Let’s talk about soy isoflavones. Soybeans contain phytoestrogens called isoflavones. There are some who claim that these soy isoflavones act as the female sex hormone, estrogen, and potentially increase the risk of cancer (especially breast cancer), as well as reduce testosterone levels in men. But science, based on well-planned research studies, has yet to uphold any of these claims.
Soy is not only safe to eat, it is beneficial! Soy is one of the most researched foods and the bulk of research shows health benefits of soy consumption when eaten in moderation. There is a large amount of misinformation about the effects soy isoflavones have on health and we recommend the following articles for further details on the health effects consuming soy products:
What’s the deal with soy? Is it safe to eat or not? – Anya Todd, LD RD
Soy: What’s the Harm? – Jack Norris, RD
Soy Isoflavones and Estrogen – Ginny Messina, RD
Hexane is a known neurotoxic petrochemical solvent that is purified from crude oil. It is used to extract edible oils from seeds and soy protein isolates or texturized soy protein (TVP) from soybeans. The vast majority of soy protein ingredients in meat analogs have undergone hexane processing. You’ll see them listed on the label as soy protein isolate, soy protein concentrate, or textured vegetable protein. Classified as an air pollutant by the Environmental Protection Agency (EPA) and as a neurotoxin by the Centers for Disease Control and Prevention (CDC), exposure to high amounts of hexane carries risks:
Acute (short-term) inhalation exposure of humans to high levels of hexane causes central nervous system effects such as dizziness, giddiness, slight nausea, and headache. Chronic (long-term) exposure to hexane in air is associated with polyneuropathy- damage or disease affecting peripheral nerves in roughly the same areas on both sides of the body. Symptoms can include numbness in the extremities, muscular weakness, blurred vision, headache, and fatigue. (1)
But how much hexane, if any, remains in the food after processing and are consuming these trace amounts a health hazard? According to the University of California, probably not- but it’s hard to know for sure. Not only does the FDA not monitor hexane in foods, the US has yet to even set limits for allowable hexane residue levels in soy foods. The industry has stated that hexane is only used in the initial steps of soy processing, and virtually all of it is eliminated by the time the soy ingredients are incorporated into other products. Critics point to a study which found trace amounts of hexane in soy oil as evidence to avoid soy products.
This vegan dietitian says the occasional hexane-processed soy food is fine when consumed in moderation.
If you want to avoid hexane-treated soy foods, there are a couple of things you can do. Since hexane has been banned in organic food production, look for “100% organic” products that also contain the USDA seal. Keep in mind that this is different from a label that just says “made with organic” ingredients. You can also look for expeller-pressed or other physical extraction methods for oils that do not involve a solvent. (2) Tempeh is made from whole soybeans and typically does not undergo hexane processing. Check the label to be certain.
Genetically Modified Organisms (GMO)
A genetically modified organism (GMO) is any organism whose genetic material has been artificially manipulated in a laboratory using genetic engineering techniques. Scientists alter genes with DNA from different species of living organisms, bacteria, or viruses to get desired traits such as resistance to disease or tolerance of pesticides and herbicides.
There are criticisms about the practice surrounding the bioengineering and the production of genetically modified organisms. In more than 60 countries around the world, there are significant restrictions or outright bans on the production and sale of genetically modified organisms. Here in the US, the government has approved the use of GMOs based on information contained in studies conducted by the same corporations who created them (and profit from their sale). (3)
Learn more about GMOs at The Non GMO Project.
When looking at soy tempeh, unless the product is specifically labeled as GMO-free, then there’s a good chance the product was made with genetically modified organisms (GMOs). Look for organic products or products specifically labeled as using non-GMO ingredients.
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