As plant-based alternatives to animal products continue to rise sharply in popularity more and more companies are expanding their vegan product range and sales figures are steadily increasing. Soy foods have long been prized among vegetarians for both their high protein content and versatility and have been consumed for centuries and researched extensively. Yet there are various concerns regarding the sustainability as well as the health benefits of soybeans. What are the latest developments in making the cultivation of soybeans more sustainable? Which technological properties make soybeans a valuable ingredient for plant-based foods? How do phytoestrogens affect health? Is soy safe for children's diet? This article gives an overview about the science of soy as a healthy and sustainable ingredient of plant-based food.
In recent years, people have become increasingly aware of health and what they eat - and in addition, the COVID-19 pandemic has led to a surge in the awareness of the link between food, health, and sustainability, leading to a growth in the demand for plant-based foods. Soy is dominating this market, but debates have raged for decades over whether is soy healthy or not.
So, what’s in a bean?
Soybeans are technically classified as legumes - grown for their edible bean. However, the nutritional profile of soybean is much different than most others in the legume family: soy is considered a complete protein since it contains all of the essential amino acids our body needs for cell metabolism, building and repairing tissues, and providing energy. Soybean contains about 48 to 50% proteins. The main types of protein in soybeans are glycinin and conglycinin, which make up approximately 80% of the total protein content. The PDCAA score - a measure of protein quality, for soybeans is just below 1.0, with soy protein isolate at 1.0. As 1.0 is the highest score a protein can get, soy ranks right up there with milk and egg proteins. In addition to its high protein content, soy is a source of fiber, polyunsaturated fats, vitamins, and minerals.
Soy in our diets
From soya milk, soya sauce, protein isolate, and miso to tempeh, tofu, soy-based foods are no longer just a mainstay of Asian diets but are now staples in supermarkets around the world. Soy foods are relied upon by people following plant-based diets, not only for their health benefits but also for ethical and environmental reasons. Various research studies have shown that that soy has either a beneficial or neutral effect on various health conditions such as heart diseases, cognitive functions, etc. We know that protein is more satiating than carbohydrates and fat, and higher protein diets seem to be important for healthy body composition, and soy protein seems to be as effective as other proteins in this regard. Research also shows that the consumption of soy products during the day can help to control hunger and can be an effective way of weight management.
What’s all the fuss about soy?
The Nutritional fuss: The proponents of soy claim that consuming soy can decrease one’s risk of heart disease, diabetes, and hormonal cancers (like breast cancer) whereas the detractors claim that consuming soy increases one’s risk of developing breast cancer, thyroid diseases, and fertility problems in both men and women.
Both arguments come down to a component of soy called “isoflavones” which are a class of phytoestrogens — a group of naturally occurring, nonsteroidal plant compounds that are structurally similar to the hormone estrogen. Therein lies the controversy: Do isoflavones have estrogenic effects, and if they do, are those effects good or bad for us? When a person eats plant-based foods that contain phytoestrogens, they may have a similar effect to estrogen produced by the body. For this reason, phytoestrogens are known as dietary estrogens. One 2018 study that looked at nearly 2,000 adults in the Mediterranean area found a possible link between dietary phytoestrogens and a reduced risk of hypertension. Another 2018 study found that the risk of type 2 diabetes was reduced in women who took phytoestrogens.
The Sustainability fuss: Today, soy is cultivated on a global scale, and the production is doubled over the last two decades with the US and South America dominating the production. According to data from Statista, 362 million metric tons of soybean are produced globally in 2020/21. The US, Brazil, and Argentina produce about 80% of all soy in the world. There has been some criticism about the destruction of forests and the cultivation of soy on such a large scale, but 80-90% of soy production is used to feed livestock. As it is an economical source of feed due to the subsidies given to soy cultivation, thereby making soy cultivation a sustainable ingredient. Only 6% is made to feed humans, then the leftover that’s produced is made to biofuel as well. If soy production were directly consumed by humans, rather than indirectly through the livestock that people eat, it would reduce the land requirements of cultivation by 94%.
With increasing changes in the way we eat, the global population growth, and consumers are looking to incorporate more protein into their diets, thereby causing a shift in consumption patterns. Scientific research continues to explore the value of soy as a healthy, sustainable source of protein to meet future protein demand.
This article was written by Bhargavi Arvind, Editor at NUTRITION HUB.
