Oncology

Stomach Cancer in China

While all cancer rates are generally very low in China, stomach cancer leaps out as a glaring exception. Figured at a population base of 100,000, the incidence in the U.S. is just 6.5, contrasted with a 90.9 incidence for China. What’s going on here?

Three main factors appear to be responsible for China’s high stomach cancer rates: preserved vegetables, stomach bacterial infections, and low blood levels of certain antioxidant nutrients. Interestingly, China Project scientists found that even in those people predisposed to the stomach cancers, a higher intake of plant foods led to fewer cancers.

In China, where refrigerators are rare, preserving vegetables by a combination of fermenting and salting is common. Fermentation per se may not be the problem as much as the way in which it is done. Bacteria and molds often intrude into the process triggering the sequence leading to cancer. Especially, stomachs chronically infected with the bacterium Helicobacter pylori³one of the prime suspects in cases of stomach ulcers³were found to be at increased risk for stomach cancers. This is particularly alarming because in the counties studied in China, H. pylori infection affected from 27 to 96% of the population.

On a more optimistic note, a strong protective factor for stomach cancer in China appears to be a high intake of fresh plant foods, and especially those with high levels of selenium and beta-carotene.

China Report: Cholesterol and Cancer

Most of us have heard a great deal about the link between high cholesterol and heart disease. But how many have heard that high blood cholesterol levels are also associated with cancer? In China, we found that those with the highest cancer rates also had the highest cholesterol levels. Among the cancers associated with high cholesterol levels in China were: liver, colon, rectum, lung, brain, leukemia and various childhood cancers.

In what seems to be a contradiction to our China findings, large studies done in the Netherlands found no correlation between cholesterol levels and cancer. How is this possible? The difficulty here appears to be that the Dutch have one of the highest intakes of animal fat in the world. On average, cholesterol levels in the West are 210-­220 milligrams versus the Chinese 125-­130. The implication is that reducing cholesterol from very high levels to high levels may not be enough to affect cancer incidence. Only as cholesterol levels drop further, into the strikingly low levels seen in China, do cancer rates decline. How to achieve such low cholesterol levels? Doing so is possible only on a low-fat, plant-based diet, since even surprisingly small intakes of animal-based foods are associated with significant increases in cholesterol levels.

Chemical Carcinogens: How Safe Are You?

I would like to turn your attention toward a nagging question about foods, namely carcinogens in foods. We hear so much about them but what, really, are they? Mainly we’ve heard that carcinogens cause cancer and anticarcinogens prevent cancer. This idea was well articulated in an article by Professor Bruce Ames of the University of California published in l983 in the journal Science.

The Cranberry Scare

I submit, however, that despite Professor Ames’ worthy efforts, our ideas about chemical carcinogens remain much too simplistic. The working definition of a carcinogen began around 1915 when it took on the meaning of a chemical which, when tested in experimental animals, unequivocally caused cancer. During the next two to three decades, a number of chemicals were found to have these properties. By the late 1950s, the carcinogenic red flags looming over our food supplies could no longer be ignored. That’s when an herbicide used on cranberries was found to be capable of causing thyroid tumors in experimental animals. Coming shortly before the Thanksgiving holidays, the cranberry business took an immediate nose dive. What timing that was! Shortly thereafter, Congress took its own style of nose dive by amending the Food and Drug law to include the Delaney Clause. This said that any chemical shown to cause tumors in experimental animals should be banned from human use.

An Impossible Task?

How very simple it all seemed. Ever since, the U.S. government has been conducting animal experiments to test the potential of certain chemicals to cause cancer in humans. Yet, more than 30 years later, the task is barely begun. By some estimates, not more than 5% of the chemicals in our environment have been tested. Yet the amount of work that [...]

Genetic Seeds of Disease: How to Beat the Odds

How often these days do you read that genes cause cancer?

Probably nothing in biomedical science deserves more attention. In my view, it even needs attention in nutrition newsletters. Why? Because there’s a peculiar line of reasoning going around that goes something like this: If genes are primarily responsible for determining when and what kinds of cancer we get, then what difference does it make what we eat?

