Diverticular Disease: The Fibre Story

In the early part of the 20th century constipation was not generally related to any individual illness. The idealised achievement of daily defaecation meant constipation was common particularly in the elderly. Treatment was not free until the NHS came along and natural and herbal laxatives were well used medications. Diverticular disease (DD) became recognised more before WW11. The distinguishing symptoms were pain, fever and diarrhoea. A low residue diet was recommended to reduce diarrhoea and give the bowel rest. Serious pain sometimes resulted in surgery. Infection and inflammation (diverticulitis) were not always present but pieces of food and faeces were trapped in diverticula. Avoidance of coarse fruit and vegetables, seeds and pips was recommended.

Hospital diet sheet for diverticulitis 1961………”forbidden foods – all fried foods, pips and skins of fruits, pastry, suet puddings, coarse stalky vegetables, salads, onions and celery, chunky marmalade, jam with pips or skins, wholemeal or brown bread, coarse biscuits-Ryvita, digestive, Allbran, oatmeal, Weetabix, Shredded Wheat, fruitcake or scones, nuts, dried fruit.”

A significant change in diet started about 1970 when treatment for diverticular disease (DD) was suddenly reversed.

Hospital diet sheet for diverticulis 1982………..”you can eat a normal varied diet but include…… (all of the forbidden foods from 1961 except fried food)….SUPPLEMENT meals with 2 teaspoonfuls of unprocessed bran twice daily. EAT LESS white flour in any form and white and other sugars. DIETARY FIBRE ….by helping to restore normal function of the digestive tract, fibre can be useful in the treatment of constipation and diarrhoea”

  • Who persuaded health professionals that wheat bran was good for diarrhoea?
  • What was the evidence for this complete reversal of treatment?
  • Did anyone ask patients if this helped them?
  • Who was behind this change?



The individual who had the greatest influence on the treatment of DD in the last 100 years was surgeon Denis Parsons Birkitt. One biography title calls him ‘The Fibre Man’ another ‘How a Humble Surgeon Changed the World’. These volumes describe a one eyed Northern Irish man whose Christian beliefs were greatly impassioned by a group at university. Religious practice and fervour were the engine and steering wheel of his life and medical practice. After surgical qualification, a position as ships doctor and war time service with the Royal Army Medical Corps followed, then employment by the Colonial Office meant he practiced overseas for about 30 years.

Birkitt became well known in Uganda. Using the network of Christian missions and hospitals and extended safaris, he became interested in what he called ‘geographical medicine’. He found that hydrocelle cases occurred in particular areas and were caused by a microscopic worm carried by mosquitos.The same type of investigation eventually uncovered the cause of a cancer in children which became known as Birkitt’s lymphoma. An insect vector he proposed was not to blame, but the Epstein-Barr virus was discovered. The cancer/virus connection became the platform for intensive research into cancer causes by specialists worldwide. Birkitt’s fame spread, aided by his brilliant, charismatic oratory and invitations to preach and lecture worldwide on cancer.

Ugandan independence affected medical services and Birkitt’s surgical practice finished. He was employed by the Medical Research Council External Scientific Staff in London in 1964. His African travels continued collecting ‘geographical’ data on cancers and diseases. Writing, lecturing and preaching tours continued.


The fibre story only started in 1967 in London. At the age of 56, Birkitt was introduced to a retired naval physician Captain T.L. Cleave. Cleave was one of several doctors who had used wheat bran to treat constipation. Cleave thought that excessive sugar and refined carbohydrates were behind the diseases in Western countries which were not found inAfrica. Birkitt considered meeting Cleave was one of the most important occasions of his professional life. He had been introduced to the concept of ‘Western diseases’ and ‘one cause’ of different diseases and that cause was considered to be diet. In 1969 he used his network to obtain samples of faeces to weigh and with the time taken for them to pass through the body. He used groups of people who had different diets. He had contact with Dr Alec Walker, Dr Hugh Trowell and Dr Ted Dimock in Africa who had previously carried out such studies, and Dr George Campbell who had worked with Cleave. Burkitt thought Providence had brought these contacts into his life in perfect order. He was convinced that the Lord was calling him to a wider, more important commitment in medicine. He was determined to step even more wholeheartedly into popularising not only the neglected field of nutrition but preventative medicine as well. Medical researchers who had previously produced articles and books on this theme had not managed to change traditional medical opinions on dietary fibre. The role of dietary fats was then fashionable. Birkitt had the gift of oratory, the contacts and the clout from his cancer work to become the spokesman for his colleagues and previous investigators.

