Soy products have received much attention over recent years – some of which has had the result of scaring people away from what others deem to be a super-food with amazing benefits to the human body.

In this article, we aim to look into soy’s potential benefits and controversies as well as some of the alternative products that you may try if you wish to follow a diet that helps you to reach and maintain your health and athletic goals.

What is soy protein?

Soy protein is the protein that has been isolated from the soya bean, a legume which goes through a process to take away the hulls and fat and is then ground into a powder. This is the processed into an isolate, which contains around 90-95% protein.

You can find it in many different foods, including tofu, soya milk, tempeh and miso – as well as a refined ingredient in literally thousands of foods as well as supplements, especially in the West.

It has been used as a source of nutrition for thousands of years, mainly in the Far East, where it was cultivated as a food crop, before becoming popular centuries later in the Americas and then Europe.

In the West, however, the history of soya consumption is a surprisingly short one. It only became a popular alternative protein source in the late 1990’s, as awareness of its health benefits increased.

So, before we address some of the concerns about the consumption of soy protein, what are some of the main reasons that should lead you to consider adding more soy products to your diet?  

Here are a few of the main benefits:

• It has a full amino acid profile

Soya is a complete protein, which means that it contains all nine of the essential amino acids that are needed in human nutrition. This is something that is especially important if you are using soya as one of your main sources of protein.

And while the amount of each of these amino acids varies in comparison to other protein sources such as whey, both types are considered to be excellent to help with muscle repair and growth.

• Soy is highly digestible

The issue of digestibility is worth considering, as it determines how much of the food you are eating is actually digested and thereby used by the body.

There are a number of ways to measure this digestibility, one of the most popular being the Protein Digestibility-Corrected Amino Acid Score (PDCAA). This is perceived to be one of the most accurate ways to benchmark each food type and gives you an idea of its potential as a dietary aide for sports performance.

Soy protein has the highest score of 1.0, which means that it is comparable to other, animal sources of protein such a whey and egg protein.

By way of another measure, Soy protein isolate has between 93-97% digestibility, which is another indicator of its comparable effectiveness to animal-based products as a sports supplement.

• Soy protein has a broad range of vital nutrients

We have already established that soy is an excellent protein source, but what about the other nutritional benefits?

Soybeans are complete with a range of minerals and vitamins, including manganese, copper, selenium, potassium, phosphorus, magnesium, iron, calcium Vitamin B6, Folate, Riboflavin, Thiamin and Vitamin K.  

• It is extremely low in fat

Soy protein is very low in saturated fat and cholesterol, with around 3-4g of fat per 100g, most of which is polyunsaturated (the type that is good for brain function and cell growth). This means that those on low-fat dietary regimes will be able to use soy protein without fear of exceeding their daily calorie count.

• It may reduce the risk of Coronary Heart Disease (CHD)

This is one of the main benefits of introducing soy products into your daily dietary regime. Countless studies have linked the consumption of soy to a lowering of the ‘bad; LDL cholesterol, which in turn, may lead to a reduction in the risk of contracting this disease.

• Soy is great at regulating blood pressure

Randomised, double-blind, controlled trials (the most unbiased and credible in other words), have shown that soy supplementation resulted in the reduction in systolic and diastolic blood pressure. This in may play a significant role in the reduction and prevention of hypertension.

So why is soy so controversial?

For all of the benefits shown above, soy is one of the most controversial foods on the planet.

The main reasons for the uncertainty may be reduced to three main factors – how the food is produced, how it is processed and finally its effects on the human body.

• Soybean production

The vast majority of soy grown in the US is genetically modified (GM). And while may argue that there is limited evidence to show the long-term effects of GM food on humans, there have been studies on other animals that show worrying developments. For example, tests on hamsters found that, after exposure to soy products, there were worryingly high incidences of infant mortality and sterility.

• Soybean processing

Much of the research that points towards the dangers of soy are actually focussed on soy protein isolates and not soy in its purest form, such as tofu, tempeh or whole soya beans.

This is an important distinction because it is the actual processing of the beans and the resulting isolate that grabs much of this controversy.

When soybeans are processed, they are defatted and dehulled. This process is usually carried out by using a liquid solvent, called Hexane, a chemical which is known to be toxic to the human nervous system, as well as causing liver enlargement in rodents. The chemical is also a carcinogen, which must raise concerns, even if the majority of the residues are washed away after the processing is complete.

• The effect of soy on the human body

Soy is pretty unique in that it contains high concentrations of isoflavones, which are plant estrogens that have a similar function to human estrogen, albeit to a much lesser degree.

Estrogen is vital to human health and is involved in human reproduction, metabolism, bone and blood health and sexual desire, and other important processes.

The isoflavones in soy bind to the human estrogen receptors in the body and can have an estrogen-like mimicking effect, the effects of which are the subject of the controversy.

While there is some evidence that too much excess soy can lead to reduced estrogen activity, most of the research shows that daily consumption has no adverse impact on fertility or hormones such as testosterone.

The alternatives to soy protein

While there are many benefits to the consumption of soy products, there is much to be said about the policy of ‘everything in moderation.’

As a committed vegan, vegetarian, or even somebody who may want to reduce their consumption of animal products for health, ethical or environmental reasons, using soy products as your go-to means of increasing your daily protein intake may not be the best policy.

The effects of soy products on the human body may be benign when consuming in moderate amounts (around three servings per day), but why take the chance of pushing your intake above the potentially healthy levels?

If you wish to increase the amount of protein that you consume each day, whether, for sports-related or health reasons, there are plenty of good, wholesome, plant-based alternatives that you may consider, including:

• Rice and pea proteins

Rice and pea protein, when combined, contain high levels of all the necessary amino acids that you need to help you recover and grow after a workout. And now, as opposed to just being able to purchase the flavourless versions, many protein supplements with rice and pea are blended, together with natural sweeteners, digestive enzymes and other superfoods to make them irresistible and effective.

• Hemp protein

Another alternative to soy protein that contains all of the essential amino acids. Protein digestibility is a little lower than soy, meaning that you may need to up the amount that you consume to hit your macro targets, however, this is still a great post-workout choice. Buy it in its natural, flavourless state and simply add your own sweeteners such as agave or a spoon of molasses.

• Lentils

With around 9 grams of protein per 100g, lentils are a great food choice to add to your diet, They are also super-nutritious, containing several nutrients, including fibre, folate, iron, potassium, phosphorus and calcium. Combine with rice to ensure you get the full range of amino acids and maximise its effectiveness as a post-workout meal.

• Seitan

Made from wheat gluten and with up to 60 % protein, seitan is not only super-effective as a post-workout meal but is also packed with minerals, while being low in fat and carbohydrates.

Seitan is also really easy to make and therefore a real cost-effective addition to your dietary regime.

Summary

We have seen that there are many benefits to the inclusion of soy protein or soy products into your diet.

While there are some controversies around the manufacturing of soy, especially in the US, there also many types of soy products that are not sourced from the potentially controversial genetically modified or chemically treated batches.

Level of soy consumption to meet daily protein needs can be offset by the inclusion of other plant-based protein sources, such as pea, rice or wheat gluten. This would allow you to enjoy the potential benefits of soy consumption, without the risk of any potential adverse side effects.

The jury really is out as to the long-term effects of consuming soy in excess, but then that is probably also the case for many other food products, such as seitan, or even certain fruits and vegetables.

Enjoy soy products such as tofu, tempeh and soy milk once or twice a day and you’ll not only be much closer to your daily macro target for protein consumption, but you’ll also enjoy the potential benefits shown earlier.

Once again the key is, as with everything in life, take in moderation and never in excess.

What are your thoughts?