Heart Disease | Cancer ... by Greg Caton, President, Lumen Foods Heart Disease Preventive Compounds | Cancer Preventive Compounds

In 1985 when I wrote the Lumen book, there was already a large body of data connecting both heart disease and a wide range of cancers to high rates of meat consumption. The sixth chapter of that book alone cited over 190 references, most of which were related to epidemiological correlations between reduced meat consumption and lower rates of cancer, heart disease, osteoporosis, multiple sclerosis, and other degenerative diseases that are rampant in the West. In the 10 years since, there have been numerous studies that go beyond merely substantiating the benefits of a "meatless diet." Soy protein products, such as Heartline Meatless Meats and Heaven on Earth Fat Free Milk Replacer are finally being noticed for the value of their soybean protein -- protein which imparts cholesterol and triglyeride lowering properties in its own right.

The current barrage of studies coming out points specifically to correlations between soy protein consumption and these same lower rates. In 1990 Lumen Foods proudly participated in a study at the University of Toronto, funded by Canada's National Institute of Health. The study, headed by David J.A. Jenkins, M.D. at the Department of Nutritional Sciences (Faculty of Medicine, University of Toronto), was published in the July, 1993 issue of The New England Journal of Medicine. It concluded that: "... very high intakes of foods rich in soluble fiber lower blood cholesterol levels even when the main dietary modifiers of blood lipids -- namely, saturated fat and cholesterol -- are greatly reduced." In a private letter to this author Dr. Jenkins, the study's principal researcher, wrote that subjects who were served our Heartline products saw... "very significant fall(s) in total serum cholesterol... irrespective of whether they were taking soluble or insoluble fiber supplements." Nonetheless, the final paper (N Engl J Med 1993; 329:21-26(7/1/93) did not distinguish between vegetable protein and soy protein as such.

This "meta-analysis" of 38 controlled clinical studies was far more specific in addressing soy protein's affect on serum lipid concentrations. The study itself (N Engl J Med 1995; 333:276-82(8/3/95) was far reaching in methodology and coverage. Among its statements and conclusions:

• Background: It has been known for over 80 years that soy protein has cholesterol-lowering effects far exceeding those of animal protein when studied in animals. Recent studies have merely attempted to confirm that humans respond similarly to other mammals. Soy protein is well-known to produce less hypercholesterolemia and less atherosclerosis in animals than animal protein.
  
• The analysis took in account a wide variety of soy protein sources among the 38 clinical studies: textured soy protein (such as Heartline), soy protein concentrate, and soy isolates. Nonetheless, of 38 studies 89% (34) reported a net decrease and 11% (4) reported a net increase in serum cholesterol concentrations. However, in these 11% of the studies the initial serum cholesterol values among subjects was already fairly low (average, 185 mg/deciliter). Changes in serum lipid concentrations were independent of changes in body weight and dietary intake of total fat, saturated fat, and cholesterol.
  
• The net change in serum LDL cholesterol concentrations was a decrease of 21.7 mg. per deciliter. Twenty-six studies (84 percent) reported a net reduction, four studies (13 percent) reported a net increase, and one study (3 percent) reported no change.
  
• HDL cholesterol concentrations (HDL is "healthy cholesterol") were not significantly affected. A net change of 2.4% increase was noted.
  
• The amount of soy protein in the diet was not significant (P=0.39) when net changes were assessed. The type of diet, although not statistically significant, accounted for approximately 12.6% of the variance. Larger changes tended to occur when the control diets were "usual" diets rather than low-fat and low-cholesterol diets.
  
• The results of studies of adult subjects did not differ significantly from those of four studies of children; the age group of the subjects had a negligible effect on variance.
  
• The changes in the 19 studies with similar diets in terms of fat and cholesterol intake and weight change did not differ significantly from the changes in the remaining studies, in which the diets were not similar; this factor accounted for negligible variance.
  
• In a demonstration of the power of politics over true science, the University of Kentucky study showed that the conclusion of the Nutrition Committee of the American Heart Association concerning soy protein was completely falacious. The AHA position is: "consumption of vegetable proteins leads to lower cholesterol levels than consumption of animal proteins in rabbits but not in humans." Only one study supported this position, and it did so weakly.
  
