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People who do not get enough vitamin A cannot see well in darkness. They may develop a condition that dries the eyes. This can result in infections and lead to blindness.

Vitamin A is found in fish liver oil. It also is in the yellow part of eggs. Sweet potatoes, carrots and other darkly colored fruits and vegetables contain substances that the body can change into vitamin A.

BOB DOUGHTY: Vitamin B-one is also called thiamine. Thiamine changes starchy foods into energy. It also helps the heart and nervous system work smoothly. Without it, we would be weak and would not grow. We also might develop beriberi.

Thiamine is found not just in whole grains like brown rice, but also in other foods. These include beans and peas, nuts, and meat and fish.

National Institutes of Health Salmon contains B

vitaminsAnother B-vitamin is niacin. It helps cells use food energy. It also prevents pellagra -- a disease that causes weakness, reddish skin and stomach problems. Niacin is found in meat, fish and green vegetables.

FAITH LAPIDUS: Vitamin B-twelve is needed so folic acid can do its work. Together, they help produce red blood cells. Vitamin B-twelve is found naturally in foods like eggs, meat, fish and milk products. Folic acid has been shown to prevent physical problems in babies when taken by their mothers during pregnancy.

Vitamin B-twelve is found in green leafy vegetables and other foods, like legumes and citrus fruits. In some countries, it is added to products like bread.

BOB DOUGHTY: In two thousand three, Japanese researchers identified a new member of the B-vitamin group. It is a substance known as pyrroloquinoline quinone, or PQQ.

The researchers found that PQQ is important in the reproductive and defense systems of mice. They said the substance is similarly important for people. PQQ is found in fermented soybeans and also in parsley, green tea, green peppers and kiwi fruit.

FAITH LAPIDUS: Vitamin C is needed for strong bones and teeth, and for healthy blood passages. It also helps wounds heal quickly. The body stores little vitamin C. So we must get it every day in foods such as citrus fruits, tomatoes and uncooked cabbage.

Vitamin D increases levels of the element calcium in the blood. Calcium is needed for nerve and muscle cells to work normally. It also is needed to build strong bones.

National Institutes of Health
Milk products can contain Vitamin

DBOB DOUGHTY: Vitamin D prevents the children's bone disease rickets. Ultraviolet light from the sun changes a substance in the skin into vitamin D. Fish liver oil also contains vitamin D. In some countries, milk producers add vitamin D to milk so children will get enough.

Vitamin K is needed for healthy blood. It thickens the blood around a cut to stop bleeding. Bacteria in the intestines normally produce vitamin K. It can also be 本论文由英语论文网提供整理，提供论文代写，英语论文代写，代写论文，代写英语论文，代写留学生论文，代写英文论文，留学生论文代写相关核心关键词搜索。