Does the China Study prove milk causes cancer?

The China Study has sold over 500,000 copies making it one of the best selling nutrition books in history. It purports to prove that there is a connection between meat and dairy consumption and a variety of diseases including cancers of the breast, prostate, and large intestine. Animal products are also accused of contributing to diabetes, heart disease, obesity, autoimmune disease, osteoporosis, degenerative brain disease, and macular degeneration. Only 39 of the 350 pages in the book are actually devoted to the China Study.
The study was conducted by T. Colin Campbell and was influenced by the Seventh Day Adventist background of the authors. One flaw of the study is that those eating a plant based diet in China were consuming a lower calorie count that those eating meat. It is a long known fact that fasting in any form prolongs life and reduces and delays the development of a wide variety of diseases. A plant based diet does decrease caloric intake due to the high fiber intake. Plants also provide a wide variety of phytonutrients which protect from disease.
Many animal products today are produced by feeding animals grains resulting in excessive fattening of the animals and excessive levels of omega-6 fatty acids. Historically, many people have lived long and healthy lives consuming primarily animal products. These products were, however, superior nutritionally to many of the animal products consumed today. Most milk products, for example, are pasteurized today. Historically this was rare. The casein which Campbell focuses on can be produced with both low and high temperature processes. The high-temperature spray-drying process is known to create carcinogens. Campbell neglects to mention that high-casein diets protected rats from cancer when fed casein before or during the aflatoxin dosing rather than after.
Another flaw of the study is that consumption of refined carbohydrates is ignored, despite the fact that meat eaters usually have a higher income and can afford more refined foods. The data of the China Study itself suggests that sugar and soluble carbohydrate have seven times the magnitude of correlation with cancer that animal protein intake does.

Is soy a health problem?

A number of anti-soy articles have been written by a small group of individuals who suggest that soy shrinks the brain and causes Alzheimer's, causes cancer, contains anti-nutrients, and is full of toxins. The soy industry supposedly knows that soy is poison, but actively works to cover this up. This blog will discuss the kernel of truth in these allegations and the exaggeration involved in many claims.

• Firstly, a good deal of the soy products sold are manufactured from genetically modified soy. Feeding experiments on mice have shown that the genetically modified product is harmful to young mice in a way that non genetically modifies soy is not.
• It is also true that soy does contain digestive inhibitors. Cooked soybeans are more difficult to digest than animal proteins. Soy is generally processed, however, in a manner which greatly improves the ability to digest the soy making it comparable to the digestibility of meat protein. The protease inhibitors in soy have been shown to reduce the risk of colon, prostate, and breast cancer in humans. One study found a 70% reduction in prostate cancer among men who consumed soymilk daily.
• Rats and chicks are very sensitive to protease inhibitors and do poorly when fed soy. This same sensitivity has not been observed in humans, dogs, pigs, monkeys, hamsters or mice. Most of the studies suggesting problems with soy are rat studies.
• Soy is high in phytates, but so are beans, nuts, grains and seeds. No one suggests avoiding these foods for that reason. Phytates can inhibit mineral absorption, but this is rarely a problem with processed and fermented soy products. If the phytates in vegetarian diets prevented mineral absorption one would expect them to have weak bones, but vegetarians suffer less osteoporosis than meat eaters.
• Soy does have weak estrogenic properties. Many foods do have weak estrogens in them to discourage overconsomption of these foods by predators. Modest amounts of weak phytoestrogens may actually protect from some of the harmful effects of stronger estrogens in the body. Excess consumption of soy and other estrogenic foods should be avoided.
• Another charge is that soy causes dementia and Alzheimer's. One study suggested this but the results could be a defect in the study design. other studies have shown that soy improved short and long term memory in young people and cognitive function in older women.