Vitamin A is the culprit. If we don't get enough food rich in Vitamin A, we lose our ability to see well in the dark. And if people really lack Vitamin A, they can go blind. You also absorb Vitamin D from the sun's rays when working in the garden. But gardening contributes more than vitamins to health.
Gardening is good exercise.
Working in the soil with your hands provides gentle exercise for Arthritis prevention and treatment. Many people live too much of their lives in houses, cars, offices and stores. They need to get outdoors more, to feel the sun and the breeze on their skin. Gardening helps you get to know your neighbors better, and meet other people too. You can be sure your food has not been sprayed if you grow it yourself.