Understanding the controversy around soy and isoflavone supplements: A guide to making informed choices for your health

Conflicting data from historical studies has left people uncertain about the safety and efficacy of dietary soy and soya isoflavone supplementation. This article aims to clarify the issue by examining the latest research, with particular focus on support during menopause transition. 

By Neil Bridgeman
Jul 31, 2023 • 5 min read

Understanding the Controversy Around Soy


Many women consider dietary soy and soy isoflavones supplements to alleviate menopause-related symptoms and improve overall health. However, conflicting data from historical studies has left people uncertain about their safety and efficacy. This article aims to clarify the issue by examining the properties of soy isoflavones and outlining their potential benefits and risks.


Soy Isoflavones: An Overview

Soybeans are rich in isoflavones, such as genistein and daidzein, which have a biochemical resemblance to beta-17-estradiol. These isoflavones preferentially bind to certain receptors in the body, mimicking the action of oestrogen, albeit to a lesser extent. Due to this oestrogen-like effect, both dietary soy and isoflavone supplements have been associated with potential benefits for menopause-related symptoms.


The Benefits of Dietary Soy in Reducing Menopause Symptoms

Hormonal Regulation: Soy isoflavones have a chemical structure similar to oestrogen, allowing them to bind to oestrogen receptors in the body. As women approach menopause, oestrogen levels fluctuate and decline, leading to various symptoms like hot flashes, night sweats, and mood swings. Soy isoflavones can partially mimic oestrogen’s action, helping to regulate hormonal fluctuations and alleviate menopausal symptoms.

Reduction in Hot Flashes and Night Sweats: Hot flashes and night sweats are a common symptom experienced during menopause. Studies have suggested that consuming dietary soy or soy isoflavone supplements may help reduce the frequency and severity of hot flashes and night sweats, leading to improved quality of life.

Bone Health: Menopause is associated with a decline in bone density, increasing the risk of osteoporosis and fractures. Soy isoflavones may have a protective effect on bone health by stimulating bone formation and inhibiting bone resorption. Regular consumption of dietary soy could contribute to better bone density and reduced risk of osteoporosis.

“Soybeans are rich in isoflavones, such as genistein and daidzein, which have a biochemical resemblance to beta-17-estradiol.”

Cardiovascular Health: During menopause, women’s cardiovascular health becomes a concern due to changes in lipid profiles and increased risk of heart disease. Soy isoflavones have been shown to have a positive impact on blood lipid levels by reducing LDL cholesterol (bad cholesterol) and increasing HDL cholesterol (good cholesterol), promoting heart health.

Improved Mood and Cognitive Function: Menopause can be accompanied by mood swings and cognitive changes, such as memory lapses and difficulty concentrating. Some studies have suggested that soy isoflavones might have a positive impact on mood and cognitive function, potentially alleviating these menopause-related symptoms.

Breast Health: Emerging research indicates that soy isoflavones may have a protective effect on breast tissue. While the relationship between soy and breast cancer risk remains controversial, some studies have suggested that soy consumption could be associated with a reduced risk of breast cancer. However, more research is needed in this area.

Reduced Menstrual Symptoms: For some women approaching menopause, their menstrual cycles become irregular and often accompanied by uncomfortable symptoms. Soy isoflavones may help regulate menstrual cycles and alleviate associated symptoms, providing relief during the transition to menopause.


Consulting Healthcare Professionals and Personalised Approaches

It’s important to note that individual responses to dietary soy and soy isoflavones may vary, and not all women experience the same level of benefits. Additionally, the optimal dosage and duration of soy consumption for symptom relief is still being studied. Before making any significant changes to diet or starting soy supplements, you should consult with a healthcare professional, especially if you have a history of breast cancer, hormone-sensitive cancers or other medical conditions.

