Vegan Health ArticlesStraining for Relief – Damage Everywhere
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From Dr. John McDougall

Out of the Mouths of Babes

Many years ago on one summer evening when our daughter was 10 and our oldest son was nine, we were enjoying a peaceful dinner when Heather asked, “Is there something wrong with Jodi?”  Heather and Patrick had spent the previous night at their best friends’ home, Jodi and Mark.  Heather continued, “When Jodi is in the bathroom I hear these strange noises, like she is in horrible pain.”  She then made a long painful grunting sound to demonstrate.  Patrick interjected, “Mark makes the same noises and he’s in there forever.”  My children had never had to experience the Herculean exertion most people require to move their bowels.  In fact, for them this daily process was accomplished effortlessly and in seconds – back out to play before the ball stops bouncing.

Almost 30 years ago, as a general practitioner in a small rural community on the Big Island of Hawaii, I had a chance to learn all about the personal bowel habits of my patients.  The most upsetting stories were about the suffering children.  Mothers often brought them to see me because of lower abdominal pains and bleeding – blood on the toilet tissue or frank blood in the toilet bowl.  After detailed questioning, the concerned mothers told me about the straining efforts their children experienced with each bowel movement, every two to five days.  No connection was ever made between the child’s diet and this severe constipation.   Nor by patients, and nor by their concerned doctors, is there ever any connection made between this constipation and diseases in other parts of the body.

The Fiber Man – Denis Burkitt

All of my formal medical-school education focused on describing and treating the signs and symptoms of chronic illness, rather than on really important matters – cause and cure.  A turning point in my life came in the autumn of 1971, when I was a senior medical student.  During a noontime hospital conference I met the first doctor to tell me there were causes for the common chronic diseases.  Dr. Denis Burkitt was visiting the Kellogg cereal company in Battle Creek, Michigan; trying to convince them to add more dietary fiber to their products.  He believed the lack of fiber in our diet was at the root of our common chronic diseases.

Dr. Burkitt, born in Ireland in 1911, became a surgeon at Edinburgh’s Royal College of Surgeons in 1938, and was assigned to work for the colonial Medical Services in Uganda, Africa in 1946.1  He served as the Government Surgeon of Uganda from 1946 to 1964.  Here he discovered a cancer of the immune system, which carries his name – Burkitt’s lymphoma.

In Uganda, Burkitt made many important observations about his African patients.  For example, they produce several times more quantity of feces than people on the highly refined, high meat Western diet.  He noticed their feces were soft and passed without pain and attributed this to the high fiber content of their foods.  Westerners have 3 to 21 bowel movements a week and the amount of stool passed is 85 to 150 grams/day (3 to 5 ounces).  Africans have 30 to 60 movements a week with a stool weight of 200 to 500 grams a day (7 to 17 ounces).  Most importantly, he noticed that the diseases he had been trained to treat in Scotland were absent among Africans.  He saw no cases of type II diabetes, obesity, appendicitis, diverticular disease, hemorrhoids, dental caries, varicose veins, pulmonary embolism, inflammatory bowel diseases (Crohn’s disease and ulcerative colitis) or hiatus hernia. The only heart attack he saw was in a judge who had trained in London, developed a taste for roast beef and Yorkshire pudding, and then returned to Africa.  “In 20 years of surgery in Africa, I had to remove exactly one gallstone,” Dr. Burkitt claimed.

I remember only one slide from this “medical-student, mind-changing” lecture.  On one side of the slide was pictured a large hospital building with a small bowel movement next to it; and in the adjacent frame was a small hospital with a large stool.  The message was clear – those populations who eat a diet high in fiber have big bowel movements and few illnesses.  Denis Burkitt set out in the mid-1960s to tell the world how important it was to add fiber back to your diet.  He became known as “The Fiber Man.”  In retrospect, his focus was too narrow – simply sprinkling bran over bacon and eggs will not solve the health problems of Western man.

Historically, similar changes in disease patterns, as seen in Africa, have been seen as the diets of people in England, the United States, and most recently Japan, have switched to processed foods and animal products.2-4 There are many more important qualities to the plant-based diet of Africans than the fact that it was high in dietary fiber. The African diet has been traditionally a diet based on grains, legumes, vegetable and fruits – his patients ate very little meat, dairy products or refined foods.  This means the diet was very low in animal protein, fat and cholesterol, and high in complex carbohydrates, dietary fiber, and healthful phytochemicals.5-6  All these ingredients go together to define a healthy human diet – like that of Burkitt’s patients (and by no coincidence, The McDougall Diet).

