Cappagh National Orthopaedic Hospital, Finglas, Dublin, Ireland
Nutrition and hydration are influenced by many factors. These include cultural, personal and psychological (beliefs, attitudes and emotions), biological and physiological (age, gender, pregnancy, activity), socioeconomic (availability and cost), cultural and religious, educational (nutritional knowledge), extrinsic (media, time, foods in season) and food (taste and appearance) (Geissler and Powers 2005). Good nutrition plays an important role in recovery from orthopaedic injury or surgery. Musculoskeletal health can be impacted upon by poor nutrition; failure to get enough nutrients can lead to poor skeletal tissue development or rickets while the impact of a poor quality diet can contribute to obesity or osteoporosis. Poor nutrition can increase the healing time in wounds and fractures, increase the risk of infection, decrease muscle strength plus leading to constipation and delayed recovery. This can prolong the treatment and may prevent the patient returning to work or to independent living while increasing the cost to the patient and the health service.
Maintaining good hydration is also critical to maintaining good health and especially with advancing age. Poor hydration can lead to multiple problems, tendons and ligaments become less resilient, repeated urinary tract infections, constipation and fatigue can occur. Dehydration can delay recovery and discharge.
This chapter will examine the role of diet in musculoskeletal health, discuss the metabolic response of the body to trauma and surgery, analyse the importance of a nutritional assessment, the subsequent interventions and the role of hydration and dehydration.
Diet and musculoskeletal health
Healthy eating requires planning and knowledge. A balanced diet is essential for health and provides the appropriate amount of nutrients needed to meet the requirements of the body. This can be achieved by eating a variety of foods with no single food having the correct proportions of all essential nutrients. If a deficiency or an excess of a nutrient is consumed, it can have an impact on health; potentially leading to obesity, anaemia, rickets or osteoporosis. A well balanced diet containing the major components is important in maintaining musculoskeletal health, preventing disease and promoting recovery and healing.
Energy is central to recovery and healing and consideration should be given to the amount of energy required to meet individual needs. Several factors can influence daily energy requirements; for example age, gender, activity levels and basal metabolic rate.
Basal metabolic rate refers to activity within the body that maintains function (e.g. respiratory function, cardiac function, body temperature) and is affected by:
- metabolism – the processing of nutrients within our bodies.
- catabolism – the reactions that release energy and
- anabolism – the building of new tissue.
Energy requirements increase depending on demand, for example while a fracture is healing or an infection is present. Recommended daily amounts of all nutrients, including energy, are based on the average healthy adult and need to be adjusted for the individual.
Six major dietary components are considered essential: carbohydrates, fats, proteins, vitamins, minerals and water. Carbohydrates, proteins and fat are called macronutrients and are required in larger amounts than the micronutrients (vitamins and minerals). Although micronutrients are required in smaller amounts, they remain essential for metabolism, normal growth and well-being.
Carbohydrates are mainly made up of sugars and starches. They are essential in providing energy and heat, sparing the use of protein to provide energy and as an energy store (as glycogen and fat) when eaten in excess of needs.
Fats provide energy and are made up of different types of fatty acids, some of which are essential for health in small amounts. Fatty acids are classified as saturated, monounsaturated or polyunsaturated depending on their structure. Fats are a carrier for fat-soluble vitamins and are necessary for their absorption. A high intake of saturated or trans fatty acids can have adverse effects on health.
Proteins are essential for growth and repair of tissues and cells and play a role in the production of enzymes, plasma proteins, immunoglobulins and some hormones. They also are involved in the provision of energy (when there is not enough carbohydrate in the diet).
Vitamins are chemical compounds required in small quantities and are divided into two groups; the fat soluble vitamins (D, A, E & K) and the water soluble vitamins (B & C). Vitamins relevant to musculoskeletal health include:
- Vitamin D regulates calcium and phosphate metabolism by increasing their absorption from the gut and stimulating their retention by the kidneys, promoting the calcification of bones. A deficiency in children can cause rickets and osteomalacia in adults. Vitamin D is manufactured in the skin through exposure to sunlight and/or obtained in the diet from sources such as eggs, butter, cheese and fish liver oils. Cereals and margarine are fortified with vitamin D. Some groups of people such as those of Asian descent, black people, older, institutionalised and housebound people and those who habitually cover the skin (for religious reasons) are vulnerable to vitamin D deficiency as a result of limited exposure to sunlight.
