|
|
Pyruvate: Can it really help you lose weight?Not only is pyruvate reported to have a "phenomenal effect" on weight loss by burning fat, it's also supposed to boost your performance in the gym. Does it work? Or is pyruvate just another in the long line of supplements to promise much but deliver little? PyruvateSome of the initial research on pyruvate supplements was completed in the late 1970's. Scientists discovered that pyruvate (along with a compound known as dihydroxyacetone, which is in the same chemical family as pyruvate) helped to prevent the development of fatty livers in rats fed ethanol [2]. It appears that the combination of dihydroxyacetone and pyruvate (DHA-P for short) somehow reduced fat storage. Based on these early findings, researchers wanted to see if DHA-P had the same effect under normal dietary conditions [2]. A group of rats was fed liquid diets containing DHA-P for 112 days. The group consuming the DHA-P combination stored 32% less fat than rats on a normal diet. It appears that the reduced fat gain was the result of an increase in heat production. Rather than being stored as fat, excess calories were being used to generate heat. This led the researchers to conclude that DHA-P increases the metabolic rate. Several years later, further research was conducted on a species of rat known as the Zucker rat [1]. Their diets were supplemented with one of three treatments: pyruvate, dihydroxyacetone, or a combination of the two. All three supplements acted to reduce weight gain. But pyruvate appeared to have the strongest effect. It seems that pyruvate reduced weight gain in obese Zucker rats by increasing their resting metabolic rate. Once pyruvate had shown promise in rats, the next logical step was to see if it worked in humans. Human studiesIn a series of studies completed at the University of Pittsburgh, Dr. Ronald Stanko (who owns several patents linked to pyruvate use) and his research group examined the influence of pyruvate on various measures of body composition. The research shows a clear trend toward increased fat loss in subjects using pyruvate. In one study, a group of 14 obese women consumed around 1000 calories each day for a 21-day period [8]. Seven of the women supplemented with 30 grams of pyruvate, while the second group received a placebo. A placebo is a "dummy" supplement used to reduce the effect that faith and belief in the effectiveness of a treatment may have on the results of a study. Women using pyruvate lost nine pounds of fat — three pounds more than the placebo group. Based on the evidence gathered from the animal research, the researchers think that the increased weight loss was due to an elevated metabolic rate. A follow up study, again carried out over 21 days, used the pyruvate and dihydroxyacetone combination as a supplement [9]. This time, food intake was restricted to only 500 calories each day. Once again, fat loss was greater in subjects using pyruvate and dihydroxyacetone than the group given a placebo (10 pounds versus 8 pounds). A third study, completed in 1994, involved 34 subjects over a ten-week period [5]. The aims of this project were slightly different from the previous two. Dr. Stanko wanted to see what effect pyruvate had on body composition following a period of weight loss. Subjects consumed a restricted calorie diet (consisting of between 1600 and 1800 calories each day) for four weeks. During this period, the average weight loss was 1.5 pounds. The women were then assigned to one of two groups for a further six weeks. Group one supplemented with 22-44 grams of pyruvate per day. The second group received a placebo. After six weeks, fat loss in the placebo group was just 0.2 pounds. However, the group who supplemented with pyruvate lost an average of 1.1 pound. Weight gainThere's also evidence to show that the DHA-P combination may limit the gain in body fat that can occur after a period of dieting [4]. It's reasonably easy to lose weight on a restricted calorie diet. And it's even easier to put it back on when you start eating normally again! However, a study completed in 1996 shows that DHA-P could limit this fat regain. Seventeen obese females followed a restricted calorie diet for three weeks. They lost, on average, 11 pounds of fat. For the next three weeks, the subjects were fed a high calorie diet designed to increase their weight. During this period, half of the women took approximately 90 grams of DHA-P, while the rest used a placebo. DHA-P appeared to limit the regain in body fat. Subjects in the placebo group gained four pounds, which was twice as much as the group using DHA-P. Looking for clues as to why DHA-P had such a pronounced effect on fat storage, the researchers examined the subjects' respiratory quotient (RQ for short). The RQ measures how much oxygen the body is using, and compares it to the amount of carbon dioxide being produced. Because different amounts of oxygen are used to convert carbohydrate, protein or fat into energy, the RQ serves as a general guide to the type of fuel your body is using. A lower RQ indicates greater use of fat as a fuel source, while a higher RQ suggests an increase in carbohydrate metabolism. Subjects using the supplement had a significantly lower RQ than those who took the placebo. This suggests that DHA-P encourages the body to burn more fat for fuel. DownsidesThere are, however, a number of downsides to pyruvate supplementation. The first is cost. The best price I could find for a calcium pyruvate supplement was $9.89. This was for 90 capsules, with each capsule containing one gram of calcium pyruvate. Using the supplement in the quantities suggested in the research (30 grams daily), this supply would last three days. In other words, 30-days of pyruvate supplementation would cost you almost $100. Most of the subjects taking part in the research report that large doses (30-100 grams) of pyruvate leads to gastrointestinal distress, involving several uncomfortable visits to the toilet, "gurgling" noises in the stomach, and an embarrassing wind problem. Not pleasant. There is, however, one study to address some of these problems. A study published in the May 1999 issue of the journal Nutrition shows that lower dosages of pyruvate accelerates fat loss when combined with a program of regular exercise [3]. Subjects were assigned to one of two groups. Group one supplemented with a placebo, while the second group consumed 6 grams of pyruvate per day. Both groups completed 45-60 minutes of circuit training, three times each week. All subjects were monitored to ensure that calorie intake was maintained at approximately 2000 calories per day. Following the six-week program, subjects consuming the placebo were at the same weight, while those supplementing with pyruvate lost six pounds of fat. Remember that this is just one study. No follow-up trials using similar doses of pyruvate have been published in any reputable peer-reviewed journal. Most scientists prefer to rely on the results of a number of well-controlled trials. There is always the possibility that the results were due to chance, or that the original researcher unconsciously or consciously influenced the outcome of the study. What's more, many supplement companies will pay research groups to study their product. If the results are positive and show that the product works, they’ll use the study in subsequent promotional material, such as magazine adverts or press releases sent to newspapers, TV and radio stations. If the results of study are negative (meaning that the supplement didn't work) some form of "non-disclosure agreement" signed in advance means that the results will be brushed under the carpet and never published. The bottom lineIn non-exercising subjects, large doses (20-90 grams) of pyruvate and dihydroxyacetone have been shown to accelerate fat loss by 25-40%. However, the high quantities used in the research must surely put pyruvate out of most buyers' reach due to its cost. And the side effects from large amounts of pyruvate include uncomfortable visits to the toilet, "gurgling" noises in the stomach, and an embarrassing wind problem. What's more, most of the studies have used the combination of pyruvate and dihydroxyacetone, rather than pyruvate alone. Commercially available pyruvate supplements do not contain dihydroxyacetone. Although one study shows that lower doses of pyruvate aids weight loss, we need more research from a number of well-controlled trials before reaching any firm conclusions. Because of this, pyruvate is not a supplement that I use or recommend. Related Articles
References |
Not a Member?
|
|
The Facts About Fitness The Facts About Fitness Limited is registered in England and Wales No. 04538088 |
