While in Augusta, Montana, Mel's Diner had this advertisement from the January 1927 edition of The Ladies' Home Journal:
Here's the large type version. Read and learn:
Advertising in the 1920's and 1930's also included Lucky Strike's "20,679 Physicians say 'Luckies are less irritating'" and RJ Reynolds' "More Doctors smoke Camels than any other cigarette".
Maybe it's best to not trust advertising for health and nutrition advice, but instead rely on your own experience.