is a vegetarian animal is amply exemplified by
his basic anatomy. Unlike carnivorous animals,
man has teeth suited for biting and grinding and
not for tearing. The intestines of man are longer
as compared to their carnivorous counterparts.
These are but the most basic of differences that
exist between vegetarian and non-vegetarian
The digestive tract of man
starts in the mouth. The lips, the teeth and the
tongue play an important role in the mastication
and the softening of the food. Digestion
commences in the mouth with the help of the
saliva. The food, after due mastication is
swallowed whence it enters the oesophagus (or
food pipe). The food pipe empties into the
stomach. The food in the stomach is acted upon by
gastric acid and enzymes which help in digesting
the food to its more basic constituents. The
continuous churning of the stomach further helps
in breaking down the food. From the stomach the
food enters the intestines which are the longest
part of the gastro-intestinal tract. Here various
enzymes complete the digestive processes and
absorption of the various elements of the food
begins. What is undigested and unabsorbed enters
the colon (large intestine). Here the faeces are
formed which are gradually taken upto the rectum
and anal canal and egested at periodic intervals
(Refer figs. I and 2 below for anatomical
| Fig. 1
|| Fig. 2
Let us now consider the
advantages of a vegetarian diet in relation to
each of the parts of the gastro-intestinal tract.
food being high in its fibre content
increases the flow of saliva which
enhances digestion and protects the teeth
of the oesophagus is less common in
vegetarians. This is because vegetarian
foods like fresh fruit, vegetables,
especially amla and citrus fruits contain
large doses of vitamin C which has a
protective action against malignant
hernia which occurs at the junction of
the oesophagus and the stomach is less
common in vegetarians. Though the cause
of this phenomenon is unknown, it is
postulated that, vegetarian food,
particularly in the natural form,
contains very little fat. The fat when
present in the diet in excess delays
emptying time of the stomach. This leads
to pressure on the diaphragm which causes
the hiatus hernia.
virtue of the high vitamin C and fibre
content the vegetarian food offers
protection from stomach malignancy.
intestines are the home of many
parasites. The longest of
themtaenia saginata and
taenia solium (Fig alongside) are
found almost exclusively in
non-vegetarians, especially in
those who eat beef and pork.
These worms are almost never
found in vegetarians.
are clinical observations that suggest
that appendicitis (attack of inflammation
of the appendix) is less common in
large intestine (the colon) is most
susceptible to the kind of food eaten by
The advantages of a vegetarian diet have
been observed in following diseases of
larger undigestible matter present in fruits
and vegetables provides bulk which enhances
the forward passage of undigested waste
matter from the caecum to the rectum and anal
canal. It also reduces the transit time from
caecum to rectum. This prevents stasis of
poisonous end-products of digestion and
resulting diseases of the colon. Thus, while
non-vegetarians pass small stools (on an
average 100 gm), the vegetarians pass large
bulky stools (on an average 300 gm). Also
vegetarians pass less foul smelling stools. A
few years ago, in my book on 'Common Chronic
Disease Patterns in the Arabian Gulf, Saudi
Arabia and Yemen', I mentioned that
constipation is extremely common in the Arab
popula tion. It has been noticed time and
again that when these patients are given more
vegetables and fruits (in addition to plenty
of water to drink), their bowels move freely
and they are relieved of their constipation.
of the Colon
subjects the incidence of
constipation increases markedly due
to the development of the above
condition. Fig. alongside shows the
small pouches looking like
pseudopodia which appear on different
sides of the colon. Not only do these
pouches make the colon very sluggish,
but they can get inflamed like the
appendix or can bleed like an ulcer.
The modern refined and non-vegetarian
diet is responsible for this disease.
The reduced faecal bulk causes
narrowing of the colonic lumen and an
increase in intraluminal pressure.
This results in protrusion of these
pouches known as diverticula.
Diverticula may also develop due to
the attempts of the proximal colon to
overcome obstruction caused by the
segmented and narrowed distal colon.
Owing to the high fibre content of
the vegetarian food, this disease is
infrequent in a vegetarian
illness is the most common cause of bowel
irregularities and colonic gripes.
Incidentally it is less frequent in
vegetarians owing to the high fibre content
of such a diet.
amoebiasis and giardiasis which are easily
treated with drugs, ulcerative colitis is a
'lifelong bloody dysentery'. The incidence of
this disease is much less in vegetarians
because of the high fibre content.
of the Colon
been proved all over the world that the
incidence of the cancer of the colon is very
low in vegetarians. It is postulated that the
high fibre content of pulses, cereals,
vegetables and fruits increases the amount of
faeces and reduces the transit time through
the colon. As mentioned earlier, the latter
reduces the exposure to carcinogens
responsible for the development of the cancer
of the colon. These substances include
tryptophane, tyrosine, methionine, basic
amino acids, cholesterol and bile acids. The
bile acids are the most important
carcinogens. A number of epiderniological
studies have shown and several authors have
found a significant relationship between the
faecal bile acid concentration and colonic
and anal canalThe diseases of the
terminal end of the gastrointestinal
tract e.g. fissure and piles are abundant
in the normal population. In fact, the
incidence of these diseases is highest in
the Arab population as described by me in
my book on Arab diseases. The fact is
that both are related to underlying
severe constipation. The straining done
to expel the hard stools from the rectum
and anal canal, "keeps up" the
piles and the fissures.
In the medical world, it is a very common
observation that these diseases are much
less common in vegetarians. This seems to
be related to the low incidence of
constipation amongst vegetarians.
||The liver and
the gallbladder are also affected
by the vegetarian diet. Fig.
alongside shows the presence of
stones in the gall-bladder which
can occur in as much as 10% of
the population above the age of
70 years. It is interesting to
note that the incidence of
gall-stones in vegetarians is
significantly less. The high
fibre content of the vegetarian
diet causes reduced deoxycholate
absorption which in turn
increases the synthesis of
chenodeoxycholate. The latter
affects the cholesterol
saturation of the bile resulting
in less stone formation. In fact
patients having gall-stones are
prescribed high fibre vegetarian
diets in order to reduce further
Liver is discussed in a separate
malignancies are known to be less common
it appears that vegetarian food is beneficial in
prevention as well as in the management of most
of the gastro-intestinal diseases.
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development of cholelithiasis in man. N
Engl J Med 1978; 299:1221-7.
F. Wilson D, McPherson K, Mann 1. Effect
of vegetarianism on developmenl of
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Symptomless divenicular disease and
intake of dietary fiber. Lancet 1979,
MH, Littlewood ER, Baird IM, Fowler J.
Nonh WRS, Cox AG. Are fibre supplements
really necessary in divenicular disease
of the colon ? A controlled clinical
trial. Br Med J 1981; 2S2:1353-6.
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and rectum. Cancer 1971; 28:3-13.
SA, Williams DRR, Cole TJ, James WPT.
Dietary fibre consumption and regional
large bowel cancer monality in Britain.
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S. Dayal H. Swanson M, et al. Diet in the
epidemiology of cancer of the colon and
rectum. JNCI 1978; 61:790-814.
GA, Nomura A. Kamiyama S~ Shimada A, Abba
BC. Bowel transit time and stool weight
in populations with different colon
cancer risks. Lancet 1977; 2:110-1.
A, Anhus RS, Calkins BM, Nair PP, Diet,
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colon cancer; selected biochemical
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GK, Lennard-Jones JE, Bartraum CI.
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constipation: Why fiber and laxatives
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DM, Lennard-Jones JE. Severe chronic
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Fraumeni, "Cancers of the Pancreas
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