PYRUVATE: A COMPREHENSIVE REVIEW © 1997 - 2007
By William R. Sukala, MSc., CSCS
Clinical Exercise Physiologist / Consumer Health Advocate
www.williamsukala.com INTRODUCTION
Pyruvate is a dietary
supplement targeting both sedentary and active individuals. The most popular
claims for pyruvate center
about its purported ability to: 1) "significantly" increase fat and
weight loss; 2) improve exercise endurance capacity; 3) effectively reduce
cholesterol, and; 4) serve as a potent antioxidant. However, these contentions
are based mainly on faulty extrapolations of preliminary or inconclusive
evidence.
Multi-level marketing supplement distributors and internet entrepreneurs, most
without any formal training in nutrition, are leading the campaign with
reckless abandon and little regard for the accuracy of their claims. Anecdotal
testimonials from "satisfied" users permeate everything from internet
websites to fitness magazines to television infomercials. While the mere
mention of "scientific studies" is enough to impress the lay
consumer, a critical review of the original research reveals a very different
picture.
WHAT IS PYRUVATE?
Pyruvate is a three-carbon (triose) ketoacid produced in the end stages of glycolysis. It can be reduced to
lactate in the cytoplasm or oxidatively
decarboxylated to acetyl CoA in the mitochondrion (13).
Simply, it is a product of sugar metabolism.
COMPARISON OF POPULAR CLAIMS TO ACTUAL RESEARCH
Claim: "Significantly increase fat loss by 48% and weight loss
by 37%!"
Two human studies evaluated pyruvate's
role as a fat and weight reductant
(11, 12). In both investigations, treatment subjects lost more fat and weight
than the control group, but only one found these percentages (11). Considerably
smaller changes (23% greater fat loss and 16% greater weight loss) were noted
in the other study (12). This claim is particularly misleading to consumers
since these "significant" percentages actually amount to only a few
pounds. The widely popular 48% translates to a mere 1.3 kg or 2.86 lbs and 37%
is really 1.6 kg or 3.52 lbs--hardly the significant losses dieters have come
to expect. Furthermore, these percentages have no practical relevance outside
the context of a research article (How does a consumer quantify 48 and 37%?). A formal research
environment differs from the real world in that the latter presents many
confounding variables, so results (or lack thereof) may be attributable to
factors unrelated to pyruvate
supplementation.
The experimental protocol was extremely exclusive. All subjects were: 1)
morbidly obese women; 2) housed in a metabolic ward for 21 days; 3) confined to
bed except for walking to the restroom and kitchen; and 4) restricted to a 500
to 1,000 kcal liquid diet. As such, the results of these studies are specific
to these criteria and cannot be reliably generalized to the population at
large.
The relatively small differences observed in treatment subjects were induced by
dosages considerably larger (22 to 28 grams of triose) than those available to consumers.
Commercially available preparations provide about 500 mg to 1 gram of pyruvate, usually taken a few
times a day for a daily intake of 3 to 5 grams. To date, no studies have been
performed with such benign dosages.
Claim: "Prevents fat regain and eliminates "yo-yo"
effect"
This claim is based on a single study (5). Initial weight loss was induced by a
310 kcal diet followed by subsequent hypercaloric
refeeding supplemented with
large amounts of triose (15
grams of pyruvate and 75
grams of dihydroxyacetone).
The treatment group gained 1.8 kg or 3.96 lbs (36%) less weight and 0.8 kg or
1.76 lbs (55%) less fat than the placebo group. However, for a number of
reasons, these results cannot be accurately ascribed to the general public.
This study also employed morbidly obese women housed in a metabolic ward for 21
days while refraining from all physical activity. While results were
statistically significant, they were physiologically negligible; that is, from
an absolute standpoint the changes were relatively inconsequential.
Claim: "Significantly improve exercise endurance by 20%."
Stanko and colleagues found
triose-supplemented (75
grams dihydroxyacetone and
25 grams pyruvate) subjects
increased time to exhaustion by 20% during arm and leg ergometry protocols (9, 10). Unfortunately, these
results are far from conclusive and should be considered, at best, preliminary.
First, both studies employed small numbers of untrained males; no large-scale
investigations using trained subjects have been performed. Well-trained
athletes present less intra- and inter-subject variability in performance which
can increase the statistical power of the trial (2).
Second, the large amounts of pyruvate
needed to elicit improvements ranged from 20 to 100 times the amounts found in
supplements. Unfortunately, there is no evidence that the minuscule doses
available to consumers exert any physiological effect.
