SOYBEAN-PROTEIN DIET AND PLASMA-CHOLESTEROL

805 CHRONIC MASTITIS AND CARCINOMA OF BREAST

SIR,-Monson et al.in their report of an association between chronic mastitis and carcinoma of the breast did not state whether the patients had had irradiation treatment for their benign breast disease, presumably because such treatment was believed to have been rarely used. Nevertheless the extent to which radiation exposure might explain the Boston findings needs to be evaluated. A large increase in the incidence of breast cancer in women who received a total dose of 300-3000 rad from repeated fluoroscopy during pneumothorax treatment for pulmonary tuberculosis was demonstrated in Canada’and confirmed in Massachusetts.4 A two-fold or greater increase in breast-cancer incidences and mortality6 has appeared in women exposed to 90 rad or more from the atomic bombs in Hiroshima and Nagasaki. Women treated for acute post-partum mastitis with a total cumulative X-ray dose per breast from 50 to more than 1000 rad show a similar increase in risk 7 which has been attributed to the radiation rather than the mastitis. In the records of a large tumour institute in Los Angeles we have identified several hundred women who received breast irradiation as treatment for chronic mastitis between the mid-1920s and the late 1940s. The most common treatment protocol appears to have been a series of 6 treatments (range 1-30) at a dose of 250 (range 100-400) roentgens per treatment. The cumulative X-ray dose to each affected breast ranged from 100 to more than 3000 r. Many of the treated women have a history of long-standing recurrent disease and others had recurrent mastitis many years later. We have no reason to believe that this institution in Los Angeles was unique, and we cannot begin to estimate the prevalence of the experience. Since most doctors on the staff of this tumour institute from 1920 to 1950, had trained at Eastern or Mid-Western institutions, it is unlikely that radiation treatment of chronic mastitis was restricted to California. Moreover, a brief literature search provides evidence for the practice in various parts of the United States and Europe.9- 17 The wide variety of methods described in a report from New York City9 were strikingly similar to the variety we found in Los Angeles. That report concluded: "Relatively large doses of high voltage roentgen rays are essential if any results are to be obtained." Moreover, Bross 18 has suggested that women at high risk of breast cancer may also be at high risk for radiation-induced breast cancer. This hypothesis is compatible with experiments in rats demonstrating a synergism between radiation and cestrogen in the production of mammary cancer. 19 We hope that information on radiation exposure can be obtained by Dr Monson and his colleagues in further evaluating their study cohort. Several of these women may have received irradiation for breast disease years before or years after the histopathological varification of chronic mastitis. Information on radiation exposure as well as chronic cystic mas-

1. Monson, R. R., Yen, S. MacMahon, B., Warren, S. Lancet, 1976, ii, 224. 2 Mackenzie, I. Br. J. Cancer, 1965, 19, 1. 3 Myrden, J. A., Hiltz, J. E. Can. med. Ass. J. 1969, 100, 1032. 4. Boise, J. D., Monson, R. A. J. natn. Cancer Inst. (in the press). 5. Wanebo, C. K., Johnson, K. D., Sato, K., Thorshud, T. W. New Engl. J. Med. 1968, 279, 667. 6. Jablon, S., Kato, H. Rad. Res. 1972, 50, 649. 7 Mettler, F. A., and others J. natn. Cancer Inst. 1969, 43, 803. 8 Shore, R. E., and others. Personal communication. 9 Taylor, H. D., Brown, R. L. Am. J. Roentgen. Radium Ther. 1938, 40, 517. 10 Campbell, O. J. Archs Surg. 1934, 28, 1001. 11 Cutler, M. Illinois med. J. 1932, 61, 313. 12 Dietrich, A., Frangenheim, P. Neue dt. Chir. 1926, 35, 96. 13 Keynes, G. Br. J. Surg. 1923, 11, 89. 14. Knoflach, Ilg., Urban, K. Arch. klin. Chir. 1928, 150, 355. 15 Kozhevnikoff, A I. Mosk. med zh. 1930, 10, 13. 16 Meyer, A. W. in Neu deutsche Klinik; vol. ii, p. 316. Berlin, 1928 In: Neu dt Klin. 1928, Urban, Berlin, 2, 316. 17 Reynolds, R. J. Proc. R. Soc. Med. 1932, 25, 969. 18 Bross, I. D. J. New Engl. J. Med. 1977, 296, 232. 19 Segaloff, A., Maxfield, W. S. Cancer Res. 1971, 31, 166.

titis should be available before the influence of either risk from breast cancer can be measured. Department of Pathology, University of Southern California, School of Medicine, Los Angeles, California 90033, U.S.A.