- Vitamin A (retinol/carotenoids) is found in whole milk, egg yolks, liver, fish oil, cheese, butter, carrots, dark leafy green vegetables and orange-coloured fruits (e.g. mangos and apricots). It is responsible for cell growth and differentiation, promotion of immunity, as a defence against infection and promotion of growth in bones. Large amounts of retinol can cause bone damage. Some food products are now fortified with vitamin A such as margarine and reduced fat spreads.
- Vitamin B complex is divided into B1, B2, B3, B6, B12, folate, pantothenic acid and biotin. Thiamin (vitamin B1) is found in nuts, yeast, egg yolk, liver, legumes and meat. Deficiency can result in severe muscle wasting, delayed growth in children and increased susceptibility to infections. Other B vitamins do not impact directly on musculoskeletal health but have an effect on health generally.
- Vitamin C is found in fresh fruit and green vegetables. It is associated with protein metabolism e.g. laying down of collagen fibres in connective tissue. A deficiency can delay wound healing and inhibit bone repair.
Minerals are inorganic substances required by the body in small amounts for a variety of different functions. They are involved in the formation of bones and teeth, are essential constituents of body fluids and tissues and are components of enzyme systems. They are also involved in normal nerve function. Minerals relevant to musculoskeletal health include:
- Calcium is the most abundant mineral in the human body and is found in dairy products, eggs, green vegetables and some fish (e.g. sardines). An adequate supply is obtained from a well-balanced diet but certain groups can require more such as teenagers and pregnant or nursing mothers. It is absorbed from the intestines and is an essential structural component of bone where we find approximately 99% of our calcium (with the other 1% found in blood). Calcium is required for vascular contraction and vasodilation, muscle function, nerve transmission, intracellular activity and hormonal secretion. It also provides rigidity in bones in the form of calcium phosphate. Calcium regulation is controlled by the action of parathyroid hormone, vitamin D and calcitonin (Geissler and Powers 2005) with less than 1% of vitamin D and calcitonin needed to support metabolic function. As it is tightly regulated, the levels in the body do not fluctuate with dietary changes; instead the body uses bone tissue as a source of calcium to maintain concentrations. A negative calcium balance occurs when net calcium absorption fails to compensate for urinary calcium losses. Signs of calcium deficiency include stunted growth, poor quality bones, teeth and bone malformation. Bone undergoes continuous remodelling with constant resorption and deposition into new bone. The balance between these two actions can change with age. For example, in a period of growth (in children and adolescents), formation exceeds absorption. In adulthood both actions are relatively equal but in the aging population, particularly post-menopausal women, bone resorption exceeds formation resulting in bone loss and an increased risk of osteoporosis. During these periods, this results in a change in the recommended daily intake. Recommended daily calcium intakes vary from country to country. The recommended daily intake for the USA and United Kingdom are shown in Tables 10.1 and 10.2.
- Phosphorus is essential for skeletal development and is found in cheese, oatmeal, liver and kidney. It is also added to foods and drinks such as cola as polyphosphates or phosphoric acid. Where there is a normal level of calcium a deficiency of phosphorus is unlikely as bone mineral consists of calcium phosphate. Along with calcium and vitamin D, it is involved in the hardening of bones.
- Iron is an essential trace element. Sources include liver, beef, lamb, soya beans, tofu, lentils, kidney beans and green leafy vegetables. The recommended daily intake varies according to sex and age e.g. for females aged 19–50 years, 18 mg daily is advised while for males of the same age 8 mg daily is advised (Office of Dietary Supplements 2007) with only a small proportion absorbed (less than 15%). Iron is essential for the formation of haemoglobin (oxygen-carrying component) in red blood cells. Iron deficiency is a condition that causes anaemia if iron stores are depleted and is the most common nutritional deficiency. Mild anaemia in many individuals is of little health consequence due to compensatory mechanisms in the body (such as increased cardiac output, diversion of blood flow and increased release of oxygen from haemoglobin), but the body cannot compensate in severe anaemia which results in poorer oxygen delivery to the tissues and impacts on body function. Work performance is limited and this will influence the participation of patients in rehabilitation post injury and after surgery. It is essential that the patient’s haemoglobin is within an acceptable range to facilitate recovery and rehabilitation.