• Soy protein intake averaged 47 g per day and 37 percent of the studies used 31 g per day or less. These observations suggest that the daily consumption of 31 to 47 g. of soy protein can significantly decrease serum cholesterol and LDL cholesterol concentrations. The ingestion of 25 or 50 g. of soy protein per day was estimated to decrease serum cholesterol concentrations by 8.9 or 17.4 mg. per deciliter, respectively. Persons with moderate or severe hypercholesterolemia should have even larger decreases in serum cholesterol concentrations when soy protein replaces animal protein in the diet.
  
• Summary of the 38 subject studies: "The meta-analysis of 38 studies indicates that the consumption of soy protein is associated with significant decreases in serum cholesterol, LDL cholesterol, and triglyceride concentrations and with a nonsignificant increase in serum HDL cholesterol concentrations. The decreases in serum cholesterol and LDL cholesterol concentrations were strongly related to the subjects' initial serum cholesterol concentrations. (60 references follow).
  

• Soy protein, concludes Dr. A.C. Goldberg, should be as a replacement to other cholesterol-reducing therapy approachs. (Goldberg, AC (1995): "Perspectives on soy protein as a nonpharmacological approach to lowering cholesterol. J Nutr 125(3,Suppl,Mar), 675S-678S.)
  

  He writes: "... the use of adjuncts to diet such as soluble fibers, garlic and soy protein may allow target lipid concentrations to be reached without the use of drugs. Soy protein incorporated into a low-fat diet can reduce cholesterol and LDL-cholesterol concentrations. The main obstacles to greater use of soy protein in the therapy of hyperlipidemia include lack of knowledge by physicians and patients of its effects and lack of availability of easily used products. Although soy products... are available... consumers may be unaware of their presence and uses. Without the publication of articles in mainstream medical journals on the cholesterol-lowering effects of soy protein, few physicians are likely to know of possible uses..."

• One researcher went to far as to conclude that the protective agents in soy protein qualify for reclassification as "nutrients," similar to vitamins and minerals. (Hendrich, S. et al. (1994): "Defining food components as new nutrients." J Nutr 124(9,Suppl,Sep), 1789S-1792S). He writes: "When obtained from a usual diet, a food component that sustains or enhances physiological functions and/or prevents diseases is a nutrient. Isoflavones, tocotrienols, and cartenoids are candidate nutrients which may be of health benefit to humans by inhibiting cancer development and reducing risk of atherosclerosis. The amounts of some of these candidate nutrients in food are known. A carotenoid database has been developed. Isoflavone content of soy foods rantes fro 0.1mg/g (soymilk) to 2.5 mg/g (soy isolate). Isoflavones, tocotrienols, and carotenoids meet several criteria for classification as nutrients..."
  
• Another researcher focussed on the value of isoflavones in soy products. (Klein, BP; "Incorporating soy proteins into baked products for use in clinical studies." J Nutr 125(3,Suppl,Mar) 666S-674S.) He writes: "Recent research at the University of Illinois and elsewhere has shown that soy protein isolates (as contained in Heaven on Earth Fat Free Milk Replacer) and associated isoflavones are dietary constituents that are effective in decreasing risk of cardiovascular disease and cancer." Comments continue to emphasis the need for better tasting soy products. [Editor: we need to send this researcher a copy of the Whole Earth Vegetarian Catalogue.]

Below we summarize those components of soy which are known inhibitors to a wide range of conditions which lead to heart disease. A more expansive explanation of these soybean "phytochemicals" and their properties can be obtained by reading The Simple Soybean And Your Health by Mark Messina, Ph.D. and Virginia Messsina, RD (Avery Publishing Group, New York, 1994).

• Soy Flour - Like many grains and legumes soy has its own fiber or bran. Textured soy products contain ample amounts of this cholesterol reducing component, and even though soy fiber does not have the LDL-lowering power of soy protein, it is at least as significant as the much touted oat bran.
  
• Lecithin - The original studies on lecithin, conducted in the 1950's by Dr. Lister Morrison, first reported cholesterol reductions of 30% to subjects administered 36 grams of soy lecithin daily. Another study showed that just 6 grams of lecithin to a standard low-fat, low-cholesterol diet lowered LDL cholesterol 15% more than did the low-fat diet alone. Granted, with a regular intake of only 3 grams per day, people will not consume a level of lecithin with Heartline that approaches 36 grams per day, but together with its other phytochemicals, textured soy products, such as Heartline do aid in overall LDL reduction.
  
