Vitamin D is vital to your health. This is required for calcium absorption. It is a necessity for growth of bones and development of teeth. Vitamin D effects the heart, muscles, and thyroids. The best natural source of vitamin D is the sun. When the skin is exposed it absorbs the sun which penetrate the skin and is picked up by cholesterol on the way to the liver. Then converted to vitamin D. Population with low vitamin D are prone to osteoporosis, hypoglycemia and hypocalcium.
If you read milk cartons and plastic bottles it usually says added vitamin D and calcium. They work in unison to optimize your growth of bones. The liver and kidney converts foods to into vitamin D in the body.
Food source would be lettuce, oatmeal, eggs, and butter etc… Plenty of greens always.
Calcium not only helps with bone growth but helps your muscles contraction, nerves and blood clotting. It’s vital for everyday living.