Whole Food, Iodine and Goitre: The Natural Science Behind McCarrison's Work

Table of Contents

1. What the Hunza Ate, in McCarrison’s Words
2. Whole Wheat, Milk and Pulses: the Sikh Staples
3. Polished Rice and the Lost Nutrients
4. Thirty-Six Essentials and the Protective Foods
5. Soil, Manure and the Quality of Grain
6. Goitre and Cretinism in the Mountain Valleys
7. Iodine and the ‘Multiple Causes’ of Goitre
8. Cabbage, Water and Other Goitrogens
9. Iodine Today: What Later Research Found
10. Key Research Papers
11. Connections

1. What the Hunza Ate, in McCarrison’s Words

McCarrison was posted to the far north-west frontier of British India in the first years of the twentieth century, first as a regimental medical officer in Chitral and then as Agency Surgeon in Gilgit, where he was the only doctor for the troops and the local people. Hunza, a small mountain state reached from Gilgit, made a deep impression on him. In his 1921 book Studies in Deficiency Disease he described its people in a passage that his colleague and successor W. R. Aykroyd later quoted in full in his 1960 memoir.

McCarrison wrote of “a race, unsurpassed in perfection of physique and in freedom from disease in general, whose sole food consists … of grains, vegetables and fruits, with a certain amount of milk and butter, and goat’s meat only on feast days.” The grains, he recorded, were wheat, barley and maize. Fruit meant above all “an abundant crop of apricots,” which, he wrote, the people dried in the sun and used very largely in their food. In his account, “the span of life is extraordinarily long.”

He also described what his medical work there consisted of. During “some seven years spent in their midst,” he wrote, his practice was chiefly accidents, operations for senile cataract and operations on the eyelids, and “Appendicitis, so common in Europe, was unknown.” These are his own observations, made as a frontier surgeon; the passage reports what he saw rather than measured statistics.

Why the Hunza mattered to his later work

Aykroyd called this acquaintance with the Hunza “the key to much of his later work.” When McCarrison set up his feeding laboratory at Coonoor in the Nilgiri Hills, the diet he chose for his healthy stock animals was modelled on the food of the Sikhs, which Aykroyd described as “resembling that of the Hunzas whom he never forgot.” Aykroyd added a personal detail: “remembering the Hunzas he breakfasted on whole wheat chappatis.”

The foods in the passage are ordinary ones that the site covers elsewhere: wheat, apricots, milk and butter. What McCarrison emphasised was not any single food but the pattern — grain eaten whole, fresh and dried fruit, milk products, and little meat — and the fact that the food was grown and eaten locally, without refining.

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2. Whole Wheat, Milk and Pulses: the Sikh Staples

In the first of his 1936 Cantor Lectures before the Royal Society of Arts, Nutrition and National Health, McCarrison described the diets of several Indian communities and ranked them by how well young rats grew and stayed healthy on each. The diet at the top of his list was that of the Sikhs of the Punjab, and he described its parts in some detail.

• Atta. Whole wheat, freshly ground into flour (atta) and baked into unleavened chapattis. The whole grain — bran and germ included — went into the flour.
• Milk and milk products. Fresh milk, ghee (clarified butter), curds and buttermilk.
• Dhal. Pulses such as lentils and gram, cooked as dhal.
• Vegetables and fruit. Fresh green vegetables, roots and fruit.
• Meat. Eaten sparingly, he said; among the Pathans of the frontier, more freely.

The Coonoor stock diet

For his own stock colony — by his later years about a thousand rats, by his account — McCarrison translated this pattern into a laboratory ration. As he listed it in the Cantor Lectures, the animals received chapattis of whole wheat flour spread with fresh butter, sprouted Bengal gram (a chickpea pulse), raw cabbage and carrots, milk, bread crusts, meat with bone once a week, and water. He reported that in the five years before he left India there was in this stock “no case of illness, no death from natural causes, no maternal mortality, no infantile mortality.” The full story of this colony and the comparison diets is told on the Coonoor Diet Experiments page.

