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A healthy diet: how do your patients measure up?

Penny Hunking
RD ASD RPHNutr
Freelance ­nutrition ­consultant
Energise Nutrition

Eating a variety of foods in the right balance over a period of time can help promote long-term health. Unhealthy diets, physical inactivity and smoking are confirmed risk behaviours that contribute to the burden of chronic diseases, such as cardiovascular diseases, obesity and diabetes, that are presenting today. It is worth noting that a "diet" is simply a pattern of eating, although it is now used synonymously with the concept of the reducing diet. In essence, a healthy diet is one that offers sufficient nutrients to an individual at their time of life, and this is generally easier to achieve when a variety of foods are eaten. Food is an integral part of our daily lives and should also provide much pleasure. However, with the wealth of conflicting information, anecdotal theories and the vast range of foods available today, many people are confused about which foods they should eat to achieve a healthy diet.

The energy nutrients
There are three energy nutrients: carbohydrate, fat and protein. A joint FAO/WHO Expert Consultation on carbohydrates in human nutrition recommended an optimum diet of at least 55% of total energy from a variety of carbohydrate sources for all ages except children under the age of two.(1) A mixture of protein and fat should meet the other 45% of total energy intake. It would be realistic to keep fat between 25-30% of total energy intake and protein between 15-20% total energy intake.
Carbohydrate is the main source of energy for the body and provides 4kcal (17kJ) per gram. Carbohydrate is found in a range of foods, including bread, rice, pasta, cereals, potatoes, fruit, vegetables, beans, pulses, milk and yoghurt. People need to eat sufficient carbohydrate in their diet, and so sugar and sugar-containing foods can be included in moderation, as part of this strategy.
Protein is used for the growth and repair of body tissues and is composed of long chains of amino acids, some of which the body can make and others, which must be provided by food. Proteins contain 4kcal (17kJ) per gram and can also provide energy when carbohydrates are in short supply. Protein is found in meat, fish, eggs, tofu, soya products, cheese, nuts, seeds, beans, pulses, milk and dairy products, bread, rice, pasta, cereals and potatoes.
Fat provides 9kcal (37kJ) per gram. Fats are composed of basic units called fatty acids, some of which are termed "essential" because they cannot be made by the body and must be provided by the diet. Fat has many other functions, including the transportation of nutrients (eg, fat-soluble vitamins), and forms the major material of cell membranes. Fat is found in many different foods "visibly" (butter, margarine, oil, fat on meat, etc) and "invisibly" (in sauces, fried foods, cakes, etc).

Health and disease - how food can help?
A varied diet can help maintain a healthy body weight and reduce the risk of diseases including diabetes, heart disease, cancer and osteoporosis. A healthy balanced diet should contain foods that provide all the essential nutrients you need: carbohydrate, protein, fat, fibre, vitamins, minerals and water. Although no single food can provide all the essential nutrients that the body needs, some foods are seen to be particularly beneficial to our health. As far back as the 1950s, the Seven Countries Study initiated by Ancel Keys investigated the link between diet and health. It has long been observed that people living in Mediterranean countries have lower rates of coronary heart disease and certain types of cancer and live longer than people in other European countries.(2) The main characteristics of the traditional Mediterranean diet include an abundance of plant foods (fruit, vegetables, wholegrain cereals, nuts and legumes); olive oil as the principle source of fat; fish and poultry consumed in low to moderate amounts; relatively low consumption of red meat; and moderate consumption of wine, normally with meals.

Fruit and vegetables
The WHO and the UK Committee on Medical Aspects of Food and Nutrition Policy (COMA) have consistently recommended eating at least five portions of a variety of fruit and vegetables each day (400g, ie, five 80g portions).(3,4,5) Increasing fruit and vegetable intake could reduce the risk of deaths from chronic disease such as heart disease, stroke and cancer by up to 20%.(6) In addition, increased fruit and vegetable consumption may have a positive impact on other dietary goals: for example, to increase fibre intake and reduce fat intake, help in the management of diabetes and delay the development of cataracts.(7,8,9) A higher intake of fruit and vegetables will also increase the intake of antioxidants, which have many health benefits.
The Food Standards Agency Consumer Attitudes to Food Survey 2003 concluded that "correct knowledge of at least five portions" of fruit and vegetables has increased year-on-year - though there has been "little change in the number actually claiming to eat the recommended amount". This indicates that there is a great need to continue to encourage patients to eat plenty of fruit and vegetables. Fruit and vegetables in all forms contribute towards the day's intake, so fresh, frozen, dried and canned varieties all count. Smoothies and juices made with fruit and vegetables can be a quick, easy and popular way to help ensure patients eat sufficient. A portion is approximately 80g which is 1 medium apple or orange, 2 small fruits (eg, plums), 1 tablespoon of dried fruit, 2 heaped tablespoons of vegetables or 1 dessert bowl of salad.

Fats
There are three main categories of fats: saturated, polyunsaturated and monounsaturated, and most foods contain a mixture of fats. Foods tend to be labelled according to the type of fat that predominates. Butter contains a fair amount of monounsaturated fat but is often termed saturated because it contains more saturated fatty acids than monounsaturated fatty acids. Evidence suggests that the qualitative composition of fats in the diet has a significant role to play in modifying the risk of cardiovascular diseases. Dietary fats associated with an increased risk of CHD include trans fats and saturated fats, while polyunsaturated fats are known to be protective.(10)
To promote cardiovascular health, diets should provide a very low intake (

Salt
Salt is responsible for maintaining water balance and blood pressure and is essential for muscle and nerve activity. High intakes, however, have been linked to high blood pressure, which can lead to strokes, gallstones, heart and kidney disease in some individuals. The Scientific Advisory Committee on Nutrition  report stated that the Chief Medical Officer of England has endorsed the 1994 COMA recommendation for a reduction in adult salt consumption to 6g per day (2.4g/100mmol sodium).(12) A simple way to cut salt intake is to tell patients not to add salt to cooking or at the meal table and to eat plenty of naturally fresh foods in the diet such as fruit and vegetables.

