Carnitine

From Health Facts
(Redirected from L-Carnitine)
Jump to: navigation, search
Latest Edit: Iva Lloyd, ND 2016-11-11 (EDT)

See Also Food Supplements

Carnitine, also known as Carnitine tartrate or Acetyle L-Carnitine is an essential nutrient which is important for moving long-chain fatty acids into the mitochondrial matrix where the lipids go through beta-oxidation for energy production. When carnitine is deficient, it leads to decreased energy production due to an inability to transport fatty acids into the energy producing mitochondria. Carnitine is also important for oxidation of the ketoacid analogs of the branched-chain amino acids valine, leucine, and isoleucine. This is a critical function during fasting, starvation, and exercise.[1]

Food Sources

The following foods have the highest concentration of Carnitine.

Note: grains, fruit, and vegetables contain virtually no carnitine.

In general, the redder the meat the more carnitine it contains.

Uses

The following is a list of the primary uses for Carnitine.[1]

Article L- carnitine: Cardiovascular applications, IHP, [1], Feb/Mar 2011
Article NAFLD, Clinical application of betaine and L-carnitine, IHP, [2], June/July 2011
  • Cardiovascular Disease (CVD): Adequate carnitine in the heart is crucial for proper energy production. If the heart is deprived of adequate oxygen, carnitine levels in the heart decrease and this can lead to conditions such as angina and heart disease. Carnitine can be beneficial for individuals with angina because it helps to increase the utilization of oxygen and boosts energy production in the heart muscle. Improper fat metabolism is also damaging to the cell membranes within the heart and can impair contraction eventually leading to tissue death. Supplementation with carnitine can be beneficial in assuring proper fat metabolism in the heart and is useful for such conditions as angina, recovery from Myocardial infarction (Heart Attack), arrhythmias, and congestive heart failure. Furthermore, carnitine also lowers triglyceride and total cholesterol levels while raising HDL (good) cholesterol, improving the overall lipid profile. Due to the cost of carnitine, however, it should be used to lower cholesterol in cases that are unresponsive to other natural cholesterol lowering agents. In addition, carnitine is also helpful in the treatment of intermittent claudication. Carnitine can help to increase energy production during poor oxygen supply to the muscles of the legs. It can also be used for other peripheral vascular diseases.
  • Weight Loss: L-carnitine reduces appetite and increases energy by promoting fat burning.
Article L- carnitine: Athletic performance enhancement, IHP, [3], October 2010
  • Enhancing Physical Performance: Like the heart muscle, skeletal muscle also relies on proper amounts of carnitine for fat metabolism and energy production. Carnitine supplementation in the athletic population can improve cardiovascular function after exercise, improve exercise intensity, time, and energy metabolism in muscles (lower lactic acid buildup), and thus contribute to an overall enhanced physical performance. It is particularly beneficial to increase endurance.
  • Alzheimer's Disease, Senile Depression, and Age-Related Memory Defect: Much research has been done on L-acetylcarnitine (LAC) and Alzheimer's, senile depression, and age-related memory defects. LAC is the combination of acetic acid and L-carnitine bound together. LAC and acetylcholine, a neurotransmitter in the brain involved in memory and proper brain functioning, have very similar chemical structures. Due to this similarity in structure, LAC has actually been found to mimic acetylcholine and is beneficial in the treatment of these conditions. It has been found to be an antioxidant, it stabilized cell membranes, improves energy production in brain cells, and enhances the function of acetylcholine. In many studies, LAC has been shown to delay the progression of Alzheimer's Disease. It also improves mental function in those with mild mental deterioration. Finally, it also benefits elderly suffering from depression.
  • Down's Syndrome: A study has found that individuals with down's syndrome treated with LAC have shown improvement in visual memory and attention. It appears to benefit this population because Down's syndrome is associated with a deficit in cholinergic transmission and LAC exerts a direct and indirect cholinomimetic effect.
  • Kidney Disease and Hemodialysis: The kidney is an important site for carnitine synthesis and therefore is important to supplement carnitine in kidney disease. Patients undergoing hemodialysis also lose large amounts of carnitine during dialysis. Supplementation with carnitine in dialysis patients also helps to decrease ones risk for heart disease by improving lipid profile, decreases symptoms of angina, decreases muscle cramping, increases muscle mass, and improves anemia. L-carnitine may be an effective therapy which allows a reduction in the dose of recombinant human erythropoietic (EPO) therapy which is expensive and has side effects.
  • Diabetes: Individuals with diabetes typically have low levels of serum carnitine. L-carnitine supplementation is warranted in this population due to the increased risk of cardiovascular disease and reduced liver and kidney function. It can also improve peripheral vascular health and nerve function.
  • Liver Disease: There is some evidence to suggest that a carnitine deficiency can lead to fatty infiltration in the liver (steatosis/liver congestion). Excessive alcohol consumption can lead to this condition and it is believed that alcohol consumption can lead to a functional carnitine deficiency (meaning there is carnitine available but it is not functioning properly). Carnitine can inhibit and reverse alcohol-induced fatty liver disease. Supplementation is also useful in liver disorders resulting from xenobiotics (man-made chemicals).
  • Muscular Dystrophies: Individuals with a variety of types of muscular dystrophies have low levels of muscle carnitine and this may contribute to muscle weakness. Studies are still needed to determine its benefit for this condition.
  • Low Sperm Counts and Decreased Sperm Motility: High concentrations of carnitine are critical for proper energy metabolism in sperm. Low carnitine levels lead to lowered motility and a higher risk of infertility. Supplementation can increase sperm count and increase motility.
  • Chronic Obstructive Pulmonary Disease: Supplementation with carnitine in this population has been found to increase exercise tolerance.
  • Acquired Immunodeficiency: Low serum levels of carnitine are often found in individuals with AIDS. What is more significant is that levels in white blood cells (WBCs) are deficient, even in patients with normal serum levels. L-carnitine can also prevent toxicity due to the drug AZT, a commonly used AIDS drug, which is toxic to the muscles' mitochondria. This toxicity can lead to decreased energy production and can lead to muscle fatigue and pain. In addition, L-carnitine can improve immune function by improving WBC proliferation.
  • Inborn Errors of Amino Acid Metabolism: L-carnitine has been beneficial in the treatment of glutaric aciduria, isovaleric acidemia, propionic acidemia, and methylmalonic aciduria.
  • Protection Against Drug Toxicity: See "Safety" section below.
  • Attention Deficit Hyperactivity Disorder: Some preliminary studies have shown benefit in using L-carnitine for ADHD in terms of improving behaviour at home and school.[2]

