(Author of In the Cauldron of Disease)
THE question as to whether bran is digestible or not was definitely settled twenty years ago by elaborate experiments made by the foremost scientists all over the world, who all arrived at the same conclusion, i.e. that it was digestible. But old fallacies are long-lived, and the bran-bogey still haunts the minds of the majority of doctors and of most bread-manufacturers, who think they are conferring great blessings upon humanity either by discarding bran altogether, or by submitting it to all kinds of new processes in order to make a product, which has proved to be digestible, suitable for human consumption.
It seems therefore of importance to make a survey of the whole question in order to enlighten the minds of at least the bread-consumers, who are the party chiefly concerned and who actually hold in their hands the key to the whole situation. The moment the consumers fully understand this question and act accordingly, the bogey will disappear.
It was the Great War which brought the question as to whether bran is digestible or not “to the front line”, to use a military term. Food became scarce in all the European countries, and the governments naturally turned their attention to the possible nutritive value of all kinds of food which in the previous years of abundance had been discarded or, like the bran, thrown to the cows and pigs with the whole-hearted approval of great medical authorities such as, for instance, Professor Rubner in Berlin.
“Last man die Kleie zur viehfutterung verwenden, so ist das unter allen Umstanden der rationellere Weg.” “If one gives the bran to the cattle for feeding, it is in all circumstances a more rational way of using it”, he says in an article printed in Deutsche Medizinische Wochenschrift, 1915, No. 19.
This sweeping statement was built upon the results of experiments according to which 31.3 per cent. of dry substance, 38.9 per cent. of protein and 73.5 per cent. of carbo-hydrates in bran were digested by human beings, whilst according to Kellner, the great German authority on cattle-feeling, 79 per cent. of dry substance, 79 per cent. of protein and 79 per cent. of carbo- hydrates constituted the maximum percentages absorbed by animals.
How he arrived at these figures is of the greatest interest especially to laymen who have been taught to place implicit faith in the high priests of the medical profession. Rubner himself reveals the secret of the fallacy of his methods in the following paragraph translated literally from the same article:-.
“From observations which I have made on the bran of wholemeal wheat flour which I had washed with water so that only the husks remained, i was able to establish that not less than 68.7 per cent. of dry substance, 61.1 per cent. of the protein and 26.5 per cent. of the carbohydrates were entirely lost to human digestion”.
Rubner now compared these figures with those of Kellner, who had experimented with wholemeal wheat-bran from which nothing had been washed away, and in which consequently all the most easily digestible parts were preserved. That is to say, whilst Kellner made his experiments with the whole of the bran, Rubner confined his to the hardest and least digestible parts, without noticing the fundamental difference between the stuffs with which he and Kellner had been experimenting.
In comparing his results with Kellners he naturally came to a very unfavourable conclusion as to the utilization of bran as food by human beings. This huge mistake is largely responsible for the introduction of the “bran- bogey” into the scientific world, which unfortunately still haunts the minds of so many doctors. It will obviously take more than a generation to disperse it.
Great confusion has been caused in this matter by writers not stating clearly what they mean by “bran”. There is a vast difference between using the world for the cellulose part of the grain only and using it for all the constituents of the grain which are left over from grinding.
By grinding, 70, 80, or 90 per cent. flour may be obtained with a corresponding residue of bran , in which cases the nutrient properties of the bran would differ accordingly. When the percentage of the grinding is not clearly stated little or no value can be attached to subsequent statements as to the digestibility of bran.
Dr. M. Hindhede, Superintendent of the Danish State Laboratory for Food Research, was one of the first scientists in Europe to establish the nutritive value of bran used as food human beings. He had been brought up on wholemeal bread which was used largely as a standard item in the daily food of the Danish farmers, and he could not possibly believe that it would be better to feed the cattle on the bran and eat white bread instead.
Subsequent experiments which he made in his laboratory proved that he was right. He found that his test-subjects digested 67 per cent. of dry substance, 42 per cent. of the protein and 74 per cent. of the carbo-hydrates of a 30 per cent. bran, i.e. bran from 100 per cent. wholemeal grain from which 70 per cent. of white flour had been ground.
By using sifted bran, i.e. bran from wholemeal flour from which 3.8 per cent. had been sifted away, and 96.2 per cent. had been used for wholemeal bread, Hind-hede found that 77 per cent. of the dry substance, 70 per cent. of the protein and 78 per cent. of the carbo-hydrates of the sifted bran were digested. He now compared these figures with those Kellner had obtained by feeding pigs, which digested 67 per cent. of the dry substance, 75 per cent. of the protein and 66 per cent. of the carbo-hydrates; and by feeding ruminants, which digested 69 per cent. of the dry substance, 79 per cent. of the protein and 71 per cent. of the carbo-hydrates, and concludes:.