Essentially, this is a very fatalistic view. Further, if this notion about genes is accepted as being valid, then many may be tempted to simply trade in “bad” genes for “good” genes. Regrettably, this is an idea that is very much alive in science and kicking up considerable funding support. Rather than succumbing fatalistically to gene research reports or trading our genes haphazardly, let’s start to think more seriously about preventing cancer, quite literally, by getting at its “root.”
Where is the Money Going?

I’ve previously commented in this newsletter on some of my concerns about this overemphasis on gene research (see August 1995 issue). While some of the new gene discoveries may provide hopeful opportunities, many are clearly harmfulespecially when people are not properly informed. Tragically, some people have become so distraught after finding out that they or their loved ones have a particular bad gene, that they then take unconscionable actionI’ve been called twice by mothers seeking advice on possible mastectomies for their daughters.

Why do NIH and similar funding agencies provide far more research funding for investigations on the genetic control of disease rather than for the nutritional control of disease? Whose purpose is being served here? Consider this: Improper diets, when compared to genetic backgrounds, are responsible for perhaps 30–40 times more cancers (at least), [...]

China Report – Dietary Fiber: Preventing Cancer in China

The cancer-prevention properties of dietary fiber are hardly a secret. Indeed, in modern times the late Dr. Denis Burkitt (of Burkitt’s Lymphoma fame) made the so-called “fiber story” famous in his work among native Africans. This British researcher, with his colleagues Alan Walker and Hugh Trowell, spent many years in Africa tirelessly working to better understand why diseases typically found in Western countries were rare in Africa. What he discovered made worldwide news. Diets high in fiber appeared to be associated with reduced cancer incidence of the large bowel, as well as the incidence of many other diseases common to Western countries.

Looking at the Big Picture

In rural China, we took this lead to further explore the fiber–cancer association among people who were consuming very large amounts of fiber compared to Americans. In so doing, we incorporated two other understandings. First, dietary fiber is not a single chemical entity. There is an almost unlimited variety of dietary fibers. Second, our knowledge about the unique effects of specific fibers was, and still is, very sparse. So, to get a better feel for the big picture, we measured the consumption of 14 different kinds of dietary fiber.

As expected, we first noted that the average intake of dietary fiber was at least double, perhaps even triple, the intake in the U.S. Second, the rates of colon and rectal cancers in China were only about one-half the rates in the U.S., although in some areas this cancer was almost non-existent.

Also as expected, we did not see any special differences in the cancer-related effects of these different fibers. For each of the 14 different fiber types, there was an inverse correlation. That is, the higher the fiber intake, the lower [...]

Avoiding Breast Cancer with Diet

Breast cancer is clearly a terrifying disease. Out of every nine women in America, at least one will fall victim to its toll. Despite massive research and immense funding, scientists are often at odds regarding its possible causes.

At the heart of the confusion and controversy is the role of a high-fat diet. On the one hand, extensive laboratory research and human epidemiological studies often link high-fat diets to higher rates of breast cancer. On the other hand, several prominent medical studies have shown little or no relationship between fat intake and breast cancer. Lacking conclusive evidence, most nutritional experts play it safe by suggesting that the most effective way to reduce breast cancer is to reduce overall fat intake.

What we have found from the China Project is that such advice is not sufficient. The fact that significantly lower breast cancer rates exist throughout China is not simply due to low-fat diets but also because these diets are largely plant-based.

Let’s look at the findings:

  • Even though breast cancer is substantially lower in China, a broad 13-fold range can still be found between various areas of the country.
  • Fat intake in rural China ranges between 6 and 24% of total calories. By contrast, this range soars to 25-45% of total calories in the U.S.
  • Age at first menstruation (menarche) in China is typically 15-19 years, considerably later than the 10-14 years in the U.S.
  • Blood levels of the female hormone estrogen are significantly lower among Chinese women than among U.S. women.
  • As dietary fat declines from 24 to 6%, and these diets become richer in plant matter, breast cancer rates make a similar decline.

In our survey we found that girls who consumed diets that were limited in plant foods, yet were [...]