Each gram of soy protein contains three to four milligrams of isoflavones. Blood levels of isoflavones begin to peak one to two hours after you eat soy, although the major peak occurs after four to six hours. The half-life, or time it takes to eliminate half the initial dose, is four to eight hours.
From a bodybuilding standpoint the main concern is that soy may interfere with other hormones, such as thyroid and testosterone. Testosterone is a major anabolic hormone, while thyroid hormones control the metabolic rate. Too much thyroid can lead to muscle catabolism, and too little thyroid output makes dieting difficult because it blunts the rate of fat loss.
Animal studies show that soy interferes with enzymes involved in the synthesis of thyroid hormone. That research has been extended to human use of thyroid, but a recent review of human studies found that soy or isoflavone had no effect on thyroid function in healthy adults.1 If anything, soy appears to increase the level of T4 thyroid hormone in the body. It may, however, interfere with the absorption of thyroid drugs if taken concurrently. The simple solution is to take soy at a different time.
Soy still may interfere with thyroid function under two conditions. The first involves an existing problem, such as hypothyroid, or low thyroid output, that’s not being treated by thyroid drugs. The second condition is a deficiency of the trace mineral iodine, which the body requires for the synthesis of thyroid hormones. The likelihood that most people in the United States have an iodine deficiency is remote. Seafood and iodized salt are common sources of iodine, and most food supplements contain it.
The notion that soy interferes with testosterone metabolism stems from animal research, plus a few human-based studies. Studies with monkeys show that feeding infant monkeys soy lowers testosterone levels—but that doesn’t happen with adult monkeys. Some rat studies show that soy lowers testosterone, others that it increases testosterone. Studies with young men did show a minor lowering of testosterone, but the effect was transient and occurred only with a low-isoflavone soy protein, which is curious because the isoflavones are thought to be the active ingredients. Those who took a high-isoflavone soy protein experienced no change in testosterone levels.
The latest study to examine the issue featured subjects who were given a high-isoflavone soy protein supplement, a vanilla whey protein supplement or a placebo, vanilla cake mix.2 The subjects used the substances over four weeks.
Only the soy protein provided an antioxidant effect, while none of the proteins (or the cake mix) lowered testosterone levels in any of the subjects. The authors suggest that a particular amino acid pattern in soy was responsible for the lowered testosterone levels found in earlier studies, which would not occur if other proteins were also ingested.
A Surprising Estrogen Inhibitor
The enzyme aromatase converts androgens, such as testosterone, into estrogen. That’s a real problem for those who use anabolic steroids known to be subject to aromatization, including any type of testosterone injection. Too much estrogen causes water retention and fat deposition just under the skin. In addition, elevated estrogen levels are more potent than androgens in providing negative feedback to the brain, which results in depressed synthesis of testosterone in the body. Recent studies have implicated elevated estrogen levels in men in the onset of prostate cancer.
Bodybuilders and athletes on steroids counter the effects of elevated estrogen in two ways. The older solution blocks estrogen receptors with a drug such as Nolvadex. A better solution blocks or inhibits the activity of the aromatase enzyme itself. Drugs that accomplish that were developed to treat estrogen-dependent breast cancers, especially in older women. Aromatase-blocking drugs are now the most popular means of controlling estrogen.
What’s not generally known, however, is that natural aromatase blockers exist in certain foods and supplements. Red wine, green tea and grapeseed extract all contain polyphenols that have aromatase-inhibiting properties. A new study identifies another aromatase blocker: beer.3 The particular ingredients responsible for the effect are hops and barley malt.
Hops add bitterness to beer, while malt is a flavoring compound. So-called prenylflavonoids in hops are thought to explain the health effects associated with beer drinking, such as cardiovascular protection and protection against cancer. They don’t interfere with the synthesis of aromatase (as do the drug versions) but instead seem to throw a biochemical monkey wrench at its activity. The net effect, however, is lower estrogen synthesis.
What isn’t clear from the study is how much beer is effective against aromatase. That’s because the study design was in vitro, involving isolated cells. Earlier research showed that a flavonoid called chrysin was just as effective as anti-estrogen drugs. Later studies, however, showed that while chrysin works great outside the body, a living human being has difficulty absorbing it.
That doesn’t mean the active ingredients in beer suffer a similar fate. Beer’s many benefits indicate that natural substances are indeed absorbed. The information shouldn’t be construed as a license to drink vast amounts of beer. Alcohol itself can lower anabolic hormone levels and directly destroys muscle fibers. Drink beer in moderation.
