A nutritionist's main role is to be an expert on foods and nutrient value.(Rose 2000) This approach is to assess and prevent against the possible risks to health. This could be because of people taking an over consumption of certain nutrients and foods; for example fat, salt and sugar. The objective of the nutritionist is to try to find a balance that suits a certain group of people, aiming to ensure that they maintain the optimum health needed throughout life. Form a nutritionist's point of view the concept of knowledge has been evolving for the past one hundred years, ever since there was a notable relationship between disease and nutrient deficiencies and poor diet. It was not till the early 1920's that the classification was applied and foods were now been categorised into; "Indispensable" and non-essential".
Nutritional knowledge has increased and the ideas of what constitutes a healthy diet have changed considerably.
In the United Kingdom, various government reports have proposed guidelines for improving the diet and set out figures for target intakes of certain nutrients. The 1983 the NACNE Report set out to;
"To reduce total fat intake from about 40% to 30% of total dietary energy with saturated fat 10% of total energy"
"To reduce sucrose intake to 20kg per person per year"
"To increase fibre intake by about 50%"
"To reduce salt intake from about 12g per person per day to 9g per person per day"
"To eat more vegetable protein at the expense of animal protein"
"To eat sufficient food and increase exercise to maintain optimum body weight"
It was evident that by 1992 that these recommendations had not worked, as the "Health of the National White Paper" was published. The nutrition targets were set out and again;
"Total amount of fat intake to be about 35% of dietary energy"
and the paper was now having to deal with the issue of Obesity, a problem that has been evolving over time. By 1992, 25% men and 33% women were obese.
It is believed that because of the introduction of fresh, processed foods widely available in Supermarkets that the issues in nutrient deficiencies is in decline- however there is not the evidence to prove this. One key problem that has evolved over the past twenty years is "neo-phobia" - a fear of new things. In relation to food this can be the willingness to change and adopt a healthier lifestyle. Nutritionists have tried to implement new methodologies to try and address the situation. (Wilson 2002)
Nutritionists have put together a broad database of information about what nutrients are essential in the human diet. The methodologies implemented are; providing community food workshops, this is done by providing people that work with food the knowledge of which food is best, facilitating food and health initiatives within the local community, for example food co-ops, leading focus groups trying to identify peoples barriers healthier eating have made younger people more aware of the human diet by displays in local community centres; these kinds of public awareness events can be effective. However the children's perception of healthy eating: "boring" has been an issue for many years. Writing articles for local and national media are other methods that have been tried.
Nutritionists have worked closely with supermarkets, not just by raising awareness and stocking healthy products but to make these products available and affordable to the public. The diet has evolved by letting children choose what foods they eat, the role of the parents is crucial in how a child's diet is balanced so educational activities have been set up. Nutritionists believe that if children, as young as two to three years, are educated and brought up in a healthy environment then this will develop through later life. Group sessions on Healthy Toddler Nutrition have been set up. The Nutrition Society plays a key role in the development of these methodologies.
Food refusal is a major problem that has evolved, so nutritionists have adopted an approach of setting up home visits to support families with their child's eating problems. "Sure Start" centres have been set up also by the Nutrition Society for mothers to be educated on basic food issues.
Technological advances have also aided the role of nutritionists. Computerised nutrient analysis helps to calculate nutrient intake in relation to the statistical data. However there is a major challenge for nutritionists to develop better methods for rapidly screening and assessing dietary intakes. With patient care a prime objective.
However these developments have been improving as the human diet has evolved but the methodologies implemented need to continue to keep addressing the problem in diet and nutrient intake. Nutritionists still have to be high skilled, well instructed and work in cooperation with biologists, anthropologists, and dieticians.
" the focus on the study of human beings and their way of life,"(Shils 2000)
Anthropologists have tried to find distinct separation between the food as a biological necessity and also the cultural factors that condition its availability and consumption. In essence they are looking at the same preface as nutritionists however with a varied priority. Where as nutritionists seem to focus on nutrient intake of the big five in relation to achieving a healthy human diet, anthropologists assess lifestyle changes and finding the right diet and nutrient intake to suit the individual, where as the fault of nutritionists is to categorise recommendations in a group sense not on the one individual.
The technological advances that have helped nutritional anthropologists are that now bio-chemical measures for the intake of certain nutrients can now be recommended to supplement or corroborate the human diet. Micro-computers and computerised dietary analysis software can help to permit data using previous structured diets. This enables anthropologists to relate situations where someone may be suffering from a certain illness or nutrient deficiency and use previous methods to suggest certain diets that can help address their problem.
A problem that anthropologists face is the role of the media. The human diet has had many images portrayed over many years. In the late 1980's, early 1990's government initiatives have tried to encourage people to adopt healthier lifestyles and eat more fresh fruit and vegetables, an example of this is the "eat 5 a day," campaign. Now the public read about fad diets that the glitzy and glamorous celebrities swear by, for example the Atkins diet. A diet that was first started by Dr Atkins in the 1970's, high in protein and fat, low in carbohydrates. This diet was extremely popular in the last five to ten years however has resulted in the developed world with a functional outcome of death.
Food biologists are the focus on "the science of the body" they are the key link in how we understand the food that we eat and what effect it has on the body. Biologists knowledge has evolved considerably over the past fifty years. We now know a great deal of what affect carbohydrates, proteins, fats and oils and dietary fibre have on the body. The western diet has proved to be high in fat and refined in carbohydrates and low in fibre.
