The breast is a unique organ that undergoes the majority of its development postnatally. A rudimentary mammary gland ductal tree exists in both males and females at birth. Extensive development occurs during puberty in girls under the influence of ovarian hormones estrogen and progesterone.
There is growing evidence from epidemiological and animal studies that timing of puberty and the diet consumed during puberty have lasting consequences for adult breast cancer risk. Aligned with the developmental origins of adult health and disease paradigm, puberty can therefore be considered a key developmental stage that affects the risk of breast cancer during adulthood.
While specific components of the diet during puberty can increase breast cancer risk, a restricted diet may also affect healthy breast development. A high fat diet leads to sustained increased risk of cancer that cannot be reversed by a healthy diet during adulthood. On the other hand, increased adipose tissue deposition through increased consumption of a healthy diet reduces adult breast density and the associated risk of cancer.
Interventions that emphasise good nutrition for adolescent girls, rather than thinness, have potential to promote healthy breast development and reduced lifetime breast cancer risk.