We are constantly told that diet is king in prostate cancer. This may be true, but it is confusing because many specific claims seem to be transient and change as often as I change my shirt. The claims are often are made without careful study and analysis of any scientific data. If you delve into the claims, you will often find, in reality, there are conflicting claims and conflicting data about specific effects food products actually have on an individual.

Not only are prostate cancer survivors on the diet bandwagon, but as we know, many health conscious Americans have also jumped on the wagon and modified their eating habits. One of the major changes involves the consumption of tofu (processed soy) in place of meat or eggs. The soy industry has invested significant dollars in convincing us that this is a healthy move, but the evidence is not convincing.

Examination of the science has allowed me to draw the conclusion that consuming processed soy, which includes tofu, is not healthy as the soy industry claims and many of us believe.

When soy is processed, using today’s high-tech procedures, the toxins that are naturally present in soybeans remain in the food. Additionally, the high-tech processing methods, which include high temperatures, high pressure, alkali and acid baths and petroleum solvents, leave additional toxic and carcinogenic residues in the soy. Additionally, all processed soy contains phytates that block mineral absorption and trypsin inhibitors that block proper digestion.

Advocates, as well as the soy industry, say that high soy diets protect against breast, prostate and colon cancer. These claims are statistically true, soy is protective against these cancers, but we do not have any insight the role soy might play with prostate cancer progression once the disease is present. What is scary and not very well known by most of us, high soy diets have been linked to many other significant health problems including;

• Thyroid problems; including weight gain, lethargy, malaise, fatigue, hair loss, and loss of libido

• Premature puberty and other developmental problems in babies, children and adolescents

• Cancer; including increase significant incidents of thyroid, liver, esophageal. pancreatic and stomach cancers

• Brain damage, especially in young children

• Soy allergies

Even the industry claim that soy reliably lowers cholesterol has now been called into dispute. In fact, soy actually raises homocysteine levels in many people, which has been found to increase the risk of heart disease, stroke, and birth defects. A group of food researchers has submitted a 65-page petition to the FDA asking them to retract the “soy prevents heart disease” health claim that was approved in 1999.

Soybeans are high in natural toxins known as antinutrients. This includes a large quantity of inhibitors that deter the enzymes we need for protein digestion. Normal cooking does not disable these enzyme inhibitors. The result for many people is extensive gastric distress and chronic deficiencies in amino acid uptake, which can result in dangerous pancreatic impairments and cancer.

Soybeans contain hemaglutinins, which cause red blood cells to clump together. Soybeans also have growth-depressant substances, and while these substances are reduced in processing, they are not completely eliminated.

Soy contains goitrogens, which can frequently lead to depressed thyroid function.

In the American market, most soybeans (over 80%) are genetically modified, which for some people is a issue. Everyone should be concerned that soy contains one of the highest levels of pesticide contamination of all foods in the American diet.

Soybeans are very high in phytates, which prevent the absorption of minerals including calcium, magnesium, iron and zinc, all of which are necessary for optimal biochemistry in your body. Many of us supplement these minerals, but then consume enough soy to stop their absorption!

Not all soy is unhealthy. There are a few types of soy that are healthy, and all of them are fermented. 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 fermenting process also 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 enjoy soy and want to eat it without damaging your health — and in fact gain health benefits — the following are all healthy options:

1. Natto, fermented soybeans with a sticky texture and strong, cheese-like flavor. It is a very high source of vitamin K2 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.

Remember, though, that all processed soy products — soy milk, soy burgers, soy cheese, soy energy bars, soy ice cream, soy protein powders, etc. — are not health foods. To truly avoid all types of damaging soy products, you need to avoid processed foods as the vast majority of them contain soy ingredients.

The basics of healthy eating, unprocessed, fermented, and fresh foods are ideal, while processed foods should be avoided. This is true of soy as well.

Joel T Nowak, MA, MSW