The ESR1 gene regulates estrogen receptor alpha activity which is involved in hormone binding and activation and also regulates gene transcription. ESR1 is thought to enhance the effect of the estrogen (natural or synthetic) that attaches to it. This is necessary for estrogen to perform its functions in the body but can be negative if high amounts of very strong forms of estrogen (e.g. E2 and 4OH) are dominant in circulation. Variants in ESR1 are associated with enhanced receptor activity. Here we look at two variants (Pvull and Xball) known to affect ESR1 activity.
The GG genotype is associated with an increased ESR1 activity and the likelihood of higher estrogen activity in the body where estrogen receptors are present. It is important for you to maintain balanced estrogen levels and encourage CYP1A1 activity (over CYP1B1 and CYP3A4) to ensure that 'healthy' 2OH is dominant in circulation over 'stronger' 4OH and 16aOH. Optimising phase II elimination of estrogen will help to support healthy estrogen levels. Consuming cruciferous vegetables has been shown to naturally reduce ER activity.