Since childhood, we've been told to eat our vegetables. Now as adults, we are all well aware that eating a diet filled with plenty of vitamin- and nutrient-rich fruit and vegetables is highly recommended to maintain the best health possible. But it "appears" that these same benefits may not be extended to the smokers among us.
Recent research conducted by the Dutch National Institute for Public Health and the Environment in Bilthoven found that people who smoke cigarettes might actually increase their risk of developing colon cancer by eating a larger quantity of fruit and vegetables. The results of the study, conducted across Europe, suggest that greater consumption of fruit and vegetables lowers the risk of colon cancer to some extent, as was expected, but somehow has the opposite effect on those who smoke.
The participants who reported eating about 600 grams, which is approximately the recommended five daily servings, of fruit and vegetables each day were found to have reduced their risk of developing colon cancer by 20-25% as compared with the participants who said they typically eat 220 grams, the equivalent of just under two servings a day. The results for the smokers, however, do not demonstrate the levels of protection found for nonsmokers -- if anything, their risk for contracting colon cancer is higher when they eat more fruit and vegetables.
Between the years of 1992 and 2000, more than 450,000 people in 10 European countries answered questions about their lifestyles, including dietary and smoking behavior. The researchers then followed up for an average of eight and a half years. This is the first study to make a distinction between smokers and nonsmokers when considering the influence of fruit and vegetable intake.
One possible explanation for these results, according to reasearchers, is that there are certain substances within fruits and vegetables that can exacerbate the carcinogenic potential of tobacco. Another possibility is that some people eat their vegetables with practically all of the nutrients cooked out of them -- so no matter how many they are consuming, there isn't much benefit to be derived. Or perhaps by definition, smokers tend to be less concerned about health and eat "lower nutrition vegetables" like iceberg lettuce, canned corn, and bottled fruit juices as a higher percentage of their diet.
There have also been numerous studies linking long-term smoking with an increased risk of colon cancer, suggesting that maybe after many years with this vice, the damage has been done and it's too late to get the protective benefits of healthy nutrition. In one such study conducted through the American Cancer Society, researchers tracked nearly 185,000 volunteers between the ages of 50 and 74 from 1992 until 2005. Those who smoked for at least 40 years or didn't quit by the time they were 40 years old had a whopping 30-50% increased risk of developing colon or rectal cancer.
Colon cancer is the second most prevalent form of cancer in the Netherlands (where the study took place) and the third most prevalent in the United States. Worldwide, colorectal cancer is responsible for more than 600,000 deaths each year.
In addition, we shouldn't discount the effectiveness of powerful antioxidants in the foods we choose to eat, which may help protect many of us from many other types of cancers. In fact, curcumin, the yellow pigment/antioxidant found in the spice turmeric, has been shown to inhibit colon cancer cell growth. Used for centuries in Asian medicine to treat everything from heartburn to arthritis, it is now getting a closer look by Western scientists to see how it can help prevent or treat cancer.
Curcumin has been shown to slow the spread of cancer and new tumor blood vessel growth. It has even been reported to kill off cancer cells. It seems to be particularly effective in the treatment and prevention of colon cancer, with study results showing that patients taking 3.6 grams a day have slowed down the progression of the disease. Laboratory work has revealed that curcumin can decrease swelling and inflammation and clean up free radicals.
The one stumbling block found so far is that curcumin (either in turmeric or when taken as a concentrated supplement) is not easily absorbed by the body. However, mixing it with fat appears to aid in its absorption. And in fact, some curcumin supplements have been designed to have much higher absorption levels. As a side note, even if not fully absorbed, curcumin will be certain to reach the cells of the digestive tract, perhaps explaining its positive results with colon cancer. In other words, a study specifically on curcumin supplementation, colon cancer, and smoking might be particularly interesting. And while they're at it, they might want to add green tea catechins to the mix, since the combination of curcumin and green tea appears to be especially effective when it comes to colon cancer.