NUTRITION.docx

Physiology of Nutrition Digestion is the act of the body breaking down food into simple substances that are either absorbed by the bloodstream as nutrients or eliminated by the body as waste. The human digestive system enables the organs and tissues in the body to receive the nutrients they need to...

Physiology of Nutrition Digestion is the act of the body breaking down food into simple substances that are either absorbed by the bloodstream as nutrients or eliminated by the body as waste. The human digestive system enables the organs and tissues in the body to receive the nutrients they need to function. Once the digestive system has broken down food into its component nutrients, those nutrients are converted into energy for the body’s use. This involuntary process of the body begins with food consumption Saliva initiates the process of decomposing food, with digestion continuing as the food moves through different organs, propelled by muscular contractions known as peristalsis. The process of digestion involves numerous organs, including the mouth, esophagus, stomach, liver, gallbladder, pancreas, small intestine, large intestine, rectum, and anus. The esophagus is a hollow tubular organ located in the neck and chest that connects the mouth to the stomach. Muscles in the esophagus propel food down to the stomach, the organ that holds and digests food using acids and enzymes. Food remains in the stomach for 2 to 8 hours. The liver is responsible for filtering toxins from the blood and producing bile that breaks down carbohydrates, proteins, and fats. The sac-like organ that stores the bile produced by the liver and releases it when needed is the gallbladder. The pancreas produces insulin, a hormone that regulates the metabolism of sugars. Food from the stomach moves to the small intestine, where it is broken down further and nutrients are absorbed into the bloodstream. The large intestine is then responsible for removing water and electrolytes from the remaining food particles for the body’s use and converting the rest into feces. The large intestine contains billions of beneficial bacteria that perform this process. The rectum is a storage area for feces; it is located at the end of the large intestine. Lastly, feces are expelled through the external opening of the rectum known as the anus. Several conditions can disrupt the actions of the digestive system, causing discomfort in the gastrointestinal tract. Common digestive issues include diarrhea, constipation, nausea, vomiting, abdominal pain, gas, and bloating. Nurses should frequently assess clients for these issues to ensure they are not experiencing alterations in their digestive system. HEALTHY EATING PATTERNS Healthy eating patterns include maintaining a balanced diet daily, watching caloric intake, and consuming the necessary amounts of nutrients. A balanced diet provides the body with the nutrients that are needed for proper functioning. Calories are the energy that is stored in food; they are used to support processes of the body such as walking, breathing, and running. To get the nutrition that the body needs on a daily basis, calories should come from fresh fruits and vegetables, legumes, whole grains, and lean proteins. To make up a nutritious diet and stay within the calorie limit, individuals should eat low-fat or fat-free dairy products, fruits, vegetables, and whole grains, as these are nutrient-dense foods. Such foods provide a variety of nutrients without added calories. Eating a variety of foods from different food groups, such as grains, dairy, vegetables, fruits, and proteins, promotes a balanced diet. Avoiding or limiting unhealthy foods, such as foods with added sugar and salt, and those with trans fats, will help to maintain healthy eating patterns. According to the USDA, daily dietary intake for adults should include 2 cups of fruit, 2½ cups of vegetables, 6 ounces of grains, 5½ ounces of protein, and 3 cups of dairy products. Eating patterns can help someone lose, gain, or maintain their current weight. If unintentional weight loss occurs, the cause should be identified, as the client may have an undiagnosed health issue that requires treatment. Eating whole grains, fruits, and vegetables helps to control due to the bulk provided by these types of food and their fiber content. Hunger control is an added benefit of fiber intake, as this pattern allows fewer calories to be eaten. A healthy weight-loss plan consists of losing 1 to 2 pounds per week. To promote a healthy weight loss, lifestyle and dietary changes need to be made, along with implementing an exercise regimen. Even a weight loss of just 5% to 10% of total body weight can improve blood pressure, blood glucose, and cholesterol levels. Weight gain can be either intentional or unintentional. When a client experiences unintentional weight gain, the cause of the increased pounds should be identified to determine if there is an underlying health issue. A client may pursue weight gain