Diet, Race, and Colon Cancer

The recent announcement¹ by the World Health Organization regarding the link of eating processed meat to colorectal cancer is not a new finding among scientific research. Multiple publications now begin with such phrases or sentences as the following:

“Although the association between red meat consumption and colorectal cancer (CRC) is well established, ...”²

“Epidemiology shows that red and processed meat intake is associated with an increased risk of colorectal cancer.”³

“Several diets, especially a Western lifestyle with a high consumption of meat and carbohydrates and a low consumption of vegetables, have been linked to common diseases, such as metabolic syndrome, atherosclerosis, inflammatory bowel diseases, and colon cancer.”⁴

“Red and processed meat intake is an established risk factor for colorectal cancer (CRC), …”⁵

“Epidemiological studies have revealed that fiber- and vegetable-rich diets and physical activity are associated with reduced rates of colon cancer, while consumption of red and processed meat, or alcoholic beverages, and overconsumption as reflected in obesity are associated with increased rates.”⁶

or conclude with

“It is necessary to promote a regular intake of vegetables, fruits and diary products (although a moderate intake for men), and to reduce red meat (especially fat meat), processed meat, starchy vegetables, wine and sweet beverages intakes, to prevent the occurrence of cancer.”⁷

Enough studies about processed meat consumption and its resulting health effects have also made it possible for mainstream books to include such items as hot dogs and deli meat in a list of foods to avoid during pregnancy.⁸

Are Americans listening? Well, yes and no. According to the USDA's Agriculture Fact Book⁹, consumption of fruits and vegetables went up 20% per person between 1970-1979 and 2000 while the number of pounds of meat eaten annually per person increased to 57 pounds or over 40% more compared to what was eaten per person in the 1950's. While the data are not broken down into meat categories, it's likely that the amount of processed meat consumed annually per person also increased.

Some of the reasons given in the USDA report for the substantial rise in meat consumption include the following:

• rising consumer incomes, especially with the increase in two-income households

• meat prices in the 1990s that were often at 50-year lows, when adjusted for inflation

• production of many new brand-name, value-added products processed for consumers’ convenience, as well as a host of products for foodservice operators.

The USDA provides similar ease-in-packaging reasons for the rise in fruit and vegetable consumption but also added the popularity of certain specific food items and the influence of medical research:

• introduction of pre-cut and packaged value-added products

• popularity of pizza and other ethnic foods in the 1990s boosted average consumption of canned tomato products

• popularity of french fries, eaten mainly in fast-food eateries, spawned a 63-percent increase in average consumption of frozen potatoes during the same period

• consumption of other frozen vegetables rose 41 percent

• increasing health consciousness among consumers boosted average fresh carrot consumption by more than a fifth and average fresh broccoli consumption by a third between 1995 and 1998 where the latter is attributed to highly publicized medical research linking compounds in broccoli with strong anti-cancer activity in the body

According to the CDC,¹⁰ colorectal cancer is the second leading cause of cancer-related deaths in the United States and the third most common form of cancer. Data from the CDC¹¹ indicate that the rate of colon cancer deaths in both males and females of all races in the US is decreasing (Figure 1):

Figure 1

 

The number of colon cancer deaths among American women decreased 20% in the thirteen year period between 1999 and 2012. The fall in the rate of colon cancer deaths among American men in the same time period was not as large as it was for women: it decreased by 10% in the same timespan.

Similarly, the number of incidents attributed to colon cancer also decreased, by about 25%, among both women and men of all races (Figure 2):

Figure 2

More research would be required to explain the decline in rates of colon cancer. Possible explanations could include better technology to detect colon cancer, increased awareness of initial symptoms among patients and physicians, better techniques to eliminate or stem the growth of colon cancer, and positive lifestyle changes which could include more exercise, less alcohol consumption, and higher fruit and vegetable consumption.

When the data are broken down among Race, however, a different picture emerges. The resulting graphs demonstrate that Whites, both female and male, possess the highest rates of deaths attributable to colon cancer followed by Blacks. Among women and men, Whites and Blacks suffer colon cancer related deaths roughly three times as much as Asian/Pacific Islanders, American Indians/Alaskans, and Hispanics (Figures 3 and 4). Incidents of colon cancer are twice as much for women and men who are White or Black compared to the other races included in the data (Figures 5 and 6).

Figure 3

 

Figure 4

 

Figure 5

 

Figure 6

From the CDC data, it's clear the occurrence rate of colon cancer is very small among the US population, 0.002% in deaths and 0.03% in incidence among females and males. Most of the deaths and incidents of colon cancer, however, are among Whites and Blacks. What's not clear from the data are the reasons for such a disparity and, in 2009, this was noted in the research community.¹²

In 2007, a study compared the rates of different types of cancer among Korean Americans against those of Koreans living in South Korea.¹³ The researchers concluded with the following:

“The study provides evidence that the risk of cancers common in Western countries is higher for Korean Americans than for their native counterparts. Recent trends among Korean Americans also revealed a stronger Western profile.”

In fact, the incidence of colon cancer was higher for both males and females who were Korean American. In males, it was 56% higher among Korean Americans and, in females, it was 150% higher. Comparing the period between 1988 and 1992 with the period between 1997 and 2002, colon cancer incidence increased in both Korean American males, 43%, and females, 24%. Colon cancer incidence increased much more for Korean American males than for females. The authors of the study expected these rates to resemble those seen in the United States as their diets move to one that is “high in fat, protein, alcohol, and meat and low in fiber and calcium.”

The study also referenced other cancer research among Chinese, Japanese, and Filipinos in Asia compared to migrant populations in the United States. The research showed similar results to the one discussed here.

From these studies which research race populations between different geographic areas, it's clear that colon cancer is not due to racial makeup. It's the food we eat that matters.

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