Hormones have effects on multiple physiological systems in the body by controlling homeostasis and metabolic activity. The roles of hormones vary between men and women, resulting in different nutritional needs based on the impact of these hormones. A great example of this is iron, specifically with post-menopause aged women. The nutritional needs of women vary across the life course, so it is important that they are aware of how and why their needs change and how they need to adapt their diets to meet these needs.