In last month’s newsletter I explained that fiber, which is only found in plant foods, is mostly non-digestible carbohydrate, which passes through the small intestine intact to become the bulk of the stool.  The fiber pulls in water to further expand the volume of the stool.  Americans eat very little fiber because their meals are made of mostly fiber-free animal products and refined grains.  The result is tiny rock-hard fecal marbles – and so begins health problems throughout the body.  The following diseases are found commonly in populations of people who consume a “rich” diet, and are essentially unknown in people, who, like Dr. Burkitt’s Africans, consume a diet based on unrefined plant foods.


The contents of the small intestine empty into the large intestine.  The first part of the large intestine is called the cecum (located in the right lower part of the abdominal cavity).  A small pouch or diverticulum, called the appendix, is attached to the cecum.  When the opening of the appendix becomes blocked, fluids accumulate.  These stagnant fluids become infected creating a disease condition common to Westerners, called appendicitis.

The cause of this blockage is unhealthy remnants of partially digested foods, which irritate the opening of the appendix.   The observation that appendicitis is unknown in populations of people who eat a plant-based diet must be surprising (and maybe disappointing) to surgeons trained, like Dr. Burkitt, to treat this common condition in Westerners.7-9   The incidence of appendicitis is increasing among Africans as their diet changes.10

Diverticular Disease:

In Western societies, diverticulosis occurs in at least one person in two over the age of 50 years. The frequency increases with age. Denis Burkitt, practicing in Uganda, and doctors taking care of similar populations of people, never see this condition among the natives.11,12

As the food moves through the small intestine the nutrients – protein, fats, carbohydrates, vitamins, and minerals – are absorbed through the intestinal wall into the bloodstream.  Left behind are non-digestible matters (dietary fibers), colon bacteria and a few dead cells – these materials soon become the stool.  Movement from the right side of the large intestine to the left side is accomplished by rhythmic contractions, known as peristalsis.

According to a law of physics (Laplace’s Law), the pressure within a cylindrical structure with a given wall tension increases with decreasing radius.13 In other words, contractions at small diameters cause high pressures.  The remnants of digestion on the Western diet produce only a small mass, and therefore, high pressures.14  Years of elevated pressures produce ruptures in the walls of the intestine, making balloons, called diverticula.

Blood supply of the intestine begins on the outer surface, and then these small vessels dive through the muscular wall to supply the inner surfaces of the intestine.  The weakest part of the wall of the intestine is where the blood vessels pass through the wall.  As a result, the most common locations of these diverticula are next to blood vessels.  Not surprisingly, one of the most common symptoms of this disease is bleeding.  I have seen the bleeding so severe that the only way to save the person’s life was to surgically remove the bleeding portion of the intestine.

When the diverticula become irritated by the unhealthy remnants of digested food in the large intestine the openings can close, allowing the fluids to become stagnant and infected – a condition known as diverticulitis.  This disease is sometimes referred to as “left-sided appendicitis,” (remember the real appendix is located in the right lower part of the abdomen), and is usually treated with antibiotics.

A change to a high fiber diet will greatly reduce the risk of future bleeding and infection – in other words, people with diverticular disease have much less trouble after they change to a healthy, high fiber, plant-based diet.15  However, the diverticula do not disappear with a change in diet.

The Final Act – Defecation

Matter is further digested and water is removed during the movement from the right to left colon. In the final few inches of the large intestine, called the rectum, the feces accumulate.  With adequate filling the rectum becomes distended, causing reflex contractions, which initiate the evacuation of the stool into the outside world – properly referred to as a bowel movement.  Unfortunately, life is not so simple for those who make tiny rock-hard fecal marbles.  These little guys simply do not provide adequate filling to stimulate the rectum. Plus, because of their slow passage almost all of the water has been removed and they become dry and hard, thus more difficult to pass.  To get them out requires enormous effort and harmful straining.

Picture a person seated on the toilet – grunting and groaning.  The face is flushed red from blood pushed up into the head and neck.  This is not the only direction blood is forced by straining.  Blood diverted under pressure into all other body parts causes structural damage.  After many years all this translates into diseases suffered by the majority of people living on the Western diet.


Diets low in fiber cause hemorrhoids by creating high pressure in the veins found in the very last part of the large intestine, the anus.16,17  A ring of internal veins, the hemorrhoidal veins, provide a compressible lining which allows the anus to completely close – sealing the intestine closed – allowing us to act sociably by preventing release of gasses and stool at inappropriate times and places.

