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THE ROLE of salt in human nutrition has been a disputed subject for a long time. Some authors regard salt merely as a condiment or stimulant which is harmless in small quantities, possibly harmful in larger quantities, but definitely dispensable in normal nutrition, to the extent that it is not a natural content of food. Others believe that salt is indispensable in human nutrition and that the sodium chloride found in foods is not enough to meet the requirements of the normal human being.
The exponents of both views have given reasons in support of their respective viewpoints.
Wolff-Eisner asserts that salt is comparable to a vitamin, and that its complete exclusion could not be tolerated any longer than the exclusion of food itself. (It might be argued here that "complete" exclusion is impossible anyway, inasmuch as varying quantities of NaCl are found in food naturally.)
Wolff-Eisner adds, however, "... that cooking salt is the only salt which does not occur in sufficient quantities in normal nutrition and that it, therefore, must be added artificially." There are different views as to the quantity of salt which, according to this theory, must be added to cover man's salt requirements.
The average European consumes ten to fifteen grams of salt per day and in the United States the average consumption is ten to twelve grams per day, whereas the values are quite different in Asia and Africa. All physiologists agree that these values far exceed the salt requirements. In other words, they agree that people consume salt mostly because it makes food more tasty, not because the body requires it.
Bunge conducted several experiments in 1901 on the need for salt. He found a small demand for salt in animals which eat a lot of meat, whereas he discovered the demand much greater in those living on vegetation. He believed that the same relationship was to be found among human beings. He found that the population of cities, in which larger quantities of meat were eaten, consumed one-third of the quantity of salt used by the mainly vegetarian rural population. Similarly, he found little demand for salt among the meat-eating nomads. On the other hand, the salt demand among agricultural negroes was so great that, in some tribes, salt actually had barter value.
From his own experiments, Bunge gathered that the body eliminates large quantities of salt if it consumes much potassium, such as found in large quantities in vegetarian nutrition. (His classical experiment in 1901, however, is not indisputable in theory, although its conclusions are correct.)
Abderhalden shared Bunge's views as to the reasons for the increased demand for salt among vegetarian tribes: The higher potassium content of nutrition leads to increased elimination of sodium and, therefore, causes an increased demand for salt.
Bunge considered the addition of four to five grams of salt daily necessary for the maintenance of the "salt balance" (per Voit); Hermannsdorfer disputed this in his doctorate dissertation, stating that while man consumes up to 15 grams of salt per day, he could undoubtedly manage on one or two grams of salt. In fasting experiments on himself, to test the elimination of salt, Hermannsdorfer generally took two grams of salt.
These views are considered one-sided in some respects despite their having common usage. My experiments on thousands of patients, as well as on myself, reveal that the demand for salt is something to which our nerves of taste have become accustomed since youth. Just as one might say that all people have a need for alcoholic beverages and that even animals - especially the human-like apes - can become chronic alcoholics, and, concluding from this fact that alcohol is a necessary component of human nutrition, it would be just as incorrect to base a claim of the indispensability of salt on its universally practiced use.
There are certain tribes which do not use salt. Homer has mentioned them, and Sallust talked of the Numidians who did not use salt. But apart from that, even if all the people in the world had eaten salt since time immemorial, this still would not prove that it was to their advantage. After all, there had always been chronic diseases whose etiology we cannot ascertain even today; thus, we cannot judge to what extent they may have been caused by an unreasonable way of life.
Just for the sake of curiosity, we might point to the fact that, even today, there are tribes who live without salt. Professor Vrgoc reported that tuberculosis was unusually prevalent among the settled Kirghizians, whereas it occurred only rarely among the nomadic ones.147 The nomads use no salt, whereas the Kirghizian peasants do use salt, which is freely available in the Steppes, as an addition to nutrition, in the manner of the Russian peasants. (Note: the role of Kumys - strong alcohol - will not be dealt with here.) The Kirghizians reported to Vrgoc that they had noticed a deterioration of their senses of sight and smell since partaking of bread and salt. Nomads who use salt lose the ability to scent wolves. Vrgoc also reported that fishing and hunting tribes of Siberia show a marked dislike of salt. On his expeditions to the North Pole, Nansen used the Eskimos' dislike of salt to get rid of uninvited guests by offering them strongly salted food. Stanley and Livingstone, too, reported on finding tribes to whom salt was unknown and who showed certain toxic symptoms after taking it for the first time. (Also see Albert Schweitzer's report.)
