critical, too — including diet, alcohol intake, smoking, exercise and antibiotic use.
What we put into out bodies really matters.
The spread of the “westernized” diet is a clear example, Ogino says. It’s high in heavily processed foods, added sugar and red meat, but low in fruits, vegetables, fiber and “good” fats — qualities that have been linked to increased risks of certain cancers, like colon cancer.
The rise in colon cancers among younger adults has been gaining particular attention. According to the U.S. National Cancer Institute, the incidence of that disease among Americans younger than 50 has more than doubled since the 1990s — in sharp contrast to a decrease among people older than 65.
In fact, the trend spurred experts to lower the recommended starting age for colon cancer screening. It’s now age 45 for people at average risk of the disease.
Dr. Benjamin Weinberg, an associate professor at MedStar Georgetown University Hospital in Washington, D.C., is studying the potential role of the gut microbiome in earlier-onset colon cancer. He also treats patients with the disease.
When a younger adult develops colon cancer, Weinberg says it suggests that something in the immune system response to early tumors has gone awry.
There is some evidence, he adds, that greater diversity in the gut microbiome may support that immune response.
On the other hand, certain bacteria might stymie it. A bug normally tied to gum disease — Fusobacterium nucleatum — is a case in point. Research suggests F. nuc may promote cancerous growths by suppressing the immune response in the colon. And Weinberg and his colleagues have found that colon tumors from younger adults have a high presence of the bacteria.
Obesity among children and younger adults has, of course, skyrocketed in recent years. And on the population level, Weinberg says, there is a relationship between obesity and colon cancer risk. But many younger people who are diagnosed with the disease are not