Straining to pass the small stools causes retrograde pressures in the hemorrhoidal veins, dilating them.  Eventually, after years of straining they are permanently enlarged and commonly hang out of the end of the anus.  Later stages of hemorrhoid development include the displacement of the anal muscles toward the outside.  Hemorrhoids located higher up are called internal hemorrhoids; the lower ones are called external hemorrhoids, the latter are commonly the painful ones.

Since these are structural changes caused by physical forces they can be expected to be permanent.  Surgery can counter some of this damage with removal of some of the stretched-out tissue – a hemorrhoidectomy.  Surgeries include sclerotherapy (injection with a caustic substance), photocoagulation, rubber band ligation, cryotherapy (freezing) and cutting with a knife and laser.  Laser surgery is no less painful and is more expensive.18

Surgery should be reserved for those who fail to find comfort from less drastic means – like topical cleansing and creams, and most importantly, better food choices.  The main symptoms from hemorrhoids are itching, pain, and bleeding.  Sitting in a warm bath (a sitz bath) can provide much relief.  A change to a healthy plant-based diet will do wonders – the itching, pain, and bleeding usually stop.

You may wonder why other forms of straining such as lifting or straining to deliver a baby don’t cause permanent dilation of the hemorrhoid veins.  In all forms of straining, except those associated with bowel movements, there is a reflex contraction of the anal muscles (sphincter), and this compensates for the raised pressures in these veins.1

Although hemorrhoids may have been rare in rural Africa before modernization of the diet, that is not the case today.  Approximately one-fifth of modern black Africans now have these dilated veins – a direct result of their switch to a modern diet.19

Varicose Veins:

Straining to push out small stools causes great retrograde pressures into the veins of the legs.  This pressure is even higher and more damaging because of our custom of sitting to defecate on high-seated toilets.  If you have traveled to less developed countries, you may have been shocked to find their toilets are simply holes flush with the ground.  To relieve yourself, you squat.  This position bends the legs at the hips and knees cutting off the veins and preventing pressures created by straining from being transmitted down into the leg veins – thus protecting them.

Notice that when you are standing, the distance from the feet to your heart is about four to five feet.  A column of blood this tall would place tremendous pressures due to the weight of the blood on the veins in the lower leg and feet.  To prevent this, the large veins in the legs have valves that shut closed to prevent flow of the blood in the direction of the feet.  When we walk the muscles in the legs contract, pushing blood past open valves towards the heart. However, the valves are one way, preventing the blood from falling back down toward the feet.

When a person strains to move those stubborn fecal marbles, the high pressures dilate the leg veins and stretch out the valves.  After years of such damaging forces, the valves become distorted and incompetent – producing those well-recognized “blue worms,” that we call varicose veins.16,19

Varicose veins occur elsewhere:  Varicose veins in the scrotum of men are called varicoceles.  In women, this dilation of veins can occur in their vulva and around their ovaries.

Hiatus Hernia:

The action of defecation raises the pressures in the abdominal cavity above those that are in the chest.  The result is that the contents of the abdomen are pushed up into the chest.  The chest and the abdomen are separated anatomically by a large muscle used for breathing, called the diaphragm.  Three structures pass though the diaphragm – the aorta, vena cava and esophagus.  Only the esophagus is moveable.  Straining pushes the stomach into the natural opening for the esophagus causing the muscular opening to dilate.  A dilated muscle is known as a hernia.  This condition is called a hiatus (or hiatal) hernia.21-22 Eventually the top portion of the stomach may actually sit in the chest cavity.  Each breath creates negative pressures in the chest that draw acid up into the esophagus.  With the stomach out of its natural position, the sphincter (lower esophageal sphincter) that functions to close the opening between the esophagus and stomach when we are not swallowing becomes incompetent. The result is acids from the stomach can reflux into the esophagus and up into the mouth and lungs causing esophagitis, loss of dental enamel, sinusitis, and asthma (see the February 2002 McDougall Newsletter).  This condition is referred to as Gastroesophageal Reflux Disease (GERD).

Surgical repair can move the stomach back into the abdominal cavity and close the hernia.  However, this operation should be reserved for those who cannot find relief from a healthy diet, raising the head of their bed and/or antacids.

Other Possible Conditions from Straining:

I believe the following conditions are also due to straining to defecate:  prolapse of the female uterus, spermatocele (dilation of the spermatic cord), cystocele (prolapse of the female bladder), and rectocele (prolapse of the rectum).

