Soy has developed a bad reputation in recent years with some even going so far as to call the plant-based protein source unhealthy. In reality, however, soy has a variety of health benefits and should be enjoyed in a healthy, balanced diet. Before I share the health benefits of soy, I’d like to point out a few of the misinterpretations that have contributed to soy’s bad rep.

Not All Soy is GMO
In the United States, 90-95% of soy is a GMO food, [1,2]. However, most of this GMO soy is used as animal feed to cheaply speed up animal growth [3]. It’s then indirectly ingested by people consuming meat and milk. I only recommend Organic/Non-GMO Soy, which is free of the massive amounts of chemicals and pesticides used on the genetically modified crop. This is more than likely better for our health and certainly better for the planet.

Context is Key 
Studies demonstrating the dangerous effect of soy are incredibly misleading as they look at people consuming 12 servings of soy a day to achieve those results [4]. In reality, consuming most foods in such excess would be dangerous.

Image Source: thewoksoflife.com

The Estrogen Issue
The most common concerns I hear about soy are whether it causes breast cancer or ‘man boobs’ – both of which are linked to excess estrogen [5]. This is a huge misconception as soy doesn’t even contain estrogen, which is an animal hormone. Animal products actually contain estrogen in the form of estradiol [6].Soy contains plant hormones like isoflavones and phytoestrogens. Not only are they 1,000 times weaker than animal estrogen, but they have a range of health benefits including a lowered risk of heart disease, high cholesterol, breast cancer and menopausal symptoms [5].Other studies have found evidence linking soy consumption to reduced rates of prostate cancer, cardiovascular disease, obesity and type 2 diabetes [7,8].

Whilst soy has not been found to causebreast cancer, the science is less clear on how soy affects those already diagnosed with breast cancer. Some research suggests that soy, particularly processed soy in high doses, can have adverse effects on women with existing breast cancer. Until the science is settled, the Cancer Council recommends that women with breast cancer limit their soy consumption just to be safe [9]. The bottom line is that soy has not been shown to cause breast cancer.  When consumed in the right amounts, minimally processed, Non-GMO soy may even protect against many cancers and a range of illnesses.

THE BENEFITS OF SOY

Soy foods like tofu, tempeh, soy milk, miso and edamame are nutrition powerhouses and a great addition to a balanced diet. Soybeans are a good source of unsaturated fatty acids, folate, B and K Vitamins, fibre, iron, calcium, zinc, magnesium and potassium.

Soy products are also a great source of protein as they contain all the essential amino acids. Unlike animal protein, soy is low in saturated fat and rich in unsaturated fats. A 2018 study found that consuming 30g of soy each day “significantly improved a relevant set of biomarkers associated with cardiovascular risk[10]. That’s because replacing foods rich in saturated fat, like dairy and red meat, with those rich in polyunsaturated fat is proven to lower the risk of heart disease [11].

IS SOY BAD FOR OUR THYROID?

In healthy adults with no underlying thyroid-related conditions, there’s no compelling evidence suggesting soy will harm thyroid function. However, phytoestrogens in soy can have a potential effect on the endocrine system, so it’s best to consult with your GP if you have an existing thyroid problem like hypothyroidism or iodine deficiency. If you do take medication for a thyroid condition, just be sure you don’t eat soy within an hour before or after taking your medication as soy can reduce absorption.

SIMON’S TOP TIPS FOR CHOOSING THE RIGHT SOY PRODUCTS

So, after we’ve debunked the idea that soy is unhealthy, you might be wondering how to best incorporate soy into your diet.

1- Choose Organic, Non-GMO soy products as they have the least amount of processing and artificial ingredients. Highly processed soy products are higher in phytoestrogens and are the most likely to have an effect on the endocrine system. That’s why I don’t recommend consuming soy protein powders and only use pea protein isolate in the Eimele range.

Image Source: pureella.com

2 – As your main source of soy, choose Edamame and Tempeh, which are minimally processed and true nutrient powerhouses. Tempeh also contains probiotics that help with overall gut health. Whilst tofu is popular, it’s moderately processed. Tofu is fine to eat occasionally though as it’s still far healthier than animal protein sources.

3 – Choose organic soy milk with no added sugars, preservatives, or artificial additives. As a general rule, brands with the shortest shelf life typically contain fewer preservatives and have likely not been packaged under immense heat, which inevitably kills off many nutrients.

4 – Miso soup is another healthy soy-based food that you might want to add to your diet. Whilst miso soup is high in sodium, research has shown that there appears to be a balancing effect between miso and sodium when eaten together, resulting in no reported negative effects. One study even found that miso can protect against stroke despite its high salt content [12].

I hope this post cleared up some of the confusion around soy and debunked its bad reputation. I think it’s pretty amazing that a food that gets so much ‘hate’ is actually a nutrition powerhouse and should be incorporated in a healthy, balanced diet.

Featured Image Source: ethical kitchen.net

References:

[1]   Dupont V. GMO corn, soybeans dominate US market. Phys.org 2013. https://phys.org/news/2013-06-gmo-corn-soybeans-dominate.html(accessed July 22, 2019).
[2]   Schütte G, Eckerstorfer M, Rastelli V, Reichenbecher W, Restrepo-Vassalli S, Ruohonen-Lehto M, et al. Herbicide resistance and biodiversity: agronomic and environmental aspects of genetically modified herbicide-resistant plants. Environmental Sciences Europe 2017;29. doi:10.1186/s12302-016-0100-y.
[3]   [No title] n.d. https://www.usda.gov/sites/default/files/documents/coexistence-soybeans-factsheet.pdf(accessed July 22, 2019).
[4]   pubmeddev, and Lewi M. An unusual case of gynecomastia associated with soy product consumption. – PubMed – NCBI n.d. https://www.ncbi.nlm.nih.gov/pubmed/18558591 (accessed July 22, 2019).
[5]   Ruth C Travis TJK. Oestrogen exposure and breast cancer risk. Breast Cancer Res 2003;5:239.
[6]   Hassan MALEKINEJAD AR. Hormones in Dairy Foods and Their Impact on Public Health – A Narrative Review Article. Iran J Public Health 2015;44:742.
[7]   Heather B. Patisaul WJ. The pros and cons of phytoestrogens. Front Neuroendocrinol 2010;31:400.
[8]   pubmeddev, Adlercreutz H And Mazur. Phyto-oestrogens and Western diseases. – PubMed – NCBI n.d. https://www.ncbi.nlm.nih.gov/pubmed/9187225/(accessed July 22, 2019).
[9]   [No title] n.d. https://www.cancer.org.au/content/pdf/CancerControlPolicy/PositionStatements/PS_Soy_phyto-oestrogens_and_cancer_September_2006_update_August_2009.pdf(accessed July 22, 2019).
[10]Website n.d. https://www.ncbi.nlm.nih.gov/pubmed/27757595(accessed July 22, 2019).
[11]Briggs MA, Petersen KS, Kris-Etherton PM. Saturated Fatty Acids and Cardiovascular Disease: Replacements for Saturated Fat to Reduce Cardiovascular Risk. Healthc Pap 2017;5. doi:10.3390/healthcare5020029.
[12]pubmeddev, Watanabe H E al. Protective Effects of Japanese Soybean Paste (Miso) on Stroke in Stroke-Prone Spontaneously Hypertensive Rats (SHRSP). – PubMed – NCBI n.d. https://www.ncbi.nlm.nih.gov/pubmed/28985324 (accessed July 22, 2019).