We observed healthy nurses after several months of unsalted nutrition and found that their first reaction to normal home-cooking was diarrhea and nausea. This shows what far-reaching effects the habitual consumption of salt may have on the organism. After going six months without salt, a nurse who had believed that she could not do without it reacted to this spice as a young boy reacts to his first cigarette.
The evaluation of alcohol, tobacco and salt as parts of human nutrition is closely connected with national and even religious and political motives which are not always related to medical considerations. It would, therefore, be wise to omit the ethnographic aspect from a discussion of the meaning of salt in human nutrition. We should also avoid the mistake of quoting examples from the animal world to prove that the intake of salt is "natural" or necessary. We have refused to use the argument of "natural nutrition"; this term must be rejected when used - apparently - to the disadvantage of the diet. Whether a form of nutrition is natural or not has nothing to do with the question of whether or not it is of therapeutic value in diseases. This is the only decisive question in practice.
Nevertheless, for the sake of completeness, a few brief remarks regarding the desire for salt in animals are in order.
In areas of great expanse, such as in Central India and in the Dekkan, there is an enormous wealth of game and no availability of salt. Presumably, the same situation exists elsewhere. It is of special importance to note that apes in particular show no need for salt; mixed human nutrition is offered to them only in captivity, when they accept it as readily as they learn to drink alcohol, smoke tobacco and eat roast meat.
According to Dr. Gustav Riedlin, thorough experiments in the use of salt were conducted by Hahnemann, the founder of homeopathy, and his students. In these experiments, Hahnemann and his students consumed considerably greater quantities of salt for weeks and months than they were normally accustomed to consume in food. The harmful effects are described in the book (pp. 9-15).148
Arguments against a "saltless" diet ("saltless" means without addition of salt to food) were enumerated by Wolff-Eisner149 approximately as follows:
In a nutrition rich in vegetables, the body requires the addition of salt, as this does not occur in sufficient quantities in the food "as the only salt". As the potassium carbonate of vegetables combines in the organism with chloride and sodium to form sodium chloride and sodium carbonate, it causes the elimination of chloride and sodium. This means that sodium as well as chloride must be given to the body to make up this loss - hence the addition of salt!
In this work, Wolff-Eisner quotes the well-known experiments of Bunge, who asserted that regular partaking of potatoes, which contain 31-42 times more potassium than sodium, is possible only if NaCl is added to this food.
In the same work, strangely enough, it is mentioned that a) apples contain even 100 times more potassium than sodium, yet one may consume large quantities of apples - one may even have exclusive apple days - without the addition of NaCl. b) According to general opinion, the hydrochloric acid of the stomach is dependent on the body's salt intake. Therefore, if the intake of salt is missing, the formation of hydrochloric acid must decrease, which would affect appetite, digestion, etc. for "lack of salt inhibits production of hydrochloric acid". c) Finally, Wolff-Eisner remarks that the sweat of tubercular patients contains up to one per cent salt, so that perspiration deprives the body of salt.150 d) Furthermore, it is said that the kidneys regulate the body's ionic state; in fever and in the majority of infectious diseases, the salt content of the urine is diminished, even if the patients are given salt. (Consequently, it is argued, there is no need to regulate the intake of salt, if the kidneys are healthy, as the kidneys regulate the elimination of salt anyway. Since, according to Roth-Koevesti, even diseased kidneys are capable of eliminating five grams of salt in a liter of urine, the intake of five grams of salt is unobjectionable for such kidneys.)
Inasmuch as some of these arguments are also voiced by our patients, who see particular nutritive value in salt and appreciate the stimulative effect of salt upon appetite and thirst, physicians are sometimes forced to take them into consideration.
