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Nutrition and optimal health: finding the right balance

Aisling Aherne
BSc PhD RNutr
Health Professionals Manager
The Sugar Bureau
London

Chronic diseases, including those of the heart and circulatory system, diabetes, cancers and respiratory diseases, are estimated to account for 59% of deaths annually and 46% of the global disease burden worldwide.(1) The risk of developing certain diseases can be modified by environmental factors including smoking, alcohol, diet and physical activity. Nutrition plays an especially important role in the prevention and treatment of cardiovascular disease (CVD) (including coronary heart disease [CHD] and stroke), obesity, and diabetes. There is also an increasing amount of evidence showing that modest levels of physical activity can have a positive effect on body weight, general health and disease risk.
 
Obesity
Currently, over 50% of the UK adult population are overweight - of this, 17% of men and 21% of women are obese.(2) Tackling obesity involves preventing an undesirable imbalance between energy intake (from food and drink) and energy expenditure (metabolism and physical activity). Many reasons have been put forward to explain this imbalance. The most likely contributors are lack of physical activity and overconsumption of food and drink.(3) The relationship between energy balance and body weight is outlined in Box 1.

[[NIP12_box1_69]]

By eating no more energy than needed and undertaking regular physical activity, a healthy body weight can be achieved and the risk of developing obesity-associated health complications such as diabetes can be reduced.

Diabetes
In the UK, 1.4 million people have diabetes and a further 1 million are estimated to be unaware that they have the condition. These are sometimes referred to as the "missing million".(4) Over 75% of people with diabetes have type 2 diabetes. The increasing trends in overweight, obesity and sedentary lifestyles are fuelling the rise in diabetes worldwide, as overweight and obesity are risk factors for diabetes.
People with type 2 diabetes are encouraged to adhere to the same dietary guidelines as those recommended for the general population. People with diabetes have an increased chance of developing heart disease, stroke, high blood pressure, circulatory problems, nerve damage, and damage to the kidneys and eyes.(5) Healthy eating and regular physical activity can help maintain blood glucose levels and can also aid in reducing the risk of developing health complications associated with diabetes, especially cardiovascular complications. The most common cause of death among people with diabetes is CVD.(6)

Cardiovascular disease
The main forms of CVD are CHD and stroke. Although death rates from CVD have fallen in recent years the amount of people living with heart and circulatory diseases still remains high.(7) CVD is the main cause of death in England and Wales, accounting for over 200,000 deaths a year, and in 2001 was the cause of 40% of deaths in the UK.(8) Currently, over 2.5 ­million people in the UK have CHD.
High-fat diets, smoking and lack of physical activity are known to be contributory factors to CVD. Thus the risk of developing CVD can be reduced by eating a healthy, balanced diet, being physically active and stopping smoking. By adhering to a healthy lifestyle people can also lower their risk of developing health conditions such as obesity and diabetes, which may ultimately lead to CVD.

What is healthy eating?
A healthy, balanced diet is one that provides the right amount of nutrients and energy needed for optimal health.(9) Consuming a variety of foods will help prevent a deficiency of any particular nutrient. So a healthy diet must fulfil two objectives:(10)

  • It must provide sufficient energy and nutrients to maintain normal physiological functions and ­permit growth and replacement of tissues.
  • It must offer the best protection against disease risk.

Balance
Dietary energy is measured in kilojoules (kJ) or kilocalories (kcal). Most energy is provided from the metabolism of fat, carbohydrates and protein. Fat provides 9kcal per gram whereas protein and carbo­hydrate each provide 4kcal per gram. Many people do not realise that alcohol is also a source of energy and hence calories. One gram of alcohol contains 7kcal.
Energy balance controls body weight (see Box 1), and by managing the body's energy balance body weight can be regulated. It is important to remember that maintaining a healthy body weight helps prevent the development of health complications associated with excess weight and obesity.

