Is Soy Good Or Bad For You?

Nutritionist Vasundhara Agrawal
Diet & Nutrition
Published in
5 min readApr 30, 2022

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Hey readers!! 🙋‍♀️ Here we are with another interesting topic for you all to read about. Most often we hear people talk about avoiding soy products for thyroid issues. When asked, many of my clients often tell me that they avoid soy products as they suffer from hypothyroidism or are at the fear of developing some diseases. However, there is no evidence-based research that supports that people with hypothyroidism must avoid soy completely.

What is soy and what does it contain?

Soybeans/ soya beans are scientifically known as glycine max which makes an important part of Asian cuisine. Soy products are available in different forms like soy flour, soy protein, tofu, soy milk, soy sauce, and soybean oil. Soybeans are very rich in proteins, an interesting fact is soy contains all the essential amino acids that your body needs. Besides these, they are also good sources of plant fats, fiber, vitamins, minerals, and various beneficial plant compounds. Isoflavones are the major flavonoids found in legumes, especially soybeans. Isoflavones are polyphenolic compounds that have an estrogenic activity which is why they are also known as phytoestrogens — plant-derived estrogens.

Nutritional facts (Macros) of 100 grams of boiled Soybeans —

Calories- 173; Carbs- 9.9 grams

Protein- 16.6 grams; Fats- 9 grams

Nutritional facts (Macros) of 100 grams of firm Tofu —

Calories- 144; Carbs- 3 grams

Proteins- 17 grams; Fats- 9 grams

Phytoestrogens when taken through diet mimic the activities of normal estrogen by binding to estrogen receptors in the body. Ever wondered what phytoestrogens do to our body?

Effects of phytoestrogens —

Savior in Menopause:

A drop in estrogen levels during some cycles of menstruation can cause uncomfortable symptoms which can be relieved by phytoestrogens. More research is needed to know how phytoestrogens can be included in the diet safely. Perimenopause is a stage that usually starts in the late 40s. During this period females stop making estrogen and other hormones and this can lead to a variety of symptoms like hot flashes, mood changes, and decreased libido. These symptoms might also continue after menopause. Studies have shown that phytoestrogens might reduce hot flashes and other menopause-related symptoms as they can mimic the activity of estrogens.

Prevents Osteoporosis:

Natural estrogens help maintain bone density, when women reach menopause where the estrogen activity is low can put them at the risk of developing bone-related disorders. Phytoestrogens act as estrogens and stop this from happening.

Acne Treatment:

Androgens — Male hormones are mainly responsible for acne. Estrogens can counter the activity of androgens and prevent acne. Because phytoestrogens have a similar activity they can stop acne but further research is required in this field.

Risk factors associated with consuming soy and soy-based products —

Soybeans and foods derived from soy have been a part of the human diet for centuries but some people worry about consuming soy products due to several reasons like weak estrogenic activity, and the risk associated with cancer, though most studies found no negative effect. They are believed to offer some protection against cancer. Men worry to consume soy as they are responsible to inhibit androgen functions. However, human studies have found no association between them. Antinutrients are present in some plant-based foods like legumes. They may reduce the body’s ability to absorb vitamins and minerals. Soaking, fermenting, sprouting, and cooking may reduce these anti-nutrient levels. Some compounds present in soy may interfere with thyroid gland function. But a safe and limited consumption has no negative effects on the consumption of soy and soy-based products in individuals with healthy thyroid function.

What are the compounds that interfere with thyroid function?

Two major isoflavones present in soy are genistein and daidzein. These (and flavonoids from other sources as well) inhibit the enzyme thyroid peroxidase, which is involved in thyroid hormone synthesis. These effects were completely reversed with the addition of a sufficient amount of iodine in the diet.

What do the studies say about this?

Several studies suggest that the individuals who have compromised thyroid function and/ or whose iodine intake is marginal, soy foods may increase the development of clinical hypothyroidism. Therefore, the literature says that it is important for soy food consumers to make sure their intake of iodine is adequate in the diet. It is majorly due to iodine deficiency that soy foods may cause any harm, but a healthy individual whose iodine intake is adequate need not avoid soy though suffering from hypothyroidism.

Hypothyroidism is treated with synthetic thyroid hormone, and soy has been known to interfere with this thyroid medication. But there is no strong evidence to prove that soy worsens hypothyroidism condition. It is considered safe to consume soy and soy-based products after four hours of taking the medication and moderate consumption is best for people with thyroid issues. However, it has no negative effects on healthy individuals. So it is a great substitute for red meat or for people on vegan diets to ensure maximum protein. So say bye to the fear of soy!

References:

https://www.healthline.com/nutrition/foods/soybeans

https://www.healthline.com/health/phytoestrogens

https://www.uspharmacist.com/article/focus-on-phytoestrogens

https://pubmed.ncbi.nlm.nih.gov/16571087/

https://www.mayoclinic.org/diseasesconditions/hypothyroidism/expertanswers/hyperthyroidism/faq-20058188

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Nutritionist Vasundhara Agrawal
Diet & Nutrition

Lifestyle Trainer & Nutrition Coach | I help you #livehealthy