The Chemistry of Food and Nutrition - A. W. Duncan (latest books to read .TXT) 📗

and treat the question as though it were a simple one that had been quite settled. Our purpose is to clear the ground to some extent, for a better understanding of its fundamentals, and to warn against dogmatism. Our remarks, however, must be brief. It is undeniable that great eaters of meat, especially if they also take liberally of alcoholic drinks, are prone to diseases of the liver and kidneys, about or soon after the time of middle life. Flesh meat contains relatively large quantities of purins. Purins are metabolised in the body to uric acid, about half of the uric acid produced in the body disappears as such, being disintegrated, whilst the other half remains to be excreted by the kidneys.

One view is that whilst the organs of the body can readily dispose of its endogenous uric acid, or that produced by its own tissue change, together with the small amount of uric acid derived from most foods, the organs are strained by the larger quantity introduced in flesh-food or any other food rich in purins: that there is an accumulation in the system of some of this uric acid. Vegetable foods tend to keep the blood alkaline, flesh possesses less of this property; alkalinity of the blood is thought to be favourable to the elimination of uric acid, whilst anything of an acid nature acts contrarily. Dr. Alexander Haig writes "I consider that every man who eats what is called ordinary diet with butcher's meat twice a day, and also drinks acid wine or beer, will, by the time he is 50, have accumulated 300 to 400 grains of uric acid in his tissues, and possibly much more; and about this time, owing to the large amount of uric acid in his body, he will probably be subject to attacks of some form of gout or chronic rheumatism." Dr. Haig ascribes to the presence of uric acid in the system, not only gout and rheumatism, but epilepsy, hysteria, mental and bodily depression, diseases of the liver, kidneys, brain, etc.

The opinion of the majority of eminent medical men, during recent years, is that uric acid is not a cause, but a symptom of gout, that uric acid is not an irritant to the tissues, and that it is readily excreted in the healthy subject. Some of the reasons for this latter and against the previously stated hypothesis, are as follows:—Birds very rarely suffer from gout—the nodular concretions, sometimes found about their joints and which have been ascribed to gout, are of tuberculous origin—yet their blood contains more uric acid than that of man, and the solid matter of their excretion is mainly urates. If uric acid caused gout we should expect the disease to be common in birds. It is a remarkable fact that the waste nitrogen should be excreted in the form of uric acid or urates from such widely differing classes of animals as birds and serpents. Birds have a higher body temperature than man, they are very rapid in their movements and consume a large amount of food proportionate to their weight. They live, as it were, at high pressure. Serpents, on the other hand, have a low body temperature, they are lethargic and can live a long while without food. There is no obvious reason why some animals excrete urea and others uric acid. As uric acid is a satisfactory and unirritating form in which waste nitrogen is expelled from the body of the active alert bird, as well as from the slow moving reptile, it is surprising if a very much smaller quantity acts as a poison in man. Many physicians are convinced that uric acid is absolutely unirritating. Uratic deposits may occur to an enormous extent in gouty persons without the occurrence of any pain or paroxysms. Urates have been injected in large amounts into the bodies of animals as well as administered in their food with no toxic result whatever, or more than purely local irritation. The most careful investigations upon the excretions of persons suffering from gouty complaints, have failed to show uric acid in the excretions in excess of that in normal individuals, except during the later stage of an acute attack. There is an excess of uric acid in the blood of gouty subjects; some eminent medical men say it is in the highest degree probable, that this excess is not due to over production or deficient destruction, but to defective excretion by the kidneys. The excess may arise from failure of the uric acid to enter into combination with a suitable substance in the blood, which assists its passage through the kidneys. Under the head of gout are classed a number of unrelated disturbances in the gastro-intestinal tract and nutritive organs, whose sole bond of union is that they are accompanied by an excess of urates, and in well developed cases by deposits in the tissues. This is why there are so many different causes, curative treatments, theories, contradictions and vagaries in gout. There are good reasons for believing that uric acid is not in the free state in the body. In the urine it is in combination with alkalies as urates, perhaps also with some organic body. It has been shown that the blood of the gouty is not saturated with uric acid, but can take up more, and that the alkalinity of the blood is not diminished. The excess over the normal is in many cases small; it is said to be absent in some persons, and rarely, if ever reaches the quantity found in leukaemia. Leukaemia is a disease marked by an excessive and permanent increase in the white blood corpuscles and consequent progressive anæmia. Neither does the uric acid of gout reach the quantity produced in persons whilst being fed with thymus gland (sweetbread), for medical purposes. In neither of these cases are any of the symptoms of gout present. In the urine of children, it is not unusual to find a copious precipitate of urates, yet without any observed effect on them.

