceed the ability of the infant to synthesize carnitine.

Carnitine overdose, toxicity, side effects

There have been no reports of toxicity from L-carnitine overdosage. The oral LD50 of L-carnitine in mice is 19.2 grams per kilogram. D-carnitine supplements should be avoided as they interfere with the natural form of L-carnitine and may produce undesirable side effects. L-carnitine supplementation may cause mild gastrointestinal symptoms, including nausea, vomiting, abdominal cramps and diarrhea. Adverse effects may include transient nausea, vomiting, abdominal cramps and diarrhea. Less frequent reactions may include body odour or gastrointestinal symptoms. Other rare side effects include increased appetite, body odor, and rash.