The Husband-and-Wife Alkali Theory: Sodium and Potassium in Food

Table of Contents

1. The Theory in Brief
2. The Papers of 1894–1895
3. Potassium the Husband, Sodium the Wife
4. Weighing Foods by Their Ash
5. Is There One Right Ratio?
6. When One Salt Overpowers the Other
7. Wisdom and Talent: Salts and Temperament
8. White Rice, Barley Rice and the Army
9. How He Told People to Eat
10. From Husband and Wife to Yin and Yang
11. Later Research on the Sodium–Potassium Ratio
12. Key Research Papers
13. Connections
14. Featured Videos

1. The Theory in Brief

Ishizuka taught that the most important difference between foods is not their protein, fat or starch, the quantities that the nutrition science of his day measured, but the balance of two mineral salts in them: the salts of sodium, which he called by the old chemical name “natron salts” (那篤倫鹽), and the salts of potassium, “kali salts” (加里鹽). The historian Namimatsu Nobuhisa sums up the core of his teaching this way: the yin and yang of a meal are decided by the amounts of natron salt and kali salt in it, and this is the heart of Ishizuka’s theory.

In outline, as the Japanese sources report it from his books:

• Sodium and potassium salts are alike yet opposite, and they are complementary rather than hostile, like husband and wife.
• Foods rich in sodium correspond to what kanpō (漢方, traditional Japanese-Chinese medicine) called 陽 (yō, yang); foods rich in potassium correspond to 陰 (in, yin).
• Sodium-rich foods are salt itself and animal foods: meat, eggs and fish. Potassium-rich foods are plant foods: vegetables and fruit, with grains as man’s staple.
• Potassium softens and expands; sodium hardens and contracts. Potassium belongs to the “static” (静性) side and sodium to the “dynamic” (動性) side.
• When the balance tips too far either way, illness follows. A diet of polished white rice, a staple poor in potassium, eaten with salty, sodium-heavy side dishes, upsets the balance and makes people ill.

The theory is the fifth of the five doctrines into which Namimatsu sorts Ishizuka’s food cure, the one he labels 陰陽和合論, “the harmony of yin and yang”. The other four are described on Shokuyō: Sagen Ishizuka’s Food Cure.

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2. The Papers of 1894–1895

Ishizuka published the theory as a series of numbered chapters in 藥學雜誌 (Yakugaku Zasshi), the journal of the Pharmaceutical Society of Japan. Each is signed 「在大阪 石塚左玄述」, “stated by Ishizuka Sagen, in Osaka”. The journal printed a German or English subtitle under several of them.

• June 1894: 人類ハ穀食動物ナリ, “Humankind Is a Grain-Eating Animal”, the argument from human teeth that grain should be the staple (see Humans as Grain Eaters).
• 1894, in two parts: 飲食品化學的鹽類論, “A Chemical Theory of the Salts in Food and Drink”. Its subtitle states its thesis: 脚氣ノ那篤倫過剩加里減之説, “the theory that beriberi is an excess of natron and a shortage of kali”. It contains his table of foods and his calculation for the army’s barley rice (sections 4 and 8).
• 1895: 食物中ノ加里鹽ハ酸素吸収ノ媒介者ナリ, “Potassium Salt in Food Is the Mediator of Oxygen Absorption”. It opens by restating that humans, judged by their teeth, are by nature grain eaters, and that the nitrogen, carbon and potassium which come from grain are all three indispensable to health.
• 1895, “Chapter 3”: 食物中夫婦亞兒加里ノ性質論, “On the Properties of the Husband-and-Wife Alkalis in Food”, printed with the English subtitle “the properties of connubial alcali (Ehe-alkali) in the feeding matter”. This is the paper that names the theory (section 3).
• 1895, “Chapter 4”: 入浴ハ亦人體ノ脱鹽法ナリ, “Bathing, Too, Is a Way of Desalting the Human Body” (section 9).

The journal’s editor added a note to the 1895 “Chapter 3” that it continues the grain-eating paper and the potassium-and-oxygen paper. Ishizuka himself presented the series as one argument: grain is man’s food, grain is rich in potassium, and potassium has to be married to the right amount of sodium.

