Nutrition is a wide and varied subject that has become a substantial area of science within its own right. Inevitably, as with most areas of science, this leads to the creation of many theories and debates over what the truth is in relation to specific nutritional factors and optimal health. There are many experts and professional bodies where nutritional information can be sourced.
The term ‘Nutritionist’ is an unprotected term which anyone who wishes to embark on a business of advising others on what to eat can use to their advantage. It doesn’t guarantee to the client any specific level of qualification. However, this also does not mean that the individual is not skilled at their job. To be called a ‘dietician’ requires individuals to be registered with the Health Professions Council as the term is legally protected and requires certain qualifications. Most dieticians have a Bachelors or Masters degree and are qualified to translate scientific information about food into practical dietary advice. The British Dietetics Association is the professional body for dieticians and also serves as their trade union. Registered nutritionists are nutrition professionals who have met the criteria to become full members of the Nutrition Society, which requires a degree and a certain amount of evidence supporting professional practise. The term ‘Nutritional Therapist’ refers to individuals who have trained to cure and prevent ill health through nutrition. Whilst courses in nutritional therapy are not seen to be in the same depth as dietetics there is still significant effort required to qualify for this title.
The British Association of Applied Nutrition and Nutritional Therapy (BANT) oversee and evaluate nutritional therapists in the UK with the Nutritional Therapy Council regulating the industry. This course will allow you to use the term ‘Nutritional Advisor’ which clearly defines a role in advising others about healthy eating habits, but does not authorise any provision of advice directing others regarding ill health or in the use of dietary supplements to promote health or manage disease. It is important that even as a nutritional advisor that it is understood how to evaluate nutritional information and to be able to ensure that advise is given to others based on reliable evidence. This does not necessarily mean that we should only listen to the mainstream opinion or seek information only from well recognised professional bodies, but they are an obvious place to start. We have already mentioned a few professional organisations above who can provide a high standard of reliable nutritional information. Other recognised places to seek nutritional information include:
• Food Standards Agency
• Committee on Medical Aspects (COMA) of Food and Nutrition • British Nutrition Foundation
• Institute of Optimal Nutrition
• scientific nutrition journals e.g. British Journal of Nutrition
These and other similar areas are likely to provide reliable, evidence-based information on the wide and varied subjects that are included within the umbrella of nutrition. This is vital as the media and food marketing often report on or make claims regarding certain foods or nutrients and their effects on health. This will influence client’s beliefs and opinions regarding nutrition and as professionals we need to have a reliable source of information to determine the truth and debunk any myths that exist. Nutrition tends to be a world of diverse opinions and theories and as such needs to have professionals who can provide a grounded and evidence-based approach where knowledge has been proven.
It must also be taken into consideration that the United Kingdom and many other countries around the world have now become diverse cultural and ethnic melting pots. This adds to the complexity of providing nutritional advice. It is important to have some understanding of the food habits and traditions of any individual for whom a service is being provided whether they have clear English ancestry or they are from Asia, Africa, the Pacific, the Caribbean or South America. Religious practises can also affect the foods they are allowed to eat and the liquids they may be allowed to drink. These religious practises need to be respected and nutritional advice provided that is supportive of their personal decisions and their cultural heritage. Developing skills as a nutritional advisor can sometimes be a daunting process, especially with the vast amount of knowledge and information available on the subject of nutrition. If faced with a client who requires a deeper level of analysis and investigation than qualifications provide a suitable referral procedure to a Registered Dietician or Nutritional Therapist should be followed so that they may receive the guidance that they need. This is good professional practise and should be encouraged wherever necessary. It may become evident during an initial nutrition consultation that a client has specific health conditions that would require assessment and guidance from a General Practitioner to then be managed through food and diet again by a Dietician. Nutritional advisors will not have the skill base or qualifications to professionally advise on nutrition relating to disease and ill health. The types of conditions that can be improved through appropriate nutritional guidance and, therefore, should be referred are:
• diabetes mellitus • cardiovascular disease • elevated cholesterol • severe obesity • cancer
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Protein
Proteins belong to a family of organic compounds, which serve many functions within the body. All proteins are made from building blocks called amino acids, which number 20 in total. These amino acids can be thought of as forming the protein alphabet, since they build proteins in a similar way as the various combinations of the 26 letters of the alphabet can be used to create individual words. Thus one protein will differ from another according to the number and sequence of its constituent amino acids.