due to unintentional weight loss, an illness causing weight loss, or wanting to increase muscle mass. To gain weight in a healthy manner, the client should aim at increasing muscle or bone mass. While attempting to gain weight, nutrient-rich foods should be preferred over empty-calorie ones. As with weight loss, gaining weight should be a steady process to avoid unnecessary complications. NUTRITIONAL REQUIREMENTS Nutrients are vital to help disease prevention, promote growth and health, and provide nourishment. Nutrient requirements are based on gender, age, and activity level. When reviewing clients’ daily caloric needs, nurses should refer to the calorie requirements based on these three categories. Nutrients fall into two categories: macronutrients and micronutrients. Macronutrients include protein, carbohydrates, and fat, and are eaten in large amounts. They provide the body with the energy it needs to function and are the primary building blocks of any diet. Micronutrients include vitamins and minerals; only small amounts of these nutrients are required in the diet. Protein is considered the major building block of the body, as it provides amino acids that the body needs to build and repair muscle. The role of protein is to help repair body tissue as well as build and maintain it. Protein is made up of several different amino acids that help the body to function properly. Sources of protein include beans, soy, nuts, meats, eggs, and fish. Activity level, age, and gender help determine the amount of daily protein that the body requires. As each body is different, the amount of daily protein required by each person varies, ranging between 2 and 6½ ounces of protein. A person who is very physically active requires more daily protein. Protein supplements can be utilized if indicated. Since protein helps to improve muscle training response during exercise as well as during the recovery period, professional athletes and bodybuilders often utilize these kinds of supplements. In addition, supplemental protein drinks may be indicated for a client with poor protein intake related to health issues—for example, a client receiving chemotherapy or radiation therapy. The digestive system turns carbohydrates into sugar to provide the body’s cells, organs, and tissues with the energy they need to function. Carbohydrates should make up 45% to 65% of total daily calories and are the body’s primary fuel source. Naturally occurring carbohydrates can be found in vegetables, fruits, milk, nuts, grains, legumes, and seeds. Healthy carbohydrates are preferred over foods with added sugars and refined grains. The simplest forms of carbohydrates are sugars, which occur naturally in some foods. Commonly encountered simple carbohydrates include fructose (fruit sugar), sucrose (table sugar), and lactose (milk sugar). Starch and fiber are both complex carbohydrates. Fiber is found in fruits, vegetables, beans, and whole grains; starches occur naturally occur in vegetables, grains, and beans. When consuming carbohydrates, the food’s glycemic index—that is, its ability to raise the blood glucose level—should be considered. Foods with a high glycemic index, such as potatoes, white bread, and processed snack foods, increase the body’s blood glucose level rapidly. Foods that have a lower glycemic index, such as legumes, vegetable, fruits, and whole grains, increase the body’s blood glucose level slowly, without spiking it, leading to stabilized energy without a feeling of sluggishness. Fats are an essential nutrient that help the body absorb vitamins while providing energy. Fat is a part of a healthy diet in limited quantities and plays a major role in determining the body’s cholesterol levels. Some types of fats, such as trans and saturated fats, should be limited or avoided. In contrast, healthy fats include monounsaturated fats, which are much preferred over saturated fats from a nutritional standpoint. Trans fats are most often found in processed foods; these partially hydrogenated oils are not generally considered safe in human food. Trans fats raise the low-density lipoprotein (LDL) cholesterol level (“bad cholesterol) and lower the high-density lipoprotein (HDL) cholesterol level (“good cholesterol”) in the body. Saturated fats are found in full-fat dairy products, including cheese, butter, and whole milk. A diet high in saturated fat can increase the risk of heart disease and raise total blood cholesterol levels. Monounsaturated fats can be found in nuts, olives, olive oil, seeds, and avocados. These types of fat can lower cholesterol while decreasing the risk for heart disease. Eating too much monounsaturated fat can lead to weight gain, however, as these foods contain the same amounts of calories as foods with other types of fat. Vitamins are micronutrients that promote health and ward off disease while supporting the functions of the body. Vitamins aid in promoting healthy vision, bones, and skin. These nutrients are not produced in the body, so they