Protein, an essential nutrient, plays a vital role in the formation of new enzymes, muscle tissue, and hormones within your body. It is present in every cell of the human body, highlighting the significance of consuming an ample amount in your diet to sustain proper bodily functions.
Dietary protein is broken down into amino acids which are then rearranged by the body to build protein molecules that are essential for performing different physiological processes.
To guarantee sufficient protein intake, it is highly recommended to consume protein shakes, which come in numerous types of powder, each possessing its own advantages and disadvantages.
Being aware of the distinctions between soy protein and whey protein enables you to select the most beneficial option for your body, as both are widely recognized types of protein.
Soy Protein and Whey Protein
Soybeans, being a kind of legume, have a natural high protein content and are relatively low in fat. To produce soy protein, soybeans are ground into a hull- and fat-free meal by manufacturers.
The soybean meal is further transformed into soy protein isolate, containing 90 to 95% protein, according to the Soyfoods Association of America (2013). Subsequently, the powdered form of this soy protein isolate is made available for sale.
One can utilize the soy protein powder for preparing a protein shake or to increase the protein content in different dishes.
Despite the inherent high protein and low carbohydrate content of soy protein isolate, numerous manufacturers enhance its flavor, consistency, and overall nutritional profile by incorporating supplementary nutrients.
Due to its naturally low carbohydrate content, soy protein is frequently combined with extra nutrients in order to enhance flavor, texture, and nutritional value.
Soy protein isolate is frequently utilized as a substitute for meat or a protein supplement by vegetarians and vegans in various processed foods and dietary supplements.
Soy protein isolate, which is a healthy alternative for certain individuals, is a comprehensive source of protein that encompasses all the necessary amino acids essential for proper bodily functioning. Furthermore, it is a low-fat and cholesterol-free option.
In contrast, whey protein is derived from cow’s milk, which has a natural protein content of approximately 3.5% and fat content of 4% (MyProtein, 2014).
Once the bacteria are eliminated through pasteurization, the milk undergoes the addition of specific enzymes to separate casein, the milk solids utilized in cheese production, from the whey.
After undergoing additional processing, this whey is stripped of carbohydrates, fats, and excessive water to result in a powder abundant in protein, which can then be utilized for creating protein shakes.
During the cheese-making process, whey protein isolate is created by eliminating most of the non-protein elements such as fats and carbohydrates from whey, which is the liquid segment of milk that separates.
Like soy protein isolate, this process produces a powder with a protein content of 90-95% (by weight).
Containing all the necessary amino acids required by the body for proper functioning, whey protein isolate is also considered a complete protein. Its composition is notably rich in branched chain amino acids (BCAAs), which play a vital role in muscle growth and recovery.
Athletes and bodybuilders often turn to whey protein isolate as a dietary supplement to enhance muscle growth and boost athletic performance. Additionally, whey protein isolate is favored for weight management due to its high protein content and low calorie count.
One can choose to consume it either as a shake or incorporate it into food and beverages. Moreover, it is commonly employed as a component in various processed foods and dietary supplements.
It should be emphasized that whey protein isolate is obtained from milk, and individuals who are lactose intolerant or have milk allergies should refrain from consuming it. Moreover, excessive intake of whey protein isolate may harm one’s health, therefore it is crucial to consume it in moderation.
Soy Protein Amino Acid Profile
Soy protein proves to be an excellent option for a well-balanced source of protein due to its exceptional amino acid profile.
Soy protein, rich in branched chain amino acids, can be easily utilized and converted into energy. Additionally, it is a good source of arginine, phenylamine, and tryptophan.
Arginine plays a crucial role as an amino acid within the body, frequently present at active sites in proteins and enzymes. It contributes to cardiovascular well-being, fights against fatigue, and triggers the immune system.
Phenylamine plays a vital role as an amino acid required by the body for protein synthesis and the production of significant molecules.
Supporting normal growth is an important function of tryptophan, which is an essential amino acid. Furthermore, tryptophan aids in the production and maintenance of proteins, muscles, enzymes, and neurotransmitters.
Whey Protein Amino Acid Profile
Whey protein comprises the greatest proportion of crucial amino acids including leucine, isoleucine, methionine, and lysine.
