Lead absorption: Impact of dietary factors

The overall objective of this project was to investigate the effect of dietary factor (i.e. tea, protein source, canned fish) on lead status. In study I, 8 healthy humans consumed self-selected diets, with or without tea during two 7-day periods. Iron balances were more positive when diets without tea were consumed. Addition of tea to diets resulted in an increase in fecal lead and iron excretion, 30.2% and 19.4% respectively. Another ten-subject human study was conducted in which subjects were fed laboratory controlled diets with or without tea during two, 2-week periods. Feeding diets with no time limitation on tea consumption did not significantly affect iron and lead excretion of humans. In study II, sixty weanling rats were fed varied levels of dietary lead (0, 100, and 200 ppm) and varied protein sources (casein and soybean). Food consumption and body weight were significantly influenced by dietary treatments. Rat blood lead values were highly related to dietary lead content (linear relationship) (P $\u3c$ 0.1). A similar pattern was evident in other traits (femur and rib). Dietary protein did not produce any significant effects on the lead content of blood, brain, spleen, femur or rib. In study III, lead content of canned tuna apparently varied among 21 brands evaluated and with length of storage time. Lead content of the tuna increased significantly following 3 months of storage (P $\u3c$ 0.0001)