nutritional disorders
Food Additives and Contaminants
Contaminants
Sometimes limited amounts of contaminants are allowed in foods because the contaminants cannot be completely eliminated without damaging the foods. Common contaminants are pesticides, heavy metals (lead, cadmium, mercury), nitrates (in green leafy vegetables), aflatoxins (in nuts and milk), growth-promoting hormones (in dairy products and meat), animal hairs and feces, and insect parts. U.S. Food and Drug Administration (FDA)-estimated safe levels are levels that have not caused illness or adverse effects in people. However, demonstrating a causal relationship between extremely low level exposures and adverse effects is difficult; long-term adverse effects, although unlikely, are still possible. Safe levels are often determined by consensus rather than by hard evidence. So-called endocrine disrupting chemicals in the environment (eg, insecticides, petrochemicals, industrial solvents, plasticizers) can affect endocrine systems and alter hormone levels, causing alterations in sex organs, immune function, nervous system function, growth and development, and certain cancers. 