Casting the Nets

Casting the Net for a Colon Cancer Problem with SSBs

The best thing to demonize is sugar-sweetened beverages, says Harvard’s Mary Bassett. She pointed this out at the Roundtable on Obesity Solutions last month. Thus, yet another paper from Harvard about yet another danger of drinking something sweet is no surprise. This time, it’s about a link between SSBs and colon cancer. In fact, to find this correlation, these researchers drilled down even further. They focused on colon cancer before the age of 50 – early onset colon cancer. By drilling down this deep, they found a statistically significant association.

So they conclude that cutting back on SSBs may be a good strategy “to alleviate the growing burden of early onset colorectal cancer.”

Another Correlation from the Nurses Health Study

Their finding comes from the Nurses’ Health Study II, using data from 96,464 women. Among other things, they reported what they were drinking as adults under the age of 50. Some of them (41,272) also reported what they were drinking in their teens. In all, they found only 109 cases of early onset colon cancer.

But after crunching all their numbers and adjusting for all of the relevant variables they knew about, the epidemiologists came up with what they were looking for. Early onset colon cancer was twice as likely in women who say they drink two or more servings of a sweet drink per day. The comparison group was women who say they drink less than one per week.

The Leap from a Link to Policy

Of course, finding a correlation does not prove that SSBs cause colon cancer. In fact, the experience with the Nurses’ Health Study [NHS] tells us to be cautions. In PLOS One, Vicky Tai, Andrew Grey, and Mark Bolland looked at the reliability of the many observations this study has spawned. They concluded:

“NHS publications contain a large number of analyses, the majority of which reported statistically significant but weak associations. Few of these associations have been tested in RCTs, and where they have, the agreement between NHS results and RCTs is poor.”

In an editorial alongside the Harvard study, Neil Murphy, Peter Campbell, and Marc Gunter are appropriately cautious. “This provocative result needs to be validated in larger studies across different populations,” they write.

U.S. Trends in Caloric Sweeteners per Capita 1966-2019

But the mission to demonize SSBs cannot wait. Yin Cao was senior author of the new research and she tells the New York Times:

“This is an opportunity to revisit policies about how sugar-sweetened beverages are marketed, and how we can help reduce consumption.”

Will driving SSBs further down solve the problem of early onset colon cancer? We have our doubts. Consumption of SSBs and caloric sweeteners in total has been declining now for two decades. Yet obesity and early onset colon cancer keep going up.

How much harder do we need to press the demonize button?

Click here for the new study and here for the commentary that goes with it. For reporting from the New York Times, click here.

Casting the Nets, painting by Konstantinos Volanakis / WikiArt

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July 7, 2021