The Environmental Protection Agency has warned for years about limiting the amount of canned tuna we eat in order to avoid mercury poisoning. Children and pregnant women in particular should eat only around three 8-ounce portions per month if eating the canned white variety. A safer choice is canned light tuna, which has about one-third the parts per million of mercury in comparison, which is safe enough to eat once a week. An even better choice? The brand Safe Catch tests every fish for mercury before processing it, so it's almost guaranteed to be completely free of mercury with each flaky bite.