Washington ? The government is loosening restrictions on how much scientific proof is required to advertise a food’s possible health benefits on its package, a move welcomed by food makers but one that critics fear will leave consumers prey to quackery in the grocery aisles.

The Food and Drug Administration announced Thursday that it would accept applications to place “qualified” health claims on food labels beginning Sept. 1. Among the first to be considered: that eating several servings a week of salmon and certain other fish rich in omega-3 fatty acids is thought to, but not proved to, reduce the risk of heart disease.

“We want to help increase America’s nutritional grade-point average,” FDA Commissioner Mark McClellan said. “Americans shouldn’t need a science degree to figure out how foods can fit into a healthy diet. Information should be accurate, honest and easy to understand.”

Until now, the FDA has enforced a very strict standard about what health claims could be made on food labels. Before oatmeal could boast heart-healthy labels, for example, there had to be significant scientific consensus that oatmeal’s fiber helps maintain low cholesterol levels.

Under the new program — backed by food manufacturers — FDA will give a grade to applications for new food claims: A for scientifically proven claims; B where the science is good but not conclusive; C when there’s limited science to support a claim; and D when there’s hardly any evidence.