25 1 Nutrition 25 2 The Classes of Nutrients All aspects of bodily function depend upon proper nutrition A nutrient is a component of food that is needed for a specific physiological function Deficiency disorders occur when the body lacks a nutrient required for a function There are six classes of essential nutrients Carbohydrates Lipids Proteins and amino acids Minerals Vitamins Water These nutrients may be needed in large amounts macronutrients or small amounts micronutrients Introducing the Nutrients cont CLASS ROLE Carbohydrates Macro or micro Carbohydrates Energy fiber Macronutrient Lipids Energy insulation vitamin D synthesis Macronutrient Proteins Provides essential amino acids Homeostasis water balance cofactors Metabolism and development Hydration temperature control Macronutrient Minerals Vitamins Water Carbohydrates include sugars starch and fiber Sugars can be present as monosaccharides such as glucose or disaccharides such as sucrose Starch is a polymer used by plants to store glucose Micronutrient Micronutrient Fiber Fiber cont Fiber is the indigestible carbohydrates derived from plant material Fiber is not considered a nutrient because it cannot be digested to smaller molecules Insoluble fiber is important because it stimulates movement of feces in the bowel Soluble fiber binds to compounds in the intestine to deter their absorption and enhance their excretion 1 Can Carbohydrates Be Harmful Carbohydrates are important because they provide about 45 of the body s energy needs A diet containing large amounts of low fiber carbohydrates adds empty calories to the diet Excess carbohydrates in the diet can contribute to obesity diabetes and other diseases Can Lipids Be Harmful Cholesterol is a lipid that serves an important function in cells However elevated levels of cholesterol and fats in the blood can be detrimental to health Lipids should not be eliminated from the diet but should be consumed in moderation from more nutritional sources Can Proteins Be Harmful Lipids There are different forms of lipids that influence nutrition Triglycerides such as fats and oils supply cells with energy Fat is a long term storage form for lipids Triglycerides are necessary for nutrition Nutritionists recommend that fats and oils should provide 3035 of the body s energy Triglycerides contain essential fatty acids that the body requires for proper function Proteins Proteins consumed in the diet are broken down to liberate amino acids nine of which are essential in the diet While all foods contain protein plant proteins are considered incomplete because they generally lack one or more of the essential amino acids This limitation can be overcome by eating specific combinations of plant foods Minerals Proteins should supply no more than 10 15 of the calories consumed in the diet The term minerals is applied to the 20 elements that are required for nutrition Excess protein in the diet cannot be used productively and is generally excreted as urea in the urine Absence of a specific mineral can lead to mineral deficiencies Low iron can lead to anemia Low calcium can lead to osteoporosis High protein diets can lead to some health problems such as dehydration calcium loss and kidney stones Excess minerals in the diet such as sodium can also have harmful effects 2 Minerals cont Major minerals Primary Functions Minerals cont Trace minerals Primary Functions Calcium Strengthen bones nerve function Zinc Protein synthesis immune function Phosphorus Bone growth energy metabolism Iron Hemoglobin synthesis Potassium Nerve function muscle contraction Copper Hemoglobin synthesis Sodium Iodine Thyroid hormone synthesis Chloride Nerve function pH and water balance Water balance Selenium Antioxidant Magnesium Nerve and muscle function Vitamins Vitamins are essential organic compounds other than carbohydrates lipids and proteins that regulate metabolic activities Vitamins contribute primarily to energy metabolism and antioxidant defenses Vitamin deficiencies can lead to serious disease Vitamins cont Water soluble vitamin Primary functions Vitamin C Thiamine B12 Riboflavin B2 Niacin Vitamins cont Antioxidant maintains capillaries bones teeth Important coenzyme activity of nervous system Coenzyme for energy fat protein metabolism Coenzyme for energy fat protein metabolism Vitamins cont Water soluble vitamin Primary functions Fat soluble vitamin Primary functions Folic acid Helps form hemoglobin Vitamin D Bone and teeth development Vitamin B6 Helps form hemoglobin Vitamin E Antioxidant Pantothenic acid Coenzyme for fat carbohydrate metabolism Coenzyme for DNA synthesis Coenzyme for amino acid and fatty acid metabolism Vitamin K Synthesis of clotting factors Vitamin B12 Biotin 3 Water 25 3 Nutrition and Health The body of animals is about 60 water In the United States poor nutrition is a significant factor in human disease Water also contributes to a number of chemical reactions Water is also important to the movement of food through the intestine Are You Overweight For example excess body fat contributes to diabetes heart disease and certain forms of cancer Energy Intake Versus Energy Output The body mass index BMI is to determine if someone is overweight Aside from genetics another factor that contributes to obesity is a greater intake of energy than energy output The BMI is calculated with this formula Energy intake is expressed as the number of kilocalories provided by the food eaten BMI BMI 18 5 value Normal Energy output can be measured based upon body weight and physical activity weight pounds x 703 1 height 2 inches Overweight Obese 25 0 30 0 Very obese 40 0 Disorders Associated with Obesity Eating Disorders There are two common diseases associated with obesity In type 2 diabetes the body develops impaired insulin production and increased insulin resistance which leads to increased fat deposition and elevated fatty acid levels Cardiovascular disease affects the heart and can lead to hypertension heart attack and stroke Social cultural emotional and biological factors all contribute to eating disorders Anorexia nervosa is a psychological disorder in which the person is afraid to eat for fear of gaining weight People with bulimia nervosa undergo binge purge eating behavior Some people have binge eating disorders People with muscle dysmorphia are fixated upon their muscular development 4 The Food Pyramid The Food Pyramid cont There are numerous guides such as the Food Pyramid that can help consumers plan