SUBJECT KNOWLEDGE
• The chemical structure of the different food groups
• Storage and use of food in the body
• How metabolism extracts energy from food
• Social and psychological influences on nutrition
CARE DELIVERY KNOWLEDGE
• Assessing nutritional status
• Calculation of body mass index and the healthy range
• Identification of different nutritional needs related to age
• Feeding patients
• Identification of appropriate alternative and supplementary methods of feeding when patients are unable to eat normally
• Alterations in nutritional status
• A review of common disorders of nutrition
PROFESSIONAL AND ETHICAL KNOWLEDGE
• Legal aspects of food safety
• Professional accountability
• Ethical dilemmas in feeding
• Patients’ rights
PERSONAL AND REFLECTIVE KNOWLEDGE
• Explore your personal beliefs about nutrition
• Apply your knowledge to professional practice
INTRODUCTION
Food is essential for life; it provides the nutrients we need to maintain our bodies and is integral to our social and cultural life. In the UK there is a large range of affordable foods available so it should be possible to ensure the population as a whole does not suffer from diseases caused by lack of essential nutrients. Increasingly a healthy diet is implicated in the prevention of diseases such as coronary artery disease, bowel cancer and diabetes; there is no lack of information available about these facts. Why then are health professionals still dealing with impaired health and disease due to poor nutrition? Nurses should be able to explain the vast amount of occasionally conflicting information about diet to patients. They must give informed, up-to-date advice and ensure that patients are not left feeling guilty because they have not eaten all the right foods or that they have been unable to provide a healthy diet for their families.
The provision of nutritional care is a challenge to nurses in the institutional setting and also in the wider community. Despite the evidence that good nutrition is essential for individuals’ health and recovery from illness, articles appear frequently in professional journals and newspapers highlighting deficiencies in the provision and delivery of food to patients in hospitals (Savage and Scott, 2005 and Holmes, 2007).
There is no shortage of published material about nutritional assessment tools designed to identify patients at risk of malnutrition and provide recommendations for nutritional care planning (Green and Watson, 2006 and Johnstone et al., 2006). The Department of Health produced the resource pack Essence of Care (Department of Health 2001) aimed at improving standards of care by using benchmarks of good practice. The food and nutrition benchmark requires that ‘Patients/clients are enabled to consume food (orally) which meets their individual need’. Nurses are encouraged to compare practice in their clinical area to the benchmark of good practice and formulate action plans on how to improve the standard of care from initial assessment through to health promotion.
OVERVIEW
Subject knowledge
This section deals with functions of food as a source of energy, growth and repair. It outlines the physiological processes of nutritional components and considers the physiological evidence against common contemporary dietary myths. Social and psychological factors and their influence on nutrition are discussed.
Care delivery knowledge
Assessment of the patient’s nutritional status to include variation according to age, gender and lifestyle is included. Strategies for planning, implementing and evaluating nutritional care are discussed. Alternative methods of feeding when patients are unable to eat normally are explored.
Professional and ethical knowledge
Legislation, professional responsibility and ethical issues in the provision of food and drink are outlined.
Personal and reflective knowledge
This final part encourages you to reflect on what you have read, consider how you can put it to practice and produce evidence for your learning portfolio.
Four case studies are presented at the end of the chapter, each one relating to one of the nursing branch programmes.
SUBJECT KNOWLEDGE
BIOLOGICAL
ENERGY PRODUCING FOODS
All of the activities we undertake involve the expenditure of energy. Even at rest we require energy for physiological processes; this energy requirement is called basal metabolic rate (BMR) and it is variable between individuals. All of the energy for these processes is derived from food. The amount of food we need is controlled by our energy expenditure; this is called the energy balance.
The amount of food we eat is determined to a large extent by appetite. The main control of appetite is physiological, involving two centres within the hypothalamus – the feeding (hunger) centre and the satiety (full) centre – which work in opposition to each other. The satiety centre is mainly controlled by the blood glucose concentration and functions to suppress the hunger centre. As the blood glucose level decreases the power of the satiety centre is lowered and the hunger centre becomes active giving rise to the feeling of hunger and the desire to eat. Other physiological influences on appetite are the body fat deposits and the distension of the gut. Psychosocial influences are also important as will be discussed later in this chapter. How the body uses energy producing foods, i.e. carbohydrate, proteins and fats, is discussed below.
