Medical brain notes 13

  NUTRIENTS AND THEIR FUNCTIONS   To maintain health and function properly, the body must be provided with  nutrients.  Nutrients are chemical substances that are necessary for life.They are divided into six classes:   ·    Carbohydrates (CHO) ·    Fats (lipids) ·    Proteins ·    Vitamins ·    Minerals ·    Water   The body can make small amounts of some nutrients, but most must be obtained from food in order to meet the body’s needs. Those available only in food are called  essential nutrients.  There are about 40 of them, and they are found in all six nutrient classes.   The six nutrient classes are chemically divided into two categories: or-ganic and inorganic (Table 1-1). Organic nutrients contain hydrogen, oxygen, and carbon. (Carbon is an element found in all living things.) Before the body can use organic nutrients, it must break them down into their smallest compo-nents. Ino...

  CARACTERISTICS OF GOOD NUTRITION Most people find pleasure in eating. Eating allows one to connect with family and friends in pleasant surroundings. This connection creates pleasant memo-ries. Unfortunately, in social situations it is easy for one to make food choices that may not be conducive to good health.   What determines when one needs to eat? Does one wait until the body signals hunger or eat when one sees food or when the clock says it is time? Hunger is the physiological need for food. Appetite is a psychological desire for food based on pleasant memories. When the body signals hunger, that is the indication that there is a decrease in blood glucose that supplies the body with energy. If one ignores the signal and hunger becomes intense, it is possible to make poor food choices. The choices one makes will determine one’s nutrition status. A person who habitually chooses to eat, or not to eat, as a way of coping with life’s emotional struggles may be suffering from a...

  MALNUTRITION   Malnutrition  can be caused by overnutrition (excess energy or nutrient in-take) or undernutrition (deficient energy or nutrient intake). We usually think of malnutrition as a condition that results when the cells do not receive an  adequate supply of the essential nutrients because of poor diet or poor utiliza-tion of food (Figure 1-2).   Sometimes it occurs because people do not or cannot eat enough of the foods that provide the essential nutrients to satisfy body needs. At other times people may eat well-balanced diets but suffer from dis-eases that prevent normal usage of the nutrients.   Overnutrition has become a larger problem in the United States than undernutrition. Overeating and the ingestion of megadoses of various vitamins and minerals (without prescription) are two major causes of overnutrition in the United States. Nutrient Deficiency   A nutrient deficiency occurs when a person lacks one or more nutrients over a period ...

  INDIVIDUALS AT RISK FROM POORNUTRITIONAL INTAKE   Teenagers may eat often but at unusual hours. They may miss regularly sched-uled meals, become hungry, and satisfy their hunger with foods that have low nutrient density such as potato chips, cakes, soda, and candy. Foods with low  nutrient density  provide an abundance of calories, but the nutrients areprimarily carbohydrates and fats and, except for sodium, very limited amounts of proteins, vitamins, and minerals. Teenagers are subject to  peer pressure;  that is, they are easily influenced by the opinions of their friends. If friends favor foods with low nutrient density, it is difficult for a teenager to differ with them. Crash diets, which unfortunately are common among teens, sometimes result in a form of malnutrition. This condition occurs because some nutrients are eliminated from the diet when the types of foods eaten are severely restricted.   Pregnancy increases a woman’s hunger and the nee...

  CUMULATIVE EFFECTS OF NUTRITION   There is an increasing concern among health professionals regarding the  cu-mulative effects  of nutrition. Cumulative effects are the results of somethingthat is done repeatedly over many years. For example, eating excessive amounts of saturated fats for many years contributes to  atherosclerosis,  which leads to heart attacks. Years of over-eating can cause  obesity  and may also contribute to hypertension, type 2 (non-insulin-dependent) diabetes, gallbladder disease, foot problems, certain cancers, and even personality disorders. Deficiency Diseases   When nutrients are seriously lacking in the diet for an extended period,  defi-ciency diseases  can occur. The most common form of deficiency disease inthe United States is  iron deficiency,  which is caused by a lack of the mineral iron and can cause iron deficiency anemia. Iron deficiency is particularly common among children and women...

  NUTRITION ASSESSMENT   That old saying, “You are what you eat,” is true, indeed; but one could change it a bit to read, “You are  and will be  what you eat.” Good nutrition is essential for the attainment and maintenance of good health. Determining whether a person is at risk requires completion of a  nutrition assessment,  which should, in fact, become part of a routine exam done by a registered  dietitian  or other health care professional specifically trained in thediagnosis of at-risk individuals. A proper nutrition assessment includes  anthropometric measurements, clinical examination, biochemical tests,  and  dietary-social history.   Anthropometric measurements include height and weight and measure-ments of the head (for children), upper arm, and skinfold (Figure 1-3). The skinfold measurements are done with a  caliper.  They are used to determine the percentage of adipose and muscle tissue in the body. Measu...