must be derived from a person’s diet. Thus, eating a healthy, balanced diet including fruits and vegetables is important in meeting the body’s daily needs for vitamins. If indicated, vitamin supplements can be added to prevent deficiencies. Vitamins that dissolve in water are known as water-soluble. Water-soluble vitamins, which include vitamin C and vitamin B complex, are carried to the tissues of the body but are not stored in the body. Vitamin B1(thiamine) Converts nutrients to energy Whole grains, pork, seeds, trout Vitamin B2(riboflavin) Aids energy production and fat metabolism Yogurt, milk, organ meats, almonds Vitamin B3(niacin) Helps produce energy from food Meat, fish nuts, grains, legumes Vitamin B5 (pantothenic) Fatty acid synthesis Mushrooms, tuna, avocado, chicken Vitamin B6(pyridoxine) Helps the body release sugar for energy and immune function Organ meats, salmon, tuna, potatoes Vitamin B7(biotin) Breaks down carbohydrates, fats, and protein Organ meats, eggs, salmon, sunflower seeds Vitamin B9(folate) Necessary for proper cell division Leafy green vegetables, orange juice, eggs, beans, avocado Vitamin B12(cobalamin) Aids red blood cell formation, as well as proper nervous system and brain function Clams, beef, salmon, milk, yogurt Vitamin C (ascorbic acid) Promotes iron absorption, wound healing, bone formation, and immune function Brussels sprouts, citrus fruits, spinach, berries, tomatoes, potatoes In contrast to water-soluble vitamins, fat-soluble vitamins, after consumption, are stored in the liver and fatty tissues for later use. These vitamins are most abundant in high-fat foods, which allow them to be better absorbed. Vitamin A Bone formation, vision, tooth formation, immune function, cellular function  Fish liver oil, beef liver, dairy products, green leafy vegetables, sweet potatoes  Vitamin D  Bone and teeth development, absorption and metabolism of calcium and phosphorus   Fish oil, milk, eggs, dairy products, *sunlight  Vitamin E  Fight infection, healthy red blood cells  Almonds, wheat germ, sunflower seeds, spinach  Vitamin K  Blood clotting and bone health   Spinach, liver, butter, kale, parsley  *Nonfood source.  Minerals are micronutrients that help the body develop and function normally; they include iron, zinc, and calcium. Calcium helps with strengthening bones and teeth, nerve signal transmission, and muscle contraction and relaxation. Zinc helps to boost the immune system and promotes wound healing. Iron is a part of hemoglobin and provides oxygen to muscles. Water is an essential nutrient that makes up more than half of the body weight and is required for systems in the body to function properly. Water promotes brain function, hydrates and flushes out wastes from the body, regulates body temperature, and acts as a lubricant in the body. Besides drinking water, other sources of water intake include fruits and vegetables that contain large quantities of water. Common manifestations of not getting enough water include dark urine, feeling thirsty, dry skin, and headaches. Pale yellow urine is a finding of proper hydration. NUTRITIONAL VALUE OF FOOD Food’s nutritional value is determined by the impact it has on the body. A food that has very little nutritional value is known as having empty calories; such a food lacks the vitamins and minerals that the body needs for daily function. Examples of foods that can have empty calories are sodas and candies. Eating a variety of healthy foods, such as vegetables, fruits, grains, protein, low-fat or fat-free dairy products, and healthy oils, increases the overall nutritional value of the diet. Limiting the intake of empty calories, sodium, saturated fats, and added sugars helps decrease the risk of heart disease and other conditions. Another nutritional aspect to consider is the number of calories a food contains related to its volume or weight—a concept known as calorie density. With low-calorie-dense foods, a person can consume a larger amount of the food without adding calories while still feeling full. Fruits and vegetables are good examples of such foods: They are low in calories but have a high volume, so more can be eaten without adding unnecessary calories. With high-calorie-dense foods, a person consumes more calories with a smaller or equal portion size of that of a low-calorie-dense food. For example, French fries are a high-calorie-dense food: More calories are consumed per serving compared to a low-calorie-dense vegetable of the same portion size. Low-calorie-dense foods promote a nutrient-rich diet overall, which can aid in weight loss or maintenance. The serving size found on the nutritional label indicates the number of servings in the package. Serving sizes are described using units such as cups or pieces. For instance, the serving size for chips would indicate how many chips make up one serving. The serving size represents the amount of the food or drink that people usually consume; it is not a recommendation of how much people should