How does soy protein work

Several studies have shown soy protein to be inferior to whey for the production of GSH. Though soy has a reputation for reducing cholesterol, in one study, rats fed soy protein that was not fortified with methionine as 13 percent of total calories, had an increase in cholesterol and an increased susceptibility of LDL cholesterol to peroxidation. So not only did the rats' cholesterol go up, the LDL fraction oxidized more easily, potentially leading to clogged arteries.

It is well established that an increased susceptibility of LDL to peroxidation is an essential step for the development of atherogenesis. These rats were found to have low levels of GSH and did not grow as well as another groups of rats fed casein.

If that were not bad enough to convince you to avoid soy, it gets worse. Soy protein contains something known as "antinutrients" that block the digestion and absorption of many nutrients.

Two of the more important antinutrients found in soy are lectins and protease inhibitors. Lectins are nasty constituents of various plants and can cause all sorts of problems, from interfering with the absorption of important nutrients to intestinal damage. Proteases are enzymes that assist in the digestion of proteins. Soy has several protease inhibitors that interfere with the enzymes trypsin and chymotrypsin, both of which are important for the digestion and absorption of proteins in the gastrointestinal tract.

Some nutritional counselors have begun to suspect that soy may be to blame for the low energy, digestive disturbances, hypothyroidism, infertility, and other ailments they see in clients.

However, on the other side of the coin, many scientists believe soy to be relatively innocuous, and in fact beneficial for a whole range of physical ailments. The previous section does not paint a very pretty picture of soy proteins, but it's not the entire story. The problem of the antinutrients found in soy protein has been taken care of as the manufacturers of high-quality soy protein isolates remove them or dramatically reduce their activity during processing, so this is not a big point of concern anymore.

Also, the addition of methionine to soy isolates greatly improves its BV and nutritional value, though it still does not reach the BV of whole egg or a good whey protein. In other words, some of the problems with whole soy are not an issue with soy protein isolate, which gives you the good part without some of the bad parts. While some studies have shown the phytonutrients in soy to affect hormones levels, others suggest they do not decrease testosterone or raise estrogen.

Though soy proteins contain these estrogenic compounds, it appears that they are "tissue specific. The study found no difference between male animals who ate soy protein that contained the plant estrogens and those who ate soy with the estrogens removed, leading researchers to conclude the isoflavones genistein and daidzein in soy protein have no apparent negative effects on the reproductive system.

From this and other data, it seems the phytoestrogens in soy don't, in fact, have systemic estrogenic effects, such as body fat increases. Soy protein has been found to raise thyroid output in a wide range of animals, from rats to pigs.

Studies done with human subjects have been harder to quantify what else is new? Soy protein has been shown to raise thyroid hormone output, which could be a real advantage to bodybuilders trying to shed some fat.

The intake of various high-quality proteins has been associated with higher levels of thyroid hormone, but soy appears to have thyroid hormone raising abilities unique from those of other proteins. Though some research has shown changes in the thyroid hormone triiodothyronine T-3 and thyroid stimulating hormone TSH , the real effect appears to be with thyroxine T-4 , which is elevated consistently in the studies done using animals—and to a lesser degree people—eating soy proteins.

At this time, exactly how soy proteins have this effect on thyroid output is not well understood, but they're working on it. So, what does soy's relation to thyroid hormones mean to bodybuilders?

Two points are the most relevant to strength athletes:. Soy has many other potential benefits that could make it a super-healthy addition to your supplement stack. How does soy compare to whey when it comes to maximizing your results in the gym? The short answer is they're similar, but different. Some studies have suggested soy to be as effective as whey, if not more so, in terms of its ability to promote gains in lean muscle mass.

National Dairy Council, found the post-workout consumption of an isonitrogenous and isoenergetic soy drink to be statistically significant in hastening mass, fat-bone free mass FBFM , and increases in strength, when compared to other post-workout formulations skim milk and maltodextrin beverage , both of which had a similar degree of efficacy. This study demonstrated that intact proteins from both soy and milk protein are effective in supporting muscle hypertrophy , lending a degree of support to soy as a legitimate post-workout nutritional beverage.

This study's method involved randomizing 34 subjects to milk, soy beverage, or maltodextrin beverage, using a double-blind allocation process. Participants trained 5 days per week on a whole-body split resistance-training program and consumed milliliters of their assigned drink, both immediately and 1 hour post-workout.

Another study that reinforces soy as an effective aid to muscle building, as well as showing its safety for testosterone levels, was presented in , and underwritten by the Solae Company which sold soy, but the dairy-sponsored study had similar results. The study found daily supplementation of soy protein, whey, or a soy-whey blend all resulted in an increase in lean body mass and did not negatively affect testosterone or estradiol levels in 20 male athletes engaging in a weight-training program.

For example, whey protein tends to be higher in leucine, isoleucine, methionine, and lysine Misner, In contrast, soy protein is higher than whey protein in arginine, phenylalanine, and tryptophan.

Because lysine has been associated with muscle growth and methionine with accelerated fat loss, many bodybuilders choose whey protein for its superior profile of these amino acids Robson, However, both soy and whey protein contain adequate amounts of essential and nonessential amino acids to support general health. Other dietary restrictions may determine whether soy or whey protein is best for you.

For example, whey protein comes from an animal source and is not appropriate for a vegan diet. In contrast, soy protein is vegan-friendly and can be a good way for vegans to ensure they get enough protein. Additionally, people who are lactose intolerant may need to carefully consider their protein options.