Treatment of Damaged Tissues:

Unfortunately, the conditions that are caused by straining are not returned to normal with a change in diet.  But diet will relieve most of the problems associated with diverticulosis (bleeding and infection), hemorrhoids (bleeding, pain and itching) and hiatus hernia (heartburn).  Surgery for these conditions and the others discussed (diverticulosis, varicose veins, and prolapsed uterus) should be reserved for those who cannot find relief with less drastic measures.  I would expect that changing to a healthy high-fiber, plant-food based diet will slow the progression of all these conditions, preventing them from becoming worse.

Rather than wonder why so much disease is caused by the simple act of moving your bowels, you should marvel at the strength of your body to withstand these tissue-wrenching forces for so many years.  Today would be a great day to start reducing the wear and tear on your body – you will be amazed by how quickly it responds.


1)  Ginsberg A.  The fiber Controversy.  Dig Dis 1976 Feb, 21:103-112.

2)  Taylor R.  Management of constipation. 1. High fibre diets work. BMJ. 1990 Apr 21;300(6731):1063-4.

3)  Burkitt D.  Effect of dietary fibre on stools and the transit-times, and its role in the causation of disease. Lancet. 1972 Dec 30;2(7792):1408-12.

4)  Walker A.  Epidemiology of noninfective intestinal diseases in various ethnic groups in South Africa. Isr J Med Sci. 1979 Apr;15(4):309-13.

5)  Segal I. Physiological small bowel malabsorption of carbohydrates protects against large bowel diseases in Africans. J Gastroenterol Hepatol. 2002 Mar;17(3):249-52.

6)  Segal I.  Persistent low prevalence of Western digestive diseases in Africa: confounding aetiological factors.  Gut. 2001 May;48(5):730-2. Review.

7)  Friedman GD.  Appendectomy, appendicitis, and large bowel cancer. Cancer Res. 1990 Dec 1;50(23):7549-51.

8) Burkitt D.  The aetiology of appendicitis. Br J Surg. 1971 Sep;58(9):695-9.

9)  Walker A.  Appendicitis, fibre intake and bowel behaviour in ethnic groups in South Africa.  Postgrad Med J. 1973 Apr;49(570):243-9.

10)  Naaeder SB.  Acute appendicitis and dietary fibre intake. West Afr J Med. 1998 Oct-Dec;17(4):264-7. 

11)  Simpson J.  Pathogenesis of colonic diverticula.  Br J Surg. 2002 May;89(5):546-54.

 12)  Painter N. Diverticular disease of the colon, a 20th century problem. Clin Gastroenterol. 1975 Jan;4(1):3-21.

13)  Young-Fadok T.  Epidemiology and pathophysiology of colonic diverticular disease.

14)  Aldoori WH.  A prospective study of dietary fiber types and symptomatic diverticular disease in men.  J Nutr. 1998 Apr;128(4):714-9.

15)  Leahy AL.  High fibre diet in symptomatic diverticular disease of the colon. Ann R Coll Surg Engl. 1985 May;67(3):173-4.

16)  Burkitt D.  Varicose veins, deep vein thrombosis, and haemorrhoids: epidemiology and Suggested aetiology. Br Med J. 1972 Jun 3;2(813):556-61.

17)  Haas P.  The prevalence of hemorrhoids. Dis Colon Rectum. 1983 Jul;26(7):435-9.

18)  Brisinda G.  How to treat haemorrhoids. Prevention is best; haemorrhoidectomy needs skilled operators.  BMJ. 2000 Sep 9;321(7261):582-3.

19)  Ogendo SW.  A study of haemorrhoids as seen at the Kenyatta National Hospital with special reference to asymptomatic haemorrhoids. East Afr Med J. 1991 May;68(5):340-7.

20) Burkitt D.  A deficiency of dietary fiber may be one cause of certain colonic and venous disorders.  Am J Dig Dis. 1976 Feb;21(2):104-8.

21)  Sontag SJ. Defining GERD.  Yale J Biol Med. 1999 Mar-Jun;72 (2-3):69-80.

22)  Burkitt DP.  Hiatus hernia: is it preventable?  Am J Clin Nutr. 1981 Mar;34(3):428-31.

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We began this archive as a means of assisting our visitors in answering many of their health and diet questions, and in encouraging them to take a pro-active part in their own health. We believe the articles and information contained herein are true, but are not presenting them as advice. We, personally, have found that a whole food vegan diet has helped our own health, and simply wish to share with others the things we have found. Each of us must make our own decisions, for it's our own body. If you have a health problem, see your own physician.