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3. Potassium the Husband, Sodium the Wife

The 1895 “Chapter 3” paper opens with an image. Telling sodium salts from potassium salts without a chemical test, Ishizuka wrote, is as hard as telling a baby boy from a baby girl at a glance; yet as they grow up, each shows a character of its own. In food, he went on, potassium and sodium 「夫婦亞兒加里ト稱スヘキ性情ヲ具フルモノニシテ恰モ一家ノ夫婦ノ如ク」, “have natures that deserve the name husband-and-wife alkalis, just like the husband and wife of one household”. In his scheme potassium is the husband and the “male alkali” (男性亞兒加里), and sodium the wife and the “female alkali” (女性亞兒加里).

He described the two partners by what their salts do in the laboratory:

• The husband, potassium, by nature draws water and oxygen out of the air. Potassium acetate, carbonate and tartrate and potash soap all take up moisture and dissolve in it. Likewise, he wrote, plant foods from the land that are rich in potassium salts, and sea-plant foods with them, swell, soften and fall apart when boiled in water. Eaten without added sodium salt, they are digested and absorbed quickly, the body’s tissues take up water and oxygen most easily, and its functions run high.
• The wife, sodium, by nature drives water out. Sodium sulfate, carbonate and phosphate and soda soap lose their water and crumble in the air. Sea-animal foods rich in sodium salts, and land-animal foods with them, shrink and firm up when boiled, as do meat, chicken, eggs and tofu when salted or cooked, “just as the muscle fibres of our own bodies do”. Eaten in quantity without potassium-rich side foods, he wrote, they leave the organs dried out, the functions dulled, digestion slow and absorption sluggish, until the body loses “the normal measure of its vital force”.

The marriage is the point. If the male alkali is joined to the female alkali in proper measure, he wrote, the husband’s power to draw in water and to break things down is tempered by the wife’s power to drive water out and to draw things together. With the two in balance alongside the other nutrients, the body accords with the wondrous order of nature and grows tall, strong and long-lived, which he called 夫婦亞兒加里營養, “husband-and-wife alkali nutrition”. If either partner overpowers the other, he concluded, “the way of nourishing life misses the middle path, and it becomes hard to keep strength and long life”.

He supported the idea with older authorities: the pharmacology text of the German physician Nothnagel, on the effect of table salt on digestion, and an experiment on dogs by Kemmerich in which potassium salts were essential but muscle developed fully only when a little table salt was added as well. Plant food in particular, Ishizuka wrote, must have salt mixed into it in proportion, so that the balance is kept.

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4. Weighing Foods by Their Ash

To put numbers on the theory, the 1894 paper on the salts in food and drink includes a table titled 飲食品中鹽類比例表, “Table of the Proportions of Salts in Foods and Drinks”. Ishizuka took published analyses of the ash (the mineral residue left after burning) of common foods, from the German agricultural chemist Wolff, from a Japanese agricultural school and from other analysts, and, following Wolff’s method, set the sodium in each food’s ash at 1 and listed the potassium beside it. A selection of his figures, as printed (parts of potassium for every one part of sodium):

Beside many rows he set the folk sayings and old medical lore attached to that food, and he drew the moral from the whole table: the amount of potassium for each part of sodium differs enormously from food to food, and the sayings that hundreds of years and millions of people had handed down about which foods restore strength and vigour turned out, read in this light, to be about foods rich in potassium. Without knowing it, he wrote, people had chosen foods for their potassium. He quoted the popular saying that salty food is poison and that a taste for strong salt is bad for the body. He also noted that polished rice stood far below barley, a point he developed for the army ration (section 8).

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5. Is There One Right Ratio?

Readers of later macrobiotic books often meet a single “ideal” potassium-to-sodium figure. No such fixed number was found in the 1894–95 papers read for this page, nor in the Japanese historians of his work, so none is given here. What Ishizuka wrote is subtler.