The two main sources of carbohydrates come from starches and sugars and the developing knowledge is how these are absorbed into the blood stream in forms of monosaccharides (sugar), disaccharides (sugar), and polysaccharides (starch). Biologists have learnt that when these are absorbed into the blood stream 1g of carbohydrate provides 17 KJ - 4 kcal. Once these have been absorbed they are converted in fat and stored all over the body in fatty cells, which can result in obesity (in the western world). In the UK human diet cereal carbohydrates account for 47% of the total carbohydrates. Most carbohydrates have a staple food often in the form of cheap starch based cereal foods. In the eastern developing countries that have a poor standard of living, poor diet up to 90% of there energy content of their diet is provided by only one staple food.
like carbohydrates biologists have learnt that fats and oils contain the same three elements; carbon, hydrogen and oxygen, these when in the diet have shown that they are broken down by a process called oxidation which then can release energy. Biologists have proven that the consumption of these can prevent heat loss and maintain the optimum body temperature of 37°c.
One of the key nutrients that biologists have learnt about is Protein. This is measured by a biological value (BV), this being the percentage absorbed which can be converted to body protein. The BV can now be calculated by the amino acid pattern and by this biologists have learnt which contains the highest BV , eggs 97%. It has evolved that an increase in BV foods can have a positive affect on the diet, for example during pregnancy. Over time biologists have learnt that proteins can complement each other in the diet, an example of this is pasta and cheese (macaroni and cheese). The key sources that have been identified are; meat, fish, bread, milk, cheese, eggs, vegetables and nuts. The Department of Health stated a reference nutrient intake. For example for a adult 0.75g per day for every kg of bodyweight. These figures have shown that they can not be easily quantified, as it depends on the body weight, and growing stage of the individual. However in the developing world there has been a shortage of protein in the human diet, this has resulted in a protein deficiency called Kwashiorkor. This is mainly when a child has a diet that is low in protein high in carbohydrates, and is extremely common with young children. This is a result in the children only having one staple food in their diet often Yams. Its the lack of formation of the red blood cells that has leads to disease such as anaemia. Adults in the eastern world suffer from a protein deficiency; "Protein Energy Malnutrition" (PEM). The only cure to date or prevention is to feed dried skimmed milk as this has shown to be rich and accessible in protein. The only problem is this is only a short term solution. What has evolved is that the eastern population have learnt to farm their food in a more technically advanced way with highly yielded crops that are resistant to disease, they have done this by using fertilizers and pesticides.
Dietary Fibre; known to biologists as non-starch polysaccharides (NSP) formed by insoluble cellulose (fibre), Soluble pectin's (found in fruit and vegetables), hemi cellulose and gums (soluble fibre) (Bingham 2000)
Research has shown that the UK diet has a insufficient level of dietary fibre this has proven to cause constipation and bowel cancer. At present the average intake of NSP is 12g per day, however a report in 1994, The COMA report recommended an increase from 12-18g per day.
In summary the human diet is a massively broad topic and has many opinions not just from nutritionists, anthropologists and biologists. The evolvement of the Human Diet is varied all over the world with a clear black and white image that shows the western world increasingly far ahead in resources, both raw materials (food) and knowledge (technology). The situation in eastern countries are known, however its not a case of encouraging what to eat, but in the short term teaching how to make the most out of their land and foods that they do have access to.
The human diet on a whole has not really evolved. The same objectives, recommendations and guidelines are still being set out. This is evident in a report released from The Department of Health on the 12th December 2002, the report stated;
"The Plan will address food production, manufacture and preparation, access to healthier food and providing information for consumers about healthy eating and nutrition. It will build on existing work to improve diet and nutrition including:reforming the Welfare Food Scheme, the National School Fruit Scheme, the Five-a-Day programme to increase fruit and vegetable consumption, work with undustry to reduce salt, fat and sugar in the diet, local action to tackle obesity and increase physical activity and the hospital nutrition policy. The Food and Health Action Plan will pull together all of the issues that influence what we eat. Action will involve all sections of the food chain including food growing, food processing, manufacture, retailers, caterers and consumers"
Galen of Pergamus who was a personal physician of the emperor Marcus Aurelus, quotes: "You should do a lot of exercise and not overeat" (HUNT 1994)
So how much has the Human diet evolved ? not a lot if were still trying to reiterate a point that was evident thousands of years ago.
The discussion of the human diet is massive. There has been so much changing, and so much more information being found that makes it impossible to point at the exact changes of "the evolution of the human diet". To discuss this topic and focus on three various opinions in such a precise way is near impossible.
References
Books
1. SHILS, Maurice (2000) Modern Nutrition in Health and Disease. 9th Edition
2. DOBBING, John (1998) A Balanced Diet?
Journals
3. GOODMAN, Alan (1998) Nutrition and Anthropology / Biological Perspectives - on Food and Nutrition. Vol2 (chapter5)
4. HUNT, Paul (1994) National Food Guide/ Nutrition History Vol5.2 (p90-95)
5. ANDERSON, Annie C (1998) Five a Day - Nutrition & Science Vol3 (p12-16)
6. ROSE, David (2000) Knowledge of Diets, Health, Nutrition.Vol5 (p1-10)
7. STOCKLEY, Lynn (1998) Dietary Guidelines and International Perspective. Vol12 (p1-80)
8. BINGHAM . S.A. (2000) Dietary Intake Measurement Vol2 (p20-22)
9. DEAN, Ross (2000) Natural and Cultural Influences on Evolution of Human Diet - Vol16
10. DREWNOWSKI, Adam (1997) Global Dietary Trends - Department of Natural Sciences No. 7/8
11. WILSON, Christine (2002) Reasons for Eating: Personal experiences in nutrition and anthropology. Vol1 (p1-20)
11. HARRIS, Marvin (1999) Materialist Approaches - Nutrition Vol10
12. DUFOUR , Darna.L. (1996) Adopting people to food and foods to people. Vol1 (p1-30)