Some marketers have generalized that pyruvate
supplementation can improve performance across a broad spectrum of activities.
However, such quantum leaps are inappropriate since these results are specific
to arm and leg ergometry
protocols. Different activities impose specific physiological and biochemical
demands, and can vary in their motor unit recruitment patterns.
The point is that no one knows what effect it has, if any, on other sports;
claims to the contrary are based solely on speculation.
Claim: "Shown to lower cholesterol."
Two studies (7, 8) investigated pyruvate's
role as a cholesterol reductant;
however, only one showed any change (8). Treatment subjects took (large doses)
36 to 53 grams of pyruvate
over the course of six weeks while consuming a high fat (45 to 47%), high
cholesterol (560-620 mg) diet. While the results in this study (8) showed small
changes in total cholesterol (4%) and LDL cholesterol (5.4%), these effects
were negated when subjects consumed a low-fat, low cholesterol diet (7).
It is not valid to state that pyruvate
has been conclusively proven to reduce plasma lipids. While popular marketing
literature leads consumers to believe that this is an effective treatment for hyperlipidemia, one study does
not constitute a substantial body of evidence. No legitimate public health
agency would ever make broad recommendations based on such scant evidence.
Claim: "Improves cardiac function and lowers blood pressure."
In one of the cholesterol studies (8), heart rate and diastolic blood pressure
decreased by 9 and 6%, respectively; however, these changes were incidental to
the research objectives and were not the main focus of the study. These
preliminary findings should not be considered conclusive. Rather, they can
serve as the impetus for future studies in this capacity. Unfortunately,
marketers do not address this in their promotional literature.
Claim: "Pyruvate
is a powerful antioxidant!"
The effect of pyruvate as
an oral antioxidant has never been investigated. Two studies (1, 3) have shown
its potential as an in-vitro antioxidant under tightly controlled experimental
conditions; but extrapolating these results to humans is particularly
misleading since isolated tissue culture (1) and post-ischemic heart models (3)
are not the same as human trials. This is not to discount the relevance of
these clinical findings; rather, the practical application of pyruvate as an oral antioxidant
remains to be established.
Claim: Pyruvate is a
"natural alternative" to Phen/Fen
This claim capitalizes on the American public's fear
and distrust of the pharmaceutical industry. To understand why this comparison
is invalid, it is necessary to look at how drugs and supplements are evaluated.
A regulated drug must undergo extensive testing to evaluate it's safety, toxicity, side effects. With the passage
of the Dietary Supplement and Health Education Act of 1994, nutrition
supplements can be sold to consumers without being tested for safety, efficacy,
purity, or potency--although many consumers mistakenly believe that simply
because it's available it must be safe and effective.
Even if they were on par with each other, pyruvate has never been clinically tested or proven
to be more effective than Phen/Fen
(or any other prescription weight loss medication). In light of Phen/Fen's 1997, removal from the market,
many marketers are quick to trumpet its “effectiveness” over regulated
pharmaceuticals. Clearly, a reliable comparison cannot be made.
FALSE AND MISLEADING CLAIMS
While the most popular claims are supported by limited evidence,
there are many more with no basis in fact whatsoever. Some are downright false
and others are deceptive half-truths.
Claim: "Shown to be a more potent fat
burner than hydroxycitric
acid (HCA) and chromium picolinate
combined."
This claim is blatantly false since no studies have ever compared pyruvate to HCA and chromium picolinate--chromium and HCA have
not been conclusively proven to enhance fat oxidation. There is absolutely no
merit for this claim, yet it can be found on promotional literature as
"clinically proven."
Claim: "Pyruvate
is found naturally in the body and in a variety of foods."
Pyruvate is a normal
constituent of human and plant metabolism; however, the term
"natural" is ambiguous and therefore confers a deceptive stamp of
approval to the unsuspecting consumer. This tactic is grounded in the
"if-it's-natural-it-must-be-safe-and-effective" myth. Unfortunately,
natural does not mean safe or effective—E. coli and rattlesnake venom are both
“natural” but that doesn’t mean they promote health and vigor.
Claim: "Pyruvate
has been clinically proven safe with no side effects."
In all human trials (5, 7-12), some
subjects receiving large doses of pyruvate experienced gastrointestinal distress in the form of diarrhea, borborygmus,
and flatulence. It is likely that consumers do not experience
these symptoms due to the benign amounts of pyruvate found in supplements rather than
manufacturers' formulations.
Claim: "patented 4 times over."
