A genetic study published in 2026 found that eating doughnuts and sugar added to tea may increase colorectal cancer risk by 2.5 times and 1.3 times respectively, while yogurt intake appeared protective. According to Gram Research analysis, accelerated biological aging at the cellular level may explain part of this risk, though these findings are preliminary and require larger studies for confirmation.
According to Gram Research analysis, a new genetic study found that eating foods with added sugar—like sugar in tea and doughnuts—may be linked to a higher risk of colorectal cancer. The research also discovered that biological aging at the cellular level might be one way these sugary foods could increase cancer risk. However, scientists emphasize these are early findings that need more testing. The study used genetic data from thousands of people to explore connections between diet, aging, and cancer, offering new clues about how what we eat might affect our long-term health.
Key Statistics
A 2026 genetic study found that genetic predisposition to doughnut intake was associated with 2.5 times higher colorectal cancer risk compared to lower doughnut consumption.
Sugar added to tea showed a 1.3 times higher colorectal cancer risk in the 2026 study, though this finding did not pass the strictest statistical tests and should be considered suggestive evidence.
Yogurt intake was associated with approximately 25% lower colorectal cancer risk in the genetic analysis, suggesting potential protective effects of fermented dairy products.
GrimAge acceleration, a measure of cellular aging, showed a 10% increase in colorectal cancer risk per unit increase, with biological aging potentially explaining 36% of the sugar-tea and cancer association.
The Quick Take
- What they studied: Whether eating high-sugar foods and signs of faster biological aging are connected to colorectal cancer risk using genetic information
- Who participated: The study analyzed genetic data from large databases of thousands of people, examining their food choices and biological aging markers without directly testing individuals
- Key finding: People with genetic traits linked to eating doughnuts had 2.5 times higher colorectal cancer risk, and those who ate more sugar added to tea had 1.3 times higher risk. Yogurt intake appeared protective, lowering risk by about 25%
- What it means for you: This suggests reducing sugary foods like doughnuts and sweetened tea might help lower colorectal cancer risk, though these findings are preliminary and need confirmation in larger studies before making major dietary changes
The Research Details
Researchers used a special genetic method called Mendelian randomization, which is like using your genes as a natural experiment to understand cause-and-effect relationships. Instead of following people for years and watching what they eat, scientists looked at genetic variations that naturally make some people prefer certain foods. They then checked whether these genetic traits were connected to colorectal cancer risk in large databases.
The study examined 25 different high-sugar food traits and five measures of biological aging—basically how fast people’s cells are aging at a genetic level. The researchers used data from genome-wide association studies, which are massive databases containing genetic information from hundreds of thousands of people. This approach is powerful because genes are randomly inherited and don’t change based on lifestyle, making it easier to spot true cause-and-effect relationships rather than just coincidences.
The team also performed additional analysis to see if aging might be the mechanism connecting sugary foods to cancer—essentially asking whether eating sugar makes cells age faster, which then increases cancer risk.
Traditional studies that just ask people what they eat can be misleading because people who eat more doughnuts might also exercise less, smoke more, or have other unhealthy habits. Using genetic information helps separate the true effect of food from these other factors. This genetic approach is particularly valuable for understanding cancer risk because cancer develops slowly over many years, making it hard to study with regular methods.
This study has important strengths: it used very large genetic databases and a scientifically rigorous method. However, readers should know that the findings for specific foods did not pass the strictest statistical tests (FDR correction), meaning they’re considered ‘suggestive evidence’ rather than definitive proof. The mediation finding—that aging might explain part of the food-cancer link—also didn’t meet the highest statistical standards. The study authors themselves emphasize these results need validation in larger, independent datasets before being considered conclusive.
What the Results Show
The study found three main food-cancer connections. Doughnut intake showed the strongest association, with genetic predisposition to eating doughnuts linked to 2.5 times higher colorectal cancer risk. Sugar added to tea showed a more modest but still notable association, with 1.3 times higher risk. In contrast, yogurt intake appeared protective, associated with about 25% lower cancer risk.
When examining biological aging, the researchers found that GrimAge acceleration—a measure of how fast someone’s cells are aging based on genetic markers—was positively associated with colorectal cancer risk. For every unit increase in GrimAge acceleration, cancer risk increased by about 10%.
Most intriguingly, the mediation analysis suggested that accelerated biological aging might explain about 36% of the increased cancer risk from eating sugar added to tea. This means that one way sugary foods might increase cancer risk is by making cells age faster. However, this mediation finding did not achieve statistical significance in the strictest sense, so it remains suggestive rather than proven.
The study examined four other aging measures (intrinsic epigenetic age acceleration, PhenoAge acceleration, Hannum age acceleration, and mitochondrial DNA copy number) but found no significant associations with colorectal cancer risk. This suggests that GrimAge acceleration may be a particularly relevant aging marker for cancer risk, though why this specific measure matters more than others remains unclear.