As far as Wolff-Eisner's first argument is concerned, it must only be said that that which appears objectionable to him is particularly desired by me, i.e., the increased elimination of NaCl. For if, Wolff-Eisner's presentation, which is based on Bunge's view, is correct, i.e., if the elimination of NaCl from the body's salt resources is furthered by vegetarian nutrition, it is precisely that which my diet wants to achieve. The more salt is eliminated by it, the more effective the diet is in some respects. It appears to us that it would be equally inexpedient to replace the decreased sodium and chloride, which we desire, by the feeding of salt, as it would be inexpedient to make up increased elimination of sugar in the urine of diabetics by increasing sugar intake.
"No human dietaries, howsoever prescribed, even without added salt, are so low in sodium that they cannot support life."151
The argument for the necessity of the addition of salt to potatoes was mentioned above, as well as the fact that apples - containing 100 times more potassium than sodium - are not salted, except by special gourmets. (This shows the importance of the role of habit and taste. Peasants would laugh at people who add salt to apples, yet they add salt to potatoes themselves.)
It is known that there is a connection between the hydrochloric acid of the stomach and the intake of salt. However, the dependence of this hydrochloric acid upon salt intake has not been proven, and is contrary to my experience.152 According to Rosemann, the stomach juices of normal humans contain 400-500 mg. of hydrochloric acid. Its pH lies between 0.97 and 0.80. If we consider the regulation for the production of stomach juice, it shows how the entire organism, especially the liver, participates in its formation, just as it participates in all other bodily occurrences, irrespective of the organ in which the particular process takes place.
"I have to point out a happening in the modern civilization of the Hospital153, something which happened this year."
"We had to perform the first appendicitis operation on a native of this region. How it turned out that this so frequent sickness of white people did not occur in the colored of this country cannot be convincingly explained. Probably its still exceptional occurrence is traceable to a change in the nutrition. Many natives, especially those who are living in larger communities do not now live the same way as formerly - they lived almost exclusively on fruits and vegetables, bananas, cassava, ignam, taro, sweet potatoes and other fruits. They now begin to live on condensed milk, canned butter, meat-and-fish preserves and bread."
"The date of the appearance of cancer, another disease of civilization, cannot be traced in our region with the same certainty as that of appendicitis. We cannot state decisively that formerly there was no cancer at all, because the microscopic examinations of all tested tumors, revealing their real nature, has only been in existence here for a few years. Based upon my own experience, going back to 1913, I can say, if cancer occurred at all it was very rare but that it became more frequent since. However, it is not spread as much as it is among the white race of Europe and America."
"It is obvious to connect the fact of increase of cancer with the increased use of salt by the natives. In former years there was only available the little salt extracted from the ocean, which came up to the hinterland. There was a very limited traffic only. The salt had to be transferred by dealers of the tribe living at the coast to those tribes living next to them up-stream. In this way it reached one tribe after another and moved further and further to the interior, where the dealers handed over only the portion which was left over from distribution among their own tribe and the chiefs charged heavy customs for the passage through their region. With this procedure it scarcely could get farther than 120 miles inland. According to information of old people here, whom I still knew at the beginning of my activity, formerly there was no salt whatsoever in the interior."
"This changed in 1874 when the whites came to this land and handled the traffic up-stream. The European salt was shipped in small sacks of a few pounds. Still at the time of my arrival in Lambarene, salt was so precious that it prevailed as the most valuable and the most generous type of remuneration. Who ever had to make a trip on the river or travel along the paths of the virgin woods did not take along money but salt (also tobacco leaves imported from America), thus trading bananas and cassavas for his oarsmen and carriers. By and by the consumption of salt increased. Today it is used much less among the colored than among the whites. The patients we feed in our hospital receive a few grams a month and are satisfied with this small amount."
"So it is possible that the formerly very seldom and still infrequent occurrence of cancer in this country is connected with the former very little consumption of salt and the still rare use of it. Curiously enough we did not have any cancer cases in our hospital."
"It should be mentioned that the infectious diseases among the whites gradually appeared. It remains questionable if tuberculosis was spread formerly as much as now, even if it occurred at all times. According to my observations it became more frequent after the First World War."
