Vegans often consume a variety of soy based products as an alternative to dairy and meat. While these products provide a high quality source of plant protein, there is mixed information provided in the media regarding the safety of soy based food products. Have you wondered lately about the safety of soy? For your own information (and peace of mind) let’s have a look at the most recent research related to soy products.
Let’s start with the positives:
Soy foods are recommended by several national dietary guidelines as part of a healthy diet and for use in vegetarian diets. One of the reason soy foods are recommended as part of a healthy diet is because they are a source of high quality protein, are highly digestible and most soy products are also free of saturated and trans fats, making them a heart healthy choice. Soy products are also a good source of available iron and calcium-a positive for vegans who require these nutrients from alternative sources.
So, what’s all the fuss about?
Concerns about the safety of soy are based largely on the content of isoflavones in soy protein and their estrogen-like properties.
Isoflavones are classified as phytoestrogens- and phytoestrogens may exert some estrogen-like-effects under specific conditions.
Isoflavones have also been classified as endocrine disruptors. Endocrine disruptors are substances in our environment, food and consumer products that may interfere with hormone metabolism, or action. Therefore, concerns have been raised in regards to the health related effects of isoflavones in individuals who may be sensitive to estrogen.
The amount of isoflavones found in soy products is highly dependent upon differences in growing and storage conditions, the plant part from which they are derived, and the processing method used. It is however estimated that each gram of soy protein in traditional soy foods provides about 3-4 mg isoflavones.
It’s very important to note that soy protein (and therefore isoflavones) may be hidden in a variety of the foods we eat. Soy protein is found in infant formulas, and is a major component of many processed foods including baked goods, breakfast cereals, pasta, beverages, toppings, and some meat products. Non-soy foods may also contribute to phytoestrogen intake-lignans (another type of isoflavone) are found in flax, fruits, vegetables, and beverages-like coffee and orange juice.
While the amount of isoflavones found in non-soy foods may be much less than that of soy based foods-soy based products are not the only source of phytoestrogens.
As of now, it is difficult to make an overall statement regarding the safety of soy products. More research is needed to confirm concerns related to the safety of soy based products, as most of the research studies that have been completed to date are either animal studies or have been completed in vitro.
So, what are the current recommendations?
Most recent guidelines suggest aiming for two to three servings of traditional soy foods (tofu, miso, natto, fermented soybeans, soybean paste, soy milk, tofu and edamame) per day.
Health Canada also recommends that caution is noted regarding the total amount of soy protein intake per day in individuals who have a history of hormonal or gynecological disease, liver disorder or are taking hormone replacement therapy or blood thinners.
This article is meant only to provide some up to date and evidence based information regarding soy products. Your concerns related to your intake of soy should be discussed with a Registered Dietitian.
Thanks for reading!
Practice Based Evidence in Nutrition (PEN). Functional Foods/Nutricuticals. Soy Background. Retrieved from: http://www.pennutrition.com.ezproxy.msvu.ca/KnowledgePathway.aspx?kpid=4407&trid=21755&trcatid=38
Practice Based Evidence in Nutrition (PEN). Soy Evidence Summary. Retrieved from: http://www.pennutrition.com.ezproxy.msvu.ca/KnowledgePathway.aspx?kpid=4407&trid=21935&trcatid=42