Post-menopausal Women

Female life stages including premenopausal, perimenopausal, postmenopausal, are characterized by changing concentrations and patterns of hormones. The premenopause stage represents the reproductive years with normal menstrual cycles lasting between 21-35 days. The perimenopause stage is the beginning of the menopause transition and can last up to 10 years. During this transition, menstrual cycles become longer and irregular in length (7 days or longer). After 12 consecutive months with no period, the transition is complete into the postmenopause stage. Hormones that change across the lifespan are known to influence systems that regulate thirst, fluid balance, and sodium balance. Yet, fluid balance across life stages remains poorly understood, with no direct comparisons across all three life stages. The purpose of this study is to evaluate the effect of female life stage on rehydration with water and electrolyte solution after overnight fast and fluid restriction

The goal of this clinical trial is to find out if dairy is a good source of choline compared to eggs. The main questions it aims to answer are: * How the body uses choline; and, * What effect WPPC has on choline metabolism. Researchers will compare Whey Protein Phospholipid Concentrate (WPPC) to whole egg powder to see if WPPC is as effective as eggs. Participants will drink a chocolate-flavored drink mixed with either WPPC or whole egg powder.