Every tissue in the body needs these four vitamins. Thiamin occurs in fair amounts in whole grain, milk, eggs, liver, meat, and certain vegetables and fruits. Lack of thiamin can cause poor appetite, slow growth, fatigue, stomach and intestinal troubles, neuritis. Riboflavin occurs abundantly in liver, meat, eggs, milk, green vegetables, whole grains, yeast. So a deficiency is only likely if a person's diet consists mainly of refined starches and sugar.
Deficiency causes cracks in the mouth and outer lip, skin, mouth, and eye troubles.
It is necessary for the development of bones, teeth, blood vessels And plays a part in the functioning of most of the cells in the body. Vitamin d is needed in large amounts for growth, particularly of the bones and teeth. It helps get calcium and phosphorus, which are in the food in the intestines, absorbed into the blood and deposited in the growing parts of the Bones. That's why it should be added to the diet of children, especially in the period of rapid growth in infancy. The sun's rays shining on the fat in people's skins manufacture vitamin d right there, and that's how thy naturally get It when they live outdoors and wear few clothes.