Changes in Serum Concentrations of β‐Carotene and Changes in the Dietary Intake Frequency of Green‐Yellow Vegetables among Healthy Male Inhabitants of Japan

Serum levels of β‐carotene among 147 healthy male inhabitants were measured twice with an interval of one year in order to determine the relationship between changes in serum β‐carotene levels and changes in the dietary intake of green‐yellow vegetables. A positive association was found to exist between changes in the intake frequency of green‐yellow vegetables and changes in serum β‐carotene levels, whereas changes in alcohol intake and smoking were discovered to be negatively associated with changes in serum β‐carotene levels. The positive association between changes in the intake frequency of green‐yellow vegetables and changes in serum β‐carotene levels was preserved after adjustment for these negative factors.