In the 1895 paper he said that the body’s need for table salt depends on the difference between potassium and sodium in the ash of the foods eaten. Potassium-rich plant foods, “such as grains”, call for comparatively much salt; potassium-poor animal foods, “such as beef”, call for little; and this, he wrote, “seems to be nature’s own rule”. The reverse holds too: a person who eats much sea fish craves vegetables, and a person who eats many vegetables relishes salty dried fish and pickled meats as delicacies. All of this, he argued, is the body seeking 「加里那篤倫ノ一定比例タル權衡」, “the balance that is a fixed proportion of potassium and sodium”, needed to nourish human life. He spoke of a fixed proportion but did not put a figure on it.

He also made the right amount depend on the person. A labourer who sweats loses sodium and so likes salty food; a sedentary person who takes little exercise prefers lightly salted dishes; and these, he wrote, are “all nature’s own measures, which each person should regulate for himself”. Namimatsu summarises the doctrine as he found it in the books: the proportion to be eaten is not fixed, but varies with a person’s station, race, age and occupation, and with climate and season, and there is a way of cooking to suit each.

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6. When One Salt Overpowers the Other

Ishizuka traced a wide range of illness to imbalance. In the English-language history of macrobiotics by Ronald Kotzsch (1985), as quoted second-hand, he is summarised as maintaining “that human health and longevity are dependent on a proper balance in the body between the salts of sodium and potassium… it is what a person ingests through the mouth that is the main determinant of the Na/K ratio in the body… all sickness begins with an imbalance of Na/K caused by poor diet.”

In his own papers, the conditions he attributed to too much sodium include:

• Beriberi (脚気 kakke). The 1894 paper’s subtitle names beriberi as sodium excess with potassium shortage, and his 1896 book repeats that “beriberi, too, comes from an excess of sodium salt and a decrease of potassium salt”.
• Dropsy and swelling. He cited the Edo-period physician Yamawaki Tōmon, who wrote that eating much salt brings on dropsy (水腫) and that giving up salt relieves it, and the constipation of meat-eating peoples.
• Hardening and stagnation. He quoted the old Chinese medical classics: “eat much salt, and the pulse congeals and the colour changes”, a sign, he said, of the binding nature of the female alkali.
• Sores and boils among people who live on salted fish, citing an Edo encyclopedia’s note on dried salmon eaten through the snowbound winter and the classic’s description of seaside fish-and-salt eaters.
• Heat and inflammation. Foods with excess salt, like meat foods, he wrote, tend toward an inflammatory state and raise the body’s heat.

Potassium had its excess too. Unchecked by its wife, the husband’s power to draw in water and to dissolve would “run riot”, and Ishizuka was explicit that a loss of balance in either direction makes strength and long life hard to keep. He also granted sodium a use of its own: salt warms. He noted that poor people in the cold season favour salty food, that men who work in cold water drink soy sauce before going in, and that strongly salted food in quantity helps the poor through the winter, though, he added, out of balance with potassium its harm is “beyond words”.

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7. Wisdom and Talent: Salts and Temperament

Ishizuka carried the theory from the body to the mind. In his 1898 book Tsūzoku Shokumotsu Yōjōhō, as cited by Japanese Wikipedia and Namimatsu, he set two kinds of human ability against the two salts:

• 智 (chi), wisdom or knowledge, together with thoughtfulness, patience and perseverance, grows on food rich in potassium and low in sodium, the salt that softens the body.
• 才 (sai), quick talent or ability, together with physical strength, grows on food rich in sodium, the salt that hardens the body.

The two are front and back of one coin, but he insisted on their order: 「智は本にして才は末なり」, “wisdom is the root and talent the branch”. So children should be raised on potassium-rich food, to build wisdom and body, and food calling for moral judgement and reflection should lean the same way; as young people approach adult working life their diet can move gradually toward more sodium, to build talent and strength. But too much sodium, he warned, shortens not only life but body and wisdom too. Keep to the middle way (中庸 chūyō).

He drew a lesson for his own country. By the climate of Japan, Namimatsu reports him arguing, the Japanese should eat brown rice; instead they ate white rice and, following the West, more meat, so that only talent was developed. Quick decisions were prized over the slower work of wisdom, and he called for right food education to restore the balance. This is the thought behind his word 食育 (shokuiku), told on Shokuiku: How Sagen Ishizuka Coined “Food Education”.

