The NAD review was prompted by rival Procter & Gamble Co.'s Iams pet food business.
NAD concluded the evidence provided by Hill's was insufficient to support the unqualified claims and recommended future advertising disclose the longevity claim is limited to dogs experiencing kidney failure.
NAD also recommended that longevity bar graphs used to depict extended life expectancy clearly disclose the units of time measure.
In a statement to NAD, Hill's Pet Nutrition agreed to take into account NAD's recommendations for modifications to future advertising. But at the same time, it said it believes it submitted ample data to substantiate its claims of "Most Effective Pet Food for Managing the Oral Health of Cats and Dogs" and "Reduces Painful Inflammation of the Gums," and that it reserves the right to use them in future ads in the U.S.