Probiotics
Probiotics are live microbial food supplements that change either the composition or metabolic activities of the microflora, or modulate immune system reactivity in a way that benefits health.(13) The bacteria are ingested in the form of drinks, yoghurts and capsules, and there is evidence for the use of probiotics in clinical conditions such as irritable bowel syndrome and inflammatory bowel disease. Further trials are needed to clarify individual strain efficacy so that probiotics can be tailored to individual patient requirements.

Diet, physical activity and health
Physical activity is the cornerstone of a healthy lifestyle, and the WHO initiative, Move for Health, stated that: "the lack of physical activity is a major underlying cause of death, disease and disability". People who are sedentary double their risk of early death and suffering from problems such as coronary heart disease, diabetes, some cancers and obesity. Evidence suggests that modern inactive lifestyles are at least as important as diet in the aetiology of obesity and possibly represent the dominant factor.(14) In addition, activity can help alleviate other risk factors such as high blood pressure, and can lead to reduction of LDL cholesterol. Regular physical activity and healthy eating have a synergistic effect, but how much activity is needed? Recommendations are to include 30 minutes on most days of the week. Recent debates have focused on the benefits of lifestyle activity to increase physical activity, particularly when offering advice to people wishing to lose weight or maintain a healthy weight.(15) The message is clear: in our current environment, which is leading to an increasingly sedentary lifestyle, it is vital that people get as active as they can whenever they can. In other words, every little helps.

Health professionals in action
It is clear that, increasingly, many people understand that they should be eating more of certain foods and less of others but are failing to actually achieve this in practice. In addition, there is much dietary misinformation in the public domain. Health professionals are in a great position to offer realistic and evidence-based information about healthy eating to patients. It is important to strengthen skills and keep up-to-date with new dietary guidelines. Any dietary advice should be offered in a practical way that helps people to easily implement it. Ideally, advice should be tailored to the individual concerned and guidance given to help the patient understand exactly what they should be eating, when they should be eating it and how much they should be eating. It is not usually enough to tell someone to "eat more fruit and vegetables". They may consider them to be expensive or time-consuming to prepare, and guidance to help patients overcome these attitudes is invaluable.

Conclusion
The benefits of eating a healthy balanced diet are well established. It is vital that patients are made aware that foods should be eaten in the right amount and the right balance. They need to fully understand that it is what is eaten over a period of time that really counts, not the last meal or snack. The value of a food should be determined within the context of the total diet, because classifying foods as good or bad may foster unhealthy eating behaviours.(16) There are no easy ways to make people change their eating behaviours, choose different foods or eat more foods more regularly; however, always remember that the phrase "variety is the spice of life" is the key when it comes to healthy eating.

References

  1. World Health Organisation/Food and Agriculture Organisation 1998. Carbohydrates in Human Nutrition. FAO: Rome; 1998.
  2. Keys A. Seven countries: a multi­variate analysis of death and coronary heart disease. Harvard University Press: Cambridge (MA); 1980.
  3. World Health Organisation. Diet, Nutrition, and the Prevention of Chronic Diseases. World Health Organisation: Geneva; 1990.
  4. Department of Health, COMA. Nutritional Aspects of Cardiovascular Disease. Report of the Cardiovascular Review Group Committee on Medical Aspects of Food Policy. The Stationery Office: London; 1994.
  5. Department of Health, COMA. Nutritional Aspects of the Development of Cancer. Committee on Medical Aspects of Food Policy, Report on Health and Social Subjects No. 48. The Stationery Office: London; 1998.
  6. Department of Health. The NHS Plan. Department of Health: London; 2000.
  7. Cox DN, Anderson AS, Reynolds J, McKellar S, Lean ME, Mela DJ. Take Five, a nutrition education intervention to increase fruit and vegetable intakes: impact on consumer choice and nutrient intakes. Br J Nutr 1998;80:123-31.
  8. Department of Health. National Service Framework for Diabetes: Standards. Department of Health: London; 2001.
  9. Taylor A, Jacques PF & Epstein EM. Relations among ageing, antioxidant status and cataract. Am J Clin Nutr 1995;62:1439S-47S.
  10. Public Health Nutrition. Special Issue. Diet, Nutrition and the Prevention of Chronic Diseases: Scientific papers of the joint WHO/FAO Expert Consultation (Geneva, 28 January - 1 February 2002). 2004;7(1A):167.
  11. Department of Health. Dietary reference values for food energy and nutrients for the United Kingdom. Report of the Panel on Dietary Reference Values of the Committee on Medical Aspects of Food Policy (COMA). The Stationery Office: London; 1991.
  12. Great Britain Scientific Advisory Committee on Nutrition. Department of Health. Food Standards Agency. Salt and Health. 2003. p12: 2.16
  13. Macfarlane GT, Cummings JH. Probiotics, infection and immunity. Curr Opin Infect Dis 2002;15:501-6.
  14. Prentice AM, Jebb SA. Obesity in Britain: gluttony or sloth? BMJ 1995;311:437-9.
  15. Hill JO, Wyatt HR, Reed GW, Peters JC. Obesity and the ­environment: where do we go from here? Science 2003;299:853-5.
  16. Position of the American Dietetic Association: Total diet approach to communicating food and nutrition information. J Am Diet Assoc 2002;102(1):100-8.