Salmon is a popular food. Classified as an oily fish, salmon is high in protein, omega-3 fatty acids, and vitamin D, and is therefore considered to be healthy. . Salmon is also a source of cholesterol, with a range of 23–214 mg/100 g depending on the species. According to reports in the journal Science, however, farmed salmon may contain high levels of dioxins. PCB levels may be up to eight times higher in farmed salmon than in wild salmon, but still far below levels considered dangerous. Nonetheless, according to a 2006 study published in the Journal of the American Medical Association, the benefits of eating even farmed salmon far outweigh any risks imposed by contaminants.