The experiments of Kremer154 have also shown conclusively that the value of stomach acids in patients on the diet remained normal for several months, although salt intake was limited to salt contained in natural food. The appetite of patients does not suffer by lack of salt; as a rule it even improves, particularly in serious diseases, after the start of the treatment.
The elimination of a little salt in the sweat of some patients is of no importance whatever in therapy, for the therapy brings about a fast decrease and early complete cessation of perspiration. Straus correctly attributes this, as well as the decreased mucus secretion, to the water-withdrawing effect of the saltless diet. He concludes from this that the deprivation of salt also has favorable therapeutic effects upon such diseases (such as Bronchogenic, vaginal discharge and pus secretions, etc.).
The last argument, that healthy kidneys regulate the ionic state of the organism anyway, and that it is therefore unnecessary to limit salt intake, is phrased much too generally and does not take into account important factors apart from kidney function, which affect the elimination of NaCl (hormones, tonus in the visceral nervous system, circulatory regulations).
The fact that diseased kidneys are still capable of eliminating five grams of NaCl per liter of urine has no particular meaning for our problem regarding the quantity of salt intake. Nevertheless, the chloride ion deserves a special position among the substances to be concentrated by the kidneys. While the kidneys are capable of increasing concentration of uric substance 40-80 times, uric acid 25-50 times, sugar (in diabetes) 30-50 times over their concentrations in the plasma, chloride concentration can be increased only two to five times.155 For the past 40 years, practical experience was gathered about the effects of salt limitation upon diseases of kidneys. It was shown just here that radical limitation of salt intake, in the sense of Straus' "strict form" (with less than 2.5 g of NaCl per day) or the "third degree" of Noorden (with 1.5-3 g of NaCl per day) which corresponds to the usual saltless nutrition, decreases the burden on the diseased kidneys. "As soon as the diseased kidneys are not over-irritated and over burdened by the excessive intake of chlorides in nutrition, they recover in an amazingly short time and ... eliminate more NaCl on a saltless diet than on the previously salt-rich diet!"156
Noorden also pointed out that such saltless nutrition cannot cure kidney disease; the removal of a constant irritation can only improve healing conditions. Something similar applies to the effect of our diet. The elimination of salt does not serve to cure various diseases, but it is an important supporting factor of the diet. A damaging irritation is removed by the elimination of salt. Furthermore, if the elimination of salt by normally functioning kidneys is limited by fever, as Wolff-Eisner points out, and remains limited in spite of further salt intake, this should not lead to the conclusion that the body regulates salt distribution so well that physicians should leave this function to the body. This only shows that the organism cannot digest the given quantities of salt in fever states. Therefore, a temporary radical limitation of salt nutrition (fasting, refusal of nutrition) is also correct in acute diseases (infectious diseases). And, if diseased kidneys can eliminate five grams of salt, this does not mean that five grams of salt should be given. On the contrary, it would appear to be more obvious to conclude that, by sparing the kidneys and other organs, one should try to achieve in all diseases similar results as in kidney-therapy and, lately, also in heart diseases, cancer, etc.
Claude Bernard was probably one of the first to investigate the question of origin of hydrochloric acid in stomach juice. He injected potassium ferrocyanide and lactate of iron into the veins. The substances gave a Prussian blue reaction in the presence of free acid. The mucosa of the stomach turned blue after the injection but not the parietal cells of the fundic glands.
The ultimate source of the chloride is undoubtedly the sodium chloride of the blood. Chlorides are ionized Cl in the parietal cells, secreted into the stomach's free space; there they combine with free H ions and built free HCl which is not secreted as such. The venous blood leaving the gastric mucosa shows a fall in chloride and a rise in bicarbonate of Na.
In conclusion, it should be stressed that the entire mineral metabolism of the animal organism has not been sufficiently explored so far. Therefore, we cannot as yet make any definite statements about the roles of chloride and sodium-both individually - as well as in their combination in NaCl and in other combinations. We must be content by establishing certain relationships and conditions in a healthy or a sick body.