Alpha-lipoic
acid (ALA, thioctic acid) is a naturally occurring vitamin-like nutrient that
has been intensely investigated as a therapeutic agent for a variety of
conditions involving the body’s nervous, cardiovascular, immune, and
detoxification systems. It exists as two enantiomers or stereoisomers:
R-(+)-lipoic acid (RLA) and S-(-)-lipoic acid (SLA). It is produced in small
amounts in the liver and other body tissues, where it is needed by enzymes to
catalyze numerous essential chemical reactions in the body. For instance, ALA is
essential inside the mitochondria of cells, where it is needed to metabolize
glucose and direct calories into energy production.
ALA is
considered to be a multimodal supplement because, aside from its enzymatic role
in energy production, it acts by multiple mechanisms and displays diverse
pharmacologic and antioxidant properties. Recently discovered is ALA’s ability
to switch the regulation of several genes linked to cell survival, inflammation
and oxidative stress. So in addition to its enzymatic role, ALA is a powerful
antioxidant and performs a number of other vital functions related to its
ability to modify the expression of various genes. ALA is therefore not so much
a direct benefit to cells, but rather an indirect aid that "kick starts"
declining function in cells, helping them recover the functions that came more
easily and naturally in the young.
Researchers at
Oregon State University’s Linus Pauling Institute for Micronutrient research
have found that our body’s natural lipoic acid levels decline markedly with age,
but can be replenished through dietary supplementation. They describe ALA as an
"age-essential" micronutrient and have shown that, when fed to rats, it markedly
improves mitochondrial function and ameliorates many signs of aging (Hagen et
al. 2002; Suh et al. 2004; University 2007). ALA is also being extensively
studied in humans by researchers across the globe, and so far has been found to
exhibit a number of both confirmed and potential benefits for health and
longevity.
Ingredients
Benefits
Prevents oxidative damage by neutralizing free radicals
and enhancing the antioxidant activity of Vitamin C, Vitamin E, and glutathione.
*
As a potent
antioxidant, ALA it not only scavenges free radicals, but also raises the
intracellular level of antioxidants by recycling them, and chelates heavy metals
to prevent free radical generation. ALA’s antioxidant role also involves
protecting cells from damage by preventing the destruction of lipids in cell
membranes, and inducing the liver’s detoxification enzymes. Unlike other
antioxidants, ALA is soluble in both water and fat. Because of these unique
antioxidant functions, ALA is known as the “universal antioxidant” and the
“antioxidant of antioxidants”.
Gene
dysregulation occurs with age, decreasing resistance to environmental toxins.
Treatment with RLA has been shown to re-regulate gene expression, increasing the
body’s glutathione and other antioxidant levels and its ability to withstand
oxidative insult. Glutathione, vitamin C, and vitamin E are key antioxidants
that play major roles in the body’s defense mechanism. These antioxidants exert
their activity by cycling between their oxidized and reduced forms. This is
necessary to maintain the balance between oxidation and its reverse––the
neutralization of free radicals by antioxidants.
In the body,
ALA is converted (reduced) to DHLA, or dihydrolipoic acid.
Together, these two forms of LA 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 and is an essential component in the interaction
between vitamin C, E, and glutathione (Serbinova et al. 1994). Studies show that
the addition of lipoic acid to liver tissue results in increased vitamin C
levels (Biewenga et al. 1997). It has been found that DHLA is responsible for
regenerating vitamin C, which in turn regenerates vitamin E DHLA also converts
glutathione from its oxidized form back into its free radical scavenging reduced
form (Bast and Haenen 1988). The LA/DHLA pair is vital for prevention of
"oxidative stress," which occurs when the balance is tipped in favor of
oxidation in cells. DHLA helps preserve antioxidants in both the watery cell
interior and the fatty structure of cell membranes. By regenerating vitamin C,
E, and glutathione in tissue, LA/DHLA help reestablish the antioxidant/oxidant
balance in the body.