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8. White Rice, Barley Rice and the Army

The theory was born in the army’s fight with beriberi. Namimatsu records that Osaka army units had used rice mixed with barley since 1884 with good results, though no one could say why, and that in 1894 Ishizuka argued that the benefit of barley rice could be explained by the ratio of sodium salts to potassium salts. The navy, under Takaki Kanehiro, had by then cut its own beriberi by changing the sailors’ diet, on a theory of the ratio of nitrogen to carbon; Namimatsu notes the parallel between the two chemical explanations.

In the 1894 paper Ishizuka worked the numbers. Using an army analysis of rice and barley, he gave the ash of white rice as 1.01% with 0.1185% potassium, and the ash of barley as 2.69% with 0.5650% potassium, so that barley carried “almost 4.7 times” the potassium of white rice. A soldier’s daily ration of six gō of rice, which he reckoned at 852 grams, therefore supplied 1.010 grams of potassium. Change it to barley rice in the proportion of seven parts rice to three parts barley (596 grams of rice and 216 grams of barley), and the potassium rose to 1.937 grams a day. The barley-rice eater, he concluded, took in 0.927 grams more potassium every day than the man on white rice.

Polished rice, with its outer layers milled away, was for him the problem in Japan’s staple. The 1898 book, as Japanese Wikipedia cites it, says that the potassium-poor staple of polished rice, eaten with sodium-heavy side dishes, upsets the balance and causes illness, and the enlarged edition of 1909 calls white rice 「粕」, “dregs”, and recommends brown rice (玄米 genmai) as the staple. Brown rice, in the later Shokuyō-kai teaching, sat close to the balance point between the two salts.

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9. How He Told People to Eat

From the theory came practical rules, which he gave in his papers and books and in the dietary instructions he wrote for each patient at his Tokyo clinic:

• Make whole grain the staple. Brown rice if possible; failing that, in Namimatsu’s summary, seven parts rice to three parts side dishes. Barley mixed into rice raises its potassium.
• Marry the two salts in the pot. Ishizuka pointed to the traditional pairings of Japanese cooking, taro with octopus, taro with dried cod, beans with kombu, as the husband-and-wife principle at work. Hard, sodium-rich foods such as dried cod and kombu soften slowly even with long cooking; soft, potassium-rich foods such as taro, chestnuts and beans soften fast; cooked together, he wrote, they soften fastest of all. Whether a food is digestible, he concluded, depends on whether its potassium and sodium are rightly matched, not on its anatomy or fibre.
• Salt plant food in proportion. Potassium-rich grains and vegetables need salt; potassium-poor meat needs little.
• Adjust to the person and the place. More salt for those who sweat at hard work; less for the sedentary; more potassium for children. People of the coast and of the mountains, he observed, differ in their taste for salt, and each should keep to the food of the land they live in.
• Bathe to shed excess salt. In “Chapter 4” of 1895 he wrote that public baths are more necessary for a nation with much sea and little land than for one with much land and little sea, for coastal people than for those far from the sea, and for city people than for mountain people, “and above all in our country”. Their purpose is not only cleanliness but to improve circulation, loosen the pores, bring on sweating and so remove the sodium salt that lingers in the body.

Not everyone was to give up animal food. Japanese Wikipedia’s article on the Shokuyō-kai, citing the modern translation of the 1898 book, notes that he accepted that Zen monks and Western vegetarians could stay healthy without it, but in general advised a grain-centred diet kept in balance.

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10. From Husband and Wife to Yin and Yang

Ishizuka himself linked his chemistry to the old medicine: sodium-rich foods matched what kanpō called yang, and potassium-rich foods matched yin. But, Namimatsu observes, he explained the balance of the two salts with everyday examples and scientific-sounding argument rather than with the philosophy of the I Ching (易 eki), and he showed no interest in the traditional concept of 氣 (ki, vital energy).

The step into philosophy was taken by his disciple Sakurazawa Yukikazu (桜沢如一), known in the West as George Ohsawa, who had recovered from tuberculosis as a student on Ishizuka’s food cure. Namimatsu writes that Sakurazawa took over the husband-and-wife alkali theory and, to make the food cure general, recast it through the I Ching’s philosophy of yin and yang as two poles that unify the world, developing it into a cosmological principle that could be applied to everything. Sodium and potassium became the chemical face of yang and yin, and the balance of the two in food became the organising idea of what he called 正食 (seishoku, “right eating”), known abroad as macrobiotics.