• Saponins - Soybeans are rich in this substance, and in fact, saponins actually resemble cholesterol in their chemical makeup. Saponins are believed to lower cholesterol either by blocking cholesterol absorption or by causing more cholesterol to be excreted from the body. Saponin research Dr. D. Oakenfull has noted that the increase in incidence of heart disease in Western societies seems to coincide with a decline in the consumption of saponin-rich legumes.
  
• Phytosterols - Also resembling cholesterol, phytosterols compete with dietary cholesterol for absorption by the intestines, resulting in lower blood cholesterol levels -- a fact supported by several clinical studies.
  
• Isoflavones - Indian researcher Dr. M. Siddiqui first noted that isoflavones, unique to soybeans, are not only cancer preventive, but they also reduced cholesterol--in his studies--by as much as 35 percent, depending on other components in the diet.
  

Epidemiological studies in the Lumen book bombard the reader with a steady stream of confirmation that vegetarian diets reduce cancer risk of a wide variety of type. But is this because of reduced meat consumption or because of any properties of the foods that take their place or both? An analysis of the available scientific literature would solidly suggest both. (See Messina, MJ et al.; "Soy intake and cancer risk: a review of the in vitro and in vivo data." Nutr Cancer 21(2), 113-131 (1994)).

• A number of studies have concluded that soyfoods may contribute to the relatively low rates of breast, colon, and prostate cancers in countries such as China and Japan.
  
• Soybeans contain a number of anticarcinogens and a recent National Cancer Institute workshop recommended that the role of soyfoods in cancer prevention be investigated.
  
• Soybeans and soy protein products, such as Heartline are a unique dietary source of the isoflavone genistein, which possesses weak estrogenic activity and has been shown to act in animal models as an antiestrogen. Genistein is also a specific inhibitor of protein tyrosine kinases; it also inhibits DNA topoisomerases and other critical enzymes involved in signal transduction. In vitro, genistein suppresses the growth of a wide range of cancer cells, with IC50 values ranging from 5 to 40 microM (1-10 micrograms/ml). No studies from the Messina analysis reported soy intake increased tumor development.
  
• The epidemiological data are also inconsistent, although consumption of nonfermented soy products (i.e. virtually all Lumen food products) tended to be either protective or not associated with cancer risk. However, no consistent pattern was evident with the fermented soy products, such as miso. Protective effects were observed for both hormone and nonhormone-related cancers. Messina concludes that while a definitive statement that soy reduces cancer risk cannot be made at this time, there is sufficient evidence of a protective effect to warrant continued investigation. [Editor: Such closing caveats are supplied to ensure continued interest from such biased stalwarts of the medical-industrial-complex as the National Cancer Institute.]

Below we summarize those components of soy which are known inhibitors to a wide range of conditions which lead to various cancers. As with heart disease preventive components above, you will find a more expansive explanation of these soybean "phytochemicals" and their properties by reading The Simple Soybean And Your Health by Mark Messina, Ph.D. and Virginia Messsina, RD (Avery Publishing Group, New York, 1994).

When the Lumen Book came out in 1986, there were already a host of studies showing that populations that had a higher intake of soy protein had significantly lower rates of cancer than those subsisting on animal proteins. However, acknowledgement that soybeans exhibit extraordinary anti-cancer ("anticarcinogenic") properties is of fairly recent development in the scientific community.

On June 27, 1990, the National Cancer Institute in Washington, D.C. held a workshop on the anticancer effects of soybeans. Experts from various governments, research universities, and industry attended. At the conclusion of the workshop the participants agreed that there was strong evidence that soybeans may play a role in preventing cancer, and publicly identified five individual anticarcinogens in soybeans. As a direct result of this workshop, the National Cancer Institute allocated $3 million for research on the anticancer effects of soybeans. Since the time of this conference, several more important components have been discovered. Taken together these compounds point to soybeans as a significant anticarcinogenic food source, offering preventive benefits that cannot be derived by any other known stable in the Western world.

• Protease Inhibitor - For many years this phytochemical was branded a curse because of its "antinutrient" effects when taken in significant doses: that is, it inhibits the digestion of dietary protein, particularly in animals and humans when the raw soybeans are consumed.
  

  In 1980 this view began to chance when Dr. Walter Troll of the New York University Medical Center discovered that raw soybeans inhibit cancer in animals. He was able to isolate the cause: it was the protease inhibitors. Subsequent research has confirmed that they inhibit cancers of the skin, bladder, colon, lung, pancreas, mouth, and esophagus. They do this by preventing the activation of the specific genes that cause cancer. They also protect against the harmful effects of radiation and free radicals, which can attack DNA and change cellular characteristics ("mutagenic") and further cause cancer.