- Zinc can be obtained from shellfish, meat and whole grains with the recommended intake being 10–12 mg daily. Reduced growth is the only clearly demonstrated consequence of mild zinc deficiency although it is thought that zinc plays a central role in turnover and metabolism of connective tissue so a deficiency may have a negative influence on bone formation (Geissler and Powers 2005).
- Sodium is found in most foods and can also be added to food. It helps regulate water content in the body. A diet high in sodium increases urinary calcium excretion. Sodium occurs as an extracellular action and is involved in muscle contraction, transmission of nerve impulses along the axons and water and electrolyte balance. The British Nutrition Foundation (2012) recommends a salt intake (sodium chloride) of no more than 6 g daily. Currently intakes of sodium are high and although some is essential, a substantial reduction in intake is required.
- Potassium is found in fruit and vegetables and other foods. As with sodium, it is also involved in muscle contraction, transmission of nerve impulses and water and electrolyte balance and occurs as an intracellular action.
- Fluoride is involved in the mineralisation of bones. Fluoride is present in the majority of foods. Adding fluoride to drinking water is controversial; low fluoride levels may be beneficial but higher levels are toxic, resulting in fluorosis leading to joint pain and spinal defects (Geissler and Powers 2005). Fluorosis is rare in the Western world but is common in parts of Africa, China and India.
- Magnesium is important in calcium homeostasis and in the metabolism and/or action of vitamin D so is essential for the synthesis and secretion of the parathyroid hormone. A deficiency results in impaired parathyroid hormone secretion, disturbed calcium homeostasis and hypocalcaemia is a common symptom of a moderate to severe deficiency (Expert Group on Vitamins and Minerals 2003).
- Aluminum toxicity occurs in chronic renal failure or in patients receiving parenteral nutrition, or when drinking or ingesting substances that are high in aluminium, or living or working in an environment that contains high levels of aluminium or is very dusty. Osteoblast function is impaired in this toxic environment and there is reduced bone remodelling and osteomalacia.
- Manganese is required for bone health. It is found in vegetables, cereals and nuts and tea provides a rich resource. A deficiency is rare.
Table 10.1 Daily recommended intake of calcium in healthy subjects (Office of Dietary Supplements (US), 2012). Reproduced with permission from US Federal Government
|Age||Calcium intake (mg)|
Pregnant and lactating women in the age group of 14–18 years and 19–50 years should take the recommended intake for that group.
Table 10.2 Daily recommended intake of calcium (Expert group on Vitamins and Minerals 2003). Reproduced with permission from Food Standards Agency
|Age||Calcium intake (mgs)|
|1– 3 years||350|
|11–18 years (girls)||800|
|11–18 years (boys)||1000|
|50 + years||700|
|Breastfeeding women||As per the above recommendations for their age group plus an additional 550 mg|
Fibre is found in cereals, beans, pulses, fruit and vegetables and although not a nutrient, it facilitates movement in the gut and helps prevent constipation. Other dietary components can also influence bone health. Excessive alcohol consumption can affect bone quality and increase the risk of fracture. A suggested link between an increased intake of caffeine and fracture is noted in publications on bone health; however, Heaney (2002) reported in a large prospective study of caffeine intake and fracture risk that, while there was a three times greater risk of hip fracture for women consuming more than 817 mg caffeine a day (five cups of coffee), the number of hip fractures in the study were small. It is possible that this intake is not a cause of fractures but may be associated with a change in calcium intake when less milk is ingested. A high intake of carbonated beverages is also associated with a lower bone mineral density due to lifestyle and dietary factors. SIGN (2004) although supportive, report the evidence as inconclusive and do not make any recommendations in this area.
Metabolic response to tissue injury and trauma
The metabolic effect of trauma and surgery is catabolism of stored body fuels. The size and time span of this response is proportional to the injury and any complications (Desborough 2000), so energy requirements will increase depending on the demand created by the processes of recovery and healing. It is essential, therefore, that the nutritional needs of the patient are considered in the post-trauma, preoperative, peri-operative and post-operative periods. The increased demands placed upon the body during recovery from surgery, injury and associated complications can lead to malnutrition and delayed recovery and warrants careful consideration by the multidisciplinary team.
