Nutrition
Maintaining and Improving Health
Geoffrey P. Webb
- 646 pages
- English
- ePUB (mobile friendly)
- Available on iOS & Android
Nutrition
Maintaining and Improving Health
Geoffrey P. Webb
About This Book
Following the tradition of its predecessor, the fifth edition of Nutrition: Maintaining and Improving Health continues to offer a wide-ranging coverage of all aspects of nutrition while providing new information to this edition including:
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- Increased coverage of experimental and observational methods used in nutrition
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- In-depth focus on the nutritional implications of the increased adoption of vegetarian and vegan lifestyles
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- Streamlined referencing - a short selected list of key references at the end of each chapter with URL links to free additional resources where possible
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- Discussion of nutrition debates
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- Critical coverage of "medicinal uses of food" including superfoods, functional foods and dietary supplements
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- Updated bullet point summaries of key points after each major topic within each chapter
The author provides an evidence-based evaluation of many key nutrition beliefs and philosophies. The book contains in-depth and critical reviews of the methods used to evaluate nutritional intakes/status and the observational and experimental used to investigate putative links between dietary factors and health outcome. It covers the role of food as a source of energy and nutrients while discussing the non-nutritional roles of food and the social and psychological factors that influence food choice. Presenting a critical discussion on the value of nutrition research linking specific foods or nutrients to specific diseases which encourages students to question the value of some current nutrition research.
This is essential reading for all nutrition and dietetics students with different backgrounds who are studying nutrition as a specific discipline for the first time.
Frequently asked questions
Information
PART 1
CONCEPTS AND PRINCIPLES
1 Changing priorities in nutrition
Ensuring adequacy and use of food groups
- The macronutrients – carbohydrates, fats and protein are required in relatively large quantities and are the main sources of dietary energy. Within the fats category, small amounts of certain polyunsaturated fatty acids are specifically essential and needed for vitamin-like functions; one of them was originally designated vitamin F. Within the protein component, nine or ten amino acids are termed essential because they are needed for protein synthesis and cannot be made from the other 10/11 so-called non-essential amino acids; some are also needed in other synthetic pathways. We can synthesise glucose from some amino acids and from the glycerol component of fat, but in most healthy diets, carbohydrates would be expected to provide more than half of the calories.
- The micronutrients – vitamins and minerals are only required in small (milligram or microgram) quantities and do not act as sources of energy. There are 13 vitamins and 15 unequivocally established essential minerals.
- The substance is essential for growth, health and survival.
- Characteristic signs of deficiency result from inadequate intakes and these are only cured by administration of the nutrient or a specific precursor.
- The severity of the deficiency symptoms is dose-dependent; they get worse as the intake of nutrient decreases.
- The substance is not synthesised in the body, or only synthesised from a specific dietary precursor, and so is required throughout life. Note that a strict application of this rule would eliminate vitamin D, which can be synthesised in the skin in sufficient amounts by a photochemical reaction, provided it is regularly exposed to summer sunlight.
- Between 1900 and 1950 there were 3 million cases and 100,000 deaths from pellagra in the USA, a disease that was shown to be caused by a lack of niacin or vitamin B3. It has been a major cause of ill-health in many places where maize was the dominant staple food.
- In the early 1900s, there were 30,000 deaths per year from beriberi in British Malaya and up to 20,000 in the American-occupied Philippines. Beriberi was shown to be caused by a lack of thiamin (vitamin B1) and was prominent in other countries where white (polished) rice was the dominant source of dietary calories.
- In the late nineteenth and early twentieth centuries, up to 75% of children in some British industrial cities and some northern US cities like Boston suffered from rickets caused by vitamin D deficiency. Inadequate exposure of the skin to summer sunlight was the major underlying cause.
- Prior to the 1920s, a diagnosis of pernicious anaemia meant death was almost inevitable until it was found that eating raw liver (a very rich source of vitamin B12) could alleviate this condition. The condition is caused by an inability to absorb vitamin B12.
- To reduce the consumption of bread and starchy foods.
- To increase the consumption of nutrient-rich, so-called “protective foods”, like milk, butter, cheese, eggs, fruit and green vegetables.
- A taller, more active and mentally alert population.
- Less of the deficiency diseases like goitre, rickets and anaemia.
- A reduced toll of death and incapacity due to infectious diseases like pneumonia, tuberculosis and rheumatic fever.
- Body-building foods – these were all high protein, animal foods: milk, meat, eggs, cheese and fish. In a footnote it is acknowledged that many vegetable foods like peas, beans, bread and potatoes help in body-building but ar...