  And what about the "antinutrient" factor? Well, as it turns out, cooking soybeans (as is central to the production of Heartline products) disables all but 8-9% of the protease inhibitor in the case of "concentrates." (Heartline belongs to a class of textured soy protein products known as "protein concentrates"). Does this reduced amount destroy the anticancinogenic benefits? Not at all. This is because the amount of protease inhibitor required to inhibit cancer growth is quite small--and at these levels any "antinutrient" factors are statistically insignificant!
  

• Phytate - For years, phytate, the storage form of the mineral phosphorus, was also besieged with the label of "antinutrient." This is because significant levels of phytate bind (or "sequester") calcium and iron in the intestines, thus limiting their absorption into the body. In fact, researchers worked for years on ways to develop a "low-phytate" soybean, or ways to remove it from the bean. Now, further research shows that phytate not only plays a minor role in heart disease prevention, it also acts as a cancer preventive. What is more ironic is that the very processes that were thought to be harmful actually contribute to its anticarginogenics: phytate inhibits the cancer process by binding iron in the intestines.
  

  Drs. E. Graf and J.W. Eaton claimed as early as 1985 that high-fiber foods protect us from colon cancer not only because of their fiber content but also because of their phytate content. Since free radicals assist cancer growth by attacking cellular DNA and iron generates free radicals, researchers are now focussing on just how phytate controls cancer cell growth. What they are finding is that phytate acts as an antioxidant, much in the same way that Vitamin C and beta-carotene do. They are also finding that phytate prevents cancer by enhancing the immune system, in particular by increasing the activity of natural killer cells, which can attack and destroy cancer cells and tumors. Phytate content in all Lumen Foods' textured soy products, which includes all Heartline items, ranges from .8 to 1.5%.

• Phytosterols - We spoke about these compounds when we talked about heart disease. Phytosterols, the equivalent to cholesterol in the plant kingdom, are not absorbed by humans. They are transported directly to the colon where they inhibit cancer growth by protecting against the harmful effects of bile acids, the main breakdown products of cholesterol. This is why phytosterols are particularly effective in preventing colon and skin cancers--as much as 50% reduced risk in one study.
• Isoflavones - These compounds are unique to soybeans: people who do not eat soy have virtually no isoflavone in their diet. So extensive is the research on isoflavones over the past four years that only highlights can be touched upon here.
  

  Isoflavones are quite similar to the female sex hormone, estrogen--but one hundred thousandth as potent. As such, they reduce breast cancer risk in women by "tying up" receptors on certain tissue cells where estrogen is known to exert a number of effects, some of which are carcinogenic. Dr. Messina compares this process to putting the wrong key in a lock: the key may fit but it won't open the lock.

  By tying up receptors and preventing certain cancer processes to be inhibited, isoflavones prevent the onset and/or growth of breast cancer. Isoflavones are other anticancer effects as well. It affects pituitary hormones is a manner similar to the cancer-fighting drug, tamoxifen, which is prescribed worldwide by physicians to treat breast cancer. In epidemiological studies, these effects are confirmed as well. In those groups (i.e. vegetarian women consuming soy and Asian women) where soyfoods are a stable, breast cancer rates are low.

• Genistein - This chemical is the main isoflavone in soy, so why are we giving it a separate heading? Because the evidence on the anti-cancer properties on this one compound alone is so overwhelming that it should be treated separately. Since 1986 over 200 research papers have been published on this exciting anticarcinogen--with results so positive that one researcher noted that genistein may become the first in a new class of anticancer drugs--(although you can get the desired effects by just eating soyfoods!)

  What makes genistein unique is that it strikes at very fundamental processes of aberrant cell development central to all cancer growth. Cancers are created by "oncogenes" which in turn produce specific enzymes that are known to be carcinogenic. Genistein severely inhibits an array of key enzymes involved in the cancer process, including "tyrosine protein kinases." More amazingly, genistein causes existing cancer cells to differentiate, that is, to go from a cancer cell to a normal cell. Recently, it was discovered that genistein inhibits "angiogenesis," the growth of blood vessels. For cancer to grow, tumors need to stimulate the growth of new blood vessels so that they can receive the oxygen and nutrients they need. Genistein inhibits this process. Finally, genistein is a good antioxidant, further aiding in the prevention of free radical damage.