Astronauts eat yogurt in space to help prevent bone loss caused by microgravity.

When astronauts spend time in microgravity, they experience a condition known as spaceflight-induced osteopenia. Without the constant load of Earth's gravity, the body's bone-remodeling process becomes unbalanced. Osteoclasts break down bone tissue faster than osteoblasts can replace it, leading to a loss of roughly 1% to 1.5% of bone mineral density per month.To combat this, NASA and other space agencies prioritize diets rich in calcium and vitamin D. Yogurt is a staple because it is naturally high in these nutrients and contains probiotics that support gut health, which can be compromised during long missions. Research conducted on the International Space Station (ISS) has shown that nutritional intervention is critical for protecting the skeletal system during six-month stays.The physical properties of yogurt also make it an ideal space food. In microgravity, liquids form floating spheres that can damage sensitive electronics or be inhaled by the crew. Yogurt's high viscosity and surface tension allow it to stay in its container or on a spoon, making it much safer to consume than fluid milk.Studies by the National Space Biomedical Research Institute (NSBRI) emphasize that while exercise is the primary defense against bone loss, diet provides the necessary raw materials for bone maintenance. Modern space menus include heat-stabilized or freeze-dried yogurt products to ensure a shelf life of up to 18 months. These efforts are vital for future multi-year missions to Mars, where bone health will be a major factor in mission success.