“These figures show that the ruminants and the pigs digest the protein of the bran better than man himself, whilst man appears to digest carbo-hydrates better than the animals”.
Hindhedes experiments were closely examined by Professor I.E. Johansson, Professor of Physiology at the Caroline Medical Institute, Stockholm, one of the foremost medical institutes in the world, who came to the following conclusion, printed in Svenska Lakaresallskapets Forhandlingar, 1917, page 302 :.
“Hindhedes experiments, which I have just quoted, provide us with an unquestionable standard by which to judge the digestibility of bran. The only possible criticism I could make would be that his test-subjects had for a long time been accustomed to living on vegetable foods, and were therefore likely to be able to utilize the bran better than those who had lived on a mixed diet”.
Johansson now started experimenting with test-subjects who had lived on a mixed, diet, and with wheat-bran taken from a 75 per cent. grinding, i.e. his bran was one-sixth coarser than Hindhedes, and arrived nevertheless at the following figures : digested protein 49, and carbo-hydrates 70, whilst Hindhede, experimenting with a 75 per cent. grinding, had obtained digested protein 42, and carbo-hydrates 74; and with a finer grinding, digested protein 70, and carbo-hydrates 78.
Professor Johansson concludes the report of his research on the digestibility of broad bran with the following words :.
“It us if great interest that broad bran proves to be digestible to such an extent by the intestinal canal of man. The loss of the protein constituents of wheat-bran amounts to only 50 per cent., and of the carbo-hydrates to only 30 per cent. Of the potential nutritive (calorific) value of bran, not less than 64 per cent. is utilized. The bran used in these experiments was obtained from a 75 per cent. grinding, and the loss in nutritive value by discarding the bran amounts therefore to a loss of not less than 14 to 16 per cent. of the total nutritive value of the grain as food for human consumption”.
Hindhedes experiments aroused great interest, especially in Germany and Switzerland, and caused some scientists in these countries to reconsider the question as to the digestibility of bran, among them Dr. G. Wiegner, Professor of Agriculture at the technical High School, Zurich.
Wiegner had been approached during the war by a prominent manufacturer who asked him point-blank: “How does man digest bran?” Wiegner answered with his best scientific conscience : “As far as I know, not at all.” “Very well then”, said the manufacturer, “how do our domestic animals digest it ?” Wiegner answered : “The ruminants very well, the pigs fairly well, almost 60 per cent.” “Then why on earth dont we give the bran to the animals instead of baking it uselessly into our bread ?”.
This question haunted Wiegners mind. When he came across Hindhedes experiments he thought it a perfect scandal that so little had previously been done to find out definitely what was apparently so easy to prove, but which nobody but Hindhede seemed to have cared to put to a thorough test. “Here we have scientific opinions clashing with each other on a question which is of the utmost importance for the welfare of the people,” he said to himself. ”
And this state of affairs is allowed to continue when the fate of whole nations is dependent upon whether certain foodstuffs which we have in abundance are digestible or not. Ignorance on a point like this is not only dangerous, it is criminal”.
Wiegner now made a series of experiments on his own assistants and a number of students, lasting several days, and obtained the following figures for the digestibility of wheat-bran taken from an 80 per cent. grinding : dry substance 60.4 per cent., protein 53.0 per cent. and carbo- hydrates 75.1 per cent.-a very favourable result indeed considering the coarseness of the bran.
He now had bread made of 100 per cent. wheatmeal, and obtained for all the test-subjects concerned, with very small individual differences, the following figures for the digestibility of the bran contained in the meal : dry substance 87.8 per cent., protein 80.1 per cent. and carbo-hydrates 94.2 per cent.
These figures he compared with Hindhedes derived from a 100 per cent. wholemeal bread of 70 per cent. grinding : dry substance 86.0 per cent., protein 75.0 per cent., and carbo-hydrates 91.1 per cent., and with finer grinding : dry substance 90.0 per cent., protein 85.0 per cent. and carbo-hydrates 94.5 per cent. From a finer grinding Wiegner obtained : dry substance 88.7 per cent., protein 82.3 per cent. and carbo-hydrates 94.4 per cent,-a very small difference indeed as compared with the figures obtained from a coarser grinding. Wiegner concludes :.