consume. Everything on a nutritional label following the serving size is measured in relation to the serving size indicated by the label. Thus, if a package of food contains two servings and the entire package is consumed, two servings were consumed, not just one. This means that everything on the nutritional label, including calories and daily value, will need to be doubled to calculate the total nutrients consumed. The calories indicated on the nutritional food label are calculated in relation to the serving size. For example, if the food has 200 calories per serving, and there are four servings in the package, then the entire package has 800 calories. If the entire package is consumed, the individual will have eaten 800 calories. Caloric requirements are based on age, gender, and activity level. Consuming too many calories per day increases the likelihood of weight gain. When looking at a nutritional label, the nutrient breakdown is located below the calories. While reviewing the nutrient breakdown, it is important to make note of saturated fats, sodium, and added sugars, as eating an excess of these can lead to increased risk of cardiovascular disease and hypertension. It is also important to note the total sugars versus the added sugars. Total sugars are those that naturally occur in foods; the FDA has not established a daily value for them. Added sugars are added to foods during processing, packaged as sweeteners, sugars from concentrate, and syrups or honey. Added sugars are listed below total sugars on the nutrition label because the added sugars are included in the total sugars count. For example, if a food has 9 g of added sugars and 11 g of naturally occurring sugars, total sugars would be 20 g. The body needs to consume adequate amounts of dietary fiber, vitamin D, calcium, iron, and potassium daily. These nutrients provide multiple health benefits. Fiber improves bowel movements, lowers cholesterol, improves blood glucose levels, and decreases caloric intake. Daily intake of fiber for females should be 25 g per day, while men should aim to get 38 g per day. Calcium, iron, potassium, and vitamins should be consumed daily to decrease the risk of anemia, osteoporosis, and hypertension. The percent daily value (%DV) is the percentage of the recommended daily value for each individual nutrient in a single serving of the food; it provides a reference to help individuals avoid exceeding these daily values. The daily value unit is based on which nutrient it is referring to and may be stated in grams, micrograms, or milligrams. If the amount of a nutrient per serving is less than 5% of the daily value, it is considered low. If amount of the nutrient per serving is 20% or more of the daily value, it is considered high. For example, if a serving has 50% of the daily value of sodium, the person will consume one-half of the recommended sodium intake for the day by eating one serving of this particular food. Guidelines recommend choosing foods with a higher %DV of vitamin D, calcium, potassium, iron, and fiber, and foods with a lower %DV of sodium, added sugars, and saturated fat. Another piece of information found on some food labels is net carbohydrates—that is, the amount of carbohydrates in a product minus either the fiber or the sugar alcohols and fiber. Fiber and sugar alcohols essentially cancel out carbohydrates, which explains the origin of the term net carbs. Not all food labels list net carbs. To calculate net carbs if it is not shown on the label, take the total carbohydrates per serving and subtract the fiber and sugar alcohols. For example, if someone consumes food that has 10 g of carbohydrates and 5 g of fiber, the net carbs consumed would be 5 g. This is the amount used to calculate total daily carbohydrate intake. AGE AND OTHER CONSIDERATIONS Age, sex, and physical activity level have an influence on clients’ daily caloric needs. Clients who engage in exercise or increased physical activity require more calories than those who have a sedentary lifestyle. On average, females need fewer calories than males. Male bodies burn more calories because they contain more muscle mass and less fat than female bodies. Age can have an impact on a client’s nutritional status, which means that good nutrition remains just as important with aging. Older clients may need less calories depending on their activity level, yet at the same time require enough nutrients. Older adult clients can also be prone to unintentional weight loss and dehydration due to changes in their senses of smell and taste or decreased appetite related to medications. Problems with chewing and swallowing food can also make it difficult for some older adults to eat a healthy diet. Good nutrition can help prevent diseases such as high blood pressure, osteoporosis, heart disease, and type 2 diabetes. Whole foods, drinking enough liquids, eating foods low in cholesterol and fat, and avoiding empty calories can help meet the nutritional requirements of older adult clients.