Diet and Cancer: What Does an Analysis of 1.8 Million People Say About Vegetarian Diets?
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The most comprehensive study to date confirms the cancer-protective effect of a meat-free lifestyle while drawing attention to the “hidden risks” that missing nutrients can create.
On the journey to cancer prevention, “what we eat” is the subject of the greatest curiosity and speculation. Yet studies conducted in small groups can often be misleading. This new analysis published in the British Journal of Cancer followed a total of 1.8 million people from England, the US, India, and Taiwan for an average of 16 years, revealing the link between diet and cancer more clearly than ever before. This vast dataset not only confirms the restorative power offered by vegetarianism, but also sheds light on the unexpected turns involved in restrictive diets followed without sufficient knowledge (especially veganism).
Significant reductions in five main cancer types
The results proved that vegetarians have lower risks at five important cancer sites than meat eaters. Moreover, these findings were obtained independently of factors such as physical activity, body weight (BMI), smoking, and alcohol use. In other words, the protective effect appears to be related not merely to “being slim”, but directly to “what is eaten”.
A finding that challenges assumptions: why does colorectal cancer risk increase in vegans?
The study’s most surprising and controversial finding was seen in people following a vegan diet. In vegans, who exclude all animal products (including milk and eggs), a 40% higher risk of colorectal cancer was observed compared with meat eaters.
The Risk of Calcium and Vitamin B2 Deficiency
The researchers attribute this situation to two main deficiencies:
- Calcium: Not consuming dairy products can reduce intake of calcium, which is known to protect intestinal health. Calcium is thought to act as a “barrier” that balances processes of cancer development in the intestinal wall.
- Riboflavin (B2): The twofold increase in esophageal cancer risk among vegetarians is associated with a deficiency of vitamin B2, which is largely found in meat.
Vegetarians were also found to be no more protected from colorectal cancer (bowel cancer) than meat eaters. This may have resulted from the very low amounts of processed meat consumed by the meat-eating group (an average of 16g per day), or from differences in vegetarians’ fiber intake.
The protective power of fish and poultry
The study went beyond a simple distinction between “omnivores” and “vegetarians”; it also examined pescatarians (fish eaters) and people who consumed only white meat. The results show that a balanced intake of animal protein is also important on the journey to healing:
- Pescatarians: Among people who ate fish but not red meat, bowel cancer risk fell by 15% and kidney cancer risk by 27%.
- Poultry: A 7% reduction in prostate cancer risk was identified in men who consumed only chicken/turkey.
Healing lies in the balance on your plate
This vast study reminds us of the most fundamental law in oncology: “Everything is balance.” We cannot deny the tremendous power of plant-based eating in preventing cancer; however, on this journey we must not leave out building blocks our bodies need, such as calcium, vitamin B2, and protein.
It is vital for our friends who choose a vegan or vegetarian lifestyle to consume calcium-fortified foods in particular and, when necessary, vitamin supplements under a physician’s supervision. Preventing cancer is not simply removing a food from your life; it means conducting the body’s biological orchestra with the right notes (whole foods, vegetables, legumes, and healthy proteins). It is never too late to change your lifestyle habits; the silent testimony of 1.8 million people shows us this route.
Scientific sources and further reading
- 1. Dunneram Y, et al. (2026). Vegetarian diets and cancer risk: pooled analysis of 1.8 million women and men. British Journal of Cancer.
- 2. World Cancer Research Fund / American Institute for Cancer Research (WCRF/AICR). Diet, Nutrition, Physical Activity and Cancer.
- 3. Newcastle University Population Health Sciences Institute - Press Briefing (Feb 2026).
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