Vitamin B6 and colorectal cancer:Current evidence and future directions

Colorectal cancer remains the third most common cancer in both women and men worldwide.Identifying modifiable dietary factors is crucial in developing primary prevention strategies.Vitamin B6 is involved in more than 100 coenzyme reactions,and may influence colorectal cancer risk in multiple ways including through its role in one-carbon metabolism related DNA synthesis and methylation and by reducing inflammation,cell proliferation,and oxidative stress.Observational studies of dietary or dietary plus supplementary intake of vitamin B6 and colorectal cancer risk have been inconsistent with most studies reporting nonsignificant positive or inverse associations.However,published studies of plasma pyridoxal 5'-phosphate(the active form of vitamin B6) levels consistently support an approximately 30%-50% reduction in risk of colorectal cancer comparing high with low concentrations.The reasons for the discrepancy in the results between dietary-based and plasma-based studies remain unresolved.Other unresolved questions include the effects of vitamin B6 intake in early life(i.e.,childhood or adolescence) and of suboptimal vitamin B6 status on colorectal cancer risk,whether the associations with vitamin B6 differ across molecular subtypes of colorectal cancer,and whether the vitamin B6-colorectal cancer association is modified by genetic variants of one-carbon metabolism.

2型糖尿病与癌症风险 有力证据显示糖尿病与几种主要癌症之间存在相关性

在过去的50年里，很多研究将糖尿病，尤其是2型糖尿病，与癌症发生率升高联系在一起。2010年，由美国糖尿病协会和美国癌症协会共同颁布的一项共识指出，2型糖尿病与某些类型癌症的发生风险升高显著相关（如结肠癌、乳腺癌、胆管上皮癌、肝癌、胰腺癌以及膀胱癌），而与另外一些类型癌症风险的关系尚无定论（如肾癌、白血病以及食道癌）。