Transcript Chapter 2
Chapter 2 Nutritional Needs Part 1 The Importance of Food Objective • Name the key nutrients, describe their functions, and list important sources of each. © 2002 Wisconsin Milk Marketing Board, Inc. 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 • Sugars—honey, jam • Fiber sources—fruits, vegetables, whole grains • Starch sources— breads, cereals, pasta What is your favorite source of carbohydrates? photo courtesy of Fleischmann’s Yeast Key Nutrient: Fats Functions • Supply energy • Carry fat-soluble vitamins • Insulate the body • Protect organs • Provide essential fatty acids Sources of Fats • Saturated—dairy products, meats • Mono- and Polyunsaturated—fish, nuts, vegetable oils Key Nutrient: Proteins Functions • Build and repair tissues • Help body make important substances • Regulate body processes • Supply energy 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 Nutrient Functions Sources 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 clot Cauliflower, egg yolk, organ meats Water-Soluble Vitamins Nutrient Functions Sources Vitamin C Helps wounds heal Helps fight infection Thiamin Keeps nervous system healthy Pork, whole grain breads and cereals Releases energy from food Riboflavin Helps cells use oxygen Breaks down carbohydrates Niacin Keeps nervous system healthy Dried beans and peas, Helps cells use other nutrients peanuts Folate Helps protect brain and spinal cord of unborn babies Broccoli, citrus fruits, tomatoes Cheese, eggs, milk, poultry 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 Nutrient Calcium Functions Builds bones and teeth Helps muscles and nerves work Magnesium Helps cells use energy Sources Dairy products, leafy green vegetables 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 Sodium and chloride: Maintain acid-base balance in Table salt the body Potassium: Potatoes Trace Elements Nutrient Functions Sources Fluorine Helps teeth resist decay Maintains bone health Iodine Promotes normal function of Iodized table salt, thyroid gland saltwater fish and shellfish Iron Helps cells use oxygen Dried beans and fruits, egg yolk, lean meats, whole grains Zinc Helps wounds heal Promotes normal growth Legumes, meat, poultry, seafood, whole grains Fluoridated drinking water, toothpaste 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 nutrients—carbohydrates, fats, and proteins—can 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?