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Biology and You

You and Food

What are vitamins and minerals?

A vitamin is an organic, nonprotein substance that is required by an organism for normal metabolic function but cannot be synthesized by that organism. In other words, vitamins are crucial molecules that must be acquired from outside sources. While most vitamins are present in food, vitamin D, for example, is produced as a precursor in our skin and converted to the active form by sunlight. Minerals, such as calcium and iron, are inorganic substances that also enhance cell metabolism. Vitamins may be fat- or water-soluble. Recommended amounts of vitamins are to ensure normal enzymatic function, and excessive intake can be toxic.

Vitamin

Major Sources

Major Function

A

Animal products; plants contain only vitamin A building blocks

Aids normal cell division and development; particularly helpful in the maintenance of visual health

B-complex

Fruits and vegetables (folate);meat (thiamine, niacin, vitamin B6, and B12); milk (riboflavin, B12)

Energy metabolism; promotes harvesting energy from food

C

Fruits and vegetables, particularly citrus, strawberries, spinach, and broccoli

Collagen synthesis; antioxidant benefits; promotes resistance to infection

D

Egg yolks; liver; fatty fish; sunlight

Supports bone growth; maintenance of muscular structure and digestive function

E

Vegetable oils; spinach; avocado; shrimp; cashews

Antioxidant

K

Leafy, green vegetables; cabbage

Blood clotting



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