If you have not read the book Green Zones, you may find it interesting since it talks about longevity in these various communities around the world where people routinely live to ripe old ages, often over 100 while still healthy and productive. In several of them yogurt based products are part of their diets. There is a lot to learn from the manner in which the people in these communities live their lives. But to net it out, and not to spoil it for those that may wish to read it; exercise, usually through meaningful work each day, not at the gym, - diet rich in fruits and vegetables, and healthy proteins (more fish and free range animals than factory farmed red meat) and eaten in moderation - a genuine sense of community and shared experiences with extended family and those in the same community (mental health and less stress) - and some sense that a life of quality is partly spent in service to others.