A patent on a product does not mean it works; anyone can patent anything. Wise
consumers should dismiss patents as "proof" of efficacy. The only
true guarantees are big profits for the companies selling the product.
TESTIMONIALS
Emotional testimonials are often employed by supplement
promoters, usually as a way of downplaying one's natural skepticism--the
"be like Mike" syndrome. Unfortunately, testimonials have no
scientific merit since they do not separate cause and effect from coincidence.
Let there be no doubt about it; testimonials are very convincing. One should be
skeptical when a product distributor says, "it worked for me, it can work for you." Yes,
maybe the promoter experienced some type of change, but there is no way to
verify if it was a result of the product. For example, if one takes the pyruvate while reducing calories
and engaging in physical activity, there is no way to differentiate whether the
weight loss was caused by the diet and exercise or the supplement. Again, there
is no separation of cause and effect from coincidence.
There is no way to verify the validity of testimonials. A consumer would not be
able to confirm if the people are, in fact, real, or they've been paid for
their endorsement. In the case of pyruvate,
conflicts of interest abound. A pro-pyruvate
article appeared in Muscle and Fitness Magazine (4) and quickly became a highly
prized marketing tool for promoters. However, the numerous testimonials listed
in the article are questionable. According to the article:
”Terry Newsome, a 38-year old executive from Westlake
California, has battled obesity for two decades, touts the effects of pyruvate. I've lost 39 pounds in
less than 40 days. Other than the 5 grams of pyruvate, my eating and exercise habits have
remained the same and I feel better than I ever dreamed possible.....”
Ironically, Terry Newsome, at the time the article appeared on news
stands, was president of Med-Pro industries, the company that holds four
patents on pyruvate. Since
he has direct involvement in the company, this testimonial cannot be considered
objective. Even if he did lose 39 pounds in less than 40 days, there is no way
to be certain the entire composition was fat.
The First Law of Thermodynamics (Conservation of Energy) holds
that energy cannot be created or destroyed, only transformed from one form to
another. So it is unrealistic to believe he could have expended an additional
3,500 kcal (1 lb of fat = 3500 kcal) above and beyond his daily caloric
requirements, especially since he did not change his eating and exercise
habits. And 5 gram doses of pyruvate
have never been used in any published clinical research.
Famous athletes double as popular marketing tools for ergogenic aids, the obvious implication being that
average consumers will perform at elite levels. The article states: “Of
note, Olympic gold-medal gymnast Shannon Miller and her coach, Steve Nunno, are expected to endorse pyruvate because of the increased
energy Miller experienced with the product. Though not part
of a scientific study, Miller says that pyruvate
helped energize her just days before the 1996 Olympics.” This passage is
misleading to consumers for a number of reasons.
First, the terms "increased energy" and
"energize" are ambiguous and can be subjectively defined many
different ways (for some, "energy" is just getting out of bed; for
others it might be running 15 miles).
Second, elite athletes operate at such high physiological levels of performance
that there is very little room for improvement. Untrained individuals, on the
other hand, have sufficient room for improvement, with or without supplements.
Third, the women gymnasts earned their gold medals as a team. Clearly Ms.
Miller contributed her part, but there is no way to know if pyruvate had any effect on the final results.
Lastly, gymnastics differs markedly from steady-state endurance exercise--the
motor unit recruitment patterns and metabolic demands of gymnastics are not the
same as arm and leg ergometry
protocols (9, 10). So there is no way to tell how much pyruvate contributed to each activity, if at all.
COMMON MARKETING PLOYS
Pyruvate promoters have
accessed every available media outlet. By far, the internet is the preferred
marketing method, allowing pyruvate
to be marketed quickly and inexpensively. People are inculcated by internet
message boards, news groups, list-serves, and chat rooms, most of which lead to
unsolicited junk e-mail. Unfortunately, consumers have absolutely no way of
verifying what's legitimate since anyone can exploit the internet.
Print advertisements line the pages of magazines, newsletters, daily and weekly
newspapers, and many supplement industry catalogs. Eye-catching, glossy ads
featuring slender, tan bodies are often paired with the usual grandiose claims.
Infomercials trumpet pyruvate’s benefits via the late
night airwaves. As with any paid endorsement, their content should be viewed
with skepticism. Promotional audio tapes are also making the rounds.
Essentially, they mirror print advertisements, but are a convenient way to
target the non-reader.
COST
Pyruvate does not come cheap.