Why these foods, in his view

The nutrition science behind these foods is straightforward. Whole wheat freshly ground keeps the germ and the outer layers of the grain, which carry most of the grain’s B vitamins and minerals. Milk supplies calcium, vitamin A and protein of high biological value. Germinating seeds form vitamin C, which dry seeds lack, so sprouted gram adds a vitamin that dry pulses do not. Raw cabbage and carrots supply vitamin C and carotene. In McCarrison’s own words, the faults he saw in real diets were “usually those of multiple deficiencies combined with carbohydrate excess” — and the Sikh pattern, as he read it, avoided both.

His 1929 paper “White and Brown Bread” and the Cantor Lectures report a direct test of the grain itself: young rats on diets built around white flour had a mortality of 30 per cent, mostly from pneumonia, against 4 per cent on diets built around whole wheat flour.

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3. Polished Rice and the Lost Nutrients

At the bottom of McCarrison’s ranking stood the rice-based diets of the south and east of India. In the Cantor Lectures he described how the rice in the poorest of them was handled: parboiled or not, it was milled or polished, then washed in many changes of water, then boiled. The diet around it held little milk, little protein and few fresh vegetables.

What milling removes

A grain of rice has three main parts: the outer bran layers, the small germ at one end, and the starchy endosperm that makes up most of the grain. The bran and germ hold most of the grain’s thiamine (vitamin B1), much of its other B vitamins, minerals, fat and fibre. Milling to white rice strips them away, leaving mainly starch. Because thiamine and other B vitamins dissolve in water, repeated washing carries off part of what little remains. Brown rice keeps the bran and germ; parboiling, by driving some of the vitamin into the inner grain before milling, keeps more than plain milling does.

McCarrison treated this as a question of multiple losses rather than of a single vitamin. A people eating mostly washed, milled rice, in his analysis, were short not only of thiamine but of protein, minerals, fat-soluble vitamins and the “protective” foods described below.

Rice and beriberi

Beriberi, the thiamine-deficiency disease of nerve and heart, was the reason his laboratory first existed: it opened in 1918 as the “Beriberi Inquiry.” He reported producing “true beriberi” in pigeons fed diets deficient in, but not wholly lacking, vitamin B1. In his 1924 paper “Rice in Relation to Beri-beri in India” he set out his reading of the Indian evidence. The historian David Arnold, writing in 2010, summarises McCarrison’s view as being that beriberi in India predated mechanised rice milling and was largely confined to one coastal region, the Northern Circars — in other words, that the disease was bound up with the whole rice diet and how it was prepared, not with factory milling alone.

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4. Thirty-Six Essentials and the Protective Foods

In the first Cantor Lecture of 1936 McCarrison gave his audience a count of the substances then known to be necessary in food. He listed thirty-six:

• 18 amino acids, the building blocks of protein;
• 11 inorganic elements (minerals);
• glucose;
• linoleic acid, an essential fatty acid;
• vitamins A, B, C, D and E.

The point of the list, for him, was that a diet could fail in many directions at once. A food that supplied calories but lacked a share of the thirty-six — white flour, polished rice, sugar — left the eater to make up the gap from elsewhere. Whole foods carried many of the essentials together. He added a speculation of his own, clearly labelled as such: that there was also “something in the freshness of food” that gave it health-promoting value beyond the known nutrients.

Takatwar khurak: “foods that give strength”

McCarrison noted in the same lecture that the Sikhs had their own name for the foods they prized most: takatwar khurak, “foods that give strength” — milk, milk products and fresh vegetables. “Nowadays,” he told his audience, “we speak of them as ‘the protective foods’.” The term “protective foods” was in wide use by nutrition scientists of the 1920s and 1930s for milk, eggs, leafy vegetables and fruit, which supplied the vitamins and minerals that cereals and fats lacked. McCarrison pointed out that the Sikhs already had their own name for the same group of foods.

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5. Soil, Manure and the Quality of Grain

McCarrison carried his interest in food quality back to the field. In his 1924 paper “The Relation of Manure to the Nutritive and Vitamin Value of Certain Grain,” and again in the Cantor Lectures, he reported feeding experiments in which the same crop was grown in different ways and then tested on animals.

