When a food is alleged to be misbranded because the labeling is misleading, or when an advertisement of a food is alleged to be false because it is misleading, then in determining whether the labeling or advertisement is misleading, there shall be considered, among other things and in addition to representations made or suggested in the labeling or advertising, the extent to which the labeling or advertisement fails to reveal facts material in light of such representations or material with respect to consequences which may result from use of the food under the conditions of use prescribed in the labeling or advertisement or under such conditions of use as are customary or usual.