Life Extension Magazine September 2003
|Alpha Lipoic Acid, Acetyl-L-Carnitine and Carnosine |
The Latest Significant Research on This Powerful Life Extension Trio
By Tim Batchelder, B.A.
A landmark study published in the Proceedings of the National Academy of Sciences1,2 produced by noted biochemist Bruce Ames and a team of scientists describes the powerful synergistic abilities of lipoic acid and acetyl-l-carnitine to significantly combat aging. Together, these two nutrients are shown to help combat diabetes, maintain proper cognitive function, support heart health, support energy production, protect the body from radiation and chemical toxins, and maintain immunity. And, when combined with carnosine, a powerful trio for longevity is created.
New Findings in the Fight Against Diabetes
This supplement trio goes to the root of the problem of diabetes to control blood sugar levels. One recent study found that ALA increased glucose uptake from 40% (approximately the same amount as insulin) up to an impressive 300% (in insulin resistant muscles) in obese diabetic mice.1 Leading antioxidant authority Lester Packer2 notes that ALA works against insulin resistance by increasing the permeability of cell membranes, which is decreased by hyperglycemia and prevents uptake of glucose. ALC given at 1.0 milligram per kilogram per minute constant infusion increases glucose storage from 3.8 to 5.2 milligrams per kilogram per minute.3 Carnosine also works to lower glucose in cases of hyperglycemia.4
One side effect of high sugar levels is damage to the nervous system, called neuropathy. Packer claims ALA can prevent or slow neuropathy experienced by up to 70% of diabetics5 and it has been used in Germany for over 30 years for this application. ALA and evening primrose oil were found to improve blood flow and nerve function by lowering blood lipid risk factors in a recent study.6 ALA improves circulation to the sciatic nerve, which is crucial for nerve function but is reduced in neuropathy by impaired acetylcholine-mediated vascular relaxation and accumulation of superoxide radicals.7 ALA provides 85% protection against the 31% reduction in maximum endothelium relaxation to acetylcholine that occurs in diabetes by improving nitric oxide levels, vasodilation and cervical ganglion blood flow.8 ALA is shown in another study to reverse the impairment of nitric oxide (NO)-mediated vasodilation in diabetes due to increased vascular oxidative stress.9 In addition, protein glycation (denaturing) or cross linking by excessive glucose damages nervous, vascular, kidney, retinal and other tissues and carnosine is an effect anti-glycating agent due to its hydroxyl radical scavenging ability.10 Carnosine’s anti-protein glycating abilities make it very effective at delaying senescence in nervous system cells and other types of cells.11
High sugar levels can cause extensive damage to other body systems as well. For example, people with diabetes often suffer from a high incidence of eye cataracts (free radical damage to the non renewable proteins of the eye lens) since the cells of the eye lens are very susceptible to glucose damage. Eye lens cells use slower anaerobic (without oxygen) metabolism as transparent structures without mitochondria which puts them at greater risk for free radical damage. Fortunately, ALA can help this condition. Packer and his team suggest that about 60% of diabetes related cataracts can be prevented with ALA.12 ALA works by recharging levels of the potent antioxidant glutathione, which is essential for protecting the eye lens. ALA can also help protect other organs from sugar damage. A recent study found that long term ALA supplementation in rats (30 milligrams per kilogram of body weight per day) prevented kidney injury (depletion of glutathione and accumulation of malondialdehyde) due to high blood sugar levels in people with diabetes.13
Preventing Cognitive Decline
ALC works by preventing buildup of amyloid plaque that damages brain tissues and is emerging as a cause of cognitive disorders such as Alzheimer’s. A new study shows that ALC helps control amyloid by inhibiting free radical action and preserving energy production in the brain.14 Similarly, ALA protects rat cortical neurons against cell death induced by amyloid induced free radical damage.15 And carnosine works to inhibit advanced glycation end-products (AGEs), which cross-links proteins, renders them insoluble, accumulates in protein plaques and leads to oxidation of neurons.16 AGE inhibitors such as carnosine may work by chelating copper,17 which is linked to brain disorders such as Alzheimer’s.
Chemical messengers like neurotransmitters are vital to maintaining cognitive function yet often decline with age. Fortunately, a new study shows that ALC improves synthesis of neurotransmitters such as acetylcholine and uptake of choline, both of which increases learning capacity (maze learning was used in this study).18 ALC improves Alzheimer’s by helping to maintain brain energy production, phospholipid metabolism and acetylcoenzyme A levels, the latter being used by the body to re-synthesize acetylcholine.19 Degenerative ataxias are also slowed by ALC due to improved mitochondrial energy production, synthesis of acetylcholine, and antioxidant metabolism.20 ALA also controls excitotoxicity (a condition of excess glutamate, the main excitatory neurotransmitter) and improves survival in animal models of Huntington’s disease.21
ALA, ALC and carnosine work by preventing damage to nervous system tissues by free radicals. For example, one new study found that ALA protects against Alzheimer’s by preventing the oxidative stress and energy depletion caused by deranged glucose metabolism and free radical production. In this study 600 milligrams of ALA was given daily to nine patients with Alzheimer’s and related dementias for roughly a year and led to stabilization of cognitive function.22 ALA and vitamin E work synergistically to prevent free radical damage to brain cells during stroke according to new research.23 And it controls activity of a key enzyme in cell death, caspase-3 (CPP32), which increases in the hippocampus in rats with diabetes and cerebral ischemia by up to 80%.24 Together ALA and ALC improve performance on memory tasks by lowering oxidative damage to mitochondria and improving mitochondrial function.25 ALA and ALC also work synergistically to increase ambulatory activity, restore levels of ascorbate and lower levels of malondialdehyde (a product of lipid oxidation) in old rats more than either supplement alone.26
Keeping Cardiovascular Disease in Check
High glucose levels oxidize low-density lipoproteins resulting in formation of foam cells and deposits of atherosclerotic plaques. As a result, people with diabetes suffer from higher rates of heart disease, stroke, and hypertension than the general population. Fortunately, ALA inhibits monocyte adhesion and endothelial activation, which leads to atherosclerosis due to oxidative stress.27 Carnosine inhibits oxidation of low-density lipoprotein (LDL), which leads to atherosclerosis, by chelating (removing) copper, which oxidizes ascorbic acid.28
ALA prevents hyperglycemia induced hypertension in rats by lowering free radical production and raising glutathione levels.29 It also prevents hypertension and protects against kidney and vascular injuries in rats by suppressing endothelin-1 (a substance produced in blood vessels that regulates their tone).30 Carnosine is shown to suppress diabetes triggered increases in blood pressure by reacting with small carbonyl compounds (aldehydes and ketones) which accumulate on proteins during aging.31
Heart health is closely tied to how well heart cells can make energy and protect themselves from free radical attack. Recent research suggests that carnosine increases heart contractility by releasing calcium in calcium-regulated proteins in cardiac muscle cells.32 ALA improves numerous functions in the heart including oxygen uptake, ATP levels, cardiac output, pyruvate (energy) production, lactate (a waste product) accumulation and glucose and glycogen (energy) storage and breakdown. It also protects glutathione and controls hydroxyl radicals, which may account for its anti-aging, heart supporting function.33 Finally, ALA is found to protect against reperfusion arrhythmias and lipid peroxidation induced by ferrous ions and ascorbate.34
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