In the 1970s, Danish researchers observed surprisingly low frequencies of heart disease among Greenland's indigenous populations that typically ate fatty fish, seals, and whales. The researchers attributed the protective effect to the foods' content of omega-3 fatty acids. Many studies of omega-3s have been conducted since, but their findings can be interpreted differently. In 2006 the Institute of Medicine (IOM) issued a review of studies on seafood consumption, concluding that eating seafood reduces the risk of heart disease but judging the studies too inconsistent to decide if omega-3 fats were responsible. In contrast, investigators from Harvard published a very positive report, stating that even modest consumption of fish omega-3s would substantially reduce coronary deaths and total mortality. Differences in interpretation explain how scientists examining the same studies could arrive at such different conclusions. The two groups, for example, had conflicting views of a study published in the British Medical Journal that found no overall effect of omega-3s on heart disease risk or mortality, although a subset of the data displayed a 14 percent reduction in total mortality that did not reach statistical significance. The IOM team interpreted the "nonsignificant" result as evidence of the need for caution, whereas the Harvard group saw the data as consistent with studies reporting the benefits of omega-3s.