Good News About Omega-3 Fatty Acids
Omega-3 fatty acids, found in fatty fish and fish oils, offer a plethora of health benefits. Omega-3 fats lower inflammation by inhibiting the conversion of arachidonic acid (AA), a ubiquitous fatty acid found in red meat and various other proteins, into inflammatory eicosanoids (the eicosanoids produced from omega-3 fats are neutral and don’t contribute to inflammation in the body).
While that sounds good, at least one of the inflammatory eicosanoids produced from AA, known as prostaglandin F2-A, is involved in muscle growth. Various published studies show that drugs that lower inflammation, such as aspirin and Advil or Motrin (a.k.a. ibuprofen), can interfere with muscle protein synthesis following exercise, thought to be due to a blocking of the synthesis of prostaglandin F2-A. Because omega-3 fatty acids also interfere with that enzyme, it was assumed that taking a supplement such as fish oil might interfere with muscle gains as well.
A newly published study, however, dispels that notion.4 Researchers randomly assigned 162 men and women diets that contained high proportions of saturated and monounsaturated fatty acids for three months. Participants were given either fish oil capsules (3.6 grams daily) or a placebo.
Taking fish oils produced an antioxidant effect but didn’t affect the synthesis of prostaglandin F2-A in any of the subjects. In practical terms, that means you can take omega-3 fatty acid supplements, such as fish oils, without any fear of limiting your progress in building muscle and getting stronger.
Steroids and Antioxidant Protection
Exercise protects against cardiovascular disease through several mechanisms. One obvious way involves a loss of bodyfat. Losing fat improves health by lowering blood pressure, workload on the heart, and body inflammation. Since exercise requires a higher oxygen intake, the body increases the production of several natural antioxidant enzymes, such as superoxide dismutase and glutathione.
The natural, built-in antioxidants offset the greater release of noxious by-products of oxygen metabolism called free radicals, which occurs after you work out. They’re considered a primary benefit of exercise because they provide extra protection against diseases caused by excess free radicals in the body, such as cardiovascular disease and cancer.Anabolic steroids have been linked to cardiovascular disease. Particularly when used in large amounts, steroids have adverse effects on blood lipids, such as high-density lipoprotein (HDL). A new study, using rats as subjects, identifies another way that steroid use promotes cardiovascular disease.5
Researchers gave the rats large doses of the injectable anabolic steroid nandrolone decanoate, trade name Deca-Durabolin. Deca is popular among athletes because of its high-anabolic, low-androgenic profile. On the other hand, it’s also easily identified in drug tests, and markers for the drug can be detected for as long as a year after its use is discontinued.
The experiment showed that when exercised rats are given amounts of Deca comparable to levels used by athletes, the antioxidant protection exercise produces is nullified. That sets up a scenario for increased cardiovascular damage and may explain some of the cardiovascular disease effects linked to high steroid use.
Although the study involved animal subjects and awaits confirmation in human studies, the mechanism is likely to also be true of humans. It would be prudent for anyone who uses anabolic steroid drugs to increase his or her intake of various dietary antioxidants, such as vitamins C and E, and various minerals, such as selenium and zinc. Manganese is also vital because one of the antioxidant enzymes requires manganese to be activated in the body.On the other hand, it would also be prudent not to go overboard with pre-workout antioxidant supplements. Recent research shows that reactive oxygen species, or free radicals, act as signaling factors in the muscle growth and recovery process.As such, it's better to ingest your antioxidant supplements away from a workout.
References
1 Messina, M., et al. (2006). Effects of soy protein and soybean isoflavones on thyroid function in healthy adults and hypothyroid patients: A review of the relevant literature. Thyroid. 16:249-258.2 DiSilvestro, R.A., et al. (2006). Soy protein intake by active young adult men raises plasma antioxidant capacity without lowering plasma testosterone. Nutr. Research. 26:92-95.
3 Monteiro, R., et al. (2006). Effect of hop (Humulus lupulus) flavonoids on aromatase (estrogen synthase) activity. J Agric Food Chemist. 54:2938-2943.
4 Nalsen, C., et al. (2006). Dietary (N-3) fatty acids reduce plasma F-2 isoprostanes but not prostaglandin F2-A in healthy humans. J Nutr. 136:1222-1228.
5 Chaves, E.A., et al. (2006). Nandrolone decanoate impairs exercise-induced cardioprotection: Role of antioxidant enzymes. J Steroid Biochem Molec Biol. 99(4-5):223-230
©,2013 Jerry Brainum. Any reprinting in any type of media, including electronic and foreign is expressly prohibited.
