The brain requires sustained interaction with a rich physical and social environment to stay healthy. Individuals without access to such enabling environments and who instead live and grow in disabling environments tend to have greater risk of developing dementia. But research and policymaking as regards dementia risk reduction have so far focused almost exclusively on the role of how individuals' health behaviors change their risk profile. This exclusive focus on "lifestyle" is both ethically problematic and therapeutically inadequate. I highlight a growing literature on three different kinds of deprivation, an independent and overlooked risk factor for dementia that invites upstream action against inequalities. Future prevention guidelines should include explicit mention of deprivation as a risk factor and be developed around the need to make society fairer. Meanwhile, interventions and discourse based on lifestyle modification should respect the principle of "no ought without support."