Clinical nutrition : dietary fibre. Part 1.

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Dr J Cummings and Dr D Jenkins discuss dietary fibre in the diet. They describe what dietary fibre is and list the main components of fibre in different foods. They also look at the history of the introduction of fibre into the diet and compare dietary fibre intake in Britain with different parts of the world. Detailed outlines of how fibre from food is broken down in the gut are given, using tables, charts and electron micrographs - we see how stool size and texture changes according to fibre intake and how the transition time of foods through the gut are altered by changes in fibre consumption. 7 segments.


London : University of London Audio-Visual Centre, 1977.

Physical description

1 encoded moving image (38.03 min.) : sound, black and white.




Copyright note

University of London

Terms of use

Creative Commons Attribution-Non-Commercial 2.0 UK: England & Wales

Language note

In English

Creator/production credits

Presented by Dr J Cummings, MRC Dunn Nutrition Unit and Addenbrooke's Hospital, University of Cambridge; Dr D Jenkins MRC Gastroenterology Unit, Central Middlesex Hospital, London. Made by University of London Audio-Visual Centre.


This video is one of around 310 titles, originally broadcast on Channel 7 of the ILEA closed-circuit television network, given to Wellcome Trust from the University of London Audio-Visual Centre shortly after it closed in the late 1980s. Although some of these programmes might now seem rather out-dated, they probably represent the largest and most diversified body of medical video produced in any British university at this time, and give a comprehensive and fascinating view of the state of medical and surgical research and practice in the 1970s and 1980s, thus constituting a contemporary medical-historical archive of great interest. The lectures mostly take place in a small and intimate studio setting and are often face-to-face. The lecturers use a wide variety of resources to illustrate their points, including film clips, slides, graphs, animated diagrams, charts and tables as well as 3-dimensional models and display boards with movable pieces. Some of the lecturers are telegenic while some are clearly less comfortable about being recorded; all are experts in their field and show great enthusiasm to share both the latest research and the historical context of their specialist areas.


Segment 1 Cummings speaks to camera. He describes how many people don't know what dietary fibre is and that an adequate definition has not been agreed upon by experts. What is definite is that fibre can be said to consist of the polysaccharides and lignin present in plant cell walls and other plant substances that are not digested in the upper human gastrointestinal tract. He shows a table listing the main components of dietary fibre and explains why it is difficult to analyse these components chemically. Time start: 00:00:00:00 Time end: 00:04:08:00 Length: 00:04:08:00
Segment 2 Cummings talks about the now-outdated concept of 'crude fibre' and shows a printed advertisement for supposedly high-fibre bread from the US. He explains why this advert is misleading as it refers to artifically added crude fibre rather than naturally occurring dietary fibre in plants and vegetables. He refers to a table listing the various dietary fibre substances which can be found in plants and uses diagrams to illustrate the structure of various dietary fibres. Time start: 00:04:08:00 Time end: 00:10:10:10 Length: 00:06:02:10
Segment 3 Cummings shows examples of dietary fibre preparations, laid out on a table. These are from bran, carrot, cabbage and pectin. He lists how much water uptake each of them is capable of. Referring to a photomicrograph of a plant cell wall, Cummings goes on to explain how complex the structure of fibre is and why it cannot be broken down in the gastrointestinal tract. Another important aspect of fibre digestion is related to how the gut breaks down polysaccharides; the breakdown products of polysaccharides are shown in a table. Cummings then goes on to discuss how much fibre is taken in an average British diet, he refers to a table made up of information from the National Food Survey which suggests the average intake us about 20 grams a day. Time start: 00:10:10:10 Time end: 00:14:50:17 Length: 00:04:40:07
Segment 4 Cummings compares the average British intake of dietary fibre with the intake of fibre in different parts of the world - intake is particularly high in Uganda. Cummings then moves on to talk about the physiological properties of fibre, its chemistry and what happens to it when it is eaten. He refers to a graph detailing faecal size according to levels of dietary fibre intake and x-rays showing changes in the large bowel according to levels of dietary fibre intake. Time start: 00:14:50:17 Time end: 00:19:00:20 Length: 00:04:10:03
Segment 5 Cummings continues to discuss the effects of fibre on faecal output, this time in relation to faecal weight; he compares the difference in faecal weight when cabbage, bran, pectin and carrot are added to the diet. The transit time of food through the gut according to fibre intake is shown on a chart. This reveals that a high fibre intake can lead to an up to 3 times faster transition of food through the gut than a low fibre diet. Cummings hands over to Jenkins. Jenkins demonstrates various fibre-containing foods displayed on trays. These include fruits, seeds, beans and cereals. Time start: 00:19:00:20 Time end: 00:25:26:14 Length: 00:06:25:19
Segment 6 Jenkins demonstrates the viscosity of various fibres when water is added to them. For the demonstration he uses wheat as a cereal fibre, pectin as a fruit fibre and guar as a seed fibre. He adds water to each sample of fibre, mixes them and shows how viscous each becomes. Easily the most viscous is the guar. Jenkins then refers to a graph which shows the effect of guar on the intestinal absorption of nutrients from the diet. Time start: 00:25:26:14 Time end: 00:30:36:00 Length: 00:05:10:11
Segment 7 Jenkins shows an animation illustrating the effect of fibre viscosity on the rate of transport of food substances through the intestines to various sites of absorption. He shows graphs comparing the effects of guar on the absorption of glucose, insulin and electrolytes. Jenkins hands back to Cummings. Cummings ends the lecture by showing a slide which summarises the physiological effects of fibre intake. Time start: 00:30:36:00 Time end: 00:38:03:20 Length: 00:07:27:20


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