Whey protein powder has been the muscle-building weapon of choice of body builders, athletes and those wanting to supplement their protein intake for many years. However, recently a contender has arrived on the scene. Soy protein powder, which is often marketed toward vegans because it doesn’t contain animal products, is gaining popularity as an alternative to whey protein. But is soy protein powder really a smart choice for a health-conscious individual?
Let’s see how whey protein powder and soy protein powder compare in terms of their effectiveness…
Whey Protein Has a Higher Biological Value Than Soy Protein
Biological Value, or BV, is an index that indicates the digestibility and protein availability of a protein source. A whole egg has a BV of 100, which is because when the scale was introduced, it was thought that eggs were the most biologically available source of protein around.
However, modern whey protein powders have surpassed the digestibility and amino acid availability of eggs, with whey protein powders typically having an “off-the-scale” BV rating of 104. In contrast, soy protein concentrate has a BV of only 74.
The conclusion is clear: whey protein is easier to digest than soy protein, delivering a greater proportion of its essential amino acids to the cells in the body that need it most.
Whey Protein Has a Better Mix of Essential Amino Acids Than Soy Protein
Not all protein sources are the same. The trick to effectively building muscle and maintaining good health is to eat the correct proportions of the amino acids essential to human health.
In general, animal sources of protein, such as whey protein which is derived from milk, contain all the essential amino acids needed by humans, whereas vegetable sources such as beans or pulses contain only a subset of the essential amino acids. The soy manufacturing industry often describe soy as a “complete protein” – one that contains all the essential amino acids – but how accurate is that statement?
Although soy contains all of the essential amino acids, the ratios of the acids are far from ideal for the human body. Soy protein powder contains too high a proportion of isoleucine and nowhere near enough tryptophan, valine, or threonine to be useful as a muscle building aid. All natural grass-fed whey protein delivers the amino acids you need to help your body grow and maintain itself.
Soy Protein Could Have Dangerous Side Effects
Soy is a highly processed food. To make soy protein powder, manufacturers have to put soy beans through a lengthy and highly industrial process to extract their protein content.
Soy beans contain phytoestrogen a plant form of the female sex hormone estrogen. Men should not be taking in estrogen in their diets as it plays havoc with their hormones. Even for women, phytoestrogen can be harmful, a study published in the American Journal of Clinical Nutrition showed that eating just 60 grams of soy protein a day caused women to have longer menstrual cycles, a symptom that is often linked with damaged fertility.
Only by adding bacteria can soy be made digestible by humans. Even with the addition of bacteria, many people are allergic to soy products and experience unpleasant side effects after eating them.
Although people in Asia have been eating soy for centuries, it has never been a major part of their diets. All the evidence suggests that soy is not intended by nature to be relied upon by humans as a primary source of protein.