• Farmyard manure versus chemical manure. He reported that grain grown with farmyard manure was of higher nutritive quality, when fed to animals, than the same grain grown with chemical fertiliser.
• Irrigation. He reported that rice grown in standing water was less nutritious than rice grown under rain.
• Garden vegetables. He reported that spinach from a well-tended, manured garden was richer in vitamin C.

He drew a general conclusion from this work: the nutritive value of food began in the soil, so that agriculture and nutrition were one subject. His 1927 memorandum to the Royal Commission on Agriculture in India contained, as Aykroyd quoted it, the words “Malnutrition is the chief among the problems facing those engaged in agricultural research.”

The manure work was revisited in 1999 by W. W. Yellowlees in a paper titled “McCarrison, farmyard manure and the future.” The manure findings are McCarrison’s as he reported them; the later history of how they were received is described on the Legacy page.

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6. Goitre and Cretinism in the Mountain Valleys

Goitre is an enlargement of the thyroid gland, the butterfly-shaped gland at the front of the neck that makes the hormones regulating the body’s metabolism. The thyroid needs iodine to make those hormones; when it is short, the gland enlarges as it works harder to trap what iodine it can. Where deficiency is severe and begins before birth, the child’s developing brain and skeleton are harmed — the condition then called endemic cretinism, marked by intellectual disability, deafness, short stature or stiffness of the limbs.

The Himalayan and Hindu Kush valleys where McCarrison served were among the most heavily affected regions on earth. He began studying goitre and cretinism soon after arriving, and his first major paper, “Observations on Endemic Goitre in the Chitral and Gilgit Valleys,” appeared in 1906. It was followed by “Observations on Endemic Cretinism in the Chitral and Gilgit Valleys” (1908 in the Indian Medical Gazette, 1909 in the Proceedings of the Royal Society of Medicine). Aykroyd’s memoir mentions a village there known as “The Abode of Fools,” a name that reflected how many of its people were affected.

In 1911 McCarrison published “A Résumé of Researches on Endemic Goitre,” and in 1913 he was placed on special duty to investigate goitre and cretinism across India. In 1914 he described what he called “nervous cretinism” in the Proceedings of the Royal Society of Medicine, separating the form dominated by deafness, mutism and spastic stiffness from the form dominated by thyroid failure — a distinction still used today, as “neurological” and “myxoedematous” cretinism. The same year the Academy of Medicine of Paris awarded him its Prix Amussat for the goitre work. He went on combining field surveys with animal experiments until his retirement in 1935.

The site’s Goiter page describes the condition today; the history of iodine itself is on the Iodine History page.

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7. Iodine and the ‘Multiple Causes’ of Goitre

By McCarrison’s time, the link between iodine and the thyroid was established: iodine had been found concentrated in the thyroid gland in the 1890s, and iodine was already being used to treat goitre. McCarrison accepted that iodine deficiency was a cause of goitre. What set his view apart was his refusal to treat it as the only cause. As Aykroyd summarised it, his position was that “The causes of goitre … are multiple and their effects manifold.”

In his reading, iodine shortage set the stage, but other factors decided how much goitre a community actually developed and how severe it was. Among those he studied:

• Food. Diets poor in protective foods, and foods containing substances that interfere with the thyroid.
• Water. Impure drinking water (see below).
• Iodine in soil and water. A 1927 paper in the Indian Journal of Medical Research examined the iodine content of soils and waters in goitrous areas.

He brought the threads together in a 1933 paper, “A Paper on Food and Goitre,” in the British Medical Journal, and again in a late summary, “The Problem of Endemic Goitre” (1937). He also ran laboratory surveys: “A Goitre Survey in Albino Rats” (1930) reported a survey of goitre in laboratory rats. On his view, iodine deficiency was one factor among several, with water and food among the others.

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8. Cabbage, Water and Other Goitrogens

A goitrogen is a substance that makes goitre more likely, usually by blocking the thyroid’s uptake or use of iodine. McCarrison was among the early investigators of goitrogens in food.

Cabbage, soya bean and groundnut

A 1931 paper of his in the Indian Journal of Medical Research dealt with “cabbage goitre” — goitre linked to cabbage in the diet, which other laboratories were describing at around the same time. A 1933 paper in the same journal dealt with the goitrogenic action of soya bean and groundnut (peanut). Later chemistry identified the main substances involved in the cabbage family: glucosinolates, which break down into compounds such as thiocyanate and goitrin that compete with iodine or interfere with thyroid hormone production. These effects matter most when iodine intake is already low; the site’s page on cabbage goitrogens describes the current research.

