A study on the effects of milk consumption on growth hormone (GH) and insulin-like growth factor 1 (IGF-1) in children suggests that milk drinking may cause increases in pituitary growth hormone levels of prepubertal girls and boys.

The article, published in Nutrition Journal[1] measured the effects of drinking three 8-ounce tetrapak “boxes” (710 ml) of conventional U.S. UHT-pasteurized vitamin D fortified whole milk daily for one month (the producer of the milk accepts milk only from dairies that do not use bovine somatotropin). A class of Mongolian children (who rarely consume milk) were compared with American children: the Mongolian children experienced rapid linear growth (the equivalent of 12 cm/year) compared to an average height velocity of 5-6 cm/year in U.S. children age 10-11 years. It is suggested that this was not the effects of correcting undernutrition, but that milk intake may raise GH levels. This is a novel finding, and the authors suggest that "nutrients or bioactive factors in milk may stimulate endogenous GH production," that is, secretion of hormones from the pituitary gland may be increased by drinking milk.

Apart from stimulating abnormal growth in prepubertal children, what could be the long-term side-effects of an increase in the pituitary growth hormone in those with otherwise normal growth hormone levels? Another study [2] notes how GH/IGF-1 provides an anti-apoptotic environment (a situation where programmed cell death is delayed) that may favour survival of genetically damaged cells.

Follow up:

References:

1. Rich-Edwards JW, Ganmaa D, Pollack MN, et al. "Milk consumption and the prepubertal somatotropic axis"Nutrition Journal 27 Sept. 2007, 6:28 doi:10.1186/1475-2891-6-28

2. Jenkins PJ, Mukherjee A, Shalet SM. "Does growth hormone cause cancer?" Clin Endocrinol (Oxf). 2006 Feb;64(2):115-21. PMID: 16430706