Carbohydrates
Carbohydrates should account for more than half the energy intake in the diet. They have a general formula (CH2O)n and are manufactured by plants from carbon dioxide, water and energy from sunlight through the process of photosynthesis. By this means the energy of the sun is trapped and made available to animals when they eat the plant.
The most simple carbohydrates, such as glucose, fructose and galactose, contain six carbon molecules and are called monosaccharides. These three monosaccharides all have the formula C6H12O6 but the positions of the carbon atoms in relation to the oxygen atoms differ. These monosaccharides can combine to form pairs of molecules called disaccharides. This is achieved by the removal of a water molecule and is known as a condensation reaction. Depending on the combination of monosaccharides, different disaccharides are produced. For example:
• The disaccharide we are most familiar with is sucrose – table sugar – and this is simply one glucose molecule joined to one fructose molecule.
• Two molecules of glucose form maltose, which is a disaccharide.
• One molecule of glucose and one molecule of galactose form lactose.
Because of their relatively uncomplicated molecular structure, monosaccharides and disaccharides are quickly absorbed and utilized. They are also referred to as simple sugars. Many glucose molecules joined together form a polysaccharide called starch, which plants use as an energy store, for example the starch in potatoes and cereals. Foods containing these will therefore be high in complex carbohydrate.
Plants use another carbohydrate called cellulose to form their structure. Humans are unable to digest this structural carbohydrate, but ruminants such as cows or sheep are able to break it down and use it for energy.
Digestion, transport and storage of carbohydrates
All complex carbohydrates must be broken down by the digestive system into monosaccharides before they can be absorbed. The process begins with the action of salivary amylase, which converts starch into the disaccharide maltose. Other starches are split into disaccharides by the pancreatic amylase. The final step is for a series of enzymes in the small intestine to break down the disaccharides into monosaccharides. There is a specific enzyme for each disaccharide, but the names are easy to remember:
• maltose is split by maltase
• sucrose is split by sucrase
• lactose is split by lactase.
Splitting disaccharides also involves putting the water back, a process known as hydrolysis (from the Greek words ‘hydro’ meaning water, and ‘lysis’ meaning breaking down).
This is the opposite process to the condensation reaction, which removes water to join the two monosaccharide molecules. Once broken down to monosaccharides in the digestive system, carbohydrates are absorbed in the small intestine and transported via the portal vein to the liver. This raises the concentration of the plasma glucose and stimulates the secretion of insulin by the beta cells of the pancreas. This in turn increases the rate at which the large glucose molecules are able to pass through the cell walls into the cells where they will be broken down to provide energy.
Excessive plasma glucose can be converted into an insoluble carbohydrate, glycogen, which is similar to starch in plants, through the process of glycogenesis. Glycogen is stored mainly in the liver and the muscles and can be converted back to glucose (glycogenolysis) when the plasma glucose concentration falls. When glycogen stores are full any remaining glucose may be converted into fat and stored until it is needed. As the glucose in the blood is used up, insulin secretion decreases and glucagon secretion from the alpha cells of the pancreas increases. Glucagon converts glycogen back into glucose to restore the blood glucose concentration and mobilize the stored fat.
The hormone glucagon is secreted by the alpha cells of the pancreas when the blood glucose concentration falls. This causes a reduction in glycogenesis and an increase in glycogenolysis, which leads to an increase in blood glucose concentration. Glucagon can also be manufactured synthetically and administered by injection.
• What are the indications for the use of synthetic glucagon?
• What is the usual dosage?
• What are the limitations of using synthetic glucagon?