Impure water and a self-experiment

McCarrison’s best-known goitre experiments concerned water. He linked goitre with impure drinking water, and according to Aykroyd he tested the idea on himself: he drank the “suspended matter” filtered from the water of a goitrous village and found that his own thyroid began to swell. Aykroyd also records related experiments at Kashrote in Gilgit and at Kasauli in the hills of northern India. McCarrison concluded that some agent carried in contaminated water could cause or worsen goitre.

The Sanawar school

One of his studies concerned a single institution: the Lawrence Royal Military School at Sanawar, in the Punjab hills, where goitre had occurred among the pupils. His 1927 report in the British Medical Journal is titled “An Experiment in Goitre Prevention: Being the Further History of Goitre at the Lawrence Royal Military School, Sanawar, Punjab, India.” As its title indicates, it followed the further history of goitre at the school as a prevention experiment.

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9. Iodine Today: What Later Research Found

The decades after McCarrison’s goitre work turned iodine from a remedy into a public-health measure. This section reports that later research neutrally, as context for his work.

The first prevention trials

The first controlled trial of iodine to prevent goitre was run among schoolgirls in Akron, Ohio, between 1916 and 1920 by David Marine and Oliver Kimball; Kimball described the history of goitre prevention in a 1953 review in the Bulletin of the World Health Organization; iodised salt followed in Switzerland and the United States in the 1920s, Michigan beginning in 1924. A 2023 history of iodine prevention by Elizabeth Pearce and Michael Zimmermann places these early trials and the Swiss and American salt programmes at the start of the modern effort.

Iodine-deficiency disorders

Researchers now group the effects of iodine shortage under the term iodine-deficiency disorders: goitre, hypothyroidism, cretinism, and lesser degrees of impaired brain development in children whose mothers were deficient in pregnancy. A 2008 review in the Lancet by Zimmermann, Jooste and Pandav estimated that about two billion people had insufficient iodine intake, described iodine deficiency as the most common cause of preventable mental impairment worldwide, and identified salt iodisation as the main strategy for control. A 2015 review by Zimmermann and Boelaert described severe deficiency as a cause of goitre and hypothyroidism. The site’s Iodine Deficiency page covers these effects.

Gilgit and Hunza after iodised salt

The valleys McCarrison first surveyed were studied again in the second half of the century. A survey titled “Endemic goitre in the Gilgit Agency, West Pakistan” was published in the Philosophical Transactions of the Royal Society in 1972. In 1990 A. G. Stewart reported on goitre in Baltistan, to the east, linking it with iodine-poor water and proposing that the region’s geology added a further factor — a modern echo of McCarrison’s view that goitre has more than one cause. In 1992 Ali and colleagues reported on twelve years of iodised salt supplied to Gilgit and Hunza: visible goitre fell from 61.36 per cent to 4.68 per cent, while urinary iodine tests still placed 70.41 per cent of households in the mild-to-severe deficiency range. That survey also documents, as a matter of record, that Gilgit and Hunza were an endemic-goitre area — consistent with McCarrison’s own surveys of the same valleys more than eighty years before.