Aging is
accompanied by a decreased ability of the liver to recycle ascorbic acid
following oxidative stress. Supplementing rats with RLA for two weeks reversed
the age-related impairment of ascorbic acid recycling and concentration in liver
cells. Researchers determined that an RLA-supplemented diet fed to old rats for
two weeks resulted in improved mitochondrial function, decreased free radical
damage and increased metabolic rate. Whereas a significant decline was seen in
ascorbic acid and glutathione levels in the livers of the control rats, the RLA
supplemented group showed no decline in the levels of these critical
antioxidants (Hagen et al. 1999).
Supports eye, nerve, and brain health. *
Aging is
associated with oxidative damage to the brain and neurons. The brain’s high rate
of metabolism and its long-lived neurons make it particularly vulnerable to
oxidative stress. Since ALA interrupts cellular oxidative processes in both its
oxidized and reduced forms, it plays a modulatory role in the brain and nervous
system. Older rats supplemented with RLA showed improvement in mitochondrial
function, decreased oxidative damage, increased metabolic rate, and improvement
in glutathione status in brain tissue
(Hagen et al.
1999) (Suh et al. 2004). ALA prevents memory deficits in aging mice, halting the
degeneration of brain neurons (Cui et al. 2006). Pyruvate dehydrogenase complex
is an enzyme complex responsible for supplying energy to the central nervous
system. Human studies indicate RLA stimulates deficient brain pyruvate
dehydrogenase complex in individuals with compromised brain function due to
impairment to the brain’s blood supply (Frolich et al. 2004).
A team of
German and Australian researchers conducted a review of the in vitro, animal,
and human ALA studies and in 2007 published their findings regarding the use of
ALA for supporting brain health. They reviewed the multiple mechanisms by which
it supports brain health, including anti-inflammatory, antioxidant,
metal-chelating, pro-energetic, and neuroprotective properties. In addition,
they emphasized the in vitro finding that ALA stimulates the production of
acetylcholine, a key neurotransmitter in the central nervous system involved
with learning and memory (Holmquist et al. 2007).
High blood
sugar is especially damaging to certain parts of the body, especially the
nervous system, including the brain and eyes. A group of German researchers
compared three doses (600, 1200, and 1800 mg/day) of ALA to placebo in 166
individuals with poor nerve health resulting from chronically high blood sugar.
After five weeks, mean total symptom scores were significantly reduced in all
three active treatment groups compared to placebo. Since all three dosages
worked, but the 1200 and 1800 dosages resulted in increased rates of
gastrointestinal side effects, the authors concluded that 600 mg once daily
seemed to be the appropriate dose (Ziegler et al. 2006).
Studies also
indicate that supplementation with ALA supports eye health. The degeneration of
crucial cells in the retina called retinal pigment epithelial cells is often
seen at the early stages of common age-related decline in eye health. One of the
most toxic chemicals in cigarette smoke, acrolein, is especially harmful to
these cells, causing oxidative stress and mitochondrial injury. Rats chronically
exposed to low doses of acrolein lose the viability of these cells, showing a
decrease in mitochondrial function. Pretreatment of these retina cells with
lipoic acid before the acrolein exposure significantly protects them from
oxidative damage (Jia et al. 2007).
RLA is
exceptionally suitable for supporting the retina of the eye because it can enter
the mitochondria, recycle other antioxidants, and is regenerated by high blood
sugar. The mechanism by which RLA protects the retina in rats is via prevention
of the activation of nuclear factor kappa B, a protein complex found in all
cells which is involved in cellular responses to stimuli such as stress, free
radicals, ultraviolet irradiation, oxidized LDL, and bacterial or viral antigens
(Lin et al. 2006). Studies in rats show that long-term administration of ALA
prevents the destruction of retinal capillary cells that occurs with chronically
high blood sugar, helping to prevent loss of vision (Kowluru and Odenbach 2004).
RLA was also shown to decrease cataract formation induced by the toxin
buthionine sulfoximine (BSO) in rats (Maitra et al. 1995). In another in vitro
study, brain cells from rats were exposed to two toxins that inhibit synthesis
of glutathione, resulting in the degeneration of neurons via oxidative stress.
Both R- and S-lipoic acid protected cells against oxidative neurotoxicity
induced by the toxin homocystic acid. RLA also protected cells against prolonged
exposure to the toxin BSO (Lockhart et al. 2000).
