Alexander Leaf (April 10, 1920 – December 24, 2012) was a physician and research scientist best known for his work linking diet and exercise to the prevention of heart disease.
He also contributed significantly to establishing the relationship between longer, hotter summers and outbreaks of infectious diseases like malaria in regions previously unaffected by them.
Leaf received his medical degree from the University of Michigan in 1943, completing his internship and residency at Massachusetts General Hospital from 1944 to 1946.
Leaf contributed significantly to the understanding of the causes of heart disease through his research on how sodium and potassium pass through cell walls.
In 1961, he became a founding member of Physicians for Social Responsibility, opposing nuclear proliferation.