Soy is a heavily debated food. Is it a healthy addition to your diet? Or is destroying your health? Doing a search on Google will throw up strong opinions on both sides, enough to leave you completely confused as to what to believe, and indeed what to eat.
Trying to decipher the research can also be confusing. Many of the research papers I found claiming Soy had no effect or even reduced the risk of breast cancer in women made huge speculative claims. Going into more depth about these papers is out of the scope of this post, but it does make you wonder about the motivation behind such research (or indeed the interpretation) in an industry worth $4 billion (according to the Soyfoods Association of North America) that is increasingly coming under attack. As we will see, there are many experts willing to stand up and fight against an industry they feel is misleading consumers. But who is right?
What is soy?
Soy started out as a legume that was rotated with other annual crops throughout Asia. Soy can fix nitrogen, so it was used as a green manure. It was initially grown as a cover crop, not a food. Soy is actually inedible for humans without a substantial amount of processing. This in itself leads to a host of problems, as summarised by the Weston A Price Foundation;
1. Free glutamic acid, (MSG), a potent neurotoxin, is formed during soy food processing. It is often added to many soy foods as well, just for good measure.
2. Proteins are denatured during the high temperature processing that is required to make soy protein isolate and textured vegetable protein. Denatured proteins, you will unsurprised to find out, are not that helpful.
3. The processing of soy protein results in the formation of toxic lysinoalanine and highly carcinogenic nitrosamines. Lovely.
4. Soy foods contain high levels of aluminium which is toxic to the nervous system and the kidneys. Soybeans are processed (by acid washing) in aluminium tanks, which can leach high levels of aluminium into the final soy product. These toxins may not build up in the body (read my blog post on The Detox Myth here), but they can sure as hell do damage on the way through.
Soy also contains;
• High levels of phytic acid, reducing the assimilation of calcium, magnesium, copper, iron and zinc. Phytic acid in soy is not neutralized by ordinary preparation methods such as soaking, sprouting and long, slow cooking. High phytate diets have caused growth problems in children. Even more worrying, when you think of how many soy based baby formulas are on the market.
• High levels of goitrogens: Substances that suppress the function of the thyroid gland by interfering with iodine uptake, which can, as a result, cause an enlargement of the thyroid and associated problems.
• Trypsin inhibitors. Trypsin is a digestive enzyme produced in the pancreas. Trypsin inhibitors can interfere with protein digestion and lead to pancreatic disorders.
• Phytoestrogens: They lock onto estrogen receptors in the body, blocking true estrogen and other hormones. They can also disrupt the body’s production of estrogen. They have the potential to cause infertility and to promote breast cancer in adult women, although this is a heavily debated topic.
Some experts are convinced of the dangers of soy. The problem they face is getting the message out against the backdrop of a billion pound industry.
“Drinking even two glasses of soymilk daily for one month provides enough isoflavone compounds to alter your menstrual cycle. Although the FDA regulates estrogen-containing products, no warnings exist on soy”. – Dr Mercola.com
“Today’s high-tech processing methods not only fail to remove the anti-nutrients and toxins that are naturally present in soybeans but leave toxic and carcinogenic residues created by the high temperatures, high pressure, alkali and acid baths and petroleum solvents.” Dr. Kaayla Daniel, author of The Whole Soy Story.
“This is what you are eating when you eat soy: an industrial waste product. Soy as it grows in the field is not actually a low-fat paragon. It’s about 30 percent fat. Once upon a time it was grown for its oil–not because people ate it, but because it was used for paint and glue. In 1913, the USDA listed soy as an industrial material, not as a food.” Lierre Keith, author of The Vegetarian Myth
In a letter to the US Food and Drug Administration, a former employee Daniel Doerge (an expert on soya) and fellow FDA researcher Daniel Sheehana (a senior toxicologist at the FDA’s National Center for Toxicological Research) wrote:
“There is abundant evidence that some of the isoflavones found in soy demonstrate toxicity in oestrogen sensitive tissues and in the thyroid. Additionally, the adverse effects in humans occur in several tissues. During pregnancy in humans, isoflavones per se could be a risk factor for abnormal brain and reproductive tract development.”
This will frighten mothers who increasingly use soya milk for babies. Doerge also added:
“Parents are exposing their children to chemicals which we know have adverse effects in animals. It’s like doing a large uncontrolled and unmonitored experiment on infants.”
The two scientists decided to break ranks with colleagues in the US Food and Drug Administration and oppose its decision to approve a health claim that soya reduced the risk of heart disease. They wrote an internal protest letter warning of 28 studies revealing toxic effects of soya. For the full article in the Guardian, click here.
These two scientists are not alone.
“What happens to babies fed soy formula? First, soy formula provides 38 mg of isoflavones a day. That’s a hormone load equivalent to that of three to five birth control pills each and every day. That number was derived from Swiss Federal Health Service data, data they published with warnings. Are you warned yet?” Lierre Keith – The Vegetarian Myth
The arguments against soy are compelling. The amount of processing soy must undergo before it is even edible is enough for alarm bells to ring for me. My personal belief is that if something requires that much processing, we aren’t meant to be eating it. I avoid it, and I recommend my clients avoid it as well. But there are always exceptions to the rule…
Which types of soy DO Have Health Benefits?
The few types of soy that ARE healthy are all fermented varieties. After a long fermentation process, the phytic acid and antinutrient levels of the soybeans are reduced, and their beneficial properties — such as the creation of natural probiotics — become available to your digestive system.
The fermentation process also greatly reduces the levels of dangerous isoflavones, which are similar to estrogen in their chemical structure, and can interfere with the action of your own estrogen production.
So if you want to eat soy that is actually good for you, following are all healthy options:
1.Natto – Fermented soybeans with a sticky texture and strong, cheese-like flavor. It’s loaded with nattokinase, a very powerful blood thinner. Natto is actually a food I eat regularly, as it is the highest source of vitamin K2 on the planet and has a very powerful beneficial bacteria, bacillus subtilis. It can usually be found in any Asian grocery store.
2.Tempeh – A fermented soybean cake with a firm texture and nutty, mushroom-like flavor.
3.Miso – A fermented soybean paste with a salty, buttery texture (commonly used in miso soup).
4.Soy sauce – Traditionally, soy sauce is made by fermenting soybeans, salt and enzymes, however be wary because many varieties on the market are made artificially using a chemical process.
As with everything, there are two sides to the argument. The jury is out in terms of soy and breast cancer risk. The research doesn’t seem to be there to support it, although given its phytoestrogen levels and the nature of breast cancer, the jury is still out for me.
I believe there are enough proven dangers associated with unfermented soy to far outweigh any possible health benefits. Sources of unfermented soy to avoid include;
•TVP (texturized vegetable protein) or soy protein isolate
•Soy cheese, soy ice cream, soy yogurt
•Soy “meat” (meatless products made of TVP)
•Soy infant formula
Try sticking to fermented soy, and enjoy the health benefits associated with it.