Packages of almonds, hazelnuts, pecans, pistachios, walnuts and peanuts soon will be touting new labels: they're Grade B health foods.

That's part of a new grading system by the Food and Drug Administration to allow manufacturers to make certain claims on their products.

Previously, food makers needed to have "significant scientific agreement" to carry any health claim on food labels and in advertising. For example, high-fiber foods, such as certain cereals, could have a label stating that diets high in fiber can reduce the risk of some types of cancer, which scientists almost universally believe to be true.

Now foods can carry a health claim with a corresponding grade (A, B, C or D) that reflects the quality of the scientific evidence behind the claim, even if that evidence isn't conclusive. A product claim would receive an A grade if the FDA believes there is "significant agreement" backing it up. A product claim would receive a D grade if the agency believes there is "little scientific evidence" supporting it.

Nuts are the first food to apply for and receive permission to run a health claim under the new program. Mounting evidence has shown that nuts contain unsaturated fat (the good kind) that appears to lower cholesterol, but too few studies have been done to show with certainty that nuts can reduce the risk of certain diseases.

Companies that sell many types of nuts can run a level B health claim (the evidence is moderate but not conclusive) as long as they're not packaged in fatty foods, like ice cream.

The new FDA program has drawn praise from some health experts, who say it will help consumers identify healthful foods. Others have criticized the program, saying it will mislead shoppers. The Center for Science in the Public Interest, a consumer watchdog group, has filed suit against the FDA challenging the new program.

FDA officials say the system will give consumers more nutrition information that is easier to understand.