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White bread and alcohol may contribute to colorectal cancer risk, new research shows. Design by MNT; Photography by SEAN GLADWELL/Getty Images & Lucy Lambriex/Getty Images.
  • Colorectal cancer is a common cancer type that can lead to poor health outcomes.
  • Research is ongoing about risk factors for colorectal cancer and what people can do to decrease risk.
  • Data from a recent study found that consuming higher amounts of white bread and alcohol was associated with an increased risk for colorectal cancer.
  • In contrast, they found that higher intakes of fiber, calcium, magnesium, phosphorus, and manganese were associated with a decreased risk for colorectal cancer.

Cancer comes in several types that experts still do not fully understand. While cancer research has come a long way, it is still not always clear why some people develop specific types of cancer.

Colorectal cancer is one cancer type that can be severe and sometimes fatal. Experts are still seeking to understand ways that people can decrease their risk of developing colorectal cancer.

A study published in Nutrients examined the risk for colorectal cancer related to the intake of certain foods and nutrients.

Analyzing data from over 118,000 participants, researchers found that alcohol and white bread intake were associated with a higher risk for colorectal cancer, while consuming higher amounts of fiber and nutrients like calcium was associated with a decreased risk.

More research will help confirm these findings and potentially lead to guidance in clinical practice.

Researchers of this particular study wanted to understand more about how food and nutrient intake contributed to colorectal cancer. They note that certain foods and nutrients carry a risk that people can modify, making it an important area of research.

To conduct their analysis, they used data from the U.K. Biobank, which provides substantial information. They examined the relationship between 139 foods and nutrients and colorectal cancer risk. They also looked at how this risk interacted with genetic susceptibility to colorectal cancer.

Overall, researchers included 118,210 participants and followed participants for an average of almost 13 years. During the follow-up, there were 1,466 cases of colorectal cancer.

Researchers collected data on food consumption via 24-hour dietary questionnaires. All participants in the analysis completed at least two 24-hour online dietary assessments. They excluded participants who already had colorectal cancer at baseline.

They adjusted the analysis based on several covariates, like education level, family history of colorectal cancer, body mass index, and physical activity levels.

Researchers were also able to create polygenic risk scores for colorectal cancer for participants. Polygenic risk scores help determine someone’s risk for a condition based on their genetics.

They found that participants who developed colorectal cancer were more likely to have certain characteristics. For example, they were more likely to be older, have a higher body mass index (BMI), and engage in lower physical activity levels.

The study also found that white bread and alcohol were both associated with an increased risk for colorectal cancer. However, dietary fiber, calcium, magnesium, phosphorus, and manganese were all associated with a decreased risk for colorectal cancer.

The study did not find evidence that participants’ genetic background influenced risk related to consumption of nutrients.

Rick Miller, a registered dietitian at King Edward VII’s Hospital, London, in the United Kingdom, and principal dietitian at Miller & Everton, not involved in this research, shared his thoughts on the study to Medical News Today:

“An interesting finding was that the authors reported white bread, which could be defined as an ultra-processed food was associated with an elevated colorectal cancer risk, over alcohol. The authors also saw an inverse risk association with dietary fibre intake which was equal with the risk reduction seen with manganese intake.”

The impact of these risks may be different for men and women.

The study reported that, “[a]mong women, no dietary factor was significantly associated with CRC [colorectal cancer] risk after multiple corrections.”

Dr. Brian Black, a board-certified osteopathic physician specializing in family medicine and emergency medicine, not involved in this study, noted that its findings “[support] existing literature reinforcing the body of evidence that alcohol and white bread are positively associated with colorectal cancer risks.”

“These fit within a broader understanding of the potential adverse effects of diets high in refined carbohydrates and their link to a risk of cancer,” he added.

“This study would support specifically dietary fiber, calcium, magnesium, phosphorus, and manganese intake as important positive factors. This review was a helpful study which supported the current understanding of the dangers associated with refined carbohydrates and the need for a varied diet high in vitamins and minerals. Its questions and aims may lead future research in multicentered trials, including more than one continent, to lead to specific identification of genetic predisposition to colorectal or other cancers.”

– Dr. Brian Black

Overall, this study adds knowledge about potential risk factors for colorectal cancer. However, its limitations should also be taken into account.

First, it focuses on the European population, meaning the results might not be as applicable to other groups. The authors also note that they were somewhat limited in their ability to look at the independent effects of certain nutrients.

Furthermore, some data were self-reported by participants, which may lead to errors. Researchers note that future studies can help confirm what this study found. It could also further look at the difference between men and women in colorectal cancer risk.

Miller noted that future research could also look at the difference between plant and animal sources of certain nutrients and decreased risk for colorectal cancer.

“The authors also reported that high dietary intake of calcium, magnesium, and phosphorus were associated with lower [colorectal cancer] risk,” he told MNT.

” Dietary sources of these key nutrients are found in many foods both plant (eg. wheatgerm, legumes, nuts, seeds) and animal-based (dairy products, meat and shellfish). However, the relative bioavailability of these micronutrients is lower in plant-based foods and hence it is difficult to draw the conclusion that the CRC risk reduction would be the same between animal versus plant-sources and a further interventional trial would need to be conducted to ascertain this.”

– Rick Miller

Colorectal cancer includes all cancers of the large intestine and rectum. Colorectal cancer can begin when polyps form on the inner walls of the large intestine or rectum. As noted by the Centers of Disease Control and Prevention (CDC), “[c]olorectal cancer is a leading cause of cancer death in the United States.”

Doctors can sometimes detect colorectal cancer early when there is a better chance of effective treatment. This is why there is a significant emphasis on early screening for colorectal cancer.

Researchers are also interested in understanding risk factors for colorectal cancer. Risk factors include increased age, family history of colorectal cancer, eating a diet with minimal fruits and vegetables, and obesity.

When researchers understand more about modifiable risk factors, doctors can better advise patients about healthy lifestyle changes that can help reduce risk.