This research builds on earlier observations that high-glycemic foods (foods that quickly raise blood sugar) and biological aging might increase cancer risk. However, previous studies couldn’t definitively prove cause-and-effect because of confounding factors—other lifestyle differences between people who eat different diets. This genetic approach provides stronger evidence for a causal link, though the specific foods studied (doughnuts, sugared tea, yogurt) haven’t been extensively examined in prior colorectal cancer research. The finding that yogurt may be protective aligns with some previous research suggesting fermented dairy products have health benefits.
The study has several important limitations. First, the findings for specific foods did not pass the strictest statistical correction tests, meaning they could partly be due to chance. Second, the study used genetic data as a proxy for actual food intake, which may not perfectly reflect real eating habits. Third, the mediation analysis—the most novel finding about aging as a mechanism—didn’t meet the highest statistical standards and needs replication. Fourth, the study couldn’t identify which specific components of these foods (sugar, fat, additives) drive the associations. Finally, the research is based on genetic associations in specific populations, primarily of European ancestry, so results may not apply equally to all ethnic groups.
The Bottom Line
Based on this suggestive evidence (not yet definitive), consider moderating intake of doughnuts and sugar added to beverages, and increasing yogurt consumption. However, these recommendations should be viewed as preliminary. The strongest evidence for colorectal cancer prevention still comes from established guidelines: eat more fiber, maintain a healthy weight, exercise regularly, limit red meat, and avoid smoking. Consult your doctor about your personal colorectal cancer risk and screening recommendations.
This research is most relevant to people concerned about colorectal cancer risk, particularly those with family history of the disease. It’s also important for public health officials and nutritionists developing dietary guidelines. People should not make dramatic dietary changes based solely on this preliminary evidence. Those with existing health conditions or taking medications should discuss any dietary changes with their healthcare provider.
If these findings are confirmed and you make dietary changes, realistic benefits would likely take years to manifest, since colorectal cancer develops slowly. The value of these findings is in long-term prevention strategy rather than immediate health improvements. Screening remains the most effective way to catch colorectal cancer early, regardless of diet.
Frequently Asked Questions
Does eating doughnuts really cause colorectal cancer?
A 2026 genetic study found associations between doughnut intake and higher colorectal cancer risk, but this doesn’t prove doughnuts directly cause cancer. The findings are preliminary and need confirmation. Colorectal cancer develops from multiple factors including age, family history, and lifestyle habits.
Can yogurt prevent colorectal cancer?
The 2026 study found yogurt intake was associated with about 25% lower colorectal cancer risk genetically. However, this is suggestive evidence, not proof of prevention. Yogurt may help as part of a healthy diet, but it’s not a substitute for screening and other proven prevention strategies.
How does eating sugar make cells age faster?
The study suggests a possible link between high-sugar foods and accelerated biological aging (measured by GrimAge), which may increase cancer risk. The mechanism isn’t fully understood yet. High-sugar diets can affect inflammation and metabolism, which may influence cellular aging, but more research is needed.
Should I change my diet based on this study?
These findings are preliminary and didn’t pass the strictest statistical tests. Rather than making dramatic changes, focus on established colorectal cancer prevention: eat more fiber, maintain healthy weight, exercise, limit red meat, and get appropriate screening. Discuss any dietary changes with your doctor.
What’s the difference between this genetic study and regular nutrition research?
Genetic studies use inherited traits as natural experiments to prove cause-and-effect, avoiding confounding factors that plague traditional diet studies. However, they’re less direct than observing actual eating habits. This study’s findings are suggestive but need confirmation through larger studies and real-world observation.
Want to Apply This Research?
- Track weekly intake of high-sugar foods (doughnuts, sugared beverages) and yogurt servings. Set a goal to reduce sugary foods to fewer than 2 servings per week while increasing yogurt to 3-4 servings weekly. Monitor changes over 3-month periods.
- Use the app to set reminders for healthier snack choices when cravings hit. When you’d normally grab a doughnut, log a yogurt-based snack instead. Track the substitution to build awareness of dietary patterns and create positive reinforcement.
- Create a long-term dietary pattern dashboard showing monthly trends in high-glycemic food intake versus protective foods like yogurt. Combine this with other cancer-prevention behaviors (fiber intake, exercise, screening reminders) to build a comprehensive prevention strategy.
This article summarizes preliminary genetic research and should not be considered medical advice. The findings are suggestive evidence that requires validation in larger studies before clinical application. Colorectal cancer risk is influenced by many factors including age, family history, genetics, and lifestyle. Consult with your healthcare provider about your personal cancer risk, appropriate screening, and dietary changes. This research does not replace established cancer prevention guidelines or medical screening recommendations.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.