The Prevention of Goitre

Radio Record, Volume V, Issue 9, 11 September 1931, Page 7

The Prevention of Goitre

A Talk

by Dr.

Duncan

Cook

Medical Officer of Health for Dunedin

recently Broadcast by 4YA

N recent years much scientific attention has been given to the needs of the body; in consequence the treatment and prevention of disease is now centred on supplying those needs rather than the extensive -use of drugs. » One of the greatest advances of modern medical investigation has been the discovery of the substances which the body requires for its normal operation, and the diseases which result when these substances are lacking. Vitamins, iron, sunlight and iodine are only one aspect.of the problem, for other substances which are needed arise in the body itself and their deficiency results in disease. : It has been found that the thyroid gland produces a secretion which can be formed only when iodine is present in the food.supply. The secretions of the thyroid. profoundly affect a great number of different body processes. Heavy doses of thyroid extract speed up the vital engines to such an extent that unless enormous quantities of food ure provided, there ig a breakdown of the substances of the tissues themselves in an effort to get more fuel to burn; and the animal or man wastes away. . Goitre in New Zealand. . IMPLE goitres-which term is applied to enlargements of the thyroid gland-are extremely common in New Zealand, as all with trained powers of observation can see for themselves by studying the passers-by in the streets. It is not a new problem in New Zealand. . Goitre was known to the Maoris in pre-Huropean days, and in 1875 was very noticeable in the women of the uhoe tribe in the Urewera district. In 1925 300 Maoris of both sexes were examined in this district by Dr. Hercus, and 18 per cent. were found to have well-marked goitre. . The first reference in New Zealand to a goitre problem among the Huropean’ "population was made in Christchurch, in 1888, when the medical superintendent of the mental hospital was impressed by the frequent occurrence of goitre in the Christchurch district. In 1910 Dr. Colquhoun established the fact that goitre was prevalent in many districts of New Zealand. The first statistical figures of value were obtained during.the examination of reeruits in the late war, when over 1,500 men out of 180,000 examined were rejected for active service on account of goitre. In 1920, 1500 school children were examined by Drs. Hercus and Bleanor Baker in Canterbury and Westland. Thirty-two per cent. were found to have markedly enlarged glands, and in a further 29 per cent. the glands were enJarged to a less degree. An investigation ‘of "St. Helens Hospital, Christchurch, over a period of twelve months >

showed that 60 per cent. of the mothers had goitre and that 8 per cent. of the babies were born with goitre. Extensive goitre surveys of school children throughout New Zealand have now been carried out and the goitrous areas have been clearly defined. From these facts it is evident that endemic goitre presents a very real and pressing problem in this country. It is happily true that in the majcrity of

cases the enlargement of the gland gmounts to no more than a disfigurement. In an appreciable number of cases, however, in children, there are nrinor disturbances of health arising from goitre. It is well to remark that endemic goitre is a stepping stone to Cretinism in children. With an enlightened population such as ours. this should never occur, but we must. take our warning seriously and not allow this goitre problem to master us. Causation of Goitre. ESPITE centuries of observation and speculation, there still remains a sharp divjsion of opinion as to the fundamental cause of goitre. The century-old theory of a deficiency of iodine in the food supply of the affected areas receives considerable support, notably from Switzerland, America, Norway and New Zealand. This simple theory was first suggested in 1849, but has languished for

over 70 years owing to the difficulty of estimating the minute quantities of icdine involved. The field evidence in New Zealand early led to a systematic investigation of the iodine deficiency theory. If iodine deficiency is the basie cause of endemic goitre in New Zealand, it should be possible to demonstrate an inverse relationship between the incidence of goitre in different localities

and the amount of iodine in the soil. It should be possible also to demonstrate that a direct connection is maintained between the iodine content of the various soils and the vegetable and animal produce grown upon them. The chemical . investigations were commenced by Mr. Carter, under the direction of Professor Hercus, at the Otago University in 1922, and were at first limited to the iodine content of various soils. The refined methods for iodine estimation designed by FelJenberg in 1923 were not then known. In 1924 Roberts determined the iodine content of a wide range of plant and animal foods from goitrous and nongoitrous districts. Over 500 representative samples of soil were analysed. When these data were correlated with the goitre incidence among school children a very striking inverse relationship appeared. Put in ordinary language, this means that goitre is high

