Alpha Lipoic Acid
Description
Alpha-Lipoic (or Thioctic) Acid is a fatty acid which performs two roles in the body.
Most is consumed in the glycolytic pathway, whereby carbohydrates are turned into energy at the cellular level.
Therapeutic interest concerns its secondary role, although this designation is rather inaccurate for immuno-compromised individuals, for whom antioxidants can be a lifesaver. It performs as an antioxidant in a manner similar to B-complex vitamins.
It is produced naturally by the body. Endogenous supplies are usually adequate but there may be benefits for people who exercise or special populations, suffering from metal toxicity, diabetes or viral infections, for example.
Natural food sources include: red meat, liver, brewer’s yeast and green plants. It is felt that supplements can increase the energy supply. Supplements are in the form of d-l-alpha lipoic acid.
Alpha-Lipoic Acid consists of an eight-carbon fatty acid chain with two attached and inter-linked, sulfur atoms. It is readily reduced into dihydrolipoic acid (DHLA), although this process is reversible, back to Alpha-Lipoic acid.
Method of Action
Alpha-Lipoic Acid can function in complex enzymatic processes, passing hydrogen or electrons back and forth.
It seems to be most effective, as an antioxidant, at scavenging: hydroxyl and peroxyl radicals, hypochlorous acid, singlet oxygen and nitric oxide. Exceptions may include: hydrogen peroxide, or superoxide radicals.
Alpha-Lipoic Acid also enhances other antioxidants: vitamin C, vitamin E and glutathione. This reflects its unique ability to function in both lipid and water phases!
There are indications that it inhibits HIV, by deactivtaing the gene in the virus responsible for its reproduction. It is capable of reaching the HIV viruses, even within lymph cells and neurons (brain cells).
Its metal chelating activity seems to be effective for: cadmium, copper and iron.
Therapeutic Approaches
Diabetes Mellitus
Alpha-Lipoic Acid has shown to provide some protection to non-obese, diabetes-prone mice against the development of diabetes (Type I).
Alpha-Lipoic Acid levels are known to be low in diabetic animals. Raised levels seem to account for increased glucose uptake.
Alpha-Lipoic Acid (300 - 600 mg) is used clinically in Germany to provide protection against diabetic polyneuropathy.
High blood sugar is also implicated in the formation of cataracts, so Alpha-Lipoic Acid (or more specifically DHLA) may be beneficial, via its cofactors: vitamin C, vitamin E and glutathione.
Large doses may produce hypoglycemia. Diabetic usage requires constant monitoring and professional supervision.
Heavy Metals
Alpha-Lipoic Acid may be an effective treatment for heavy metal poisoning. A ratio of 8:1 was effective against arsenic in animal studies. Alpha-Lipoic Acid has also shown efficacy against: cadmium and mercury but not gold, or lead.
Hypercholesterolemia
While the early stages of LDL (low density lipoprotein) oxidation seem to remain unaffected, Alpha-Lipoic Acid does reduce further damage.
Ischemia-Repurfusion
Ischemia-Repurfusion injury occurs when oxygen-starved tissue is re-oxygenated. This produces a burst of free radicals which damage the tissue. Alpha-Lipoic Acid may, therefore, be an ideal adjunctive therapy with clot dissolving drugs employed in the Emergency for myocardial infarctions (heart attacks), strokes and head trauma.
Radiation injury
Radioactive metabolites, as in children living in Chernobyl, appear to have been chelated by Alpha-Lipoic Acid and vitamin E. Kidney and liver functions were normalized.
Smart Nutrients
Alpha-Lipoic Acid improved memory in aged mice in an open field memory test. Alpha-Lipoic Acid also maintains calcium homeostasis.
Alpha-Lipoic Acid may also be of benefit in neurodegenerative diseases which include severe oxidative damage.
Toxicity Factors
Dosages used in research studies ranged between 200 and 600 mg per day, delivered intra-venously (IV) or orally.
Based on these studies, a safe and effective oral intake for a diabetic adult weighing less than 120 pounds may be 400 - 500 mg; 600 - 700 mg for those at 150 pounds.
A similar range has proven effective against the pain associated with diabetic neuropathy (200 - 600 mg).
As little as 20 - 50 mg prevents deficiency in people consuming diets which are deficient in red meat and greens. (Commercial capsules commonly contain 50 mg.)
Toxicity may occur at over 10 mg per pound i.e. 1,000 mg for a person weighing 100 pounds.
Alcoholics, or anyone suffering from thiamin deficiency, should supplement thiamin together with Alpha-Lipoic Acid.
In studies involving HIV-negative volunteers, decreased blood platelets (thrombocytopenia) and nausea were reported by those taking higher doses of thioctic acid (900 mg). However, the data singling out thioctic acid as the cause of these effects are unsubstantiated.
Like most antioxidants, thioctic acid is a chelating agent, and can purge minerals from your body. In one study of thioctic acid in HIV-negative volunteers, the amount of iron in their blood was shown to decrease significantly. This depletion can often lead to anemia. Monitor iron levels with regular blood tests.
References
Cadenas, E. & Packer L. (Eds): Biological Oxidants and Antioxidants: New developments in research and health effects. Hippokrates Verlag. 1993.
Cao X & Phillis JW: The free radical scavenger, alpha-lipoic acid, protects against cerebral ischemia-reperfusion injury in gerbils. Free Radic Res 1995 Oct;23(4):365-70
Constantinescu, A. et al: Alpha-lipoic acid protects against hemolysis of human erythrocytes induced by peroxyl radicals. Biochem. Mol. Biol. Int. 1994, 33(4): 669 - 679.
