The first dietary supplement I want to discuss is chromium. Chromium is an essential trace element in humans (Moore and Friedl, 1992) and is involved in the utilization of sugars for energy through its actions on the hormone insulin (Groff, Gropper and Hunt, 1995). Because of preliminary evidence which seemed to show that chromium may enhance weight loss and promote muscle gain, it has become the one dietary supplement which refuses to go away despite the tremendous amount of peer-reviewed scientific evidence showing that it does not do either of its reported effects in normal healthy individuals. Studies suggesting promotion of weight loss and muscle gain from chromium use, it turns out, sometimes arrived at their conclusions because the weight loss was based upon what the scale said as opposed to determination of body composition by more acceptable methods, such as underwater weighting (McArdle, Katch &Katch, 1999). Studies using such diverse populations as overweight military personal (Trent et. al., 1995) to collegiate football players (Clancy et. al. 1994) using chromium dosages from 200 ug – 400 ug and above have failed to show significant reductions in weight gain or gains in muscle mass following chromium supplementation. While it is true that an acute bout of exercise (for example running a mile) does lead to enhanced chromium excretion in the urine (Anderson, 1989), it is unknown if athletic performance is hindered by this heightened excretion (Moore and Friedl, 1992). One recent study of chromium picolinate supplementation published in the Journal of Strength and Conditioning Research found that chromium supplemented at 500 mg per day for 6 weeks did not alter strength or body composition in 15 female softball players who strength trained three times per week at 80% of their maximum strength output (Livolsi, Adams, & Laguna, 2001).
Some preliminary evidence suggests that high levels of chromium picolinate-the most popular form of chromium today - may result in genetic damage (Stearns et. al., 1995). Enhanced chromosomal damage may mean a greater risk of developing diseases, such as cancer. This particular line of research seems to be based upon very few studies (only one that I can find) and has not been documented in humans. It’s also unfortunate that other studies refuting or corroborating its conclusions still seem to have not been conducted. Chromium is found naturally in foods such as broccoli, nuts, apples (with the skins) and cheese (Mcardle et. al. 1999).
My opinion: get your chromium from food and not the local health food store.
Next up is Vanadyl Sulfate. Vanadium (sold in the stores as vanadyl sulfate) is a trace element found in the body (McArdle et. al. 1995). Just as hemoglobin makes our blood red, vanadium makes the blood of some sea dwelling animals green (Moore and Friedl, 1992). In fact, one of the classic signs of overdosing on vanadium is a green color on the tongue (Moore, Friedl, 1992). Vanadium sulfate is one of those compounds often touted by bodybuilders as something that gives one a “pumped look” indicative of muscle hypertrophy as well as to provide the extra energy needed to get through tough workouts. Interestingly, research has concluded that vanadium seems to work in the body like insulin, helping the body make use of sugar for energy (Moore et al.; 1992 Groff, 1995, McArdle e al 1999). Studies of type II diabetics have shown that vanadium can enhance the body’s sensitivity to insulin (McArdle et. al. 1999), an effect which I should point out has not been observed in non-diabetic individuals (McArdle et. al. 1999). There seems to be no well-designed scientific research showing that vanadium improves strength, power, endurance or body composition in normal, healthy individuals (McArdle et. al. 1999). Natural sources of vanadium include cereal and grain products as well as poultry, fish and red meat (McArdle et. al. 1999). Because high levels of vanadium have been shown to be toxic to the liver (McArdle, et. al. 1999), it is prudent to not take it in excess. Currently no recommended dietary allowance for vanadium exists (McArdle et. al. 1999). Thus, it’s hard to know what is a safe level of intake for this mineral.
My opinion: save your money on vanadium supplements and get it from food.
