Anna L. Bruenn, 79, a dentist who practiced in New York City for 54 years and who taught nutrition for four years at the Washington Saturday College of D.C., died of cancer April 28 at the Wisconsin Avenue Nursing House.

Dr. Bruenn, who is the mother of Washington columnist Nicholas von Hoffman, was born in Weehawken, N.J. She graduated from the University of Pennsylvania Dental School in 1919.

While practicing dentistry in New York City's Lower East Side Tenament House during the 1930s, Dr. Bruenn educated its residents to the importance of nutrition and preventive dental care. When she retired from her New York practice five years ago, she moved to Washington and began teaching nutrition one day a week at the Washington Saturday College of D.C., a free university. She taught there until last year.

Dr. Bruenn was secretary to the Homeopathic Laymen's League of New York City for many years.

In addition to her son, Dr. Bruenn leaves a brother, Richard Bruenn, of Berwyn, Pa.; a sister, Minna Bruenn Satterfield, of Boston, and three grandsons.

The family suggests that expressions of sympathy be in the form of contributions in the memory of Dr. Bruenn to the Foundation for Homeopathy, Falls Church, Va.