More Evidence for Eye Health
Lower AGE with Acetyl L-Carnitine
At the Medical College of Georgia in Augusta, new research has shown that acetyl L-carnitine (ALC) can be of significant value for the protection of ocular tissues, especially in diabetics, who are subject to depletion of this important vitaminoid.1 Diabetics and others who become susceptible to high levels of glucose in blood serum as they age suffer from the formation of deleterious hybrid protein-sugar complexes known as advanced glycation end products (AGE). Implicated as a benchmark of aging, the aptly named AGEs can accumulate in the lens of the eye (or elsewhere in the body) and cause serious complications, such as cataracts.
In the study, some samples of calf lens tissue were incubated in a glucose solution with L-carnitine (nonacetylated carnitine, also known as Vitamin BT), and other samples were incubated in a solution of ALC (acetylated carnitine) for 15 days. The results were clear: L-carnitine had no effect on glycation (formation of the protein-sugar complexes) in the lens tissue in vitro, while ALC decreased the glycation by 42%. ALC also affected the formation of antibodies to AGEs. For the first time, it was shown that ALC can inhibit potential glycation sites of lens tissue and protect them from glycation-mediated protein damage. If, as suspected, it can do the same in vivo, ALC may be able to prevent the blindness caused by cataracts.
The Glycation Theory of Aging holds that the primary cause of aging is cellular damage resulting from the modification of macromolecules induced by nonenzymatic glycation. This is a series of chemical reactions that result in the irreversible crossed linking of protein molecules such as collagen, which is an important constituent of bone, cartilage, tendon, and other connective tissues.
The levels of Vitamin E and lutein (a yellow carotenoid pigment) have also been shown to be inversely associated with cataracts: the lower the levels, the higher the incidence of cataracts.2 Other studies have found that various chronic vitamin deficiencies can influence the occurrence of some chronic degenerative diseases, including cataract formation.3 This will not surprise those who are familiar with the widespread damage that free radicals can do. Vitamins E and C, as well as beta-carotene (precursor to Vitamin A) have received the most attention for their ability to arrest oxidative damage caused by free radicals.
The lenses of our eyes have a special, built-in chemical "pump" for the aminosulfonic acid taurine because taurine is so important to lens function. Changes in lens protein structure and lens function due to glycosylation (another mechanism of forming protein-sugar complexes, called glycoproteins) and oxidation are thought to play a significant role in the pathogenesis of cataracts. Taurine is thought to inhibit glycosylation and protect against free radical damage, which also plays a role in cataract formation.4 Indeed, in rabbits, taurine did inhibit the formation of galactose (sugar)-induced cataracts.5
Other antioxidants are also believed to be of value in protecting the lens from becoming opaque. They are tocopherol (Vitamin E), ascorbic acid (Vitamin C), alpha-lipoic acid, and taurine. A study examining astronauts, jet crews, and military radiation-accident personnel whose eyes were damaged by low-level radiation, leading to protein leakage from capillaries, verified the positive function of all four of these compounds in repairing the damage.6
For those who are vulnerable to cataracts or prone to other age-related lens-degeneration problems, taking 1,500 mg of acetyl L-carnitine per day is an intelligent addition to your antiaging program. Furthermore, vinpocetine, the periwinkle phytonutrient, has been shown to be valuable for a wide spectrum of eye problems. An extract of bilberry (another name for the familiar blueberry) contains a variety of polyphenolic compounds that help to reduce oxidative damage in the eyes.7 Together these two supplements can help maintain and protect proper eye function.
- Swamy-mruthinti S, Carter AL Acetyl-L-carnitine decreases glycation of lens proteins: in vitro studies. Exp Eye Res 1999 Jul;69(1):109-15.
- Lyle BJ, Mares-Perlman JA, Klein BE, Klein R, Palta M, Bowen PE, Greger JL. Serum carotenoids and tocopherols and incidence of age-related nuclear cataract. Am J Clin Nutr 1999 Feb;69(2):272-7.
- Filiberti R, Giacosa A, Brignoli O. High-risk subjects for vitamin deficiency. Eur J Cancer Prev 1997;6(Suppl 1):S37-42.
- Devamanoharan PS, Ali AH, Varma SD. Prevention of lens protein glycation by taurine. Mol Cell Biochem 1997;177:245-50.
- Malone JI, Benford SA, Malone J Jr. Taurine prevents galactose-induced cataracts. J Diabetes Complications 1993;7:44-8.
- Bantseev V, Bhardwaj R, Rathbun W, Nagasawa H, Trevithick JR. Antioxidants and cataract: (cataract induction in space environment application to terrestrial aging cataract). Biochem Mol Biol Int 1997;42:1189 97.
- Frisse D, Carnat A, Lamaison JL. Polyphenolic composition of the leaf of bilberry. Ann Pharm Fr 1996;54(6):280-3.
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