March 2, 2026, 10:13 am | Read time: 4 minutes
Whether with meat, vegetarian, or purely plant-based: For years, research has been examining how different diets affect cancer risk. A large analysis published in the “British Journal of Cancer” has now evaluated these relationships for 17 types of cancer.
What Did the Study Examine?
An international research team led by the University of Oxford analyzed data from 1,817,477 men and women from nine major long-term studies in the United Kingdom, the United States, India, and Taiwan.1 Participants were followed for an average of about 16 years. Five dietary patterns were compared, with regular meat consumers serving as a fixed reference group:
- People who eat red or processed meat
- Individuals who eat poultry but no red meat
- Pescatarians who eat fish but no meat
- Vegetarians
- Vegans
It is important to note: In the underlying studies, meat consumption was generally moderate. High consumption was not separately examined.
Overall, the researchers looked at 17 different types of cancer. In their calculations, they considered key influencing factors such as smoking, alcohol consumption, physical activity, and body weight.
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The Results
The differences were not observed in all types of cancer, but only in some.
Cancer of the Intestines and Digestive Organs
For colorectal cancer, a pescatarian diet was associated with a 15 percent lower risk. However, for vegans, there was a 40 percent higher risk of colorectal cancer. This result is based on only 93 cases and should therefore be interpreted with caution. Additionally, the association weakened significantly after excluding the first four years of observation from the analysis to reduce potential biases. Researchers discuss a possible explanation as the partially low calcium intake in a purely vegan diet.
For pancreatic cancer, a vegetarian diet was associated with a 21 percent lower risk. However, this association weakened in additional analyses. A peculiarity was observed in a specific form of esophageal cancer, squamous cell carcinoma. Here, vegetarians had nearly twice the risk. This finding is based on only 31 cases.
Hormone-Dependent Cancers
For breast cancer, the risk was 7 percent lower for pescatarians and 9 percent lower for vegetarians. This difference was observed only in postmenopausal women.
For prostate cancer, the risk was 7 percent lower for poultry eaters and 12 percent lower for vegetarians. Again, this association weakened in additional analyses.
Kidney and Blood Cancer
For kidney cancer, pescatarians had a 27 percent lower risk and vegetarians a 28 percent lower risk compared to meat eaters.
For multiple myeloma, a rare cancer of the bone marrow, a vegetarian diet was associated with a 31 percent lower risk. However, this association was less clear in further analyses.
Other Types of Cancer
For stomach, liver, ovarian, uterine, bladder, and several forms of blood cancer, the researchers found no clear differences between the dietary patterns.
There were also no differences for lung cancer. This evaluation was deliberately limited to lifelong non-smokers to exclude biases from smoking.
Important: According to the researchers, the findings on esophageal cancer and the lower risk for kidney cancer are among the most consistent results of the entire analysis. These associations remained in additional calculations.
What Does the Study Mean?
The evaluation shows that certain dietary patterns were associated with a lower, but sometimes also a higher, risk depending on the type of cancer. These are observed associations, not evidence of cause and effect. Some results are also based on a small number of cases and should be interpreted with caution. Since numerous types of cancer and dietary patterns were examined simultaneously, it is also possible that some differences arose by chance.
It is also important to note: Vegetarians and vegans had a lower body weight in many studies. Since a lower weight can itself reduce the risk for several types of cancer, this factor was statistically considered. In practice, the potential benefits of a plant-based diet could therefore be partly mediated by lower body weight.
Finally, dietary patterns differ significantly depending on the country and culture. Therefore, the results cannot be universally applied to all populations. Additionally, the quality of each dietary pattern was not assessed. Some participants may have consumed many highly processed foods or large amounts of sugar, which could affect the actual health effects.
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