Utilization of carbohydrate: respiration
Carbohydrates are made in the chloroplasts of plant cells through the action of photosynthesis as follows:
When the equation is moving in this direction, energy from the sun is used to form carbohydrate. However, in the mitochondria of animal cells this action is reversed, in the process of respiration, as follows:
The energy produced in respiration takes two forms, heat and chemical energy. The heat energy maintains the body temperature. This explains why we get hot when we exercise, as an increase in the metabolism of food in the muscles generates more heat. The chemical energy is used to join phosphate to another molecule to store energy for future use. The commonest example of this action is phosphate (P) joining adenosine diphosphate (ADP) to form adenosine triphosphate (ATP). When energy is required the phosphate bond is broken to revert back to ADP and P so releasing the stored energy.
The process of obtaining energy from glucose occurs in three stages:
1 The first stage, glycolysis, takes place in the cytoplasm of the cell. Here the six-carbon glucose molecule is split into two three-carbon pyruvate molecules. Glycolysis releases eight ATP molecules.
2 If there is no oxygen present (i.e. anaerobic conditions) pyruvate is converted to lactate, which will be reconverted to pyruvate when oxygen becomes available. This costs six ATP molecules. Therefore in the absence of adequate oxygen, the energy yield from glycolysis drops two molecules of ATP. In the presence of oxygen, however, the pyruvate is transported to the mitochondria where it is converted to carbon dioxide and acetyl coenzyme A (acetyl CoA). The acetyl CoA enters the Krebs cycle where the hydrogen is removed and carbon dioxide is released (aerobic metabolism).
3 In the third stage of the process, called the electron transport chain, the energy is once more used to combine phosphate with ADP to produce ATP. The hydrogen is then combined with oxygen to form water.
The three stages of this glucose metabolism will release sufficient energy from one molecule of glucose to produce 38 molecules of ATP.
The more mitochondria there are in a cell the more reactions can take place and the greater the amount of energy available. The mitochondria increase in response to the energy demand made upon a cell. Consequently this increases the individual’s basal metabolic rate. When there is less demand the number of mitochondria decrease. You may notice this effect if you decide to increase your fitness by regular exercise. You will notice that as you continue a programme of training the length of time you are able to engage in activity increases. You see yourself becoming fit. Cells are able to engage in more activity as the number of mitochondria increase in response to the demand made on them during training.
Fats
Fats are solid and oils are liquid, and they are referred to collectively as lipids. They are insoluble in water and have the general formula CH3(CH2)nCOOH, which looks complicated but like carbohydrate they only contain carbon, hydrogen and oxygen. Most lipids in the diet are in the form of triglycerides. These are made up of three fatty acids, each attached to a glycerol molecule to form a structure like a letter E, with the glycerol being the vertical stroke. Fatty acids are a line of carbon atoms with hydrogen atoms attached. There are three different forms of fatty acids known as:
• Saturated fatty acids, which contain the maximum possible number of hydrogen atoms.
• Monounsaturated fatty acids, which have two hydrogen atoms missing from each molecule.
• Polyunsaturated fatty acids, which have more than two hydrogen atoms missing from each molecule.
Saturated fats are solid at room temperature whereas mono- and polyunsaturated fats are liquid oils. Generally animal fats are saturated and those from vegetables and fish are unsaturated (two exceptions to this rule are palm and coconut oil). Saturated fat in the diet tends to raise the concentration of the blood cholesterol level whereas monounsaturated fats such as olive oil tend to lower it. Because a high blood cholesterol concentration is linked to arterial disease, the current recommendation is to reduce the total amount of fat in the diet and to limit the intake of saturated fat so that it constitutes not more than 10% of the energy intake (Food Standards Agency 2008a). Examples of fatty foods include butter, margarine, lard, cooking oil and the fat on meat.
Read the Cochrane Review: Dietary advice for reducing cardiovascular risk (Brunner et al 2005)
• Reflect on your personal dietary habits and review whether there is a need for you to change your habits to maintain your health.
• Make notes on how you would advise a patient with a high risk of cardiac disease to achieve a healthy diet.
• Write a short information sheet explaining the differences between saturated fatty acids, monounsaturated fatty acids and polyunsaturated fatty acids.
• How would you explain the difference between high density and low density lipoprotein cholesterol?
Under supervision provide the above information to a patient/client at risk and complete for your portfolio of evidence.