Leucine, an essential BCAA, plays a crucial role in protein synthesis and repairing muscles. Additionally, it aids in controlling blood sugar levels and promoting the production of growth hormones, which assist in healing.
Isoleucine, one of the BCAAs, plays a crucial role in muscle metabolism and is predominantly found in muscle tissue. Additionally, it is vital for maintaining immune function, regulating energy levels, and promoting hemoglobin production.
Methionine is essential for metabolism and the growth of healthy tissues, as well as facilitating the absorption of vital vitamins like zinc and selenium, which are necessary for maintaining overall health.
Lysine’s significance extends to protein synthesis, as well as being crucial for hormone and enzyme production, calcium absorption, and energy generation.
Building Muscle with Soy and Whey Protein
By using soy and whey protein powders at different times, one can optimize their effectiveness and provide support.
Soy Protein Benefits
Soy protein is preferable for consumption prior to and during exercise due to its lower capacity to generate ammonia, which is a major contributor to muscle fatigue.
Phytochemicals, found in soy protein, are thought to promote cardiovascular health and help prevent osteoporosis.
While soy protein does aid muscle synthesis and offers a rich source of BCAAs that can be easily converted into energy production, it may not be the optimal protein option for building muscle mass.
Soy protein falls in the middle range in terms of its effectiveness for muscle protein synthesis. According to a study conducted in 2009, soy protein was found to be less effective than whey protein in promoting muscle mass gains through protein synthesis.
When consuming soy, it is likely to be more advantageous if taken alongside other proteins such as rice protein, pea protein, or hemp protein.
Soy Protein Potential Drawbacks
Although soy protein has various advantages, there are a few notable concerns.
Phytates, also referred to as antinutrients, are present in soy protein and have been found to decrease the absorption of iron and zinc. It is important to note that unless you solely rely on soy food as your primary source of iron and zinc in an imbalanced diet, phytates should not have a negative impact on your overall health.
There is an added worry that soy might impact thyroid function due to isoflavones that can disturb thyroid hormone production and hinder iodine uptake in the thyroid gland. Nevertheless, research has revealed that soy has only a slight impact on thyroid function.
Due to its phytoestrogen content, like soy isoflavones, some consumers avoid consuming soy protein. Phytoestrogens are chemical compounds that possess properties similar to estrogen and can bind to estrogen receptors in the body. Consequently, these phytoestrogens have the potential to interfere with natural hormone levels.
Whey Protein Benefits
Arguably, whey protein is the most rapidly absorbed protein out of all protein sources, which makes it have the highest biological value (BV). The BV indicates the availability of a protein source after it is consumed.
For the past 50 years, whey protein has been considered the ultimate protein supplement, making it perfect for consumption after a workout. When it comes to building muscle, it may exceed all other types of protein powders.
After consumption, whey protein is quickly absorbed by the body due to its relatively fast absorption rate. It is easily digested and almost all of the whey protein consumed is absorbed.
Whey Protein Potential Drawbacks
Digestion is the main cause of the majority of adverse effects associated with whey protein.
Lactose is the primary carbohydrate found in whey protein. If a person is lactose intolerant, it means they don’t produce sufficient lactase, which is the enzyme necessary for breaking down lactose. The least processed form of whey, known as whey concentrate, tends to cause the most gastrointestinal discomfort. To alleviate the GI symptoms in individuals with lactose intolerance, it is recommended to switch to either whey isolate or whey hydro-isolate. These forms are more processed and contain less lactose, making them the preferred and suitable choice for those who are lactose intolerant.
Individuals who have an allergy to cow’s milk may also exhibit an allergic reaction to whey protein as it is an animal protein derived from cow’s milk. Nonetheless, cow milk allergies are uncommon in adults as the majority of people, around 90%, tend to outgrow them by the age of three.
Although some people claim to experience constipation after consuming whey protein powder, it is not a common side effect. However, individuals who are lactose intolerant may sometimes encounter constipation as a result of reduced gut motility.
Considerations When Choosing Between Soy and Whey Protein
When deciding between soy protein and whey protein, there are various factors to take into account. While these factors may vary depending on the brand, here are some general aspects to consider when selecting a particular type of protein powder.