Han, D. et al: Alpha-lipoic acid increases intracellular glutathione in human T-lymphocyte Jurkat cell line. Biochem. Biophys. Res. Comm. 1995, 207(1): 258 - 264.
Hornberger, C.S. et al: Synthetic preparation of Lipoic acid. J. Am. Chem. Soc. 1952, 74: 2382.
Jayanthi S et al: Effect of DL alpha-lipoic acid in glyoxylate-induced acute lithiasis. Pharmacol Res 1994 Oct-Nov;30(3):281-8
Maitra I: Stereospecific effects of R-lipoic acid on buthionine sulfoximine-induced cataract formation in newborn rats. Biochem Biophys Res Commun 1996 Apr 16;221(2):422-9.
Merin JP et al: Alpha-lipoic acid blocks HIV-1 LTR-dependent expression of hygromycin resistance in THP-1 stable transformants. FEBS Lett 1996 Sep 23;394(1):9-13.
Mizuno M & Packer L: Effects of alpha-lipoic acid and dihydrolipoic acid on expression of proto-oncogene c-fos. Biochem Biophys Res Commun 1994 Apr 29;200(2):1136-42.
Muller U & Krieglstein J : Prolonged pretreatment with alpha-lipoic acid protects cultured neurons against hypoxic, glutamate-, or iron-induced injury. J Cereb Blood Flow Metab 1995 Jul;15(4):624-30.
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Packer L.: Generation of probucol radicals and their reduction by ascorbate and dihydrolipoic acid in human low density lipoproteins. Free Rad.Res. Comms. 1991,15: 265-276.
Packer L.: Thioctic acid protects against lschemia-reperfusion injury in the isolated perfused Langendorff heart. Free Rad. Res. Comms. 1992, 17(1): 49-58.
Packer L.: Recychng of vitamin E in human low density lipoproteins, Journal of l,ipid Res. 1992 , 33: 385-397.
Packer L.(Ed): Alpha Lipoic Acid Research and Information System. November, 1993.
Packer L.: NMR study of lipoic acid binding to bovine serum albun-dn. biochemistry and molecular biology international. 1994(5): 879-886.
Packer L.: Alpha lipoate can protect against glycation of serum albumin, but not low density lipoprotein. Biochemical and Biophysical Research Comm. 1994, 203(1): 99-104.
Packer, L. et al: Alpha-Lipoic Acid as a biological antioxidant. Free Radical Biology & Medicine, 1995, 19(2): 227 - 250.
Panigrahi M et al: alpha-Lipoic acid protects against reperfusion injury following cerebral ischemia in rats. Brain Res 1996 Apr 22;717(1-2):184-8.
Podda M : Alpha-lipoic acid supplementation prevents symptoms of vitamin E deficiency. Biochem Biophys Res Commun 1994 Oct 14;204(1):98-104.
Schonheit K et al: Effect of alpha-lipoic acid and dihydrolipoic acid on ischemia/reperfusion injury of the heart and heart mitochondria. Biochim Biophys Acta 1995 Jun 9;1271(2-3):335-42.
Scott BC et al: Lipoic and dihydrolipoic acids as antioxidants. A critical evaluation. Free Radic Res 1994 Feb;20(2):119-33.
Serbinova B. & Packer L.: Dihydrolipoic acid - a universal antioxidant both in the -membrane and in the aqueous phase. reduction of peroxyl, ascorbyl and chromanoxyl radicals. Submitted for publication 1992
Stoll S et al: The potent free radical scavenger alpha-lipoic acid improves memory in aged mice: putative relationship to NMDA receptor deficits. Pharmacol Biochem Behav 1993 Dec;46(4):799-805.
Sumathi R et al: Relationship between glutathione and DL alpha-lipoic acid against cadmium-induced hepatotoxicity. Jpn J Med Sci Biol 1996 Apr;49(2):39-48.
Suzuki YJ et al: Lipoic acid and dihydrolipoic acid are novel aritioxidants which interact with reactive oxygen species. Free Rad. Res. Comm.. 1991, 15(5): 255-261.
Suzuki YJ et al: Lipoate prevents glucose-induced protein modifications. Free Rad. Res. Comm. 1992, 17(3): 211-217.
Suzuki YJ et al: Determination of structure-antioxidant activity relationships of dihydrolipoic acid. Methods in Enzymology, 1994 ,234: 454-457.
Suzuki YJ & Parker L.: Alpha Lipoic acid is a potent inhibitor or NF-KB activation in human T cells: Does the mechanism involve antioxidant activities? USC Toxicology Joint Spring Meeting, March 14, 1993.
Whiteman, M. et al: Protection against peroxynitrite=dependent tyrosine nitration and alpha 1-antiproteinase inactivation by oxidized and reduced lipoic acid. FEBS Lett. 1996, 379(1): 74 - 76.
Xu DP & Wells WW: Alpha-Lipoic acid dependent regeneration of ascorbic acid from dehydroascorbic acid in rat liver mitochondria. J Bioenerg Biomembr 1996 Feb;28(1):77-85.
Ziegler D et al: Treatment of symptomatic diabetic peripheral neuropathy with the anti-oxidant alpha-lipoic acid. A 3-week multicentre randomized controlled trial (ALADIN Study). Diabetologia 1995 Dec;38(12):1425-33.
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