We’ve been hearing it for years: a healthy, wholesome diet is enormously important to long-term health, and can also help hold off diseases such as cancer.
And now the relation between diet and, specifically, cancer risk is underscored by an important new study. Researchers at Tufts University found that maintaining a poor diet plays a major role in cancer risk, and it shone a light on what kinds of healthy foods, such as whole grains, can help prevent cancers.
Read MoreColorectal cancer had the highest number and proportion of diet-related cancer cases, with about 52,225 diagnoses, or about 38.3% of colorectal cancer diagnoses attributable to poor diet.
“It’s especially relevant with colon cancer, because when you eat something, the majority of its time it spends in your colon,” says Dr. Yeo. By contrast, “small bowel cancer is rare because food moves through the small bowel really fast.”
People who didn’t eat a lot of whole grains had the highest incidence of cancer. About 27,763 cases or 1.8 percent were attributable to this dietary problem. People who didn’t consume enough dairy products followed in second with 17,692, attributable cases, or 1.2 percent.
The data in these results comes from a huge number of studies. “Basically, it’s a study of a lot of studies,” says Dr. Yeo about the process of collecting this data. “Diet is really hard to study, so what we’ve typically done is have these large cohort studies of big numbers of people who fill out weekly surveys about their average diet. Over those people we compile meta-analyses, and this is a study of meta-analyses.” A meta-analysis is a method of reporting data collected from multiple studies. This study is a collection of those collections.
And they usually try to predict cancer risk given certain lifestyle factors. “Most of these meta-analyses try to give our average risk,” Dr. Yeo continues. “For example, if you are person with a high fiber diet or a low fiber diet, who is more likely to get cancer? In this study, they used all of these meta-analyses, and then they tried to say, ‘okay, if the person had all these different risk factors, how much does that put them at risk for cancer overall.'”
High intake of processed meats was also important, with 14,524 cancer cases attributable to too much consumption, or 1.0 percent. “So we know red meat, processed meat put you at risk,” says Dr. Yeo. “In countries where they eat a lot of processed foods, like in Japan where they eat a lot of cured meats, there is high incidence of gastrointestinal cancers.”
The study didn’t talk about fiber, but fiber is really good for decreases colorectal cancer risk. “People with the highest fiber diets, have the lowest risk of colon cancer,” says Dr. Yeo. “When you eat fiber, your transit time is a little faster in your colon, and the second thing is that it helps with good bacteria, so it helps the micro-bio, and high fiber diets are usually lower in sugar, and we know that sugar puts you at higher risk for cancer because of inflammatory factors. There’s a link also between high dietary sugar and colon cancer.”
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