Ingredients
Alpha-lipoic acid (ALA) is a sulfur-containing fatty acid that performs vitamin-like roles in the body. Also known as "lipoic acid" or "thioctic acid," ALA functions, in a similar way to B complex vitamins, as a co-enzyme in the metabolism of carbohydrates that produces energy inside cells for the body's metabolic needs.
ALA is required for the synthesis of "acetyl CoA," a key metabolite in the cellular process that turns glucose (blood sugar) into energy. Because the body produces ALA on its own, it is not classified as a true vitamin. As with other so-called "non-essential" nutrients, however, internal ALA production may not always be optimal.
Alpha-lipoic acid functions as both a water-soluble and fat-soluble antioxidant. (Antioxidants neutralize free-radicals, normal by-products of metabolism that, while necessary at normal levels, may damage tissues over time if not properly kept in check by antioxidants.) ALA's ability to act upon free radicals in both a watery and fatty environment makes it a highly versatile antioxidant. In the body, alpha-lipoic acid can be converted (reduced) to DHLA, or dihydrolipoic acid. (It is not necessary to take DHLA as a supplement; the conversion of ALA to DHLA occurs as a normal biochemical process in the system.) Together, these two forms of ALA make up a "redox couple," which means that each form can chemically change into the other and back again. DHLA also functions as an antioxidant.
Benefits
- Supports the body's defense against free radicals
- Recycles antioxidant nutrients such as Vitamin C and Vitamin E
- Helps maintain a healthy blood sugar levels when used as part of the diet
Alpha-lipoic Acid: the "Ideal Antioxidant"
The antioxidant potential of a substance is based on a number of criteria, including:
- Ability to quench specific free radicals
- Ability to bind or "chelate" metal ions that can generate free radicals
- Supports function of other antioxidants
- Absorption/bioavailability
- Concentration in tissues, cells and extra cellular fluids
- Ability to function as an antioxidant in fatty and watery environments
The "ideal antioxidant" would meet all the above criteria. Very few antioxidants do, yet a particular antioxidant with but a few of these characteristics is still valuable and effective. Vitamin E, for example, is one of the most important dietary antioxidants, yet it only works in fatty environments such as cell membranes.
As a team, ALA and DHLA come close to the ideal, for the following reasons:
- ALA is easily absorbed when consumed orally
- ALA is readily converted to DHLA in various tissues
- As a pair, ALA and DHLA neutralize superoxide, hydroxyl, peroxyl, and hypochlorus radicals
- ALA and DHLA form stable complexes with metal ions such as iron, manganese, copper and zinc ions
- ALA and DHLA scavenge free radicals in fatty environments and watery environments
- DHLA recycles other important antioxidants
DHLA-regenerate Vitamin C, Vitamin E and Glutathione
Within the cell, antioxidants work as a team to keep free radicals from damaging cell structures. In order to neutralize a free radical, an antioxidant such as Vitamin C must give up an electron, which means it becomes oxidized. Before it can function as an antioxidant once again, it must be generated back to its "reduced" form, by gaining an electron to replace the donated electron.For this, it needs the help of other antioxidants.
Vitamin C, Vitamin E and Glutathione are key antioxidants that can be generated by cycling between their oxidized and reduced forms. This is necessary to maintain the balance between oxidation and its revers - the neutralization of free radicals by antioxidants.
DHLA is an essential component in the interaction between these antioxidants. Studies show that additional alpha-lipoic acid to liver tissues results in increased Vitamin C levels. It has been found that DHLA is responsible for regenerating Vitamin C, which in turn regenerates Vitamin E. DHLA also converts glutathione from it oxidized form back into its free radical scavenging reduced form.
The ALA/DHLA pair is thus vital for prevention of "oxidative stress," which occurs when the balance is tipped in favor of the oxidation in cells. DHLA helps preserve antioxidants in both the watery cell interior and the fatty structure of cell membranes. Evidence from animal studies suggest that DHLA protects the brain against free radical damage.
Alpha-Lipoic Acid and Blood Sugar
Alpha-lipoic acid is a key factor in the cellular process that metabolizes glucose to produce energy for cellular functions. The importance of ALA's role in blood sugar metabolism is evidenced in studies on ALA and type-2 diabetes.
In a small pilot study, thirteen people with type-2 diabetes showed improved utilization glucose in muscle tissue in response to intravenous administration of ALA. In a four week controlled multi center trial, 74 people with type-2 diabetes took ALA in oral doses of 600, 1200 or 1800 mg per day.
After 4 weeks, the normal lowering of blood sugar levels in response to insulin improved. In vitro studies have shown that ALA has a positive effect on insulin-stimulated uptake of glucose by muscle cells. Source: Doctor's Best
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Scientific References
- Packer L., Witt E., Tritschler H. Alpha-lipoic acid as a biological antioxidant. Free Rad Biol Med. 1995; 19(2): 227-50.
- Suzuki, Y., et. al. Thioctic acid and dihydrolipoic acid are novel antioxidants which interact with reactive oxygen species. Free Rad. Res. Comms. 15(5): 255-63.
- Biewenga G., Haenen G., Bast A. The pharmacology of lipoic acid. Gen. Pharmac. 29(3): 315-31.
- Serbinova E., Maitra I., Packer L. The synergy between Vitamin E and alpha-lipoic acid - possible relationship against oxidative stress in vitro. Life Chemistry Reports 1994; 12:17-21.
- Bast A., Haenen G. Interplay between lipoic acid and glutathione in the protection against microsomal lipid peroxidation. Biochemica et Biophysica Acta 1988; 963: 558-561.
- Kagan, V., et. al. Dihydrolipoic acid - a universal antioxidant both in the membrane and in the aqueous phase. Reduction of peroxyl, ascorbyl and chromanoxyl radicals. Biochem Pharmacol. 1992; 44(8): 1637.
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