Medical Uses Of Pyruvate (pyruvic Acid)

Pyruvate (also known as pyruvic acid) occurs naturally in the body and is an end product of the metabolism of sugar or starch. It is formed from the sugar glucose (blood sugar) during the process known as glycolysis. Glycolysis is one of the energy generating pathways that our bodies use every second of everyday to make ATP (adenosine triphosphate) - our "ultimate" energy molecule. The molecule ATP provides us with all the energy we need to do everything from exercising and washing the car, to reading these very words. Basically, when you make energy in glycolysis, you start with the sugar glucose, run in through some metabolic steps, and end up with pyruvate. ATP, our energy source, is formed during the process.

Pyruvate in turn has a couple of fates. First, pyruvate has the opportunity to be transformed into another molecule, which in turn is sent to another energy producing pathway known as the Krebs cycle, named in honor of Hans Krebs, the biochemist who discovered it. This reaction, where pyruvate turns into another molecule and then enters the Krebs cycle to make more energy only occurs if oxygen is present. To put it another way, this reaction only occurs during aerobic activities (like walking, running etc.).

On the other hand, if insufficient oxygen is present in the cells-such as during anaerobic activities (like sprinting or weight lifting) - pyruvate cannot enter the Krebs cycle. In this case our cells transform the pyruvate into another molecule - lactic acid. Lactic acid is responsible for the burning sensation in muscles that people feel when they exercise too hard, as well as for causing muscles to fatigue during exercise.

A surprising discovery was made with pyruvate by scientists at the University of Pittsburgh School of Medicine; they showed that dietary supplementation with pyruvate increased fat loss by up to 48% and minimized the associated loss of body protein!

This is unusual because fat loss during dietary restriction virtually always occurs with a corresponding and substantial loss of muscle (body protein). The scientists who have been studying pyruvate believe it accelerates fat loss by increasing "cellular" respiration, or the amount of energy the mitochondria (the cells metabolic furnace) uses. Pyruvate has even been shown to reduce fat without exercise, which would obviously make it an extremely attractive "fat burner" for lazy, mainstream Americans!

It seems that pyruvate was first employed as a means to prevent fatty build up in livers from chronic alcohol use. It was these studies that first sparked University of Pittsburgh researcher Dr. Ronald Stanko to investigate whether pyruvate might work as a weight loss product. To date, Dr. Stanko is responsible for practically all of the published studies on pyruvate and it's role in weight and fat loss.

The fact that pyruvate has also been shown to increase endurance (by up to 20%!) in some studies could make it even more attractive for body builders anyone who has gone on a diet knows that it's hard to maintain the stamina necessary to get super-intense workouts once you cut back on those calories!

Other possible benefits of pyruvate may include: as an antioxidant to help slow aging, to help lower blood pressure and cholesterol, increased glycogen storage, retention of lean muscle mass, increased anabolism or body protein uptake, and increased fat utilization and resting metabolic rate!

There are few studies on pyruvate and its effects on weight loss. Those that have been done suggest that pyruvate works under laboratory conditions, but its effect is not very impressive. In one study, for example, obese women (defined as weighing over 200 pounds) added 30 grams of pyruvate to a 1000-calorie/day liquid diet for 21 days. This resulted in 37% more weight loss and 48% more fat loss compared to control subjects who were on the 1000-calorie/day diet only (American Journal of Clinical Nutrition 56:630-635, 1992).

These figures seem impressive until one looks at the actual pounds of weight and fat lost. Specifically, the 37% enhancement in weight loss amounts to an average of only 3.5 pounds difference between the group taking the pyruvate and the one not taking it. With respect to the 48% increase in fat loss, this too is misleading because only 3.2 pounds more fat were lost in those consuming pyruvate.

In a second study, obese women were placed on a 500-calorie/day diet for 21 days, with some of the women supplementing with 16 grams of pyruvate and 12 grams of dihydroxyacetone (American Journal of Clinical Nutrition 55:771-776, 1992). Again, women supplementing with pyruvate did lose significantly more fat and weight than those not supplementing, but those using pyruvate lost an average of only 1.98 pounds more weight and 1.76 pounds more fat. It's important to note that these weight-loss studies took place under controlled laboratory conditions. No published peer-reviewed study to date has ever been conducted in real-life situations where calorie intake is not strictly controlled.

Of the claim that it decreases appetite, this claim is based on only one study--a study that was performed not on humans but on laboratory rats. In this investigation, laboratory rats were allowed to eat as much food as they wanted. At the end of the study, researchers found that the rats that received pyruvate and dihydroxyacetone consumed less food than rats not receiving the supplements (Journal of Clinical Nutrition 53:847-853, 1991). To date, however, such a study has never been performed on humans.

There is only one published peer-reviewed study suggesting that pyruvate can increase muscle endurance--and the only published study done on men (Journal of Applied Physiology 6811]: 119-124, 1990). This is the study that is most quoted to people interested in increasing their exercise ability. The study showed that a mixture of 25 grams of pyruvate and 75 grams of dihydroxyacetone taken for 7 days increased triceps endurance by 20%.

Much hype surrounds the claim that pyruvate can increase one's metabolism and therefore help one lose weight. Unfortunately there is no solid evidence to support this claim. Earlier studies in rats did show that pyruvate increased resting metabolism (the number of calories used at rest), but these results have never been confirmed in human studies. In fact, in the most recently published pyruvate study, the group of people who did not receive pyruvate had a higher resting metabolism at the end of the study than those who did receive the pyruvate. Therefore, the idea that pyruvate enhances human metabolism remains speculative at best.

With respect to side effects expected with pyruvate use, most studies report occasional diarrhea, lose or softened stools and a rumbling sound in the gut which is caused by gas passing through the intestines. Since pyruvate is a normal constituent of metabolism and is found naturally in our diets, its safety should be high. Even in studies using very high doses (100 times the recommended dosage) no changes in laboratory tests or clinical evaluations that measured heart rate, blood pressure, body temperature, urine output or EKG were noted.

If you are considering using pyruvate and have high blood pressure you might want to switch to a sodium free brand. To be on the safe side however, if you are on any medications or have any medical problem whatsoever, I would strongly advise that you talk to your physician first before you begin using pyruvate, or any other weight loss product for that matter. Pyruvate seems to be immediately absorbed when taken. Also, since other studies mixed pyruvate with food, it seems logical that you don't have to take it on an empty stomach. At the present time no study has looked at how pyruvate -induced weight loss works in athletes so any claim that it works in athletes is misleading and presumptuous. You can't tell how something will work in athletes using data obtained from studies which used obese women and laboratory rats. Thus far, all of the studies on pyruvate except one have been done by Ronald Stanko of the University of Pittsburgh. More investigations are surely needed before a definitive final verdict ca n be given on pyruvate.

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