Taste and Texture
Personal preference ultimately determines the taste and texture of soy protein compared to whey protein, with soy protein offering a more pronounced nutty flavor and slightly grainier texture, while whey protein possesses a smooth, somewhat creamy consistency and a mildly nutty taste.
Both come in different flavors and formulations. Some brands might contain additives or stabilizers to attain a smoother and more indulgent consistency. Experimenting with multiple brands prior to selecting one can assist in avoiding protein powder that has an unappealing texture resembling “chalk.”
Shelf Life
You can have peace of mind regarding the long shelf life of both soy and whey protein, even though they are derived from milk products.
According to Ketchiff (2015), the expiration date on a usual protein powder container is typically set for a year or longer in the future.
Using protein past its “sell by” date is unlikely to cause any negative health effects. While the taste of the product may decrease, the nutritional value and stability of the product are unlikely to be affected (Ketchiff, 2015).
Type of Protein
The amino acid profile is a crucial criterion to consider when assessing a protein powder product. The human body relies on 22 varieties of amino acids, with nine of them being essential and requiring intake from dietary sources as they cannot be produced internally.
Soy and whey protein are both considered “complete” proteins because they contain all nine essential amino acids. However, their relative concentrations of these amino acids vary slightly.
In comparison, whey protein generally has higher levels of leucine, isoleucine, methionine, and lysine, according to Misner (2015). On the other hand, soy protein surpasses whey protein when it comes to arginine, phenylalanine, and tryptophan.
Many bodybuilders opt for whey protein due to its superior profile of amino acids, with lysine being associated with muscle growth and methionine with accelerated fat loss (Robson, 2016).
Nonetheless, soy and whey protein both possess sufficient quantities of essential and nonessential amino acids required for promoting overall wellbeing.
Dietary Restrictions
Depending on any other dietary limitations you have, the choice between soy or whey protein may vary to suit your needs.
When considering a vegan diet, it is important to note that whey protein, sourced from animals, is unsuitable. Conversely, soy protein offers a vegan-friendly option, enabling vegans to adequately meet their protein requirements.
Moreover, individuals with lactose intolerance should carefully evaluate their choices for protein. Soy protein, which lacks lactose, is a suitable alternative for those unable to digest lactose.
The form of protein you choose when it comes to whey protein will determine its properties. Whey protein is available in three primary forms, namely whey concentrates (the least processed form), whey isolates, and whey hydro-isolates (the most processed form) (Axe, 2015).
Even though whey concentrates have had a portion of lactose removed, they can still lead to gastrointestinal issues in individuals who are lactose intolerant. On the other hand, whey isolates or hydro-isolates have undergone a process to eliminate lactose, rendering them more suitable for people with lactose intolerance.
Other Nutritional Considerations
When selecting whey or soy powder, protein is not the sole factor to consider. These powders also offer additional nutrients that contribute to overall well-being. For instance, soy contains B complex vitamin, vitamin E, zinc, iron, phosphorus, and potassium as natural components (Robson, 2016).
Before purchasing whey protein, it is essential to examine the nutrition labels as the quantities of vital vitamins and minerals like calcium, iron, potassium, phosphorus, and magnesium differ from brand to brand.
When comparing whey and soy protein, it is important to take into account the phytoestrogen content in soy. Soybeans naturally have phytoestrogens, which imitate the effects of estradiol, the main hormone in females (Robson, 2016).
In the past, there have been concerns among certain individuals about soy consumption potentially causing an increase in estrogen levels and a decrease in testosterone levels. However, recent scientific studies indicate that consuming soy does not have any negative impact on hormone levels or overall human health.
The presence of phytoestrogens in soy protein is not a compelling justification to favor whey protein over soy alternatives as studies have actually demonstrated that soy protein consumption promotes lean muscle development and aids in weight loss (Robson, 2016).
Personal Preference
When it comes to foods, there is no universal approach that suits everyone. Identifying the most suitable type of soy or whey protein for your needs may require some experimentation and testing.
Experiencing gas, bloating, or gastrointestinal issues after consuming specific protein types might indicate an unfavorable reaction towards certain ingredients within the protein. However, it does not imply that trying a different brand of soy or whey protein won’t be effective for you.
Keep trying out various kinds, tastes, and proportions of ingredients while preparing protein shakes until you find the optimal combination that suits you.
