Bioactive Compounds, Carnatine.

The therapeutic benefit of any substance can be defined by estimating its bioactivity. This property can help to determine usefulness of that substance. The term bioactive has been derived from bios (in Greek) means life, and activus (in Latin) means dynamic.

Therefore, bioactive compounds are biologically active and can provide direct effect on living organisms. This kind of effect may be good or bad depending on the nature, dose, and bio-availability of the compound. [1] Bioactive compounds are considered as extra-nutritional constituents, which are present in small quantities in plants, micro-organism, marine products and other food items. The structural variation is a distinct factor which varies from one to the other bioactive compound. [2] Some bioactive compounds can also be synthesized in human body. Carnitine is one of such compound that can be synthesized in the human liver and kidney and stored into skeletal muscles, brain, heart, sperm and body tissues. The researchers found it to be a promising agent to treat several diseases due to its anti-oxidant effect. To know more about its benefits, let us get some basic understanding about the compound. [3]

What is Carnitine?

The term ‘carnitine’ is derived from a Latin word 'carnus', which means flesh. Carnitine is a derivative of amino acid and is used as a generic term for acetyl-L-carnitine, L-carnitine, and propionyl-L-carnitine. [4]

Carnitine has a major bioactivity in conversion of fat to energy in the mitochondria (it is a kind of organelle present in cells, responsible for biochemical processes of respiration and energy production). [3] In addition, carnitine also assist in transportation of toxic substances produced during this biochemical reactions from tissues including cardiac and skeletal muscles, as these tissues utilizes maximum fatty acids as a dietary fuel. Thus, carnitine can act as a protector by preventing the accumulation of toxic substances in the body tissues. [4]

Chemical Structure

Carnitine is chemically known as levocarnitine or L- carnitine and the molecular formula is 
C₇H₁₅NO₃. [5] Pure carnitine powder is highly soluble in water and has good heat stability. The chemical structure of carnitine remains unaltered upto 200⁰C temperature. [6] Carnitine is also stable in air for prolonged period. Carnitine is palatable and odorless, therefore it can be orally taken without compromising our taste buds. [7] The toxicity study performed with carnitine also provide evidences that carnitine is safe, as it has very low toxicity. [6]

Synthesis in Human Body

Carnitine is naturally synthesized in plants, bacteria, fungi and animals, including human body cells. Biosynthesis of carnitine follows five steps, while initial four steps are conducted in every cells, but the final fifth steps are conducted only on few organs, like liver and kidney of human. [6]

Healthy children and adults are able to prepare sufficient amino acids like lysine and methionine in the liver and kidney, which gets converted to produce sufficient carnitine to meet daily requirement. This is a reason why the Food and Nutrition Board (FNB) of the National Academies do not consider that carnitine is an essential nutrient for every individual. However, some genetic or medical condition causes insufficient production of carnitine in the body due to which supplementation of carnitine is essential for them to maintain the energy supply to body tissues. [4]

Food Sources of Carnitine

The following are some foods which contains carnitine.

Source: https://ods.od.nih.gov/factsheets/Carnitine-HealthProfessional/ [4]

Deficiency of Carnitine

Deficiency of carnitine has been classified in two types - primary carnitine deficiency and secondary carnitine deficiency. Primary carnitine deficiency is a rare condition and occurs due to genetic disorder, whereas, in secondary carnitine deficiency an excessive carnitine loss can be observed, which can be influenced by metabolic disorder, certain drug therapy or renal failure. However, malnutrition or poor diet also cause secondary carnitine deficiency. [8] The different disease conditions associated with carnitine deficiency include fatigue, severe muscle ache, muscular tissue death, cardiomyopathy, fatty liver, hypoglycemia (decreased blood glucose level) and confusion. [9]

Health Benefits of Carnitine

Therapeutic researchers propose that carnitine supplementation can deliver health benefits without providing any harmful effect. Following are some health benefits obtain through carnitine supplementation:

Weight Management

We often do regular exercises and visit gyms with an aim to reduce body fats without compromising muscle mass. Carnitine supplementation can assist in weight management, as it has the capacity to burn fats and improve muscle mass. [3] Carnitine has the potentiality to bind with long-chain fatty acids and assist in passing them into mitochondria for breakdown or fat burning. [10] Recent data showed carnitine supplementation can prevent fat accumulations in belly and legs through modulating energy metabolism in a healthy individual. [11] However, in obese individuals, carnitine alone may not be effective to provide significant weight loss in absence of effective physical activity. [12]

Increased Muscle Mass

Carnitine supplementation has several benefits towards empowering muscles which include, reduction of muscle damage during high-intensity exercise and prevention of muscle soreness. However, one study reported that it can improve muscle mass by increasing androgen receptor density in

the skeletal muscles. [13] Supplementation of Carnitine can contribute in improving physical performance and endurance, as it promotes muscular oxidation and prevents oxygen deficiency in the muscle tissue. [14]

Fertility improvement

A small-scale clinical trial showed that L-carnitine therapy had been effective to improve semen quality in infertile male patients. [15] Another clinical trial conducted to check the efficacy of L-carnitine on idiopathic infertile male which gave encouraging results. [16] One more study conducted with the therapy of L-carnitine, and L-acetyl-carnitine alone or in combination showed that it can increase the sperm count. [17] Therefore, such research-based data gives evidence to support carnitine to be a safe, effective and economic therapeutic agent for an infertile male.

Type 2 diabetes prevention

Insulin resistance is a major factor for the development of type 2 diabetes. It is assumed that defective oxidative reaction of fatty acid in the muscle, due to mitochondrial dysfunction plays an important role in this metabolic disorder. In type 2 diabetes, body fat enhancement is a key finding. [4] Study findings supported that carnitine infusion can improve insulin resistance. [18] It has also been proposed that carnitine supplementation can act as adjuvant therapy for patients suffering from diabetes mellitus. [19] Moreover, carnitine also provides protection from diabetes-related neuropathy complications like pain and nerve-degenerative diseases. [20]

Improve brain function

Carnitine supplementation can improve memory and brain functioning. An animal study shows treatment with carnitine can facilitate attention, learning and memory functioning. [21] These effects can be achieved as carnitine supplementation can reduce lactate production in brain tissue and thus improve energy level and modify neurotransmitter activity which promotes active brain functioning. [22] Age related alteration in brain tissue and inflammatory changes can also be protected by consuming carnitine supplementation. [23] Researchers also expect that carnitine supplementation can have positive role in prevention and treatment of Alzheimer-type dementia. [24]

Dosage

Prior to start taking any supplementation, it is imperative to discuss with healthcare practitioners about its necessity and then to decide on appropriate dose for you. However, the scientific literature proposes the standard dose of carnitine should be between 500mg -2000mg. [25]

There are different carnitine supplementation available for different requirements, like Acetyl-L-Carnitine (ALCAR) is specifically recommended for cognitive improvement. L-Carnitine L-Tartrate (LCLT) is used for improving physical performance and Glycine Propionyl L-Carnitine (GPLC) is recommended for circulatory system disorders. The usual dose of ALCAR is 630mg-2500mg, LCLT dose range is 1000mg-4000mg and GPLC dose in between 1000mg-4000mg. [25]

The versatility of this bioactive substance shows an immense scope to add it to the wish-list for those who are really concerned with health and to stay fit. Additionally, there is vast research opportunity for carnitine and to evaluate its long-term benefits.