Soy Much to Love: The Tiny Bean with Big Health Benefits!
Soy is one of my favorite ingredients and one of the new additions in my garden this year. Even though many people enjoy soy products, others are not convinced. Because I love it and to help clear up some of its misconceptions, this article focuses on soy.
Soy is a versatile and nutrient-dense ingredient that is popular in diets worldwide. With its wide range of culinary uses and health benefits, soy products, such as tempeh, edamame, and soy milk, are praised for their health-promoting qualities, nutritional value, and sustainability.
In China and South East Asia, soybeans have enjoyed great culinary significance and tradition. Historically, people in that part of the world ate whole soybeans and it was regarded by the less affluent people of that region as “the meat without bones” and “the meat of the field1.”
In contrast, in Western nations, food manufacturers have used isolated soy ingredients and more highly processed soy products instead of the whole bean. In this part of the world, given that soybeans have a lengthy history of being used as a commodity and product suited for animal feed, some individuals might see them more as a novelty, or not even consider them suitable for human consumption.
Soybeans belong to the legume family, meaning they are related to other beans, as well as lentils, peas, and peanuts. Compared to other legumes, whole soybeans offer higher protein per serving. They also provide a variety of vitamins and minerals such as potassium, calcium, magnesium, and vitamin C. While soybeans are relatively low in fiber when compared to other legume species, isoflavones can be found in abundance. These substances are responsible for many of soy’s health-promoting qualities1.
Why soy much conflicting information?
It can seem like there are two opposing schools of thought when it comes to soy consumption. On the one hand, some promote soy as a health food, claiming it helps prevent cancer, heart disease, and bone loss. However, some people steer clear of soy out of concern that it could cause thyroid issues and breast cancer.
Let’s examine this confusion more closely, shall we?
One main reason for this contradictory information has to do with the metabolism of the isoflavones in soy. Scientists used rodents in many of the early investigations and studies on the effects of soy. Even though rodents, like rats and mice, are frequently the research subjects in medical studies, the outcomes, in this instance, do not correlate to those outcomes seen in humans. This is because rodents metabolize isoflavones differently than humans.
To understand this concept, it is essential to illustrate the process of soy metabolism in humans. When we consume soy, isoflavones are ingested as glycosides (attached to sugar molecules). In the small intestine, enzymes and gut bacteria hydrolyze these glycosides, removing the sugar portion and converting them into aglycones–the active isoflavone forms (genistein, daidzein, and glycitein). In the liver, isoflavones undergo phase II metabolism, where they are conjugated with glucuronic acid or sulfate to increase their solubility in water. This helps in their circulation in the blood and eventual excretion. Conjugated isoflavones can interact with estrogen receptors as they circulate throughout the body. Because of their structural similarity to estrogen, they can either mimic or block estrogen’s effects, depending on the tissue type. When isoflavones reach the large intestine, gut bacteria continue to break them down into secondary metabolites. It’s crucial to remember that rats and mice cannot perform the previously mentioned phase II metabolism in contrast to humans. As a result, their systems may contain up to 150 times more unconjugated isoflavones than humans, which may lead to greater tumor growth2. Essentially, all of this indicates that research done on animals might not provide findings that apply to humans.
Now that we’ve cleared up some of the confusion and differing opinions about soy, let’s examine some of its specific benefits.
Preventing bone loss
Osteoporosis is a condition that leads to reduced bone mineral density and weakened bones, allowing them to fracture more easily. It is partially caused by decreased estrogen secretion due to aging and a reduced ability to absorb minerals in the intestinal tract. Several studies have demonstrated that consuming soy isoflavones through diet can improve bone mineral density. Based on the results of these studies, soy isoflavones may help reduce bone loss and prevent or treat osteoporosis3.
Cancer risk reduction
The connection between soy and cancer risk has been well studied. Consuming soy has been linked to a lower chance of developing some cancers, especially those that are hormone-related and affect the breast and prostate. The isoflavones in soy, which are plant phytoestrogens, can attach to estrogen receptors in the body and potentially counteract the stronger effects of natural estrogen. According to a recent analysis of eight research studies, soy consumption and, therefore, isoflavone intake improves the prognosis and lessens the risk of breast cancer4. Women who consume large amounts of soy and isoflavones are less likely to be diagnosed with breast cancer than women whose diets do not include soy. Furthermore, a study found a correlation between higher soy consumption in youth and adulthood and a lower risk of premenopausal breast cancer5. This suggests that a regular soy intake, especially when started at an early age, may help reduce the incidence of cancer.