on

the

SUSAN PRESTON MARTIN THOMAS M. MACK

SOYBEAN-PROTEIN DIET AND PLASMA-CHOLESTEROL

SIR,-Dr Sirtori and his colleagues (Feb. 5, p. 275) report hypocholesterolaernic effect of a textured soybean product (’Temptein’, Miles Laboratories, not further specified) which they ascribe to properties of the vegetable protein, a hypothesis supported in your editorial (p. 291). This theory contrasts with the fact that Eskimos on diets with very high animal-protein calorie percentages have low plasma-lipid concentrations.1 a

Sirtori

give no details about the energy content of the amount of soybean-protein given, the carbohydrate content of the product, or the nature of the carbohydrate in textured soybean proteins. et

al.

diets, the precise

If the average energy content of the diets is estimated to be 200 kcal, 20% is equivalent to 100 g protein. The experimental group took 63% of their proteins from the soybean product (i.e., 63 g, corresponding to 100 g temptein which holds 23 g carbohydrate 2). The chemical nature of the carbohydrate is not specified, but it is safe to assume that 15-20 g is indigestible, non-cellulose polysaccharides that have attracted attention as cholesterol-lowering agents.3-7 I suggest that the effects of textured vegetable soybean-protein on blood lipids be ascribed to the carbohydrate fraction of the product not the protein. Institute of Hygiene, University of Aarhus, DK 8000 Aarhus, Denmark

*<*

This letter has been shown whose reply follows.-ED. L.

PETER HELMS

to

Dr Gatti and Dr

Sirtori,

SIR,-Dr Helms makes some interesting remarks about our studies of the soybean-protein diet which are helpful for discussion on this unexplained hypocholesterolaemic effect. Although we did not provide details of our diets, Dr Helms is correct. We gave about 1800 kcal daily to our patients and, at most, 90 g of ’Temptein’. Of this about 20 g is carbohydrate-10 g of monosaccharides and oligosaccharides (sucrose, stachyose, raffinose, and so on), 8 of the other 10 g being nondigestible, non-cellulose material The low-lipid diet used for comparison was rich in indigestible fibres (fruits and vegetables) as suggested by Kay." Calculation of the noncellulose fibrous content of the two diets yields a difference of about 8 g in favour of the soybean diet. This daily amount of indigestible fibre is unlikely to achieve any significant hypocholesterolaemic effect. The findings of Durrington et all and Jenkins et al.,1U even for 15 g daily of pectin or guar gum, indicate cholesterol decreases of 7-9% which are far less than the dramatic effect of soybean protein. 1. Dyerberg, J., Bang, H. O., Hjorne, N. Am. J. clin. Nutr. 1975, 28, 958. 2. Marschall Products and Services. Textured Vegetable Proteins. Miles Laboratories Ltd., Jan. 31. 1975. 3. Groen, J. J. nutr. Soc. 1973, 32, 159. 4. Jenkins, D. J. A., Leeds, A. R., Newton, C., Cummings, J. H. Lancet, 1975, i, 1116. 5. Jenkins, D. J. A., Leeds, A. R., Slavm, B., Jepson, E. M. ibid. 1976, ii, 1351. 6. Kay, R. M. ibid. 1976, ii, 799. 7. Kiehm, T. G., Anderson, J. W., Ward, K. Am. J. clin. Nutr. 1976, 29, 895. 8. Kay, R. M. Lancet, 1976, ii, 799. 9. Durrington, P. N., Manning, A. P., Bolton, C. H., Hartog, M. ibid. 1976, 10.

ii, 394. Jenkins, D. J. A., Leeds, A. R., Slavin, B., Jepson, E. M. ibid. 1976, ii, 1351.

806 Finland would yield 84 000 worm carriers. Less than 1 in 50 of the Finnish population harbours the fish tapeworm today. Hatanpää Hospital, MATTI SAARNI

33100 Tampere 10,

ILMARI PALVA

Finland of North Karelia,

Central

Hospital 80210 Joensuu 21

PIA AHRENBERG

SERUM-25-HYDROXYCHOLECALCIFEROL IN HYPERTHYROIDISM

SIR,-Velentzas et al.’ have reported a low mean serum-25-

hydroxycholecalciferol (25-H.C.C.)

in

patients

with

hyperthyimportant the understanding of the pathogenesis of bone compli-

roidism, and they suggested that this could be

soybean protein diet. This patient, after two weeks of a standard low-lipid diet, was placed on the soybean protein diet for five weeks in the hospital and three more months at home. The soybean diet was supplemented with methionine (1.39 g/daily).