Pyruvate is a relative newcomer to the nutrition supplement world but it is not without its share of peer-reviewed scientific evidence. In fact, of all the dietary supplements reviewed here, I feel pyruvate has the most well designed studies showing that it may promote positive results in some individuals. However, as well designed as these studies are, there are major problems that you need to know about. Pyruvate is a molecule formed in the body as carbohydrates are broken down to make energy. The claims made for pyruvate are many and include – but are not limited to -reductions in weight and fat, improvements in exercise endurance and suppression of appetite. The weight loss claims for pyruvate are based upon very overweight women (over 200 pounds) who were put on a 300-500 calorie per day diet and who supplemented with up to 75 grams of pyruvate per day (this is much more than the 3-5 gram dose recommended by products sold in stores) (Stanko Tietze and Arch, 1992a.; Stanko, R., Tietze, Arch, J.E. 1992b). While it is true, women who used large amounts of pyruvate lost more weight, this comes to only about a 2 – 3.5 pound difference – hardly the monstrous amounts of weight one is lead to believe in the advertisements. Also, this effect has never been demonstrated in men or women who ate a diet of more than 300-500 calories per day. With respect to appetite suppression, this claim seems to be based on a single study that used laboratory rats (Cortez, 1991). Claims of improved muscular endurance are also based upon one study (Stanko, 1990).
My opinion: Unless you are an overweight woman who uses a lot of pyruvate and combines it with a very restrictive diet –or unless you are a laboratory rat, I’d save my money and keep counting calories and exercising until more research is done.
Next up are glandulars. The term ‘glandulars” is an all encompassing generic term which, in a nut shell, refers to “ground up” body parts. Ancient Chinese beliefs held that eating ground up monkey testes could restore sexual vitality (Moore et al, 1992). Because we know today that testosterone comes from the testes, many (ignorantly) believe that eating ground up testes will increase ones blood levels of testosterone! This is a prime example of seeing the bottom left hand corner of the big picture. The level of testosterone in testes is only slightly higher than what one would find in other body parts (Moore, et al, 1992). Even if a person could ingest a bunch of testosterone, it would quickly be cleared from the body by the liver (Moore et al, 1992). Incidentally, we would hope that this would be the case because if the liver didn't clear the extra testosterone from the body, our body would shut down its own production of testosterone via its build in safety mechanisms. Some manufacturers sell ground up brain parts like pituitary glands and hypothalamus glands in the hopes of attracting customers (Moore, et al, 1992). The idea behind this ploy is that the hormones released from these glands will stimulate the testes to make more testosterone. Again, there is a problem with this. You see, these hormones are really nothing more than complex protein molecules -and just like any other protein that is eaten - they are quickly broken down in the stomach and never reach the blood as intact hormones. In other words, your body treats these hormones just as it would a T bone steak. It breaks the protein down into its constituent amino acids and uses those amino acids in what ever way it wants.
My opinion: Eating glandulars is an expensive and a gross way to get your daily protein requirement!
Now, let’s move onto carnitine. Carnitine or L-Carnitine as it is also referred, is a substance that is responsible for moving fat molecules into the mitochondria (the main energy -producing machine in cells) where they can be broken down for energy (Baechle, 1994). The idea with this dietary supplement is that if one were to ingest more carnitine, then more fat would be brought to the mitochondria which would in turn give us more energy. There may actually be something to this reasoning since during prolonged exercise, blood fat levels rise to a greater degree than needed (McArdle et. al. 1999). This has lead some to theorize that this ‘backing up” of plasma fats is due to a carnitine deficiency (McArdle et. al. 1999). If this is true, in theory, adding carnitine to the diet may enhance fat breakdown during exercise. But, of course, this is all speculation.
Unfortunately, only one study has shown a positive effect from carnitine supplementation (Bachle et. al. 2000). In addition, the intestine can absorb only 2 grams or orally ingested carnitine (Baechle, 1994), a level that has been estimated to raise muscle carnitine levels by only 1% - 2% (Bachele, 1994). And as if that weren't enough, studies in animals and humans show that ingesting the wrong kind of carnitine (either D carnitine or a mixture of D and L carnitine) can actually result in a carnitine deficiency (Baechle et. al. 2000).
My
opinion: Don't waste your money on carnitine and keep
working out.
Note: This article represents an updated version to the original Let the Buyer Beware piece that I wrote for Philly Health & Fitness Magazine in 1997. My decision to re-address and update this piece was my finding that it has become almost a cult favorite among many fitness and bodybuilding sites on the web today. I hope you have enjoyed reading it as much as I have enjoyed writing it.
References
References provided upon request at [email protected].
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