Fats are often thought of as being bad but a certain amount is essential for our health and well-being. Fats are needed to make cell membranes, steroid hormones, prostaglandins and bile, and to store energy. However, because fats pack many calories into a small volume it is easy to take too many calories in a high fat diet.
Digestion, utilization, transport and storage of lipids
Lipids are insoluble and form large globules in water; therefore they need to be emulsified. This is achieved in the body by the action of bile (Fig. 8.1). Once emulsified the triglycerides are split by the enzyme lipase into fatty acids and monoglycerides. Short chain fatty acids are absorbed into the blood directly at this point. Most fatty acids are long chain (i.e. they have more than 12 carbon atoms) and these and the monoglycerides take a different pathway to the blood. By combining with bile salts, long chain fatty acids and the monoglycerides form micelles and in this form are then able to enter the epithelial cells of the villi. Once in the epithelial cells lipase acts on the monoglycerides to reduce them to glycerol and fatty acids. Here they are combined with cholesterol and phospholipids to form chylomicrons. These in turn are absorbed into the lacteals of the small intestine and transported through the lymphatic system to enter the blood at the subclavian vein.
 |
| Figure 8.1 (from Montague et al 2005, with kind permission of Elsevier). |
As fats are insoluble, absorbed fats are either transported in the blood as chylomicrons or as free fatty acids attached to albumin. These transport molecules are also known as lipoproteins. Because fat is lighter than water the higher the percentage of fat in a lipoprotein the lower the density. Low density lipoproteins (LDLs) carry a high percentage of cholesterol and are therefore associated with a risk to health. The high density lipoproteins (HDLs) on the other hand transport fat from the tissues to the liver to be excreted.
Lipids are either stored on adipose tissue as triglycerides or metabolized by the liver in a process called beta oxidation. The liver cells split pairs of carbon atoms from the fatty acids to form acetyl CoA, which can then enter the Krebs cycle. Excess acetyl CoA is converted into ketones and circulated to other tissues in the body where it is converted back to acetyl CoA and used for energy.
High cholesterol increases the risk of heart disease and strokes; for more information on diagnostic tests and treatment see Evolve 8.1.
Proteins
Chemical structure
Proteins share the same properties of fats and carbohydrates. They contain the same three chemicals – carbon, hydrogen and oxygen – but additionally all proteins contain nitrogen. Complex proteins are made up of amino acids linked together by a peptide bond. There is no general formula, but all amino acids have an amine group (NH2) and an acidic carboxyl group (COOH) in common, with the remainder of the molecule varying depending on which amino acid it is. Although there are only 20 naturally occurring amino acids, the number of possible combinations to form proteins is almost infinite. One very important characteristic of proteins is that each one tends to fold itself into a particular shape which will determine its function. For example if the haemoglobin molecule does not assume its correct shape sickle cell anaemia results. The action of enzymes, which are proteins, also relies on their shape and if this is altered by heat or pH they will not function.
Sources
Many amino acids can be synthesized in the body; those that cannot are known as essential amino acids and must be taken in the diet. Many plants are deficient in one or more of the essential amino acids but a mixture of plant proteins is capable of supplying all the amino acids needed. Meat, fish, eggs and milk have high protein content. Plant sources rich in protein are seeds, with peas, beans and nuts particularly valuable. Cereals and potatoes have a comparatively low percentage of protein but because of the large amount in most diets they can make a significant contribution to total intake.
A colleague has spent the weekend demonstrating against the export of live farm animals. She has decided to become a strict vegan. Of the 20 amino acids in the body it is only possible to synthesize 10 in adequate amounts and it is not possible to synthesize eight at all, nor is it possible to store protein in the body. Therefore if amino acids are to be synthesized it is only possible if combinations of foods containing the elements of amino acids are consumed together.
• What are the implications of protein synthesis for your colleague?
• Which foods contain essential amino acids?
• Which foods contain no essential amino acids?
• Using this knowledge, how would you help your colleague to devise a dietary plan to ensure she receives enough protein?
NON ENERGY PRODUCING DIETARY COMPONENTS
The remaining components of the diet do not provide energy but are essential for health. These are water, vitamins, minerals and fibre.