May help maintain healthy glucose metabolism. *
Not only does
ALA help protect the nervous system from the damaging effects of unhealthy blood
sugar metabolism, it appears to support healthy glucose uptake and utilization
directly. As mentioned previously, endogenously produced lipoic acid is a key
factor in the cellular process that metabolizes glucose for energy production.
In vitro studies have shown that LA has a positive effect on insulin-stimulated
uptake of glucose by muscle and fat cells, and acts by activating important
molecules in insulin signaling (Estrada et al. 1996; Yaworsky et al. 2000).
Animal studies
also indicate RLA stimulates insulin signaling and helps cells take up glucose
from the blood. In fat rats bred to have faulty leptin receptors in their
brains, so that they have no appetite control, RLA (30 mg/kg body weight daily
for 15 days) increased glucose uptake into muscle by 45%. When the rats combined
treadmill exercise with the RLA, glucose uptake jumped to 124% (Saengsirisuwan
et al. 2004). After helping to initially increase glucose uptake into cells, RLA
subsequently increases glucose utilization via activation of an enzyme complex
called the pyruvate dehydrogenase complex, a group of enzymes involved in energy
production inside the mitochondria of cells (Korotchkina et al. 2004).
Human studies
using oral doses of ALA to support healthy glucose metabolism have only recently
begun, although a number of studies using intravenous ALA have shown positive
results. In one of the few human trials, a randomized, placebo-controlled,
multi-center study, 74 individuals with unhealthy blood sugar metabolism were
administered LA 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 all
of the groups receiving the different doses of LA. Compared to the placebo
group, the ALA groups combined showed a significant (p<0.05) 17% improvement in
their metabolic clearance rates of glucose, the main indicator of the body’s
ability to release insulin in healthy amounts (Jacob et al. 1999). In another
human study, researchers examined the effect of oral alpha lipoic acid
supplements on 12 individuals with a history of unhealthy blood sugar
metabolism, aged 43 to 62, and compared that to the effect on 12 normal subjects
(Kamenova 2006). The researchers treated the subjects with 600 mg of ALA twice
per day for four weeks. All of the individuals were overweight, with a body mass
index (BMI) averaging 34 percent. The amount of glucose metabolized in the
treatment group significantly increased and reached a level that was virtually
the same as that in the normal subjects.
Resets and normalizes metabolic processes to help maintain
cardiovascular health. *
According to
Linus Pauling Institute researchers, ALA supplements may offer several different
mechanisms to improve cardiovascular health in addition to its antioxidant and
glucose metabolism functions. ALA also appears to reset and normalize metabolic
processes in a variety of other ways, including helping to support healthy
arterial function, helping to maintain healthy weight as part of a healthy diet,
and supporting healthy lipid metabolism. High levels of ALA inhibit the
formation of the “adhesion molecules”, which normally allow white blood cells
called monocytes to enter the walls of arteries. Once there, monocytes become
inflammatory cells that, when confronted with LDL cholesterol, they can
ultimately transform into arterial fat deposits that contribute significantly to
poor cardiovascular health (Zhang et al. 2007).
ALA’s newly
discovered ability to help maintain healthy weight may be another mechanism by
which it helps support cardiovascular health. This newfound mechanism—so far
observed only in animals— appears to be reduction of weight gain via appetite
suppression, enhanced metabolic rate, and stimulation of higher levels of
physical activity. Mice given lipoic acid supplements simply chose to eat less
than a control group that did not receive supplements. They also gained less
weight than other mice in a control group that were given identical amounts to
eat, suggesting a higher metabolic rate and enhanced activity levels. In this
same study, the mice also expressed lower levels of proinflammatory chemical
messengers inside the circulatory system, as well as lower levels of
triglycerides. These results suggest the potential role of ALA in supporting
cardiovascular health via its effects on the immune, and circulatory systems, as
well as on the maintenance of healthy weight. Of course, these results need to
be reproduced in humans before any firm conclusions about this newly discovered
role for ALA are definitively drawn (Zhang et al. 2008).
Safety
Suggested Adult
Use:
One to two
capsules daily, or as recommended by a nutritionally-informed physician. Take
with or without food.
DOES
NOT CONTAIN: milk, egg, wheat, corn, sugar, sweeteners, starch, or
preservatives.
Scientific
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