People who attended Birkitt’s messianic talks write mostly about the slides showing the voluminous heaps of the stools of Ugandan rural villagers. He certainly knew how to get their attention. His biographers describe how he used slides and stories to get his points across. Biblical parables come to mind. He could demonstrate that increased weight of stools was generally associated with quicker passage of food through the body. This was the basis of his opinions and conclusions. His subjects did not include the old or infirm but were predominantly young and healthy with different lifestyles and diets. There was much overlap between diets and individuals, the amount of fibre in the different diets was  perversely assumed according to the size of stools. It was obvious that the stools of the rural villagers were in a class of their own in size. At the sides of paths in the bush a squatting position was inevitable. The location suggests some urgency. Is this the model the western world should achieve by increasing dietary fibre levels to the 150g per day? This figure was calculated from a “personal communication” which said that men eat at least 1Kg of plantain at each main meal. Plantain is 6g fibre per 100g therefore the total dietary fibre intakes are 150g/day. Similar calculations gave fibre levels of 130g/day for the Kikuyu tribe and 100g/day for Venda males in South Africa. These levels are equivalent to about 50 portions/day of porridge oats! Vegetarians in the West have about 40g/day of fibre. The claim that diverticular disease is caused by not using a squatting position on Western toilets is also based on the rural Ugandans habits. This is used to promote sales of devices to modify water closets. Birkitt himself did not comply with this claim. Helping constipation should not be confused with causing disease



There are reports that Ugandans have large, wide bowels and a common surgical emergency is twisting of the colon (volvulus). Widespread use of herbal laxatives to meet African defaecation ideals has been mentioned. We didn’t hear much about the ‘African’ problems. Earlier missionaries and doctors were aware that some diseases becoming common in the Western world were not found in Africa. Birkitt’s information from his networks and travels agreed. Coronary heart disease, gallstones, appendicitis, diverticular disease (DD), diabetes, varicose veins, haemorroids, hiatus hernia, peptic ulcer and colon cancer were the Western diseases. They were only occasionally found in African individuals who had adopted an urban, Western lifestyle, but not necessarily a Western diet as found by other researchers. Also noted was that a Western individual could have more than one of these typical diseases.

Apart from the Inuit, who Birkitt described as one hiatus in his dietary research, there was no mention of any peoples who had little dietary fibre but no Western diseases. The Massai, Chewya and Watus tribes were noted by other African missionaries. Mormons and Seventh Day Adventist had Western diets but low levels of Western diseases; no smoking was offered as a possible explanation. Birkitt knew that coronary heart disease was linked to cigarette smoking but persisted with a low dietary fibre explanation of its cause.


  1. The distribution (epidemiology) of Western diseases found in the 1960s/70s was distinctive, suggesting a lifestyle and possibly single cause.
  2. Wheat bran can help relieve constipation in some people.
  3. Increased dietary fibre will in general pass through the body faster with speedier evacuation and softer stools.


  1. The rural African diet protects against Western diseases
  2. The change in disease patterns when individuals emigrated to Western countries was due to a change in diet.
  3. Increase in prevalence of Western diseases in countries which were previously low was caused by the adoption of a Western diet.
  4. Western diseases are caused by insufficient fibre in the diet. Copious amounts of wheat bran would prevent, treat and cure the ailments of the Western world.

There is no evidence, biological link or possible extrapolation between the facts and conclusions. There are many lifestyle differences to account for individual and regional variations in disease patterns and colon function. Choosing assumed dietary fibre levels and ignoring examples which do not conform is not valid epidemiological evidence. There are many food ingredients which promote bowel movement, not just wheat bran. For example, Birkitt found in Ireland, that plenty of potatoes matched the effects of bran; or was it an effect of the national beverage? It is an essential physiological mechanism that more undigested food residues will give quicker passage and larger stools, just like drinking more fluids results in increase urination. If disease affects these mechanisms, can they be overloaded?


Neil S Painter was a surgeon at the Manor House Hospital in London. He had spent most of the 1960s studying diverticular disease. Unlike Birkitt he had patients to treat. He was responsible for insight into the mechanisms of diverticula formation and researched the effects of drugs on the diseased colon. Segmentation in the sigmoid colon resulted in pockets of high internal pressure which forced hernia through the colon wall to give diverticula on the outside.

