The Nutrients A nutrient is a chemical substance that helps maintain the body. You need over 50 nutrients, which can be divided into six groups. –Carbohydrates –Fats –Proteins –Vitamins –Minerals –Water
Key Nutrient: Carbohydrates Functions Supply energy Provide bulk Help the body digest fats Spare proteins
Sources of Carbohydrates Sugarshoney, jam Fiber sourcesfruits, vegetables, whole grains Starch sources breads, cereals, pasta What is your favorite source of carbohydrates? photo courtesy of Fleischmanns Yeast
Key Nutrient: Fats Functions Supply energy Carry fat-soluble vitamins Insulate the body Protect organs Provide essential fatty acids
Saturateddairy products, meats Mono- and Polyunsaturatedfish, nuts, vegetable oils Sources of Fats
Functions Build and repair tissues Help body make important substances Regulate body processes Supply energy Key Nutrient: Proteins
Sources of Proteins Complete proteins dairy products, eggs, fish, meat, poultry Incomplete proteins beans, grains, nuts How can you find out if a food is a good source of protein? National Chicken Council
Key Nutrient: Vitamins Vitamins can be divided into two main groups. Fat-soluble vitamins –dissolve in fats –can be stored in fatty tissues of the body Water-soluble vitamins –dissolve in water –are not stored in the body
Fat-Soluble Vitamins NutrientFunctionsSources Vitamin A Keeps skin and mucus membranes healthy Prevents night blindness Promotes growth Butter, dark green and yellow fruits and vegetables, egg yolk, liver, whole and fortified milk Vitamin D Builds strong bones and teeth Egg yolk; fortified butter, margarine, and milk; the sun Vitamin E Acts as an antioxidant to protect cell membranes Eggs, liver, salad oils, whole grain cereals Vitamin K Helps blood clotCauliflower, egg yolk, organ meats
Water-Soluble Vitamins NutrientFunctionsSources Vitamin C Helps wounds heal Helps fight infection Broccoli, citrus fruits, tomatoes Thiamin Keeps nervous system healthy Releases energy from food Pork, whole grain breads and cereals Riboflavin Helps cells use oxygen Breaks down carbohydrates Cheese, eggs, milk, poultry Niacin Keeps nervous system healthy Helps cells use other nutrients Dried beans and peas, peanuts Folate Helps protect brain and spinal cord of unborn babies Bananas, fortified breads and cereals
Key Nutrient: Minerals Minerals can be divided into two main groups. Macrominerals are needed in amounts of 100 mg or more per day. Trace elements are needed in amounts less than 100 mg per day.
Macrominerals NutrientFunctionsSources Calcium Builds bones and teeth Helps muscles and nerves work Dairy products, leafy green vegetables Magnesium Helps cells use energy nutrients Regulates body temperature Beans, dark green leafy vegetables, whole grains Phosphoru s Builds bones and teeth Regulates bodily activities Protein and calcium food sources Sodium, chloride, potassium Control osmosis Maintain acid-base balance in the body Sodium and chloride: Table salt Potassium: Potatoes
Trace Elements NutrientFunctionsSources Fluorine Helps teeth resist decay Maintains bone health Fluoridated drinking water, toothpaste Iodine Promotes normal function of thyroid gland Iodized table salt, saltwater fish and shellfish Iron Helps cells use oxygenDried beans and fruits, egg yolk, lean meats, whole grains Zinc Helps wounds heal Promotes normal growth Legumes, meat, poultry, seafood, whole grains
Key Nutrient: Water Functions Aids digestion and cell growth and maintenance Facilitates chemical reactions Lubricates joints and cells Regulates body temperature
Sources of Water Liquids Food Breakdown of energy nutrients Which source do you think provides most of your water needs? Agricultural Research Service, USDA
Objective Analyze the effects of various nutrient deficiencies and excesses.
Nutrient Deficiencies Failure to get a sufficient amount of a nutrient may result in an illness called a deficiency disease. Such diseases include protein-energy malnutrition (protein) night blindness (vitamin A) rickets (vitamin D) scurvy (vitamin C) osteoporosis (calcium)
Nutrient Excesses Excess energy nutrientscarbohydrates, fats, and proteinscan lead to unhealthful weight gain. Excesses of some vitamins and minerals can lead to toxicity (poisoning) and other complications.
Apply It! Your grandmother has been diagnosed with osteoporosis. What is the likely cause of this affliction? What health effects may your grandmother suffer as a result of this disease?
Objective Explain the processes of digestion, absorption, and metabolism.
The Digestion Process Digestion is the bodily process of breaking food down into simpler compounds the body can use. The mechanical phase involves the physical breakdown of food caused by chewing and muscle activity in the digestive tract. The chemical phase involves the chemical breakdown of food caused by enzymes in saliva and digestive juices.
The Absorption Process Absorption is the process of taking in nutrients and making them part of the body. A large surface area in the small intestine allows tiny nutrient particles to pass into the blood and lymph systems and travel where needed. What would happen if your body were unable to absorb the nutrients you consumed through foods?
Metabolism Metabolism is the chemical processes that take place in the cells after the body absorbs nutrients. Carbohydrates are converted into glucose for use as an energy source. Fatty acid chains from fats are shortened and fats are used for fuel. Amino acids from proteins are used for maintenance, growth, production of enzymes and antibodies, and energy.
Key Question What are your nutritional needs?
Other Questions to Consider What role should dietary supplements play in meeting nutrient needs? What is cholesterol and why is it a nutritional concern?