Readers should note one detail of the original. In the 1895 paper potassium is the husband, the “male alkali”, and sodium the wife, the “female alkali”, while in the yin-yang language of the 1898 book potassium is yin and sodium yang. Ishizuka’s marriage metaphor and the later yin-yang labels do not line up in the way a reader might expect, and the two should not be merged. Kotzsch’s history of macrobiotics places the sodium–potassium balance at the root of the movement in its chapter titled “Sagen Ishizuka: the Founder of Modern Macrobiotics”. The story of the disciples is told on From Shokuyō to Macrobiotics: Ishizuka’s Disciples and Legacy.

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11. Later Research on the Sodium–Potassium Ratio

More than a century after Ishizuka’s papers, the balance of sodium and potassium in the diet became a subject of epidemiology in its own right. Researchers now commonly measure it as the sodium-to-potassium (Na/K) ratio, from food records or from urine. The studies below are later research on the same subject; they do not set out to test Ishizuka’s theory.

• Japan, 1977–1981. Ikeda and colleagues collected 24-hour duplicate diets from 49 regions of Japan and found that regional sodium intake correlated with death rates from cerebrovascular disease; the Na/K ratio correlated with those death rates in men but not in women.
• NIPPON DATA80. In a representative sample of 8,283 Japanese adults followed for 24 years from 1980, Okayama and colleagues found the dietary Na/K ratio, measured by three-day weighed food records, to be a significant risk factor for death from stroke, cardiovascular disease and all causes. A 2023 review of the NIPPON DATA80/90 cohorts by Kondo and colleagues covers the same cohorts’ dietary findings.
• Japan’s National Health and Nutrition Survey, 2003–2017. Among 48,800 adults, Okada and colleagues found a higher dietary Na:K ratio associated with more hypertension, and reported that the average ratio fell over the period.
• A Japanese health checkup. In Tome City, Miyagi, Kogure and colleagues measured urinary Na/K with a spot-urine device in 12,890 people and found that changes in the ratio between 2017 and 2018 went together with changes in blood pressure.
• United States. In the Trials of Hypertension Prevention follow-up, Cook and colleagues found that the ratio of sodium to potassium in repeated 24-hour urine collections was associated with later cardiovascular disease more strongly than sodium or potassium alone.
• International cohorts. O’Donnell and colleagues, in patients with cardiovascular disease or diabetes, reported a J-shaped relation between estimated sodium excretion and cardiovascular events, and a lower risk of stroke with higher potassium excretion.

For what is known today about each mineral, see the site’s pages on Sodium and Potassium. A different physician of the next generation, Max Gerson, also built a diet around sodium and potassium; see Max Gerson’s saltless diet.