Deficiency Symptoms

Carnitine deficient states are divided into two groups:

  1. systemic carnitine deficiency
  2. myopathic or muscular deficiency.

All patients with carnitine deficiency experience progressive muscle weakness due to buildup of fats in muscle cells because the fats cannot be properly metabolized. Systemic carnitine deficiency responds well to supplementation. Adults are typically able to adapt to deficiency whereas children are not able to as well. Secondary carnitine deficiency in children may present with loss of muscle tone, failure to thrive, recurrent infection, swelling of the brain, hypoglycemia, heart disturbances, and may be fatal.

A primary myopathic carnitine deficiency is a result of an inborn error in carnitine metabolism which is limited to the skeletal muscles. Fat accumulates to a high extend in muscle cells as a result. Supplementation does not benefit this form of deficiency. Treatment of this condition would include a diet high in medium-chain fatty acids and low in long-chain fatty acids.[1]

Prescribing Considerations

The recommended dosages have not yet been established. To determine what your specific requirements are talk to your naturopathic doctor or other trained medical professional.

  • Supplementation: 1500-4000mg in divided doses (lower doses should be used in patients with impaired renal function).[1]
  • Always use the form of L-carnitine alone or bound to either acetic or propionic acid. Never use the D form.
  • For Alzheimer's disease and brain effects - L-acetylcarnitine (LAC) is best
  • For Angina - L-propionylcarnitine (LPC) may be best but L-carnitine (LC) has also been found to be effective.[1]

Safety

L-carnitine is generally regarded as safe. Specific safety precautions include:

  • Rare side effects may include: GI complaints such as nausea and vomiting; sleeplessness may occur if taken before bed.
  • Children: Supplementation is not recommended unless otherwise indicated as essential.
  • Pregnancy and Breastfeeding
  • Lack of evidence showing its safety in this population suggests avoiding supplemenation during pregnancy and nursing.
  • Contraindications
  • low or borderline-low thyroid levels (may impair thyroid hormone)
Caution in cases of seizures
  • Precautions
  • DL-carnitine may produce muscle weakness; D-carnitine should be avoided
  • Drug Interactions:[3]
Supportive or Beneficial:
  • Allopurinal restores carnitine levels in individuals with Duchenne muscular dystrophy. Co-administration of carnitine could enhance this intervention.
  • Doxorubicin and Related Anthracycline Chemotherapy - Co-administration of carnitine before, during, and after chemotherapy can prevent and reduce cardiomyopathy and other toxic drug effects.
  • Isotretinoin Retinoids - Carnitine can prevent or reduce adverse effects of drug, particularly myalgia (muscle pain) and elevated triglycerides.
  • Nitroglycerin - Carnitine can support cardiac function and reduce ischemia and angina. Co-administration may reduce incidence and severity of angina and enable reduced nitroglycerin dosage. Theoretical risk of additive response.
  • Pivalate Prodrugs - Carnitine support can prevent or reverse depletion and adverse sequelae typically in cases of long-term drug use.
  • Simvastatin and Related HMG-CoA Reductase Inhibitors (Statins) - Several trials show therapeutic benefits from L-carnitine, particularly in combination with simvastatin, in treating dyslipidemia especially in those with type II diabetes.
  • Zidovudine (AZT) and Related Reverse-Transcriptase Inhibitor (Nucleoside) Anti-Retroviral Agents - Carnitine can prevent and reduce adverse effects of AZT and related antiviral medications.
Addresses Drug-Induced Deficiency:
  • Valproic Acid and Related Anticonvulsant Medications - Co-administration of carnintine can prevent or reverse adverse medication effects and depletion in carnitine status but may be unnecessary in many patients.
Contraindicated:
  • Levothyroxine and Related Thyroid Hormones - Carnitine inhibits thyroid hormone nuclear uptake and may partially block activity of thyroid hormone. Carnitine is contraindicated in hypothyroidism but valuable in hyperthyroidism.

References

  1. 1.0 1.1 1.2 1.3 1.4 Murray Michael T (1996) Encyclopedia of Nutritional Supplements, The Essential Guide for Improving Your Health Naturally, Prima Publishing. Cite error: Invalid <ref> tag; name "murray" defined multiple times with different content
  2. Pizzorno Joseph E, Murray Michael T (1999) Textbook of Natural Medicine, Elsevier
  3. Stargrove Mitchell Bebell, Treasure Jonathan, McKee Dwight L (2008) Herb, Nutrient, and Drug Interactions, Clinical Implications and Therapeutic Strategies. Mosby