The six classifications of nutrients are protein, carbohydrates, fats, vitamins and minerals. Water is also classed as a nutrient. These nutrients are essential to survival; the human body cannot function without them.
Water is found in beverages and high-moisture foods such as fruits and vegetables. It accounts for the majority of human body weight and helps the body function by transporting nutrients and removing waste. The recommended amount of water for the average adult varies based on activity level and environment.
Protein primarily comes from animal products including meat, eggs and milk. It helps build and repair cells. Sources of carbohydrates include fruits, vegetables, bread and pasta. Carbohydrates provide energy to the brain and body. If not enough carbohydrates are consumed, the body uses protein for energy instead. Fat sources include animal products, oils and nuts. Fat provides energy and helps the body break down certain vitamins. It also protects organs and maintains heat in the body.
Vitamins can be consumed in supplements or through food, though certain foods contain different vitamins. Each of the 13 different types of vitamin performs its own function in the body. Minerals also come in food or supplement form. Examples of minerals include sodium, calcium and potassium.