Dietary recommendations
Dietary recommendations are usually set in numerical terms. For instance, 55% of our total daily energy intake should be provided from carbohydrate-containing foods.(11,12) Dietary energy intake from fat should be around 30-35% and the remaining 10-15% should be supplied from protein. But what does this actually mean? It means that most people should be eating more carbohydrate-containing foods with only moderate amounts of protein and fat in their daily diet.
 
Carbohydrates
The amount of carbohydrate required in the diet depends on the amount of energy used by the body. Carbohydrates (starches and sugars) are an important source of energy and can also provide important nutrients and phytochemicals.(12) Carbohydrate-containing foods fuel physical activity and help provide the body's energy needs. Dietary sources of carbohydrates include pasta, rice, potatoes, bread, cereals, yams, fruit and milk.
Many people see carbohydrate-containing foods as fattening and need to be reassured that the opposite is true. Moderately high carbohydrate-containing diets have been shown to passively decrease fat intake, increase satiety (feel full for longer), delay hunger and therefore reduce the risk of overconsumption.(13)
 
Protein
Protein is essential for both the structural and metabolic operations of the human body. It provides amino acids which are necessary for the growth and continuous replacement of body tissues and enzymes. Most people consume substantially more protein than they need.
Lean red meat is a concentrated source of protein and micronutrients. Some meat and meat products such as pies and sausages can contribute a high proportion of fat to the diet but lean meat contains relatively little fat.
Poultry is also a source of protein but only the white meat (breast meat), eaten without any skin or visible fat, is low in fat. Darker poultry meat (leg) has a higher fat content.
White fish is low in fat and high in protein. Oily fish (such as herrings, mackerel, sardines, salmon) are an important part of a cardioprotective diet as they contain n-3 polyunsaturated fatty acids.
 
Fat
As mentioned earlier, dietary fat is a concentrated form of energy that comes from food. There are different types of dietary fat. Some fats provide essential fatty acids necessary, for example, for the construction of cell membranes. However, others, especially saturated fats, can raise blood lipid levels. The amount of saturated fats in the diet should be reduced as high intakes are linked to elevated blood cholesterol levels.(14) Remember, dietary advice on fat intake is one of reduction and not of total exclusion.
To lower fat intake choose leaner cuts of meat and remove visible fat. With poultry, remove the skin and fat underneath. Avoid frying foods; grill, bake, boil, steam or casserole instead. Use minimal amounts of cooking oil and avoid the addition of fat to cooked foods. Instead of using full-fat versions of foods use lower-/reduced-fat options, especially of spreading fats and dairy products.

Vitamins and minerals
Vitamins are required in minute quantities but are essential for many processes carried out in the body. Minerals such as calcium and iron and trace elements are also required by the body for functions such as tissue structure, metabolism, fluid balance and cellular function. Sufficient amounts of these essential vitamins and minerals can be obtained by eating a healthy, balanced diet.

Fluid
Water is needed for many bodily functions and poor fluid intake leads to dehydration, which can result in a number of ill-effects such as constipation. People should be encouraged to drink plenty of water throughout the day. A target of one litre of water per day would be advisable, not forgetting that additional amounts of fluid should be taken when exercising.

Fruit and vegetables
It is recommended that we eat five portions of fruit and vegetables a day.(15) Fruit and vegetables can be fresh or raw, canned, dried, frozen or juiced (see Table 1). These five portions should be in addition to any potatoes eaten.

[[NIP12_table1_72]]

Processed foods with only small fruit/vegetable content (such as fruit yoghurt, vegetable soups, fruit cake) should not be counted as part of the five-a-day total.(10)
Salads, fruits and vegetables should be included with meals and can also be used as snack foods and desserts. It is important to emphasise that the addition of butter or spreads to vegetables will substantially increase fat and calorie consumption.
 