Cardiovascular disease
Researchers have also studied the relationship between soy consumption and cardiovascular disease—specifically, blood pressure, cholesterol, and inflammation. It has been demonstrated that isoflavones boost the body’s nitric oxide production, resulting in increased artery diameter or vasodilation, which lowers blood pressure. Potential pathways for soy’s effects in connection to elevated cholesterol include inhibiting intestinal cholesterol absorption and improving its elimination. Lastly, the isoflavones in soy reduce inflammation by preventing the creation of inflammatory substances and genes within the body6.
Now that we’re clear on the reasons to incorporate soy for your overall health, let’s discuss practical ways to include soy in your diet.
- Grow soybeans, or edamame, yourself at home. Edamame is not commonly grown in home gardens but has been gaining popularity in recent years. It’s a low-maintenance crop, similar to bush beans. It can be planted in garden beds or large pots and is best planted in late spring. After 10-12 weeks, the beans will be ready to harvest7. Soy cannot be consumed raw but must be cooked to improve digestibility. Soybeans can be quickly steamed and eaten straight out of the pod! They have a sweet, nutty, creamy flavor and are protein rich.
- When choosing a plant milk, make it soy milk. Soymilk has the most protein per gram compared to all other plant milks. This is especially important for children and seniors who typically need slightly higher intakes of protein. Other plant milk does not provide adequate protein to serve as the primary milk for toddlers. In addition, make sure the soymilk is fortified. This means it has added calcium, vitamin D, and vitamin B12. Once again, this can be especially important for children’s growth and development and keeping bones strong in seniors8,9.
- Soy comes in many forms and is versatile in many recipes. For example, whole soybeans can be consumed straight out of the pod or, once shelled, can be incorporated into salads or Buddha bowls. Tofu and tempeh can also be used in many ways and integrated into various recipes. A couple of my favorite recipes are included below.
Edamame Mango Salad – Running on Real Food
Baked Tofu Slices (Chick-it Seasoning – for Baked Tofu Slices)
In conclusion, soy is a healthful, delicious, and versatile ingredient to include in your diet. Other cultures have consumed it for thousands of years. Despite some initial controversy, it has been shown that soy has a plethora of benefits and is a healthful addition to any diet.
1.) Reinwald S, Akabas SR, Weaver CM. Whole versus the piecemeal approach to evaluating soy. J Nutr. 2010 Dec;140(12):2335S-2343S. doi: 10.3945/jn.110.124925. Epub 2010 Oct 27. PMID: 20980652.
2.) Setchell KD, Brown NM, Zhao X, Lindley SL, Heubi JE, King EC, Messina MJ. Soy isoflavone phase II metabolism differs between rodents and humans: implications for the effect on breast cancer risk. Am J Clin Nutr. 2011 Nov;94(5):1284-94. doi: 10.3945/ajcn.111.019638. Epub 2011 Sep 28. PMID: 21955647; PMCID: PMC3192476.
3.) Arjmandi, B. H., & Smith, B. J. (2002). Soy isoflavones’ osteoprotective role in postmenopausal women: Mechanism of action. The Journal of Nutritional Biochemistry, 13(3), 130–137. https://doi.org/10.1016/s0955-2863(02)00172-9
4.) Boutas I, Kontogeorgi A, Dimitrakakis C, Kalantaridou SN. Soy Isoflavones and Breast Cancer Risk: A Meta-analysis. In Vivo. 2022 Mar-Apr;36(2):556-562. doi: 10.21873/invivo.12737. PMID: 35241506; PMCID: PMC8931889.
5.) Baglia ML, Zheng W, Li H, Yang G, Gao J, Gao YT, Shu XO. The association of soy food consumption with the risk of subtype of breast cancers defined by hormone receptor and HER2 status. Int J Cancer. 2016 Aug 15;139(4):742-8. doi: 10.1002/ijc.30117. Epub 2016 May 5. PMID: 27038352; PMCID: PMC5114023.
6.) Ramdath DD, Padhi EM, Sarfaraz S, Renwick S, Duncan AM. Beyond the Cholesterol-Lowering Effect of Soy Protein: A Review of the Effects of Dietary Soy and Its Constituents on Risk Factors for Cardiovascular Disease. Nutrients. 2017 Mar 24;9(4):324. doi: 10.3390/nu9040324. PMID: 28338639; PMCID: PMC5409663.
7.) Boeckmann, C. (2024, March 9). How to grow edamame: The Complete Guide. Almanac.com. https://www.almanac.com/plant/edamame
8.) Davis, B., Melina, V., & Davis, C. (2023). Infants and Toddlers. In Plant Powered Protein (pp. 73–78). Healthy Living Publications.
9.) Davis, B., Melina, V., & Davis, C. (2023). Energetic Elders. In Plant Powered Protein (pp. 95-100). Healthy Living Publications.