The dietary needs of children and adolescents must take into account their age, growth and development which can make them susceptible to nutritional imbalance and deficiencies. Consideration needs to be given to additional demands related to exercise, sport and training programmes. As individuals age, the risk of chronic disease increases and nutrition plays a role in the development of, susceptibility to and outcome of disease. Other groups at risk of under nutrition and malnutrition include those with learning disabilities, dementia and other mental health conditions. Lee and Kolasa (2011) identify the difficulties of providing adequate nutrition to people with advanced dementia who need assistance with feeding.
Nutrition assessment and intervention
Malnutrition refers to both under-nutrition and over-nutrition. Nutrition deprivation does not imply a lack of food, but the provision of a diet that does not meet the physiological needs of the patient (Kneale 2005). Patients are at risk of malnutrition if the intake of nutrients is affected by comorbidities, surgery or underlying problems that affect appetite or absorption of food. Malnutrition can have a wide range of consequences including impaired immune response, muscle fatigue, impaired wound healing and growth (BAPEN 2011). Patients at risk of malnutrition remain in hospital for longer than those who are well nourished and are more likely to be discharged to alternative settings rather than home. The risk of malnutrition is increased in the older person, leading to impaired coordination with an increased risk of falls. Nutritional support is essential for those who are malnourished; i.e. with a Body Mass Index (BMI) of less than 18 kg/m2, unintentional weight loss of >10% in the previous 3–6 months or a BMI of <20 kg/m2 and an unintentional weight loss greater than 5% within 3–6 months (NICE 2006).
Obesity is a common nutritional problem in many developed countries. It exists where there is an excess accumulation of body fat when the BMI exceeds 29.9 (Box 10.1) and associated with high morbidity and mortality rates. Obese patients may prove challenging during all phases of care due to an associated risk of complications. The role of the nurse during preparation for surgery is critical in providing support and advice with respect to achieving weight loss.
Table 10.3 Essence of Care Benchmarks for Nutrition (Department of Health 2010). Reproduced with permission from Crown copyright
|Benchmarks for the management of food and drink in the health care setting and the community|
|Factor||Benchmark of best practice|
|1. Promoting health||People are encouraged to eat and drink in a way that promotes health|
|2. Information||People and carers have sufficient information to enable them to obtain their food and drink|
|3. Availability||People can access food and drink at any time according to their needs and preferences|
|4. Provision||People are provided with food and drink that meets their individual needs and preferences|
|5. Presentation||People’s food and drink is presented in a way that is appealing to them|
|6. Environment||People feel the environment is conducive to eating and drinking|
|7. Screening and assessment||People who are screened on initial contact and identified at risk receive full nutritional assessment|
|8. Planning, implementation, evaluation and revision of care||People’s care is planned, implemented, continuously evaluated and revised to meet individual needs and preference to food and drink|
|9. Assistance||People receive care and assistance when required with eating and drinking|
|10. Monitoring||People’s food and drink intake is monitored and recorded.|
Measuring nutritional status can be predictive of health outcomes and the assessment of nutritional intake is required if there may be a need to provide advice to the person or interventions such as enteral or parenteral support. Nutritional assessment approaches include dietary assessment, the use of anthropometry (physical measurement of aspects of human body size) and the use of biochemical, functional and clinical measures or indices. Biochemical status measures are defined for each nutrient and assess the concentration of the nutrient or its derivative in body fluid. Functional indices are assessments of the metabolic processes that are nutritionally dependent. Clinical indices are the signs and symptoms of a nutritional deficiency.
Dietary assessment involves attaining a dietary history from the individual or carer for the previous 24 hours or by administering a questionnaire to determine the frequency of different food groups eaten over the previous week. Anthropometry includes the measurement of body weight and height from which the BMI is calculated (Box 10.1). The percentage of body fat can be estimated by measuring the sum of the thickness of skinfolds over the biceps, triceps, subscapular and supra-iliac sites. The fat content varies with age and gender. It is now recognised that intra-abdominal fat measurement has a greater influence on the development of heart disease and diabetes than fat measurement in subcutaneous sites and is useful in orthopaedic assessment in preparation for surgery.