Vitamins
Vitamins are a series of unrelated organic substances that are needed in very small amounts for normal body metabolism. They are divided into those that are fat soluble and those that are water soluble: see Table 8.1 and Table 8.2.
| Vitamin and chemical name | Source | Functions | Recommended daily intake (adult) | Effects of deficiency |
|---|---|---|---|---|
| A Retinol (provitamin carotene in plants) | Milk, butter, cheese, egg yolk, fish liver, oils, yellow and green vegetables | Maintains healthy epithelial tissue, cornea and is required for the synthesis of visual purple | 600–700 micrograms | Night blindness; atrophy and keratinization of the epithelium; increased infections of ear, sinuses, urinary and alimentary tracts; drying and ulceration of the cornea |
| D Calciferol | Can be synthesized by the action of ultraviolet light on 7-dehydrocholesterol in the skin; milk, butter, cheese, eggs, fish liver | Aids the absorption and utilization of calcium and phosphorus to promote healthy bones and teeth | 10 micrograms | Rickets (in children), osteomalacia in adults |
| E Tocopherol | Egg yolk, nuts, seeds, olive and other vegetable oils, green vegetables | Prevents catabolism of polyunsaturated fats, needed for the structure of cell membranes | 3–4 milligrams | Anaemia; ataxia; cystic fibrosis |
| K Phylloquinone | Dark green leafy vegetables, liver, fish | Needed for the formation of prothrombin and factors VII, IX and X | 60–70 micrograms | Easy bruising and prolonged blood clotting time |
| Vitamin and chemical name | Source | Functions | Recommended daily intake (adult) | Effects of deficiency |
|---|---|---|---|---|
| B1Thiamine | Yeast, liver, germ of cereals, nuts, pulses, egg yolk, legumes | Metabolism of carbohydrate and nutrition of nerve cells | 0.8–1 milligram | Fatigue; neuropathy; loss of memory; beriberi |
| B2Riboflavin | Liver, yeast, milk, eggs, green vegetables, kidney and fish roe | Carbohydrate metabolism; maintains healthy skin and eyes | 1–1.3 milligrams | Angular stomatitis; dermatitis; blurred vision |
| B6Pyridoxine | Meat, liver, fish, vegetables, bran of cereals | Protein metabolism; production of antibodies | 1.2–1.4 milligrams | (Rare) |
| B12Cyanocobalamin | Liver, milk, poultry, fish; not found in plants | Maturation of the red blood cells, DNA synthesis | 1.5 micrograms | Pernicious anaemia |
| B Folic acid/folacin | Synthesized in the colon; dark green vegetables, liver, kidney, eggs | Formation of red blood cells; DNA synthesis | 200 micrograms | Anaemia; N.B. pregnant women need to take a supplement |
| B Nicotinic acid/niacin | Synthesized in the body from tryptophan; yeast, offal, fish, pulses, wholemeal cereals, potatoes | Inhibits production of cholesterol; needed for cell respiration | 12–17 milligrams | Prolonged deficiency causes pellagra |
| B Pantothenic acid | Meat, liver, yeast, fresh vegetables, egg yolk, grains | Amino acid metabolism | 3–7 milligrams | Vague – loss of appetite, abdominal and limb pains; associated with alcoholic neuropathy |
| B Biotin | Yeasts, liver, kidney, pulses, nuts | Carbohydrate and fat metabolism (essential for Krebs cycle) | 10–200 micrograms | Scaly skin; anorexia; elevated blood cholesterol levels |
| C Ascorbic acid | Citrus fruits, currants, berries, green vegetables, potatoes | Formation of collagen; absorption of iron from the gut; required to convert folic acid to its active form | 40 milligrams | Slow wound healing; anaemia; scurvy |
Minerals
These inorganic salts are an essential part of the diet and are required for many processes. They include sodium, potassium, chlorine, iron, iodine, chloride, copper, cobalt, zinc, calcium and selenium. The most common minerals are shown in Table 8.3.