Alcohol
Current recommendations on safe limits for alcohol consumption state that men should consume no more than 3-4 units of alcohol per day and that women should consume no more than 2-3 units per day. Intakes are expressed on a daily basis rather than weekly in order to discourage binge drinking.
In the UK, one unit of alcohol is defined as 8g alcohol and is approximately equal to one pub measure of spirits (25ml); one measure of sherry or fortified wine (50ml); or half a pint of standard strength beer, lager or cider. One small glass of wine contains 1.5 units of alcohol.

Advice
The diversity of nursing roles in the primary care setting allows nurses to play an important role in the promotion of good nutrition and health.(16) The public regard health professionals as credible and acceptable sources of information and will listen to the advice given.
The key to giving dietary advice is to be consistent, make it simple and emphasise the positive. Remember to move away from prescriptive advice that can come across as negative or restrictive, such as "don't eat" or "cut out". Advice must be based on the scientific evidence available. State registered dietitians (SRD) and registered nutritionists (RNutr, RPHNutr) are qualified to provide evidence-based advice and are an important resource for other health professionals.
 
Conclusion
Nurses, midwives and health visitors play an important role in the promotion of good health to the public. To achieve optimal health and lower the risks of ill-health and premature death it is important to adhere to a healthy lifestyle which involves eating a balanced diet, being active and fit, avoiding smoking, and consuming alcohol in moderation.(9) By getting these messages across to the public, health professionals can help people achieve optimal health, wellbeing and have a good quality of life for longer.

References

  1. World Health Organization. Chronic disease - key risk factors include high cholesterol, high blood pressure, low fruit and vegetable intake. 2003. Available from URL: http://www.who.int/hpr/NPH/docs/gs_chronic_disease.pdf
  2. National Audit Office. Tackling obesity in England. London: NAO; 2001.
  3. Prentice A, Jebb S. Obesity in Britain: gluttony or sloth? BMJ 1995;311:437-9.
  4. Diabetes UK. Who gets diabetes and what causes it? 2003. Available from URL: http://www.diabetes.org.uk/ diabetes/get.htm
  5. Diabetes UK. Reducing the risk of serious health problems. 2003. Available from URL: http://www.diabetes.org.uk/ diabetes/reduce.htm
  6. British Heart Foundation. Mortality from diabetes. 2003. Available from URL: http://www.dphpc. ox.ac.uk/bhfhprg/ stats/2000/diabetes2001/2.html
  7. British Heart Foundation statistics website. 2003. Available from URL: http://www.heartstats.org/datapage.asp?id=713
  8. Department of Health. Health and personal social services statistics England. 2001. Available from URL: http://www.doh.gov.uk/hpsss/
  9. Buttriss J, Wynne A, Stanner S. Nutrition: a handbook for community nurses. London: Whurr Publishers; 2001.
  10. British Dietetic Association. Manual of dietetic practice. Oxford: Blackwell Science; 2001.
  11. Department of Health. Dietary ­reference values for food energy and nutrients for the United Kingdom. Report on Health and Social Subjects 41. London: HMSO; 1991.
  12. World Health Organization/Food and Agriculture Organization. Carbohydrates in human nutrition. Rome: FAO; 1998.
  13. Saris WH, Astrup A, Prentice AM, et al. Randomized controlled trial of changes in dietary carbohydrate/fat ratio and simple vs complex carbohydrates on body weight and blood lipids: the CARMEN study. Int J Obes Relat Metab Disord 2000; 24:1310-8.
  14. Mann J. Diseases of the heart and circulation: the role of dietary factors in aetiology and management. In: Garrow JS, James WPT, Ralph A, editors. Human nutrition and dietetics. London: Churchill Livingstone; 2001. p.689-714.
  15. Department of Health. Nutritional aspects of cardiovascular disease. Report on Health and Social Subjects 46. London: HMSO; 1994.
  16. Royal College of Physicians. Nutrition and patients. A doctor's ­responsibility. London: RCP; 2002.

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