Firms sell pyruvate supplements for anywhere from $50
to $65 per bottle of 120 capsules. Usually for a nominal fee, anyone can become
a multi-level marketing distributor which would further lower the price even
more. No matter how you look at it, this is an expensive price to pay for a
product that hasn't been conclusively proven to do anything.
THE BOTTOM LINE
A number of irrefutable certainties exist: 1) The
minuscule doses available in commercial supplements have not been proven
effective in any available research. No dose-response relationship has been
established so there is no way of knowing the minimum effective dose; 2)
Existing research does not conclusively support marketers' claims, many of
which are based on faulty extrapolations from inconclusive, preliminary
findings; and 3) Most studies were conducted by Ronald Stanko and have not been replicated by other
researchers in other laboratories under various conditions in various sample
populations. But don't expect marketers to readily embrace these facts. Whether
pyruvate works or not seems
to be unimportant to marketers. Customers will continue to be exploited for
profit as long as the existing volume of misinformation surrounding pyruvate persists.
Perhaps all the attention stirred by promoters will spark the interest of other
researchers and may eventually answer some of the questions presented in this
article. Existing research is valuable in that it can serve as a preliminary
foundation to guide future investigations. Nevertheless, at this point in time,
pyruvate should be
dismissed as nothing more than a too-good-to-be-true supplement.
REFERENCES
1. Borle, A., and R.T. Stanko. Pyruvate
reduces anoxic injury and free radical formation in perfused rat hepatocytes.
J. Appl. Physiol. 270: G535-G540, 1996.
2. Burke, L., and P. Heely. Dietary supplements and
nutritional ergogenic aids
in sport. In Clinical Sports Nutrition, L.
Burke, and V. Deakin (Ed.). Sydney, AUS: McGraw-Hill, 1994, pp. 227-284.
3. DeBoer, L.W.V., P.A. Bekx, L. Han, and L. Steinke. Pyruvate enhances recovery of rat hearts after
ischemia and reperfusion by preventing free radical generation. J. Appl. Physiol. 265: H1571- H1576, 1993.
4. Roufs, J.B. Pyruvate:
Does it amp endurance and burn more fat? Muscle
and Fitness. 57: 87-88, 195- 197, December 1996.
5. Stanko, R.T., and J.E. Arch. Inhibition of regain in
body weight and fat with addition of 3-carbon compounds to the diet with hyperenergetic refeeding after weight reduction.
Int. J. Obes. 20: 925-930,
1996.
6. Stanko, R.T., H. Mendelow, H. Shinozuka,
S.A. Adibi. Prevention of alcohol-induced fatty liver by
natural metabolites and riboflavin. J. Lab. Clin. Med. 91: 228-235, 1978.
7. Stanko, R.T., H.R. Reynolds, R. Hoyson, J.E. Janosky,
and R. Wolf. Pyruvate
supplementation of a low-cholesterol, low-fat diet: Effects on plasma lipid
concentrations and body composition in hyperlipidemic
patients. Am. J. Clin. Nutr. 59: 423-427, 1994.
8. Stanko, R.T., H.R. Reynolds, K.D. Lonchar, and J.E. Arch. Plasma
lipid concentrations in hyperlipidemic
patients consuming a high-fat diet supplemented with pyruvate for 6 wk. Am. J. Clin. Nutr.
56: 950-954, 1992.
9. Stanko, R.T., R.J. Robertson, R.W. Galbreath, J.J. Reilly, Jr., K.D.
Greenawalt, and F.L. Goss. Enhanced leg exercise endurance with a
high-carbohydrate diet and dihydroxyacetone and pyruvate. J. Appl.
Physiol. 69 (5): 1651-1656,
1990.
10. Stanko, R.T., R.J. Robertson, R.J. Spina, J.J. Reilly, Jr., K.D. Greenawalt, and F.L. Goss. Enhancement of arm exercise endurance capacity
with dihydroxyacetone and pyruvate. J. Appl.
Physiol. 68 (1): 119-124,
1990.
11. Stanko, R.T., D.L. Tietze, and J.E. Arch. Body composition, energy
utilization, and nitrogen metabolism with a 4.25-MJ/d low-energy diet
supplemented with pyruvate.
Am. J. Clin. Nutr. 56: 630-635, 1992.
12. Stanko, R.T., D.L. Tietze, and J.E. Arch. Body composition, energy
utilization, and nitrogen metabolism with a severely restricted diet
supplemented with dihydroxyacetone
and pyruvate. Am. J. Clin. Nutr. 55: 771-776, 1992.
13. Stryer, L. Biochemistry.