Dr. Karl E. Mason, 78, a retired program director with the National Institutes of Health, died Friday at Suburban Hospital in Bethesda following a heart attack.

Dr. Mason joined NIH in 1965 as director of the gastroenterology program with the National Institute of Arthritis, Metabolism, and Digestive Diseases. A year later, he became nrtrition program director of the NIADD, a job he held until retiring in 1975. he remained as a consultant until shortly before his death.

He was an authority in the fields of vitamin deficiencies and reproduction, the metabolic role of vitamin E, and the histopathology of nutritional deficiencies. He also had done research in in the fields of leprosy and muscular dystrophy. He wrote a number of articles for technical journals on these topics.

Before joining NIH, Dr. Mason had been a professor and chairman of the anatomy department at the University of Rochester's School of Medicine and Dentistry for 25 years.

He was a native of Kingston, Nova Scotia, and came to this country in the early 1920s.

He earned a doctoral degree in zoology and anatomy at Yale University in 1925. He taught anatomy at Yale and then at Vanderbilt University for 14 years until becoming a member of the University of Rochester faculty in 1940.

Dr. Mason was a member of the medical advisory board of the Muscular Dystrophy Association from 1951 to 1974 and of the Nutrition Study Section of NIH during the early 1960s.

His professional membership included the American Institute of Nutrition, the British Nutrition Society, and the Canadian Association of Anatomists. He was president of the American Association of Anatomists from 1967 to 1968.

He is survived by his wife, Pearl S., and a daughter, Donna Jean Fusonie, both of the home in Rockville; a brogher, the Rev. Merle Mason, of Ontario, Calif.; and three sisters, Marjorie Robertson, of Aylesford, Nova Scotia, Mrs. Mark Lohnes, of Milton, Mass., and Enid Davis, of New Brunswick, Canada.

The family suggests that expressions of sympathy be in the form of contributions to the Muscular Dystrophy Association.