The symptoms of gout point to the presence of a toxin in the blood, and it is this which produces the lesions; the deposition of urates in the joints being secondary. This poison is probably of bacterial origin, derived from decomposing fæcal matter in the large intestine. This is due to faulty digestion and insufficient or defective intestinal secretions and constipation. This explains why excessive feeding, especially of proteid food, is so bad. The imperfectly digested residue of such food, when left to stagnate and become a mass of bacteria and putrefaction, gives off poisons which are absorbed in part, into the system. This bacterial poison produces headache, migraine, gouty or other symptoms. Because of the general failure of gouty persons to absorb the proper amount of nutriment from their food, they require to eat a larger quantity; this gives a further increase of fæcal decomposition and thus aggravates matters. The voluminous bowel or colon of man is a legacy from remote pre-human ancestors, whose food consisted of bulky, fibrous and slowly digested vegetable matters. It was more useful then, than now that most of our food is highly cooked. About a third part of the fæcal matter consists of bacteria of numerous species, though chiefly of the species known as the bacillus coli communis, one of the less harmful kind which is a constant inhabitant of the intestinal tract in man and animals. This species is even thought to be useful in breaking down the cellulose, which forms a part of the food of the herbivora. Flesh meat leaves a residue in which the bacteria of putrefaction find a congenial home. Poisons such as ptomaines, fatty acids and even true toxins are produced. It is believed that there exists in the colons of gouty persons, either conditions more favourable to the growth of the bacteria of putrefaction, or that they are less able to resist the effect of the poisons produced. It has generally been found that milk is a very good food for gouty patients. This seems due to its being little liable to putrefaction, the bacterial fermentation to which it is liable producing lactic acid—the souring of milk. The growth of most bacteria, particularly the putrefactive kinds are hindered or entirely stopped by acids slightly alkaline media are most favourable. This explains how it is that milk will often stop diarrhoea.

Dr. Haig condemns pulse and some other vegetable foods, because, he says, they contain uric acid. Pulse, he states, contains twice as much as most butcher's meat. Vegetable foods, however, contain no uric acid and meat but a very small quantity. The proper term to use is purins or nucleins. Dr. Haig has used a method of analysis which is quite incapable of giving correct results. Many vegetarians have accepted these figures and his deductions therefrom, and have given up the use of valuable foods in consequence. We therefore give some of the analyses of Dr. I. Walker Hall, from "The Purin Bodies in Food Stuffs." The determination of the purins has proved a very difficult process. Dr. Hall has devoted much time to investigating and improving the methods of others, and his figures may be accepted with confidence.

The first column of figures indicates purin bodies in parts per 1,000, the second column purin bodies in grains per pound:—

Sweet bread 0.06 0.4 Liver 2.75 9.3 Beef steak 2.07 4.5 Beef Sirloin 1.30 9.1 Ham 1.15 8.1 Chicken 1.30 9.1 Rabbit 0.97 6.3 Pork Loin 1.21 8.5 Veal loin 1.16 8.14 Mutton 0.96   6.75 Salmon 1.16 8.15 Cod 0.58 4.07 Lentils and haricots 0.64 4.16 Oatmeal 0.53 3.45 Peameal 0.39 2.54 Asparagus (cooked) 0.21 1.50 Onions 0.09 0.06 Potatoes 0.02 0.1

The following showed no traces of purins: white bread, rice, cabbage, lettuce, cauliflower and eggs. Milk showed a very small quantity, and cheese consequently must contain still less.

The researches of Dr. Hall show that the purins of food are metabolised or broken down by gouty patients, almost as well as by normal individuals, any slight retention being due to increased capillary pressure. A portion of the purins remain undigested, the quantity depending upon the particular purin and the vigour of the digestive organs. Two rabbits had the purin hypoxanthin given to them daily, in quantities which if given to a man in proportion to his weight, would have been 17 and 3 grains respectively. These rabbits showed malnutrition, and after death degenerative changes were visible in their liver and kidneys. Dr. Hall has made a large number of personal experiments, and says that when he has taken large doses of purin bodies—such as 7 grains of hypoxanthin, 15 to 77 grains of guanin or 7 to 15 grains of uric acid, apparently associated symptoms of general malaise and irritability have frequently appeared. In gouty subjects such moderate or small quantities of purins which are without effect on the healthy subject, may prove a source of irritation to the already weakened liver and kidneys.

Professor Carl von Noorden says of gout, "with regard to treatment we are all agreed that food containing an excess of purin bodies should be avoided, and those words embody almost all there is to be said as to dietetics. Alcohol is very injurious in gout. Salicylic acid is a dangerous remedy. Alkalies in every form are utterly useless." Dr. J. Woods-Hutchinson says, "the one element which has been found to be of the most overwhelming importance and value in the treatment of gout and lith¾mia, water, would act most admirably upon a toxic condition from any source; first, by sweeping out both the alimentary canal primarily, and the liver, kidneys and skin secondarily; and secondly, by supplying to the body cells that abundant salt-water bath in which alone they can live and discharge their functions." Dr. Woods-Hutchinson proceeds to state, that the one active agent in all the much vaunted mineral waters is nothing