where iodine content of soil is low, and low where soil iodine is high. Iodine in Foodstuffs. ‘THE results may be summarised by stating that marine products are richest in iodine, next in order comes food derived from fresh water (e.g., watercress), and then eggs, wholémeal cereal products, leafy vegetables and milk. . Refined cereals and root yvegetables are low in iodine content. ‘ Summary of Causation. WHEN the important and varied functions of the thyroid land are considered, it is evident that many different demands may induce thyroid enlargement. Lo, Certain enlargements of the -gland occur despite adequate iodine in, the food. It is not, therefore, contended that iodine deficiency is the only cause of goitre in New Zealand, and that other accessory factors cannot produce goitre in isolated cases. , The weight of evidence in this country clearly indicates that the deficiency of iodine in the soil and food supply is the basic cause of the widespread endemic type of goitre occurring in well-marked areas. In 1929 Dr. R. A. Shore, of the Health Department, and R. L. Andrew, of the Dominion Taboratory, published a series of similar investigations in the North Island to those which have been carried out in the South Island. ..One of the main findings is as follows :- Generally speaking, where the iodine content of the soil is high the incidence of goitre is low, and when the former is low the latter is high. Similar mineral deficiency diseases have been demonstrated in New Zealand. On the Moutere hills, where there is a deficiency of phosphorus and lime, stones are common in the kidneys of sheep. Bush sickness of cattle has been found to be due to a deficiency of jron in the soil. Animals in goltrous areas in New Zealand develop a craving for soil containing salt and iodine in high concentration, and instinct guides them to the correct areas for obtaining it. Preventive Measures. yf goitre in New Zealand is due to iodine deficienzy, it should be possible to prevent the disease by supplying the need. The value of iodine in the prevention of goitre has been abundantly proved on a commercial scale in the prevention of goitre in sheep, pigs and trout. It is essential in man that iodine should be supplied in carefully controlled dosage, or better, as a constituent of a natural food. The amount required daily can best be appreciated by considering that 1 ounce of iodide of potassium is sufiicient to supply roughly the whole population of New Zealand for one day. a _ The freedom from goitre of .:the coastal tribes of Maoris in pre

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-- European days was doubtless due to their fondness for marine food, and this is a habit that everyone of us would be advised to cultivate. Fish and oysters are particularly rich in iodine, and one oyster a day would be sufficient to prevent goitre. If we are unable to supply the deficiency from foodstuffs, the restoration ot iodine to the depleted soil-by means ef iodine-rich fertilisers would appear to be the best method of attack. Various experiments have been earried out on this part of the problem, but are not yet completed, but it may be found that iodine is essential to the healthy growth of plants, as it is to animals. If this is the case, maximum yields of crops are not being obtained at the present time.

The final method of prevention to ccusider is the addition of a prescribed quantity of iodine to a suitable article of diet in common use. Common salt to which a trace of iodide of potassium has been added would appear to be the most suitable means of restoring the deficient element. This method is in extensive use in Europe and in America, and to a certain extent in New Zealand. Since 1924, when the: New Zealand branch of the British Medical Association urged the Government to introduce iodised salt into endemic areas, this method has been available in New Zealand. The amount of iodine in the salt is 1 part in 250,000 parts. This is calculated to supplement the intake of the average individual by 38 micro-

grammes, which is about the daily winimum requirement. To accomplish this it is essential that the iodised salt should be used both for cooking and table purposes. In the mental hospital at Christchurch, the result of this method of administering iodine has been remarkable, patients with huge goitres improving both in appearance and in actual health. It is disappointing to find, however, that despite the efforts of the Health Department and the medical profession, the importation of iodised salt is less than one-sixth of the actual domestic requirements of the population. No danger can accrue from the use of iodised salt, and it is hoped by giving the public the reasons for its introduction that its value will be appreciated by all and that ultimately only iodised salt will be used throughout New Zealand. In addition to the use of iodised. salt, the importance of a well-balanced diet must not be forgotten. This should include sea food: fish, oysters, etc., whole milk, milk products, eggs, whole cereals, green leafy vegetables and fruit. It is to be noted that this diet is also the richest in natural vitamins and is to be preferred for that reason also.