Soy protein does not contain lactose and is perfectly appropriate for people who are lactose intolerant. When it comes to whey protein, it depends on the form of protein you choose. Whey protein comes in three main forms: whey concentrates the least processed form , whey isolates, and whey hydro-isolates the most processed form Axe, Although whey concentrates have some lactose filtered out, they may still cause gastrointestinal problems for lactose intolerant people.

Whey isolates or hydro-isolates have been processed to remove lactose, making them more appropriate for lactose intolerant individuals. Protein is not the only consideration when choosing whey or soy powder. These powders also contain other nutrients that support your general health. For example, soy naturally contains B complex vitamin, vitamin E, zinc, iron, phosphorus, and potassium Robson, Whey protein also contains important vitamins and minerals, including calcium, iron, potassium, phosphorus, and magnesium.

The exact amounts of these nutrients varies by brand, making it important to check nutrition labels before you buy. Another nutrition consideration when evaluating whey versus soy protein is the phytoestrogen content in soy.

Soybeans naturally contain phytoestrogens, which mimic the activity of estradiol, the primary female sex hormone Robson, Historically, some people have been concerned that eating soy could increase levels of estrogen while decreasing testosterone levels.

However, more recent scientific research suggests that consumption of soy has no ill effects on hormone levels or general human health. In fact, consumption of soy protein has been shown to promote lean muscle growth while stimulating weight loss Robson, Thus, concerns about the phytoestrogen content in soy protein is not a strong reason to choose whey protein over soy alternatives. It may take some trial and error to determine the specific variety of soy or whey protein that works best for you.

Some people experience gas, bloating, or gastrointestinal problems after using certain types of protein. This may be a sign that your body is reacting poorly to some ingredient in the protein, but it does not mean that another brand of soy or whey protein will not work for you. Experiment with different types, flavors, and ingredient ratios when making protein shakes until you determine what works best for you. The following recipes utilize whey or hemp protein powder, though substitutions can be made.

It may take some slight experimentation to find the right amount of soy or whey powder to use for a substitution- but, once a balance is found, the results are sure to taste great! A delicious smoothie in a bowl, this recipe uses whey powder to fit the needs of those seeking a small meal that delivers a protein with more lysine than the powders derived from plant-based sources.

Ingredients: Frozen strawberries, almond milk, whey protein powder, acai powder, banana, fresh fruit toppings. Though this smoothie uses hemp powder as its protein source, you can ensure that this drink offers an adequate amount of all nine essential amino acids by substituting soy or whey protein powder.

Soy powder can even keep the drink vegan. Ingredients: Almond milk, frozen banana, spirulina, hemp protein powder optional , fresh mint, chia seeds, hemp hearts. Total Time: 5 minutes Yield: 2 servings. For a more robust list of protein powder and protein shake ingredients, be sure to check out our protein shakes page! For those that are seeking a powder for making more than basic beverages, this isolated protein powder offers the perfect powder to use in energy bars and other confections.

This variety of soy powder is less refined to offer 25 grams of protein with every ounce. Measure ad performance. Select basic ads. Create a personalised ads profile. Select personalised ads. Apply market research to generate audience insights. Measure content performance. Develop and improve products.

List of Partners vendors. The soya bean is a widely grown crop throughout the world. Its value is derived from its high protein content, which is higher than all other beans grown for human consumption. The soya bean is also a complete protein, which means it contains all of the essential amino acids EAA your body can't make itself and needs to obtain from food. Soy products are food staples in some parts of Asia, and soy protein is used extensively in manufactured products in many countries.

These products include soy milk, meat substitutes tofu, and fermented products miso, tempeh , and soy sauces. Bodybuilders and weight trainers like to take commercial protein supplement powders to support their training and, hopefully, build muscle. That hope is generally realized. According to the International Society of Sports Nutrition ISSN , which issued a review of the intake of protein for healthy exercisers in , results from many studies indicate that in both men and women protein supplementation exerts a small-to-modest impact on strength development.

And pooled results of multiple studies consistently indicate that protein supplementation—specifically 15 to 25 grams over four to 21 weeks—exerts a positive impact on performance.

Most protein powders are derived from either the milk proteins casein and whey, egg protein, or the extracted soy protein from soya beans. Soy protein is particularly well suited for vegetarians and vegans. Of course, there is great debate among purists on the best type of protein powder and also the best commercial brands for athletes and weight trainers. Many varied formulas of protein powder supplements exist.

Whether you actually need to take special protein powder supplements is another discussion, as some believe skim milk powder will do a satisfactory job at less cost. Of all the plant proteins, soy overwhelmingly has the most research. However, that research has shown that soy is considered a lower-quality complete protein when it comes to increasing muscle mass and strength gains, according to the ISSN report.

One key point from the report is that while soy is considered a complete protein, research shows that products containing animal- and dairy-based proteins contain the highest percentage of essential amino acids and result in greater gains following resistance training when compared to vegetarian proteins like soy. Soy contains lower amounts of "branched chain amino acids" BCAAs than cow milk as well. Of the three, leucine is one that's considered the switch that stimulates protein synthesis.

Research also finds that dietary soy phytoestrogens inhibit "mTOR expression," which regulates numerous components involved in protein synthesis, in skeletal muscle.

In short, not only does soy contain lower amounts of the EAAs and leucine, but it may also be responsible for inhibiting growth factors and protein synthesis.