Alpha-Lipoic Acid
Alpha-lipoic
acid (ALA, thioctic acid) is a naturally occurring vitamin-like nutrient that
has been intensely investigated as a beneficial agent for a variety of bodily
functions involving the 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
health-enhancing and antioxidant properties. Recently discovered is ALA’s
ability to regulate several genes linked to cell survival and oxidative stress.
Therefore, 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. Supplementing with ALA is, therefore, not so much a
direct benefit to cells, but rather an indirect aid that effectively "kick
starts" declining function, helping cells recover functionality that came more
easily and naturally in youth.
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.
What is Stabilized R-Lipoic Acid?
ALA exists in
two forms, designated as “R-lipoic acid” and “S-lipoic acid.” R-lipoic acid
(RLA) is naturally synthesized by humans, animals and plants. S-lipoic acid is
formed during chemical synthesis of alpha lipoic acid, which produces a mixture
of the two mirror-image compounds containing equal parts of each. This “racemic”
mixture is the product used most often in human clinical studies on ALA,
although other forms have recently become available and are beginning to be the
preferred form of many ALA researchers.
Best
Stabilized R-Lipoic Acid contains BioEnhanced™ Na-RALA, the sodium salt of R-Lipoic
acid. Pure RLA is a very unstable molecule that has a tendency to polymerize
with exposure to heat, light and moisture, turning into a sticky and ineffective
product. It is also hygroscopic, or water seeking. This presents problems for
those wishing to supplement with pure RLA, since any of these conditions can
lead to deactivation of the beneficial activity of lipoic acid.
Unlike pure
RLA, BioEnhanced™ Na-RALA is a stabilized form of RLA that will not polymerize
at high temperatures, is more bioavailable and has no solvent residues (Carlson
et al. 2007). On a weight basis Na-RALA reaches a much higher maximum
concentration in human plasma. Stability, pharmacokinetic, plasma and tissue
studies reveal that commonly used 'raw' (unstabilized) R-Lipoic Acid utilized in
most commercially available RLA products has very low GI absorption and
bioavailability, significantly lower than even the mass-produced racemic mixture
of R,S-ALA.
Na-RALA
requires no refrigeration and has a shelf life of at least 3 years without
polymerization. Solid R-Lipoic Acid is prone to quickly polymerize upon exposure
to heat, light, and moisture. In addition, RLA is poorly soluble in water,
whereas Na-RALA is completely water-soluble.
Unstabilized
RLA can also contain harmful heavy metals and residual solvents that are very
difficult to remove. There is a tendency for RLA to hold on to high amounts of
cyclohexane, ethyl acetate or toluene, but the processing and stabilization of
Na-RALA removes all traces of residual solvents from the raw material.
Stabilized R-Lipoic Acid vs. Controlled Release Products
Some companies
are marketing controlled release or sustained release alpha lipoic acid
products, which maintain plasma concentrations for a longer period of time.
However, available research adequately demonstrating the superiority of such
products is lacking. In fact, research performed on various alpha lipoic acid
products over the last fifty years is more indicative of the opposite: that
controlled release formulas may not only be of limited effectiveness, they may
also pose tolerability and safety risks (Carlson et al. 2007).
Marketers of
controlled release products claim that the therapeutic effectiveness of other
lipoic acid products is limited due to the fact that it reaches peak
concentrations in the bloodstream very quickly and therapeutic concentrations
are not maintained. However, this is a misrepresentation of the large body of
research indicating this is a fundamental beneficial property of lipoic acid,
not a shortcoming. Current scientific research into lipoic acid’s mechanisms
inside the body, rather than in the Petri dish, suggest that the rapid plasma
clearance is fundamentally related to its safety and therapeutic action.
Reaching an effective concentration is critical to the therapeutic action of
lipoic acid, and rapid uptake and clearance from the bloodstream is a beneficial
attribute rather than a shortcoming. Instead of being a scavenger of free
radicals, which would be more likely to benefit from a controlled release
formula, recent evidence indicates that inside the body, the “antioxidant
effect” of lipoic acid is due to its ability to modulate gene expression and
cell signaling molecules and stimulate glutathione synthesis (Suh et al. 2004;
Yaworsky et al. 2000) (University 2008).
Note regarding sodium:
The RLA in this product is stabilized with Na (sodium). However, one serving of
this product contains less than 1% of the Daily Value for sodium, an
insignificant contribution to dietary sources. Research suggests that sodium may
impact blood pressure in some individuals only when it is consumed as sodium
chloride (NaCl, table salt) and not in other forms. The sodium in this product
is unlikely to affect blood pressure levels.
D-Biotin
Best
Stabilized R-Lipoic Acid includes optically pure D-Biotin, the natural form of
biotin. D-Biotin is a water-soluble vitamin and member of the vitamin B-complex
that aids in the utilization of other B-complex vitamins. Integral to many of
the activities of enzymes in the human body, D-biotin is necessary for the
breakdown and conversion of fatty acids and carbohydrates into energy, allowing
for the production of fats and excretion of protein breakdown products.
Chronic
administration of lipoic acid can lower the activities of the biotin-dependent
enzymes pyruvate carboxylase and beta-methylcrotonyl-CoA carboxylase by
competing with biotin (Zempleni et al. 1997). Supplementing with ALA may thus
increase the body’s requirements for this vitamin.

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 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 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 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 the maintenance of a healthy
inflammatory response, as well as its 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 mg and 1800 mg doses resulted in increased rates of
gastrointestinal side effects, the authors concluded that 600 mg once daily
seemed to be the appropriate dose for supporting nerve health (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 retinal 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 maintain healthy vision (Kowluru and Odenbach
2004). RLA was also shown to support eye health in eyes exposed to 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 were administered LA in oral doses of 600,
1200 or 1800 mg per day. After 4 weeks, all of the groups receiving the
different doses of LA had significantly improved glycemic responses. 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 enhance 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 (Zhang et al. 2007).
ALA’s newly
discovered potential to help maintain healthy weight in conjunction with wise
dietary and lifestyle choices may be another mechanism by which it supports
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 directed by a health care
professional.
Does Not
Contain: milk, egg, wheat, corn, sugar, sweeteners, starch, or preservatives.
Scientific
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