Toxicological evaluation of brominated vegetable oil in Sprague Dawley rats

Brominated vegetable oil (BVO) has been approved by the US Food and Drug Administration on an interim basis as a food additive. Past studies have raised concerns about potential toxicities from consuming BVO. To investigate further these toxicities, we conducted a 90-day dietary exposure study in Sprague Dawley rats and analyzed tissue distribution of the main metabolites. Six-week-old male and female rats were fed diets containing 0 (control), 0.002%, 0.02%, 0.1%, or 0.5% BVO by weight. Statistically significant increases were observed in the serum bromide in the high-dose group of both sexes and in the incidence of thyroid follicular cell hypertrophy in the two highest dose groups of males and the high-dose group of females. An increase in serum TSH was observed in the high-dose group for both sexes, as well as a decrease in serum T4 in the high-dose males. A clear dose-response was observed in di- and tetra-bromostearic acid levels in the heart, liver, and inguinal fat. These data expand upon previous observations in rats and pigs that oral exposure to BVO is associated with increased tissue levels of inorganic and organic bromine, and that the thyroid is a potential target organ of toxicity.