| Mineral (chemical symbol) | Source | Importance in the body | Problems | |
|---|---|---|---|---|
| Excess | Deficit | |||
| Sodium (Na) | Fish, table salt, cured meats, most other foods | The most common cation found in the extracellular fluid; principal electrolyte in maintaining osmotic pressure and water balance; essential for normal neuromuscular function | Implicated as a cause of hypertension | Nausea; abdominal and muscle cramps; convulsions |
| Potassium (K) | Most foods, especially fruit and vegetables | Helps maintain intracellular osmotic pressure; essential for normal nerve impulse conduction, muscle contraction, protein synthesis and glycogenesis | Cardiac arrhythmia; paraesthesia; muscular weakness | Cardiac arrhythmia; heart failure; muscular weakness; paralysis; nausea and vomiting |
| Calcium (Ca) | Milk, cheese, eggs, vegetables and shellfish | Required for the hardening of bones and teeth, blood clotting, transmission of nerve impulses and muscle contraction, normal heart rhythm | Impaired neural function; lethargy and confusion; muscle pain and weakness; calcium deposits in soft tissue; renal stones | Muscle tetany; osteoporosis; retarded growth and rickets in children |
| Chlorine (Cl) | Table salts | With sodium, helps maintain osmotic pressure and pH of extracellular fluid; required for the formation of hydrochloric acid in the stomach | Vomiting | Alkalosis; muscle cramps; apathy |
| Iron (Fe) | Red meat, liver, green vegetables, wholemeal bread, egg yolk | Essential for the formation of haemoglobin in the red blood cells and the oxidization of carbohydrate | Damage to heart, liver and pancreas | Iron deficiency anaemia; pallor, lethargy, anorexia |
| Iodine (I) | Salt water fish, cod liver oil, vegetables grown in iodine rich soil, iodized table salt | Required to form thyroid hormones T3 and T4 which help to regulate metabolic rate | Depressed synthesis of thyroid hormones | Myxoedema; impaired learning and motivation in children |
| Magnesium (Mg) | Nuts, fruit, leafy green vegetables, whole grains | Needed for normal neural function; lactation; oxidization of carbohydrates and protein hydrolysis | Appears to be linked to obsessive behaviour, hallucinations and violent behaviour | Not known |
| Zinc (Zn) | Seafood, meat, cereals, nuts, wheat germ, yeast | Required for normal growth, wound healing, taste, smell and sperm production | Ataxia, slurred speech, tremors | Loss of taste and smell; depressed immunity |
Fibre
Fibre is the indigestible part of the diet that comes from plants; it consists of bran, cellulose and other polysaccharides. Although fibre is not essential for life, deficiency is associated with a variety of diseases. Fibre passes unchanged into the colon adding bulk to the faeces, stimulating peristalsis which prevents constipation. Fibre may reduce the risk of bowel cancer by diluting any toxins and carcinogens in the faeces and reducing the length of time they are in contact with the colon.
PSYCHOSOCIAL
PSYCHOLOGICAL AND SOCIOCULTURAL ASPECTS OF NUTRITION
So far the physiology of nutrition has been considered. This assumes that people are rational dispassionate consumers who will choose to eat the quantity and type of foods best suited to maintaining their energy balance and supplying all the essential nutrients when they feel hungry. Nutritional value is only one of many things taken into account by the majority of people when faced with a choice of food. Sweet things may be associated with being given rewards or treats as a child and in buying them we may be rewarding ourselves for a job well done or comforting ourselves when feeling rejected.
Food plays a part in religion and culture, not only the type of food consumed but in the preparation and timing of meals. The taste and texture of food also influence the choice of foods. Fat, salt and sugar have a very widespread appeal as evidenced by the popularity of chips and crisps and chocolate.
Food advertising encourages us to eat the manufacturer’s product whether we are hungry or not. This huge industry is very versatile and can respond to current fashion by targeting the consumer, for example with low fat, low calorie foods. Food cookery programmes appear on the television every day; few of these are aimed at low income groups though some demonstrate that interesting meals can be made quite cheaply. Much has changed in family life; often both parents are working and families may eat at different times of day with snacks in between. Ready meals that can be microwaved are often preferred to homemade meals, which take time and planning, despite being cheaper and usually tastier.
