Combined results from 3 studies spanning 50 countries has found no link between moderate egg consumption (about one egg per day) and heart disease and cardiovascular-related mortality.

Stress activates the fight-or-flight response, which can cause permanent damage to stem cells in hair follicles that regenerate pigment. Stress leads to the premature depletion of the pigment reservoir.

Living less than 50 meters from a major road or less than 150 meters from a highway was linked to increased risk of dementia, Parkinson's, Alzheimer's, and MS, likely due to increased pollution.

Sun exposure regulates how fat cells produce energy; spending too much time indoors may disrupt this. Sunlight is required for normal energy metabolism, which could prevent metabolic syndrome.