How To Get More Soy Into Your Diet

Dietary soy foods are derived from soybeans and come in various forms, offering a wide range of options. Here are some examples of popular dietary soy foods:

  • Tofu: Also known as bean curd, tofu is one of the most well-known soy products. Tofu has a soft and spongy texture, making it versatile for use in both savory and sweet dishes. It can be grilled, stir-fried, added to soups, or used as a meat substitute in various recipes.
  • Soy Milk: Soy milk is a dairy-free alternative to cow’s milk, made by grinding soaked soybeans with water. It is creamy and nutritious and can be used in cooking, baking, or as a beverage on its own.
  • Edamame: Edamame refers to young, green soybeans that are harvested before they fully mature. These are commonly boiled or steamed and served as a nutritious and delicious snack. Edamame can also be added to salads, soups, and stir-fries.
  • Soy Yogurt: Similar to traditional dairy yogurt, soy yogurt is made by fermenting soy milk with live cultures. It provides a creamy and probiotic-rich alternative for individuals who are lactose intolerant or prefer plant-based options.
  • Tempeh: Tempeh is a traditional soy product made by fermenting cooked soybeans. The fermentation process results in a firm and nutty-textured cake that is rich in protein and probiotics. Tempeh can be sliced, marinated, and cooked in various dishes.
  • Miso: Miso is a fermented soybean paste that is commonly used in Japanese cuisine. It is made by fermenting soybeans with salt and a specific type of fungus called koji. Miso adds depth of flavour to soups, dressings, marinades, and sauces. Just be mindful of the high salt content, particularly if suffering with high blood pressure.
  • Soy Nuts: Soy nuts are roasted soybeans that offer a crunchy and protein-rich snack option. They can be flavoured with various seasonings and are a convenient on-the-go snack.
  • Soy-based ‘meat’ alternatives’: In recent years, soy-based ‘meat’ alternatives’ have become popular plant-based alternatives to traditional meat products. These products are often made with soy protein isolate and other plant-based ingredients to mimic the taste and texture of meat. Just watch for additives, colouring and preservatives. A handy hint: if you can’t pronounce an ingredient, it’s probably not worth consuming.

“Watch for additives, colouring and preservatives. A handy hint: if you can’t pronounce an ingredient, it’s probably not worth consuming”

Why You Should Opt For Organic Soy

Organic soy is often considered better than non-organic soy due to several factors that contribute to its overall quality, environmental impact, and potential health benefits. Here are some reasons why organic soy is preferred over non-organic soy:

  • No Synthetic Chemicals and Pesticides: Organic soy is grown without the use of synthetic fertilisers, pesticides, herbicides, or genetically modified organisms (GMOs). Instead, organic farmers use natural and sustainable methods to control pests and enhance soil fertility, reducing the exposure of both the environment and consumers to harmful chemicals.
  • Reduced Environmental Impact: Organic farming practices prioritise sustainability and environmental conservation. By avoiding the use of synthetic chemicals and promoting natural ecosystem balance, organic soy production has a lower impact on water quality, soil health, and overall biodiversity.
  • Non-GMO and Sustainable: Organic soy is non-GMO, meaning it has not been genetically modified to resist pests or increase yields. This maintains the natural genetic integrity of the crop and helps support sustainable agricultural practices.
  • Better for Soil Health: Organic farming practices emphasise soil health and fertility through techniques like crop rotation, cover cropping, and composting. These practices enrich the soil with essential nutrients, leading to improved soil structure and long-term sustainability.
  • No Antibiotics or Hormones: In organic soy farming, the use of antibiotics or growth hormones for livestock feed is prohibited. This ensures that the soybeans produced in organic systems are free from any residues of these substances.
  • Nutritional Content: While the nutritional content of organic and non-organic soy may not significantly differ, some studies suggest that organic soy may contain higher levels of certain nutrients, such as certain polyphenols and antioxidants.

So, hopefully you’ve gotten this inside track on how soy and soy isoflavones can benefit your health. However, while some studies have suggested potential benefits in managing menopausal symptoms and migraines, some conflicting evidence exists, particularly regarding reduced breast cancer risk and anyone with a history of hormone sensitive cancers should consult with their GP or healthcare practitioner before adding these foods or supplements into their diet. 


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