Cleave persuaded Painter to use unprocessed wheat bran in his medical practice and for the treatment of constipation in uncomplicated diverticular disease. The trial took place between 1967 and 1971, involved 70 patients, replacing previous laxative use and an assessment of symptoms at 1 and 2 months. Many of the aged, 70 patients had other western diseases whose treatment may not have helped their bowel problems. The results were presented by how many of the 12 symptoms were relieved or abolished, not by how many patients had been helped. It is possible that the 17% of the patients with repeated problems could have produced a majority of the symptoms in this type of presentation. Some patients could not tolerate bran, some still required occasional laxatives. Some symptoms were not relieved by bran, some were reduced and just over half disappeared during the trial period. Stools were softer and passed with less straining thus helping constipation. Painter emphasised that the bran regime did not prevent attacks of painful diverticular disease or acute diverticulitis. 3 patients were admitted to hospital. The amount of bran added to the diet varied to meet the trial end point of daily defaecation and varied between 6 teaspoons/day to several tablespoons daily. 3 patients had frequent passage of small hard stools with diarrhoea episodes attributed to laxatives, these became more regular with bran. This type of constipation appears to be the basis of treating diarrhoea with bran. That diarrhoea might be a symptom of irritation, infection or inflammation was not considered.

Painter asked Trowell to write a letter to the British Medical Journal to support the use of bran for intestinal conditions. A mutually beneficial collaboration with Birkitt published a paper on fibre and diverticular disease in 1971. Although headed ‘for debate’ it transformed treatment of diverticular disease by previously sceptical health professionals. Painter had got on board the bran wagon.


Medical research for decades tried to find evidence to support Birkitt, his colleagues and Painter. Trials did not consider anything but dietary fibre, involved small numbers of subjects and no controls. Effects of bran and high fibre diets were always balanced by a change in proportion of other foodstuffs. This was particularly relevant in animal tests which attempted to produce diverticula by reducing fibre in their natural diets. Publications which did not agree with the fibre theory were counteracted. The letters pages of medical journals were the equivalent of today’s Twitter and Facebook. Opinions were divided but Birkitt welcomed the disagreement as publicity.

How did the fibre gospel achieve such worldwide publicity? Described as a human dynamo obsessed with fibre, Birkitt’s charisma and lecturing prowess were reasons that attracted the media and publishers. Increased sales of breakfast cereals were another. Kellogg sponsorship of lecture tours, worldwide medical symposia on the fibre content of diet and paying for the publication if a bibliography by Trowell, gave medical backing for promotion of cereal products. For patients, bran could be a useful cheap medication in the absence of any other treatment on offer for diverticular disease. There was also an element that patients could be blamed for their problems because of their choice of diet.

The fibre message was far more effective in the USA than in the UK. Particularly controversial was Birkitt’s opinion that colon cancer could be prevented by a high fibre diet. Medical journals were reluctant to publish the idea of many diseases having a common cause. However in 1972 the British Medical Journal agreed to publish a lecture beforehand. This was Birkitt’s breakthrough in getting into print his opinions on diseases which were increasing in Western countries in the 20th century. He theorised the relationship of dietary fibre as the cause of the various diseases.

The voluminous flow of articles by Birkitt and his colleagues in medical journals had slowed down considerably by 1976. Now he felt that he could only write about fibre and not medical conditions he had no involvement in. He had no new personal research to report on and maybe exhausted usable medical journals. He did continue involvement in collaborative books on dietary fibre.

At the age of 65, Birkitt had to retire from the Medical Research Council resulting in reduced income. He believed that the Lord would provide, as he had done in the past, if he wanted the work to continue. His friends found him an appointment as Honorary Senior Research Fellow and a room at St Thomas’s hospital. Kellogg, who had sponsored lecturing tours since 1972, provided an honorarium, secretary and expense account for lectures “on the understanding that their cereal products would not be promoted”. Kellogg sponsorship of symposia and speaking appointments continued.

Other authors had jumped on the fibre bandwagon with popular publications. Birkitt had been unable to find a publisher for a book for the general public. After several rejections, in 1977, a 28 year old Martin Dunitz approached Birkitt about producing a book. A property company registered in 1977 changed its name to Martin Dunitz Ltd in 1978. The book ‘Don’t forget fibre in your diet’ appeared in 1979 to be the first from this publisher. There was emphasis that readers should look for the word “bran” in cereal products.


A means of continually controlling constipation would be preferable to the stop/start regime of laxative use. Daily wheat bran can achieve this in many people but not all. Concerns arose about wheat bran’s ability to reduce absorption of minerals such as iron from food. Bran could provoke urgency which the less mobile and elderly could not cope with. Painter’s trial showed that a standard dosage, taken like a medicine, did not take into account the fibre present in a person’s normal diet. Wheat intolerance and gluten sensitivity were not considered at that time and a requirement for daily defaecation is now outdated.  One patient was satisfied by a sterculia product. Nowadays, regular supplementation with an ispaghula preparation is popular to keep stools soft. So many foods and lifestyles affect bowel function as well as health, age and disease. Exercise and hydration are important. DD can have such variable effects that only an individual can find by trial and error what is best for them.