Addition of methionine to the

This does not rule out an activity of the indigestible fibres of ttxtured soybean protein; it only suggests that the effect on blood lipids is more likely to be due to the protein fraction of

soybean.

accompanying editorial you suggest that methionine deficiency of soybean protein may be responsible for the cholesterol-lowering effect. Being aware of this, we did test the addition of methionine (in a daily amount sufficient to simulate the aminoacid pattern of egg albumin) in five of our patients. We were interested in evaluating long-term treatments with this diet, when aminoacid deficiency might develop. In all five patients, the addition of methionine did not appear to hinder the hypocholesterolaemic effect of soybean protein (see figure). In your

Department of Nutrition, Maggiore Hospital, Milan, Italy Center E. Grossi Paoletti,

University

of Milan

an

clue to cations in hyperthyroidism. We have measured the serum concentration of 25-H.C.C., calcium (corrected for individual variation in serum-albumin), phosphorus, and immunoreactive parathyroid hormone’ in 34 untreated hyperthyroid patients in whom transiliac bone biopsy was done after double labelling with tetracydine. The diagnosis of hyperthyroidism was based on total serum-thyrox. ine (T 4)’ triiodothyronine uptake (T3 test), and absolute iodine-132uptake. The degree of hyperthyroidism was expressed by the free thyroxine index (F.T.I.=serum-T4xT3 test). Serum-25-H.C.C. was measured by a competitive proteinbinding assay described by Haddad and Chyul with modifications in extraction and chromatography. The coefficient of variation of repeated measurements at 15 ng was 135%. The sensitivity in the routine assay was 1.5ng/ml. SERUM

25-H.C.C.

(MEAN:!:S.D.), SERUM-T4 AND SERUM T3 UPTAKE

TEST IN HYPERTHYROID PATIENTS AND CONTROLS

The table shows that serum-25-H.C.C. was slightly but siglower in the hyperthyroid patients than

nificantly (P<0001) ENNIO GATTI CESARE R. SIRTORI

FINNS AND THE FISH TAPEWORM

SIR,—YoU state (Feb. 5, p. 292) that about a fifth of adult Finns harbour the fish tapeworm, but this is a 30-year-old estimate and tapeworm infestation in Finland is now much less common. Up-to-date figures have not been published. In 1947 the prevalence of tapeworm infestation in Finland was about 20%,’ and in some areas 55% of the inhabitants were worm carriers.2 The Central Hospital of North Karelia is located in the eastern part of the country where tapeworm infestation has been common. The proportion of fish-tapeworm carriers among the patients in that hospital was 15.6% in 1958,’ 7.4% in 1968-70," and 3.3% in 1976. The most up-to-date figure for fish-tapeworm infestation in the country as a whole is based on 270 000 faecal samples obtained during 1968-70.4 Of these samples 4800 were positive (1.8%). Applying this figure to the whole population of

in 596 controls. The blood-samples were collected equally throughout the year in both patients and controls. The differnce was, however, far less pronounced than that reported by Velentzas et al.’ This could not be explained by a difference in the degree of hyperthyroidism because the relative increase in F.T.I. was equal in the two hyperthyroid populations. No correlation was found between serum-25-H.c.c. and serum concentrations of calcium, phosphorus, alkaline phosphatase, or iP.T.H. Serum-25-H.C.C. was, however, positively correlated to F.T.I. (r=038, P<0.05). No correlation was found between serum-25-H.c.c. and bone histomorphometry, measured on undecalcified and decalcified bone sections using the point-count principle.4 We have found a high prevalence of hypercalcæmia (51%), hyperphosphataemia (16%), and subnormal serum-ip.T.H, (29%) in 45 patients with hyperthyroidism.1 Serum calcium and phosphorus was positively correlated to the degree of hyperthyroidism, and serum-ip.T.H. was inversely correlated to serum-calcium. Morphometric analyses of bone disclosed a high prevalence of bone changes.4 These were characterised by an increased osteoclastic activity and porosity in cortical bone. In trabecular bone the percentage of osteoid-covered surfaces C., Oreopoulos, D. G., From, G., Porret, B., Rapoport, A. Lancet, 1977, i, 370. Christensen, M. S. Scand. J. clin. Lab. Invest. 1976, 36, 313. Haddad, J. G., Chyu, K. J. J. clin. Endocr. Metab. 1971, 33, 992. Melsen, F., Mosekilde, L. Acta path. microbiol. scand. A, 1977, 85, 131. Mosekilde, L., Christensen, M. S. Acta endocr. (in the press).

1. Velentzas, 1. Huhtala, A. Ann. Med. intern. Fenn. 1950, 39, suppl. 6. 2. Tötterman, G. Acta med. scand. 1944, 118, 410. 3. Palva, I. ibid. 1962, 171, suppl. 374. 4 Wikström, M. Comm. biol. Soc. sci. Fenn. 1972, 48, 1.

2. 3. 4. 5.