For many people with diabetes, the importance of a healthy diet is most closely tied to blood glucose control and cardiovascular health. But as important as it is to eat in a way that’s best for your diabetes and heart health, there are other health conditions to keep in mind when you decide what and how to eat — including certain forms of cancer.
Colon cancer is one of the most common forms of cancer, with over 100,000 new cases diagnosed each year in the United States, according to the American Cancer Society. This rate has actually dropped since the mid-1980s, due to both better screening for pre-cancerous growths and improvements in diet-related risk factors. But the burden of colon cancer remains high, and the rate of diagnosis has actually grown alarmingly in younger adults.
Now, a new analysis highlights two of the most important dietary risk factors for colon cancer: alcohol and red meat intake.
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Heavy alcohol use most important dietary factor
The analysis, published in the journal JAMA Network Open, looked at many different previous studies on risks for colon cancer with the aim of evaluating the quality of the evidence. Researchers looked at 45 meta-analyses (combined analyses of previous studies), which described a total of 109 different links between dietary factors and colon cancer risk.
At first, the researchers found that out of the 109 dietary factors described in the previous studies, 35 were statistically significant. But 17 of them showed large differences between studies, a clue that they might not actually be clear factors in colon cancer development. And 11 other factors were found to be vulnerable to skewed results due to a small study size. In the end, the researchers identified only five dietary factors that could be rated as “convincing” due to the strength of the evidence: a high intake of alcohol or red meat contributed to colon cancer risk, while a high intake of dietary fiber, calcium or yogurt reduced this risk.
Drinking at least four alcoholic beverages per day was linked to a 58% higher colon cancer risk, while a high intake of red meat was linked to a 13% higher risk. A high total dietary fiber intake was linked to a 16% lower colon cancer risk, while a high calcium intake was linked to a 23% lower risk, and a high yogurt intake was linked to a 19% lower risk.
The researchers also identified some other factors that they rated as “highly suggestive” of a link to colon cancer. A higher intake of total dairy products was linked to a lower colon cancer risk, while a moderate intake of alcohol — defined as one to three drinks per day — was linked to a higher colon cancer risk. There was some weaker “suggestive evidence” for several other factors that might help protect against colon cancer, including adherence to a Mediterranean diet, healthy diet, pesco-vegetarian diet, or semi-vegetarian diet; and intake of whole grains, nonfermented milk or calcium supplements.
How much should you change your diet?
This analysis demonstrates just how difficult it can be to figure out how certain foods affect our risk for various health conditions, since there are so many different kinds of studies that sometimes yield different results. But even so, a few factors stood out as being convincingly linked to a person’s colon cancer risk.
It should be reassuring that two of the strongest findings in the analysis — those concerning heavy drinking and high red meat consumption — relate to dietary practices that most people probably already know are unhealthy, and should be avoided for reasons other than colon cancer risk. Higher fiber intake, on the other hand, has wide-ranging health benefits, including on both digestive and heart health. And yogurt is widely touted for its probiotic qualities, meaning that it typically contains healthy bacteria that may improve your digestive and overall health.
So for the most part, this analysis just confirms dietary advice that you’ve probably already been given, both for your diabetes and for general health. It also seems to confirm the importance of getting enough calcium in your diet, especially by eating dairy foods. So eat more yogurt, if you like it — but look out for sugar — and continue to follow a healthy diet to make sure your colon cancer risk is as low as possible.