Dietary fibre can increase comfort and reduce symptoms but it does not follow that reduced levels are the cause of disease. In bowel complaints characterised by pain and diarrhoea such as IBD (Crohn’s and ulcerative colitis) and IBS (irritable bowel syndrome) wheat bran is far from helpful. Bran is not appropriate when there is diarrhoea with diverticular disease (DD).The problem with DD is to distinguish the reason for pain and symptoms. Are there muscle spasms, strictures or narrowing of the colon, chronic inflammation or age-related dysfunction compounded by the structural damage to the colon? Increasing numbers of research publications disprove the dietary fibre theory of the cause and treatment of DD and suggest other relevant factors, yet after half a century there are still some believers to be found. Maybe this is because medicine still has little else to offer patients.


Colon cancer was probably the first of the western diseases to be successfully disputed as a dietary fibre deficiency disease, others have followed over the decades, diverticular disease is hopefully the last. Fibre can have varied sources and bran is less fashionable now, fats and sugar wax and wane in popularity and publicity. Research into the relationship between diet and disease however has not faltered. Surveys and computers programs produce data which often disagrees and confuses. The popular headlines present results as risk levels which may or may not be relevant to actual numbers. There are fashions in recommendation of superfoods, supplements etc. Regional differences in diet are still used to claim reduced risk of western diseases. We have Mediterranian, Japanese, Eskimo etc. diets. Currently emphasis is on fermented foods from Eastern Asia to counteract western diseases through effects on gut microorganisms. Are omnivore humans so sensitive to small changes in diet? Should more emphasis be placed on how food is produced and treated before it is eaten? Diet is not the only way noxious substances can get into the body, we breathe as well as eat.

An overlooked but important work by Birkitt, Painter and their colleagues was the value of their epidemiology research. For DD in particular was the look at its early appearance in the 20th century. The suggestion that there could be one cause of western diseases was not appreciated at the time. Was it a mistake to choose the level of dietary fibre? At that time only lung cancer and heart attacks were considered the effects of smoking. Epidemiology is not static and other cancers and the western diseases including DD, follow a same pattern of prevalence and mortality during the 20th century. That pattern follows the worldwide use of cigarettes. Western diseases appear when and where Western cigarettes are smoked, diet can only modify their effects.

© Mary Griffiths 2017


The Fibre Man by Brian Kellock , 1985, Lion Publishing plc, ISBN 0 85648 583 7

Burkitt, Cancer, Fibre. How a humble surgeon changed the world. By Ethel R. Nelson, 1998, TEACH Services Inc, ISBN 1-57258-093-3

Diverticular disease of the colon, A deficiency disease of western civilisation. By Neil S Painter. 1975, William Heinemann Medical Books Ltd, ISBN 0 433 24660 x

Don’t Forget Fibre In Your Diet. To help avoid many of our commonest diseases. By Dennis Burkitt. 1979, Martin Dunitz Ltd, IBSN 0 906348 07 2 Pbk

Dietary Fibre, Fibre-depleted Foods And Disease, Edited by H. Trowell, D. Birkitt and K. Heaton, 1985, Academic Press, ISBN 0-12-701160-9.

Nutrition and Killer Diseases. Edited by J Rose. 1982, Noyes. Diseases of affluence, DP Birkitt, Pp 1-7. Essential fatty acids and chronic degenerative diseases, HM Sinclair, Pp 69-83.

The Saccharine Disease, Conditions caused by the taking of refined carbohydrates such as sugar and white flour. By T.L. Cleave. 1974, John Wright & Sons Ltd. ISBN 0 7236 0368 5.

Out of Africa. What Drs Price and Burkitt discovered in their studies of Sub-Saharan Tribes. By The Weston A Price Foundation.


Medical Aspects of Dietary Fibre. A report of the Royal College of Physicians of London, 1980, Pitman Medical, ISBN 0-272-79609-3.

Some Diseases Characteristic of Modern Western Civilisation (Crookshank lecture 19.5.72) By DP Burkitt. Br med J. 1973, 1, 274.

Diverticular Disease of the Colon: A Deficiency Disease of Western Civilization. NS Painter & DP Burkitt. Br Med J. 1971, 2, 450.

The Diet Delusion. By Gary Taubes. 2007, Vermilion. ISBN 9780091891411.

Trick and Treat. By Barry Groves. 2008, Hammersmith Press Ltd. ISBN 978-1-905140-22-0.

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