Lead is a heavy metal that can be present in some lipsticks due to pigments used. Brominated vegetable oils (BVOs) are used as emulsifiers in some soft drinks, though their use is controversial and restricted in some regions. Monosodium glutamate (MSG) is a flavor enhancer commonly used in Chinese fast food, and while generally recognized as safe by regulatory bodies, it is often associated with adverse reactions by some individuals and is thus considered controversial by a segment of the population.