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Key Research Papers

1. Ishizuka S. 人類ハ穀食動物ナリ [Humankind is a grain-eating animal]. Yakugaku Zasshi. 1894;(148):532-8. — DOI: 10.1248/yakushi1881.1894.148_532
2. Ishizuka S. 飲食品化學的鹽類論 [A chemical theory of the salts in food and drink]. Yakugaku Zasshi. 1894;(149):650-67. — DOI: 10.1248/yakushi1881.1894.149_650
3. Ishizuka S. 飲食品化學的鹽類論（續キ） [A chemical theory of the salts in food and drink, continued]. Yakugaku Zasshi. 1894;(151):886-901. — DOI: 10.1248/yakushi1881.1894.151_886
4. Ishizuka S. 食物中ノ加里鹽ハ酸素吸収ノ媒介者ナリ [Potassium salt in food is the mediator of oxygen absorption]. Yakugaku Zasshi. 1895;(153):1066-73. — DOI: 10.1248/yakushi1881.1895.153_1066
5. Ishizuka S. 第三章 食物中夫婦亞兒加里ノ性質論 [On the properties of the husband-and-wife alkalis in food]. Yakugaku Zasshi. 1895;(155):48-58. — DOI: 10.1248/yakushi1881.1895.155_48
6. Ishizuka S. 第四章 入浴ハ亦人體ノ脱鹽法ナリ [Bathing, too, is a way of desalting the human body]. Yakugaku Zasshi. 1895;(156):150-9. — DOI: 10.1248/yakushi1881.1895.156_150
7. Ikeda M, Kasahara M, Koizumi A, Watanabe T. Correlation of cerebrovascular disease standardized mortality ratios with dietary sodium and the sodium/potassium ratio among the Japanese population. Prev Med. 1986;15:46-59. — PubMed PMID: 3714659
8. Okayama A, Okuda N, Miura K, Okamura T, Hayakawa T, Akasaka H, et al. Dietary sodium-to-potassium ratio as a risk factor for stroke, cardiovascular disease and all-cause mortality in Japan: the NIPPON DATA80 cohort study. BMJ Open. 2016;6:e011632. — PubMed PMID: 27412107
9. Kondo K, Miura K, Okamura T, Okayama A, Ueshima H. Dietary factors, dietary patterns, and cardiovascular disease risk in representative Japanese cohorts: NIPPON DATA80/90. J Atheroscler Thromb. 2023;30:207-19. — PubMed PMID: 36436878
10. Okada E, Okada C, Matsumoto M, Fujiwara A, Takimoto H. Dietary sodium:potassium ratio and CVD risk factors among Japanese adults: a retrospective cross-sectional study of pooled data from the National Health and Nutrition Survey, 2003-2017. Br J Nutr. 2021;125:79-91. — PubMed PMID: 32674745
11. Kogure M, Nakaya N, Hirata T, Tsuchiya N, Nakamura T, Narita A, et al. Sodium/potassium ratio change was associated with blood pressure change: possibility of population approach for sodium/potassium ratio reduction in health checkup. Hypertens Res. 2021;44:225-31. — PubMed PMID: 32801312
12. Cook NR, Obarzanek E, Cutler JA, Buring JE, Rexrode KM, Kumanyika SK, et al. Joint effects of sodium and potassium intake on subsequent cardiovascular disease: the Trials of Hypertension Prevention follow-up study. Arch Intern Med. 2009;169:32-40. — PubMed PMID: 19139321
13. O’Donnell MJ, Yusuf S, Mente A, Gao P, Mann JF, Teo K, et al. Urinary sodium and potassium excretion and risk of cardiovascular events. JAMA. 2011;306:2229-38. — PubMed PMID: 22110105
14. Sugiyama Y, Seita A. Kanehiro Takaki and the control of beriberi in the Japanese Navy. J R Soc Med. 2013;106:332-4. — PubMed PMID: 23897451

PubMed Topic Searches

1. https://pubmed.ncbi.nlm.nih.gov/?term=sodium+potassium+ratio+Japan
2. https://pubmed.ncbi.nlm.nih.gov/?term=macrobiotic+diet
3. https://pubmed.ncbi.nlm.nih.gov/?term=beriberi+Japan+history

Further Reading

• 並松信久. 近代日本における食養論の展開 [The development of food-cure theory in modern Japan]. Bulletin of the Institute of Japanese Culture, Kyoto Sangyo University. 2015;20. — Handle: 10965/1239
• 藤井義博. 石塚左玄の食育食養法：栄養療法の知的枠組についての研究11 [Ishizuka Sagen’s food-education and food-cure method]. Bulletin of the Faculty of Human Life Sciences, Fuji Women’s University. 2014;51:25-38. — Repository record
• Kotzsch RE. Macrobiotics: Yesterday and Today. Japan Publications; 1985. Chapter 2, “Sagen Ishizuka: the Founder of Modern Macrobiotics”, p. 29 (quoted second-hand in section 6).
• Japanese Wikipedia, 石塚左玄, which cites the pages of his 1896 and 1898 books on the National Diet Library Digital Collection.

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Connections

• Sagen Ishizuka: Founder of Shokuyō
• Sagen Ishizuka: Life and Career
• Shokuyō: Ishizuka’s Food Cure
• Grain Eating and Brown Rice
• From Shokuyō to Macrobiotics
• Sodium
• Potassium
• Max Gerson’s Saltless Diet
• Hypertension
• Thiamine and Beriberi
• Brown Rice
• Nutrition and Orthomolecular Medicine

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