Peptides
Animal and plant cells join amino acids together to form peptides. This process results in the formation of chains of amino acids of varying lengths, which eventually become proteins.
Peptides
Two amino acids Dipeptide Di meaning two
Three amino acids Tripeptide Tri meaning three
4-9 amino acids Oligopeptide Oligo meaning few
10 or more amino
acids Polypeptide Poly meaning many
Proteins themselves are formed when the chain of amino acids total 100 or more, or when two or more polypeptide chains combine and repeatedly fold together to form specific three-dimensional shapes. The shape or structure of a protein will dictate its function within the body.
Essential amino acids
Of the twenty amino acids, nine are considered to be essential to the daily diet because the body is unable to produce or synthesise them itself. Only when sufficient quantities have been ingested, are we able to synthesise the remaining non-essential amino acids.
Macronutrients
Essential amino acids • phenylalanine • methionine • tryptophan • threonine • lysine • isoleucine • leucine • valine • histidine
Conditionally essential amino acids
These are also present in many foods, but are not always required to be a part of the daily diet. So long as we successfully absorb sufficient amounts of the nine essential amino acids, the liver is able to synthesise the remaining eleven conditionally essential amino acids. At certain times in life and in certain population groups these amino acids must be supplied by the diet to ensure good health. An adequate intake of the conditionally essential amino acids will also help to spare valuable resources of essential amino acids.
Conditionally essential amino acids
• glycine • alanine • tyrosine • serine • cysteine • proline • isoleucine • leucine • valine • histidine Complete proteins
These foods contain all nine essential amino acids in sufficient amounts necessary for the liver to synthesise the remaining non-essential amino acids. Most are animal based foods, though some experts claim that there are a number of plant based complete proteins. Soy, buckwheat, and quinoa are some examples. However, it should be noted that soy, like all legumes, is deficient in methionine whilst fragile lysine is often damaged by processing.
Complete proteins
Animal sources Non-animal sources
• eggs • meat • poultry • dairy • fish • soy foods • buckwheat • quinoa
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Incomplete proteins
Plants contain many nutrients, including protein. However, these proteins are of a lower biological value, since they are deficent or ‘incomplete’ in one or more of the essential amino acids. Plants often contain smaller concentrations of protein thus making it difficult to ingest enough solely from plant produce.
Incomplete proteins
• cereals and grains (wheat, rye, barley, oats, rice) • cereal products (bread, pasta etc)
• pulses (beans, lentils, peas) • nuts
• vegetables
Complementary proteins
For many years it has been advised to vary or combine plant based protein sources to boost amino acid intake for vegetarians. This may help to provide a full spectrum of the essential amino acids in the diet.
Whilst these carbohydrate based foods contain energy in the form of glucose, it is important to remember that they also contain smaller amounts of protein. Including a variety of unrefined carbohydrate foods is, therefore, particularly important for anyone on a no meat or low meat diet. Good variations or combinations include:
• rice and pulses • vegetables and seeds • nuts and vegetables • grains and pulses
Functions of protein
The types of protein within the body can be placed under three headings, along with their corresponding functions:
• structural: form the main framework of many components of the body; collagen present in bone and connective tissue, keratin in the skin, and muscle tissue all provide structure. Muscle tissue is also contractile for movement.
• homeostatic: hormones regulate various processes e.g. insulin controls blood sugar, enzymes speed up reactions, and white blood cells fight infection. • fuel: although not the primary source, protein is a useable source of energy,
especially during endurance events or periods of fasting. They can be converted into glucose, fatty acids or ketones to help produce ATP.
Catabolism
Catabolism relates to the breaking down of larger structures into smaller ones. Protein catabolism occurs to some extent all of the time, as existing proteins from damaged cells are broken down into their amino acids and recycled to build new proteins elsewhere. Further muscle catabolism occurs during intensive exercise, as a result of both micro-tear damage and the partial utilisation of key amino acids as fuel. Anabolism
Anabolism can be defined as a building up process within the body. The anabolic phase mostly occurs during rest. Since proteins form a major component of most cell structures, adequate dietary protein is required to maintain both health and performance.