Alpha lipoic acid (ALA) is a thioctic acid (thiol compound) that occurs naturally as a sulphydryl compound synthetized in the mitochondrion 1 and is found in every plant and animal species 2. It has been proven to be a very powerful natural free radical scavenger and antioxidant preventing oxidation related diseases 2–4. ALA is a nutritional coenzyme involved in the proteins, carbohydrates and fats metabolism. This compound is water and lipid soluble, which makes it unique among biological antioxidants. Since it is a natural antioxidant, it neutralizes free radicals in the body, either inside or outside the cells5.
Chemical structure of ALA
The chemical name of lipoic acid is 1,2-dithiolane-3-pentatoic acid and is present in most cells. This compound is linked to enzymes in which it acts as cofactor, meaning that it gets reduced to dihydrophilic acid (DHLA) which as great antioxidant properties 3. The special abilities of ALA are the result of the two sulfur (S) atoms in the ring6.
Uptake, metabolism and degradation of Alpha-Lipoic Acid
Although ALA is naturally synthetized in the cells from fatty acids (like octanoic acid) and cysteine, this process happens in the liver and it is called β-oxidation. The amount produced is too low, therefore the take of ALA supplements is necessary 7.
Undoubtedly, the administration of a ALA dietary supplement influences the body. When it is absorbed in the cells it’s transformed in DHLA which has a great antioxidant power8. In humans it is bond to proteins and it can be found in the free form in which it is capable to trap the excess of metals in circulation, preventing the damage and improving it’s secretion 3.
The main sources of ALA are muscle meats, heart, kidney, liver, fruits and vegetables such as spinach, broccoli, potatoes, yams, carrots, yams and yeast (in lower levels). Although its bioavailability on the diet, the ALA’s consumption is lower than expected 1,9. ALA is rapidly absorbed in the gut and it is transported to the tissues where it is metabolized and later excreted 4. The tissue than shows a greater concentration of ALA in its free form is the heart, liver and skeletal muscle 1,4. It plays a fundamental role in metabolism and has been used as supplement since it affects cellular metabolic processes in vitro, being able to participate in oxidation reactions having an important therapeutic potential in conditions where oxidative stress (a biological process whereas there is the unbalance of the production of reactive oxygen species and their detoxification; this imbalance is responsible for the development of pathologies such as diabetes, cancer, neurodegenerative diseases, heart failure, atherosclerosis, among others) is envolved4,10.
Health benefits of Alpha Lipoic Acid
The living being need energy to function, in aerobic organisms (beings who breathe oxygen) the energy is gotten by the oxidation of molecules that act as a fuel (such as glucose and fatty acids) 3. ALA has been proposed as a potential therapeutic agent for treating and preventing some pathologies 4 Studies and clinical trials suggest that α-lipoic acid has a benefit effect in the treatment of neurodegenerative conditions, AIDS, diabetes, hepatic, Alzheimer’s and hepatic-associated diseases 4,11.
ALA is a necessary cofactor for transforming the glucose obtained from diet in energy on the mitochondrion (the powerhouse of the cell) 1. A higher concentration of ALA will lead to an increase of the mitochondrial activity, leading to a major conversion of glucose (from diet or stored in the tissue) in energy. Also ALA helps keeping dopamine levels, providing a better sports performance 12.
Regeneration of Antioxidants
To be considered as a potent antioxidant, a compound must correspond to a several number of criteria (like bioavailability, safety, interaction with other antioxidants, metabolic regeneration, among others), since ALA meets these criteria, it can have this designation. Both compounds can fight oxidative processes on the organism, preventing oxidation related diseases. Besides ALA presents all the desired characteristics, its metabolized formula dihydrolipoic acid (DHLA) also has these properties. ALA and DHLA present metal chelating properties which prevent the intoxication and eases the excretion. Since ALA and DHLA present a great antioxidant capacity, they can prevent symptoms of vitamin C and E deficiency 13.
Obesity is a health condition that is associated with an increased risk of developing other pathologies including hypertension, type 2 diabetes, stroke, respiratory problems, cancer (such as endometrial, colon, bladder, prostate, kidney and breast cancer). Besides physical problems obesity may lead to psychological problems such as low self-esteem and depression 14. ALA has been shown to have anti-obesity properties causing weight lost by reducing food intake and enhancing energy expenditure being one of the ideal antioxidant candidate for the therapy of obesity related diseases 14,15. Some authors have found that ALA also lowers elevated glucose levels in animals and individuals with type 2 diabetes 6.
Many clinical trials have shown that oral administration of alpha lipoic acid happens without any adverse events, therefore more than 35 clinical studies support the safety and benefits for humans. On the studies made is the past, more than 1300 individuals have been tested and taking ALA in concentrations that rage from 600mg to 2400mg/day from time periods that can go from 4 weeks to 24 months 2.
The effects of ALA have been object of many studies, allowing us today to say that it is safe to take and has numerous benefits for our health thanks to its antioxidant properties. Besides preventing numerous oxidative stress related diseases, it is a great ally to losing weight and to prevent obesity related problems.
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