“The most rational utilization of the grain is to bake it into 100 per cent. wholemeal bread. An extra fine grinding of the bran, almost to the pulverization of the cells, renders it, as we have shown, on the whole, more digestible, but does not produce any new digestible foodstuffs. As man is able to digest bran just as well as ruminants and pigs, the feeding of animals with bran represents, to human beings, the great loss of nearly nine- tenths of the nourishing parts of the grain”.
Even Rubners chief argument, giving as a cause of mans supposed inability to digest bran as well as ruminants and pigs : “because his digestive juices were not able to dissolve the aleuron-cells which form a thick layer on the inside of the outer skin of the grain”, was disproved by Wiegner, who submitted these cells to a test by immersing then in pepsin-hydrochloric acid, and found that nearly the whole, or 87.2 per cent. of these cells were soluble.
An account of Wiegners experiments is printed in Mitteilungen der Gesellschaft Schweizerischer Landwirte, 1918, No.5.
In support of Hindhedes and Wiegners results two American authorities, Langworthy and Deuel may be quoted. They made thirty-three tests with Graham bread (full wholemeal bread), and arrived at the following average figures : dry substance 92.2 per cent., protein 84.2 per cent., and carbo-hydrates 94.4 per cent.
A greater unanimity in the results of experiments carefully carried out by men of high standing in the scientific world could not be wished for. They have certainly settled, once and for all, the question as to the digestibility of bran in the opinion of everyone who is able to understand the significance of the figures presented above.
There are, however, other scientists who have been interested in the same question, and have made experiments with the digestibility of bran, but who have arrived at other seemingly contradictory results. If we examine their methods and the duration of the experiments we soon find that almost everyone is at fault in some way or other. Much depends upon the percentage of the husks in the bread, and upon other foodstuffs eaten with the bread. It is easy to understand that a bread made exclusively of the husks of the grain is bound to give a less satisfactory result as to its digestibility.
An excess of cellulose will naturally alter the composition of the a fair amount of raw, juicy fruit, which in itself is almost invariably more rich in cellulose than ordinary bread. a meal of that kind will naturally act as an irritant to the walls of the bowels, and may cause slight diarrhoea, with a smaller percentage of the protein content, etc., digested. Still, experiments like this have been carried out by certain scientists who nevertheless claim the results to be valid. They are generally quoted by bread- manufacturers and doctors in favour of white bread, and also by those who are in favour of wholemeal bread but are afraid of the coarser part of the meal, which has therefore been sifted away.
The only experiments which are valid are those carried out with 100 per cent. wholemeal bread eaten, not in conjunction with acid fruits or other foodstuffs even richer in cellulose, but in conjunction with alkaline foodstuffs such as, for instance, vegetables.
Starch digests in an alkaline medium, not in an acid one. It is therefore radically wrong to eat starchy food of any description with acid food, as for instance with juicy acid fruits which partly suspend and prevent their digestion. The great Russian physiologist, Pavlov, proved that the saliva in the mouth changes in its chemical composition according to the food we eat. Acid fruits produce a quite different saliva from that produced by starch and are, furthermore, also likely to interfere with the proper digestion of starch in the small intestine.
If, therefore, a pound of acid fruit is eaten with a pound of bread made exclusively for the sake of experiment, of husks of the grain, the result as to its digestion must necessarily be a poor one, as has been shown to be the case with some experiments referred to by many doctors. As long as scientists remain ignorant of fundamental digestive principles like these, the present confusion about the digestibility of bran will continue.
Another serious point of omission on very much the same lines is the neglect of the fact that foodstuffs digest better in their own natural “milieu” or in the company of other foodstuffs, produced by Nature in the same fruit, berry or vegetable. It is easy to understand that only a berry or vegetable. It is easy to understand that only a bread made of all the constituents in the saliva and in the intestinal juices necessary for the full digestion of its various food elements, as also that certain parts of the grain may provide the digestive juices with the elements needed for the digestion of other parts.
If one part of the grain is eliminated or omitted, the digestibility of the other parts may suffer accordingly, because the accessory elements needed for a better utilization of the others by the human intestine are missing. To use an analogy: if from a piece of music certain parts are omitted, the euphonic value of the component parts will suffer accordingly, producing disharmony instead of a harmonious whole.
We are obviously living in a time when the rudiments of digestion, taken as parts of a symphony or as a whole are only beginning to be realized, and when ignorance concerning the effect of the most primitive food-elements on the alimentary canal is appalling.
