BRITISH MEDICAL JOURNAL
1155
30 APRIL 1977
CORRESPONDENCE Diet and coronary heart disease Sir John McMichael, FRCP, FRS; J I .......... