Vitamin A and D are two vitamins that are needed for human growth and development. It is usually better to supplement vitamin A and D about half an hour after breakfast, not on an empty stomach, otherwise it is easy to stimulate the gastrointestinal tract, especially for infants and young children, eating on an empty stomach can easily lead to nausea, acid reflux and other gastrointestinal reactions. If the sunshine is good that day, you can properly sunbathe, which can promote the absorption of calcium. Vitamin A and D not only have a good role in promoting growth and development of fetuses and infants, but also have a good effect on the prevention and treatment of night blindness, mouth ulcers and chondromalacia in adults, and people who lack vitamin A and D in their bodies or want to supplement them can do so half an hour after breakfast. There are various ways to supplement vitamin A and D. Not only can you rely on vitamin A and D supplements, but you can also supplement them in your daily life. Vitamin A can be obtained in foods such as carrots, spinach, cod liver oil, animal liver, etc., while vitamin D can be supplemented through daily sun exposure. Infants need to be careful to cover their eyes and reproductive organs with eye shields or clothing during sun exposure to prevent UV rays from harming their eyes and reproductive organs. However, it should be noted that although vitamins A and D are good, taking large amounts for a long time may cause toxic reactions to vitamins A and D, such as nausea, diarrhea and loss of appetite.