Reduction in Oocyte Number Following Prenatal Exposure to a Diet High in Galactose

Abstract

When pregnant rats were fed a 50 percent galactose diet there was a striking reduction in oocyte number in the offspring. The most prominent effects were noted after exposure to galactose during the premeiotic stages of oogenesis. Prenatal exposure to galactose or its metabolites may contribute to the premature ovarian failure characteristic of human galactosemia.

Ovarian effects of a high lactose diet in the female rat

“…The ovary has relatively abundant levels of three of the major enzymes involved in metabolism of galactose (galactokinase, galactose-1-phosphate uridyltransferase (GALT) and UDP-galactose-4-epimerase) [6]. This fact is thought to be causally related to the observation that women who have absent or low GALT activity have a propensity to develop premature ovarian failure and premature menopause [2,17]. However, since human diets contain foods high in lactose versus free galactose, our data are suggestive that women would not have the adverse effects observed in rodents that consume a high galactose diet.…”

“…Since the disaccharide lactose, consisting of one glucose molecule and one galactose molecule is the primary carbohydrate in milk, those who consume large quantities of dairy products in an effort to increase calcium intake for osteoporosis prevention ingest large quantities of lactose. The toxic effect of galactose or its metabolites within the ovary became apparent from the observations of extremely early ovarian failure (before age 30 years) in women with galactosemia (genetic absence of the enzyme galactose-1-phosphate uridyl transferase) [2]. Animal studies have suggested that diets rich in galactose produce insults that are at least somewhat comparable to those seen in galactosemics [2][3][4].…”

“…The toxic effect of galactose or its metabolites within the ovary became apparent from the observations of extremely early ovarian failure (before age 30 years) in women with galactosemia (genetic absence of the enzyme galactose-1-phosphate uridyl transferase) [2]. Animal studies have suggested that diets rich in galactose produce insults that are at least somewhat comparable to those seen in galactosemics [2][3][4]. Furthermore, the importance of galactose metabolism for healthy ovarian function is also suggested by the relative abundance of galactose-metabolizing enzymes in ovarian tissue [5].…”

“…The implication is that women ingesting large amounts of galactose may unknowingly foreshorten the functional lifespan of their ovaries. Animal studies showing toxic effects of dietary galactose have used diets rich in galactose [2][3][4] which differs from the human situation where galactose exposure results from dietary lactose. Thus, discrepancies in the literature regarding galactose and ovarian failure may be attributable to the different forms of the dietary sugar (monosaccharide versus disaccharide) used in animal experiments.…”

Premature Ovarian Failure and Ovarian Autoimmunity

“…POF or premature menopause is a syndrome clinically defined by failure of the ovary before the age of 40 yr (1). POF is a heterogeneous disorder with a multicausal pathogenesis, and chromosomal (2-9), genetic (4, 10 -12), enzymatic (13)(14), iatrogenic (15)(16)(17)(18)(19)(20), or infectious (21)(22) aberrations may all form the basis for the disappearance of ovarian follicles. These aberrations may influence the ovary at any stage of life, including the prepubertal, pubertal, or reproductive stages (23).…”