Very few of the doctors and scientists who cry out against wholemeal bread because of its bran content are aware that of cellulose, hitherto considered indigestible, whole wheat contains only 2.5 per cent., whilst strawberries contain 2.3 per cent. of cellulose, radishes 2.8 per cent., raspberries 6.7 per cent., raisins 7 per cent., hazel-nuts, almonds, walnuts and hickory nuts 3.7 per cent., and asparagus, cantaloupe, water-melon, mushrooms, apples and celery contain as much cellulose as whole wheat.
Of the protein in wholemeal bread, we digest according to Hindhede 84.5 per cent., according to wiegner 86.3 per cent. and according to Langworthy and Deuel 84.2 per cent. Professor G. Bunge, the great physiologist, demonstrated as long ago as 1889 that the unabsorbed protein of lentils amounted to 40 per cent., of carrots 39 per cent., of potatoes 32 per cent., of cabbage 18 per cent., and of cows milk 7 to 12 per cent.
In view of these facts, the outcry about the indigestibility of bran seems to be based upon assumptions devoid of any foundation whatever. If we take into account the fact that the cellulose part of bran is of the greatest value in fighting constipation, and that it furthermore contains invaluable mineral substances in organic form, the criminality of excluding it from bread must be obvious to every reader.
“White bread”, says the well-known American food expert, McCann, “becomes white because from the ground grain of wheat three- fourths of the mineral salts and colloids are removed”.
The bran is found to consist of rough, canvas-like, brownish particles, with a very remarkable suggestion of woof and warp. The germ, difficult to distinguish from bran with the naked eye, will be found to consist of rich, oily, cream-coloured particles.
A chemical analysis of this bran and germ, which take up large quantities of water and hold it in the intestines for lubricating purposes, shows that they are rich in vitamins, in silicon, sulphur, nitrogen, iron, iodine, potassium, manganese, phosphorus, nucleo proteins, or phosphorized albumens, lecithins, or phosphorized fats, and the simple phytin compounds and phosphates without which no animal can be properly nourished, as proved in a series of experiments carried out in St. Petersburg.
Of these twelve mineral substances in organic form, a pound loaf of whole wheat bread contains 70 grains, whilst a pound loaf of white bread of the ordinary kind contains only 18 grains, which makes a difference of 52 grains. In order to regain these 52 grains by eating some kind of animal foodstuff especially rich in them, approximately two dozen eggs, or two pints of milk would have to be consumed.
There is nearly 50 per cent. more value for the money in a loaf of wholemeal bread than in loaf of white bread of the same weight. In view of these facts, any bakery which produces a full 100 per cent. wholemeal bread should be given all possible support by the consumers.
The best 100 per cent. wholemeal bread I have ever tasted is baked by William Beattie, 116 Paton Street, Glasgow, E. It is hoped that this firm will soon have a branch bakery in London, though the bread is so good and keeps so well that a weeks supply can be ordered without disadvantage from Glasgow. Wholemeal bread generally tastes best after being kept for three or four days, unwrapped, in an open, airy place.
A more recent 100 per cent. wholemeal product is “Nomolas Sunbred”, manufactured by Nomolas Limited, at 33 St. Jamess Street, London, S.W.I, which should appeal to all those who would like to eat wholemeal bread, but are afraid that the bran content might irritate their weakened digestion. The manufacturers of “Nomolas Sunbred” claim to have overcome this difficulty by introducing a new process which “bursts” the bran-cells and liberates their mineral content. This 100 per cent. wholemeal bread ought, therefore, to suit even the weakest digestion, and appeal to everybody, as its taste certainly is far superior to that of any white bread.
Many people will, however, prefer a coarser loaf made of 100 per cent. flour ground and baked in the old way, because of its greater appeal to the eye and the taste. The statement made by Nomolas Limited, that “the digestive juices of the bodies of animals are no more able than those of human beings to break up the cells of the bran and liberate their riches”, cannot be upheld in view of the experiments referred to above. Bran is certainly digestible to an extend of at least 64 per cent. by man, and to a far greater extend by ruminants.
If baked into wholemeal bread, its digestibility is undoubtedly increased, so that there is a loss of only 8 to 10 per cent. of dry substance, 16 per cent. or protein, and 6 to 7 per cent. of carbohydrates- a very low and almost negligible percentage of unused food constituents indeed.
However, any new methods which are able to further the digestibility of bran and produce a wholemeal loaf suitable for even the weakest digestion must be hailed by all who have the welfare of their people at heart, as a new means of combating the old “bran-bogey” of the past.