The “best” source depends on the person. Key criteria are: (1) high calcium density, (2) good absorption, (3) sustainability, and (4) tolerance (lactose issues, allergies, IBS, etc.). For many people, yogurt and other dairy foods are strong options in both density and bioavailability. For those avoiding dairy, calcium-fortified beverages and calcium-set tofu are major alternatives. Canned fish eaten with soft bones can also be effective. Leafy greens contain calcium, but bioavailability can be reduced in high-oxalate greens. Therefore, absorption and realistic portions matter. Also consider vitamin D status—low vitamin D reduces calcium absorption. Finally, bone health is not calcium alone: adequate protein, resistance training, and balance work to reduce fall risk are part of the full strategy.