Current government guidelines recommend five portions of fruit and vegetables daily to help reduce the risk of death from chronic diseases such as heart disease, stroke and cancer (Food Standards Agency 2007a). However, achieving this can be difficult for those on a low income or for those working in areas that have restricted food available, for example out-of-town industrial estates (McKevith 2004). Schools throughout the country have been looking at ways of improving the diet of children supported by a variety of government initiatives (Department for Education and Skills, 2003 and Department for Education and Skills, 2004). Many innovative schemes and government initiatives are being tried: offering free fruit at infant schools; breakfast clubs; tokens issued for choosing healthy options to enable cheap access to sports centres; and inviting celebrity chefs to host cookery classes (Department of Health, 2002 and Department of Health, 2004). The Food in Schools website, a joint initiative of the DH/DfES which provides educational tools and guidance, has reports of pilots which can be accessed by teachers, parents and pupils (see Annotated Websites at end of chapter).
We live in a multicultural society and nurses need to have an awareness of dietary restrictions that may be part of a patient’s culture or religion. For example the Islamic religion requires all healthy adults to fast (i.e. to take no food, drink or medication) from dawn to sunset during the month of Ramadan. People with diabetes would be able to refrain from fasting, as exceptions are made for those who are ill, but many people are reluctant to accept this concession (Khodabukus 2003). Nurses must be able to advise on how best to avoid or minimize the problems observing the fast might cause, while respecting the individual’s right to observe his/her faith.
Institutions such as hospital and care homes must have a flexible menu available and be able to provide halal or kosher meals to clients that require them and facilitate any special requirements relating to the timing and way food is served. Many families wish to provide the food and will often wish to serve the client or help feed them.
CARE DELIVERY KNOWLEDGE
All the components of a healthy diet are required by everyone at all stages in the life cycle in both health and illness. However, nutritional needs change throughout the various stages of our lives. By carrying out a nutritional assessment on patients nurses can help individuals by educating them about diet and the part it plays in health and well-being. The following section gives a brief overview of special requirements at different stages in the life cycle.
NUTRITIONAL REQUIREMENTS THROUGH THE LIFE CYCLE
Pregnancy
Energy requirements increase during pregnancy to provide for the increase in tissue mass of the fetus and the mother. The energy requirement varies according to the trimester; extra food intake is only required in the latter stage of the pregnancy. The actual calorie requirement will vary in individuals but an increase of no more than 200 kcals is adequate for most well-nourished women (British Nutrition Foundation 2004a). A well-balanced diet provides most of the nutrients to maintain a healthy pregnancy, but evidence suggests that some supplements are advisable.
Lack of essential micronutrients (vitamins and minerals) is thought to be a cause of some birth defects and possible susceptibility to diseases later in life. Folic acid is particularly important as its deficiency is implicated in neural tube defects of the newborn. Most literature suggests that women should take a supplement of folic acid as it is difficult to achieve the recommended daily intake in pregnancy by diet alone. It is recommended that all women of child-bearing age who may become pregnant or who are planning a pregnancy should take a supplement that provides 400 micrograms of folic acid per day (Food Standards Agency 2008c). In May 2007 the Board of the Food Standards Agency (FSA 2007b) suggested that a form of mandatory fortification of food with folic acid be recommended to UK health ministers. It is suggested that adding folic acid to either flour or bread will not only increase the folate intake of young women, reducing the number of pregnancies affected by neural tube defects, but will also improve the diets of 13 million people who currently do not eat enough folate.
Other supplements that may be required by some pregnant women include vitamin D and iron. Women of Asian origin or those that always cover up their skin when outside may be particularly short of vitamin D (Food Standards Agency, 2007a and Scientific Advisory Committee on Nutrition, 2007).
Pregnant women are also advised not to eat dishes containing raw or partially cooked eggs, soft or mould ripened cheeses, as these foods are possible sources of the bacteria Salmonella and Listeria monocytogenes. Current opinion is that liver and liver paté should be avoided during pregnancy as they contain high concentrations of vitamin A which may be teratogenic in high doses in early gestation (Goldberg, 2003 and Hale, 2007).