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Key Research Papers

1. McCarrison R. Observations on Endemic Goitre in the Chitral and Gilgit Valleys. Med Chir Trans. 1906;89:437-70. PubMed PMID: 20897060
2. McCarrison R. Observations on Endemic Cretinism in the Chitral and Gilgit Valleys. Proc R Soc Med. 1909;2(Med Sect):1-36. PubMed PMID: 19973738
3. McCarrison R. A Résumé of Researches on Endemic Goitre. Ind Med Gaz. 1911;46(7):253-260. PubMed PMID: 29005529
4. McCarrison R. Nervous Cretinism. Proc R Soc Med. 1914;7(Sect Study Dis Child):157-64. PubMed PMID: 19978295
5. McCarrison R. Rice in Relation to Beri-beri in India. Proc R Soc Med. 1924;17(Sect Trop Dis Parasitol):65-82. PubMed PMID: 19984111
6. McCarrison R. The Relation of Manure to the Nutritive and Vitamin Value of Certain Grain. Br Med J. 1924;1(3300):567-9. PubMed PMID: 20771526
7. McCarrison R. An Experiment in Goitre Prevention: Being the Further History of Goitre at the Lawrence Royal Military School, Sanawar, Punjab, India. Br Med J. 1927;1(3445):94-95. DOI: 10.1136/bmj.1.3445.94
8. McCarrison R. White and Brown Bread. Br Med J. 1929;2(3593):913-4. PubMed PMID: 20775068
9. McCarrison R. A Goitre Survey in Albino Rats. Br Med J. 1930;1(3621):989-92. PubMed PMID: 20775488
10. McCarrison R. A Paper on Food and Goitre. Br Med J. 1933;2(3797):671-5. PubMed PMID: 20777816
11. McCarrison R. The Problem of Endemic Goitre. Br Med J. 1937;1(3965):29-31. PubMed PMID: 20780395
12. Aykroyd WR. Major-General Robert McCarrison, Kt, C.I.E., M.A., M.D., D.Sc., LL.D., F.R.C.P. (15 March 1878–18 May 1960). Br J Nutr. 1960;14:413-418. DOI: 10.1079/bjn19600055
13. Kimball OP. History of the prevention of endemic goitre. Bull World Health Organ. 1953;9(2):241-8. PubMed PMID: 13094512
14. Chapman JA, Grant IS, Taylor G, Mahmud K, Mulk SU, Shahid MA. Endemic goitre in the Gilgit Agency, West Pakistan with an appendix on dermatoglyphics and taste-testing. Philos Trans R Soc Lond B Biol Sci. 1972;263(856):459-90. PubMed PMID: 4401218
15. Stewart AG. Drifting continents and endemic goitre in northern Pakistan. BMJ. 1990;300(6738):1507-12. PubMed PMID: 2372605
16. Ali A, Khan MM, Malik ZU, Charania BA, Bhojani FA, Baig SM. Impact of the long term supply of iodized salt to the endemic goitre area. J Pak Med Assoc. 1992;42(6):138-40. PubMed PMID: 1369614
17. Yellowlees WW. McCarrison, farmyard manure and the future. Nutr Health. 1999;13(1):23-9. PubMed PMID: 10376276
18. Zimmermann MB, Jooste PL, Pandav CS. Iodine-deficiency disorders. Lancet. 2008;372(9645):1251-62. PubMed PMID: 18676011
19. Arnold D. British India and the “beriberi problem”, 1798-1942. Med Hist. 2010;54(3):295-314. PubMed PMID: 20592882
20. Zimmermann MB, Boelaert K. Iodine deficiency and thyroid disorders. Lancet Diabetes Endocrinol. 2015;3(4):286-95. PubMed PMID: 25591468
21. Pearce EN, Zimmermann MB. The Prevention of Iodine Deficiency: A History. Thyroid. 2023;33(2):143-149. PubMed PMID: 36795091

PubMed Topic Searches

1. McCarrison R — goitre papers
2. Endemic goitre in Gilgit
3. Iodine-deficiency disorders and salt iodisation
4. Goitrogens, glucosinolates and the thyroid
5. Beriberi history in India

Further Reading

• McCarrison R. Studies in Deficiency Disease. Oxford Medical Publications; 1921.
• McCarrison R. Nutrition and National Health: the Cantor Lectures. Royal Society of Arts, 1936; republished by Faber & Faber, 1953. Full text (journeytoforever.org)
• Sinclair HM, editor. The Work of Sir Robert McCarrison. Faber & Faber; 1953.
• Wellcome Collection archive GC/205: papers of Sir Robert McCarrison, including posters of his nutrition observations and experiments, 1913–c.1947.

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Connections

• Sir Robert McCarrison: Hunza, Coonoor and the Science of Whole Food
• Robert McCarrison: Life and Career
• The Coonoor Diet Experiments
• McCarrison’s Legacy
• Nutrition and Orthomolecular Doctors
• Weston Price
• Iodine
• Iodine History
• Goiter
• Cabbage Goitrogens
• Wheat
• Brown Rice