Table 2.
Summary of the role of vitamins in gastrointestinal and liver diseases based on published intervention trials
| Vitamin | Colorectal cancer | Other gastrointestinal malignancies | Inflammatory bowel disease | Chronic hepatitis C | Other |
| A | No role | No role | No role | Controversial (not enough data) | May improve chronic pancreatitis pain |
| B1 | No data | No data | Improved IBD fatigue syndrome | No data | No data |
| B2 | Probably protective (non-randomized trials) | No role | No data | No data | None |
| B6 | Probably protective (non-randomized trials) | No role | No data | No data | Possible benefit in celiac disease |
| B9 | Probably protective (non-randomized trials) | Probably protective for pancreatic cancer | No data | No data | Possible benefit in celiac disease |
| B12 | No role | No role | No role | Probable adjunctive effect (one RCT) | Aphtous stomatitis |
| Possible benefit in celiac disease | |||||
| C | No role | Probable protective role in esophageal and pancreatic cancer | No role | No role | Prevention of gallstones |
| D | No role | Not protective against esophageal or pancreatic cancer | Inverse relation probable preventive and therapeutic effects | Additive effect to standard therapy (two RCTs) | Beneficial role in cholestatic liver diseases |
| E | No role | No role | No role | No data | Therapeutic role in non-alcoholic steatohepatitis |
| K | No role | Probably protective in HCC | No role | No role | None |
No role: No evidence by currently available interventional trials; No data: No good quality interventional trials available; Most vitamins had an inverse relationship with the risk of CRC, however interventional trials failed to prove a beneficial preventive role. Probable role: Data from observational studies or inconsistent RCTs results.