Lactation
During lactation the extra energy required by a breastfeeding mother is approximately 450 kcal per day rising slightly as the baby gets older. To achieve these extra requirements only a small amount of extra food is needed as the mother can use energy from stores laid down during pregnancy.
Babies
In the first few months babies receive all their energy requirements of life from breast or formula milk. Breastfeeding is best for babies for the first 6 months of life but infant formulas are available for those who cannot or choose not to breastfeed. Cows’ milk is not suitable for babies under a year old as it contains too much salt and protein. After about 6 months, milk no longer fulfils all the baby’s nutritional needs and other foods should be introduced. It is currently recommended that this process, known as weaning, does not commence before the age of 6 months as the infant’s gut is limited in the type of foods it can digest and absorb. The ideal time for weaning will vary as all babies have individual needs. Mothers should be advised that solid food should not be introduced until the baby is 17 weeks at the earliest and foods such as wheat, gluten, eggs, liver, citrus fruits and unpasteurised cheese should not be given (Department of Health, 2005 and Food Standards Agency, 2008a). Infant diets need to be high in lipid for energy and for essential long chain fatty acids and fat soluble vitamins. Infants are also at risk of iron and zinc deficiency so it is important to ensure the diet has sufficient micronutrients. There is much evidence and continued research into the effects of a weaning diet on long-term health and health professionals need to be well informed about this aspect of child care.
Schoolchildren
A varied diet containing adequate energy and nutrients is essential for normal growth and development of children. They have a high energy requirement for their size so foods that are high in energy and also rich in nutrients should be eaten as part of small frequent meals. A good supply of protein, calcium, iron and vitamins A and D are also necessary as childhood is an important time for tooth and bone development (British Nutrition Foundation 2004b). Concern is growing over the increase in obesity among schoolchildren. The combined effect of an increased intake of high-fat snacks and sugary fizzy drinks with less physical activity has been cited in several papers (Haslam and James, 2005 and National Institute for Health and Clinical Excellence, 2006b). There is increasing evidence that overweight children and adolescents are being diagnosed with type 2 diabetes, a condition that is normally associated with adults over 40 (Pocock 2007).
Teenagers
Teenagers are particularly susceptible to media images which portray thinness as desirable. They are also at a stage where mood swings may be compensated for by comfort foods. As a result they can be prone to eating disorders which leave them short of nutrients and threaten their physical as well as mental health. Teenagers are the most common age group to suffer the disorders of anorexia nervosa and bulimia nervosa (Harris & Cumella 2006; see also later in this chapter).
Adults
Adults need to eat a well-balanced diet to maintain their optimum weight. A healthy diet contains a variety of types of food – fruit, vegetables, starchy foods, protein foods. A guide to the proportions of each type is shown below:
• Base your meals on starchy foods – bread, other cereals and potatoes 34%.
• Fruit and vegetables – five portions a day 33%.
• Milk and dairy foods 15%.
• Meat, fish and alternatives 12%.
• Cut down on saturated fats and sugary food 7%.
• Eat no more than 6 grams of salt a day.
• Drink 6–8 glasses of water a day (1.2 litres).
Often activity decreases with age; if a middle aged person consumes the same amount of food as when an active teenager, weight gain will occur. The government’s recommendation of eating five portions of fruit and vegetables daily and reducing intake of saturated fats has been linked with improved health benefits, especially in the prevention of heart disease and some cancers (British Nutrition Foundation 2004d).
Older people
Older people are particularly at risk of poor nutrition and its consequences. Between 30 and 50% of older people admitted to hospital are undernourished (Holmes 2006). There is a variety of causes including: loss of appetite due to decreased sense of taste and smell; poor dentition; lack of agility and mobility; social isolation and depression. Medical conditions or the side-effects of drugs can interfere with nutrient absorption and metabolism as well as suppressing appetite. Particularly at risk are patients with dementia as they often refuse food and exhibit choking behaviour when attempts to spoon-feed are made; this causes stress and poses ethical problems for the carers. Tube feeding may be used if tolerated but the risk of the procedure and issues surrounding informed consent need to thoroughly explored.
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