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by Subhuti Dharmananda, Ph.D., Director, Institute for Traditional Medicine, Portland, Oregon

A growing number of reports indicate that soy products may be helpful both in preventing cancer and in helping to treat it.  The active components of soy that are thought to be primarily responsible for this beneficial action are a group of isoflavones, of which one of the most important (making up around half the total isoflavones in the soybean) is genistein.  Genistein has the ability to bind to estrogen receptors and partly block the effects of estrogen.  Because of this, it may help reduce the growth of estrogen-dependent cancers, as occurs with many breast and ovarian cancers.  It also can bind to testosterone receptors in similar manner, making it useful in controlling prostate cancer.  Genistein has other properties, such as inhibiting angiogenesis (the mechanism by which tumors develop their own blood supply to aid their growth) and inhibiting enzymes (such as tyrosine kinase) directly involved in cancer cell growth and regulation, believed to help with many kinds of cancers. 

The amount of isoflavones that is likely to be valuable for cancer patients is obtained from two or more servings of soy products per day.  A serving of soy milk is just one cup; a serving of tofu is just four ounces.  In Japan (and China and Singapore), the consumption of soybean products is believed to be partly the basis of reduced incidence of colon, breast, and prostate cancers (the other major dietary factor is lower saturated fat intake).  In addition to tofu, the Japanese consume miso soup, nato, and tempeh, as well as other soy foods, yielding a daily ingestion of soy isoflavones of about 40–120 mg. The typical American diet contains less than 5 mg/day of the isoflavones.

Persons with cancer often need a high protein, low fat, high calorie diet.  Soy products are naturally high in protein and have relatively low fat.  For example, Japanese tofu yields 33% or less of its calories from fat.  Often, medical nutritionists recommend elemental nutritional drinks, such as EnsureTM, for patients who are having trouble eating full meals.   However, these lack the phytonutrients.

This year, ITM has introduced a soy protein powder for beverage purposes that includes added isoflavones (as well as soy saponins and phytate) for use by persons who are unlikely to consume a sufficient amount of soybean foods to get the level of potentially beneficial substances that are desired (60–120 mg/day).  This product, called Nutra-Soy, provides 60 mg of isoflavones in a serving of just one ounce.  It also provides 13 grams of protein per serving, without the soy polysaccharides that tend to cause indigestion and bloating.  By combining it in a blender drink with, for example, yogurt and fruits, one can get a reasonable amount of fiber, carbohydrates, vitamins, and a small amount of beneficial fats.  Two servings per day are suggested for persons dealing with cancer who do not otherwise consume soy foods.  In addition to using this easy-to-consume soy powder, one can make a quick meal with tofu and rice that will provide a good balance of proteins and carbohydrates.


Persons with cancer may experience reduced appetite, partly as the result of the cancer activity (and body’s immune responses) and partly the result of standard cancer therapies.  Meal sizes tend to be smaller; instead of three meals per day, a person may need to spread out the daily intake of essential nutrients over four to six healthy snacks.  The taste of the meals deemed suitable may tend to be mild or sweet rather than having a blend of tastes as common to more complex meals, and the preparation needs to be very simple if one is going to successfully eat several times per day to get enough nutrients, as is often suggested.   While special liquid nutrient products have been recommended as food substitutes,  real foods with similar nutritional profiles may be of great benefit, and are considerably less expensive.

Tofu is an example of a food that can be used to boost the nutrition of persons with cancer while providing the soy isoflavones.  The nutritional content of a high protein Japanese-style tofu (made by Dae Han Inc.) and a standard Japanese style tofu (made by Azumaya), for a four ounce serving (which should yield about 30–40 mg of isoflavones) is:

Nutrient Component

High-Protein Tofu

Standard Japanese Tofu

Total Calories



Protein (grams)



Carbohydrate (grams)



Fat (grams)



Tofu is usually purchased in packages of one pound content; after opening, the tofu should be rinsed, any portion to be used sliced off and the remainder stored in water in a closed container in the refrigerator.  Change the water every time more tofu is taken out, or at least every other day (try to use up the opened tofu within five days).  Tofu can be heated in the microwave for quick preparation.

Rice is a carbohydrate and calorie rich food that is easy to digest; it provides the following nutritional profile (one cup cooked): 223 calories, 4.1 grams protein, 49.6 grams carbohydrate, and 0.4 grams fat. An automatic rice steamer is ideal for preparing rice without spending much time and with assurance of good results every time.  Extra cooked rice can be stored in a sealed container in the refrigerator and reheated by microwave in a minute.

To yield a product like the elemental nutritional supplements EnsureTM, AdveraTM, or PeptamenTM (standard 8 ounce serving), combine 4 ounces of tofu with one cup cooked white rice (brown rice can be used instead). Here are some comparisons, with ranges of nutrient levels for the two brands of tofu with one cup cooked rice and for the three representative elemental nutrition drinks, and a sample profile for a Nutra-Soy beverage made with 1/2 cup plain yogurt (do not use fat-free), 1 banana, 1/2 cup strawberries:

Nutrient Component

Tofu and Rice

Elemental Nutritional Drinks

Nutra-Soy Blender Drink

Total Calories




Protein (grams)




Carbohydrate (grams)




Fat (grams)




As these figures illustrate, one could get comparable nutritional benefit in terms of calories, proteins, and carbohydrates from tofu and rice, with less fat, compared to the elemental nutrition drinks.  And, a similar nutritional profile is attained with the Nutra-Soy Blender drink, which provides even more protein.  The elemental nutrient drinks include a mix of vitamins and minerals, which are obtained easily—and in larger quantities—by taking a nutritional supplement in tablet form; but the drinks contain none of the phytonutrients, like isoflavones, found in the tofu or the Nutra-Soy.  One could add some vegetables to the tofu and rice, which would increase slightly the carbohydrate, but have little effect on the other totals.  If additional fat is desired in the tofu-rice combination, one may add a small amount of walnuts (85% of their calories are in the form of fat; virtually all the rest is protein), or a teaspoon of vegetable oil or butter (butter contains butyric acid, a cancer-inhibiting component).  Alternatively or additionally, small amounts of meat or fish could be added to increase the protein and fat levels.

The low fat, low fiber tofu and rice can be ideal as a snack or, with some additions, a small meal.  The volume of the food is not much greater after chewing than the volume of the liquid foods.  As importantly, the cost of tofu and rice plus vitamin/mineral supplements is about one-third that of the elemental nutrient drinks. The items listed above all represent snacks or adjuncts to other foods.  The daily caloric requirements are about 2,000–2,100 for an adult who is not very physically active, and each of the above listed items represents one-seventh of that.  By alternating, as desired, between meals based on tofu/rice, with 30–40 mg isoflavones per serving, and beverages made from Nutra-Soy, with 60 mg isoflavones per serving (blender drinks with natural yogurt also provide butyric acid and lactobacillus), it will be possible to get all necessary nutrients and isoflavones in a form that is convenient, inexpensive, tasty, easy to digest, and health promoting.

December 1997