Plasma micronutrient antioxidants in cancer patients

The distribution of breast, colon, gastric, thyroid, oral, rectal, pancreatic and renal cancers were determined in 71 Kuwaitis, 45 other Arabs, and 26 Indians. Plasma levels of micronutrient antioxidants, retinol, alpha -tocopherol, lycopene, and alpha -carotene were measured in the groups and in 90 matched controls for comparison. Cholesterol was measured to determine its association with the micronutrient antioxidants. Pancreatic cancer occurred exclusively in Kuwaitis, while breast and colon cancers were disproportionately higher in Kuwaitis than in the other groups. Micronutrient antioxidant levels were similar in the groups, except for higher lycopene levels in Kuwaitis. In most instances, the micronutrient antioxidants, except beta -carotene, decreased significantly in levels in patients than in controls. Low levels of retinol, lycopene, and beta -carotene were strongly associated with pancreatic cancer. Compared to controls, significantly increased levels of beta -carotene occurred in breast, colon, thyroid, and renal cancers; increased lycopene occurred in oral cancer, and increased alpha -tocopherol occurred in pancreatic cancer. Alpha-tocopherol strongly correlated with cholesterol. Generally, changes in alpha -tocopherol/cholesterol ratios mimicked those of alpha -tocopherol levels. Micronutrient antioxidant levels were significantly lower in male patients than female patients. Age showed a negative but statistically insignificant relationship with micronutrient antioxidants. Lycopene strongly correlated with beta -carotene and alpha -tocopherol with retinol. Among the patients, all micronutrient antioxidants except retinol decreased significantly in levels in smokers than nonsmokers, suggesting susceptibility to cigarette smoke oxidative stress. We conclude that micronutrient antioxidant depletions and altered associations may imply tumor utilization or antioxidant burden in oxidative stress or both. Furthermore, the incidence of pancreatic, colon and breast cancers among Kuwaitis warrants further study.