Soy has been heavily promoted by the soybean industry as being "the perfect food." The truth is, it is more like "the perfect storm" for anyone with diabetes.
Soy is thyrotoxic. Isoflavones in soy foods block receptors for thyroid hormones and causes people to become hypothyroid. Since lowered thyroid function raises blood sugar and leads to weight gain, lowering your thyroid by eating too much soy is the last thing anyone with diabetes needs to do to themselves. For people who are already taking thyroid hormones, soy makes it necessary to take a higher dosage to get to a healthy hormone level than you'd get if you did not eat soy.
Soy causes other problems. It contains too much manganese, a mineral that can build up to toxic levels in people.
Phytates in soy foods block the absorption in the gut of other minerals that your body needs. There's some evidence that toxins in soy damage the lining of the digestive tract. This causes "leaky gut syndrome" where the damage to the gut allows larger proteins to enter the blood stream where they provoke allergic reactions that lead to severe food allergies. It is possible that the huge amounts of soy that have invaded processed foods is one reason for the spike in Type 1 diabetes which is increasingly seen as being linked to gluten intolerance. With a leaky gut, gluten is more likely to get into the bloodstream, provoke the formation of the anti-gluten antibodies which may also be attacking the pancreas.
Soy also mimics estrogens. Eating a lot of soy foods can decrease androgen levels in males and lead to ED and the unwanted growth of breast tissue.
Some mainstream research has found higher levels than normal of dementia in populations who eat a lot of tofu. There's also there's some evidence that soy promotes hormone sensitive cancers and gut cancers.
But avoiding soy is not easy, especially if you are trying to cut back on carbohydrate and looking for sources of protein rich food. Soy hides in many foods under names like "textured vegetable protein" and "hydrolyzed plant protein." It's the main ingredient in many "protein" bars. It's in all high protein breakfast cereals. And it is often used as an extender in restaurant meats.
But it's worth taking the time to read labels and ask questions so you can avoid these industrially produced soy foods. There's just too much evidence that the only real benefit they provide is for food processors who get high profits from a cheap raw material.
Beware Industry Sponsored Soy Research
There is a lot of misleading research published about the health benefits of soy. Much of it is funded by companies that produce soy frankenfoods. The hallmark of deceptive food research is that a claim will be made that the food "prevents diabetes," but this claim is not based on tests where people are given the food and then had their blood sugars tested. Instead researchers will find that the food contains some substance like a phytochemical, and extrapolate from the presence of this phytochemical that the soy food would have the anti-diabetic properties.
In addition associational studies that link soy intake to a reduced risk of diabetes generally refer to the intake of the kind of soy foods--tofu, etc, which are sold at expensive "health food" stores. Consumption of these foods is a socio-economic indicator which points to higher income and education levels, which are independently associated with lower risks of diabetes for reasons unrelated to soy. There are NO studies showing that higher intake of processed foods with soy additives is linked to any health benefits. These processed foods and the fast food "meats" where soy protien has been added as extenders are where most people get their major soy exposure, not tofu.
REFERENCES==========The Whole Soy Story: The Dark Side of America's Favorite Health Food
by Kaayla T. Daniel, Ph.D. An extensive look at the problems of soy and how the soy industry has spun the facts to turn a toxin into a "health" food. Extremely well footnoted. Soy Brain Atrophy Link?
An excellent analysis of the research on this topic with links to all relevant journal articles.Use of soy protein supplement and resultant need for increased dose of levothyroxine.
Bell DS, Ovalle F. Endocr Pract.
2001 May-Jun;7(3):193-4.Click here to read New Findings on the Soy Thyroid Connection
Pointers to research from thyroid expert Mary Shomon.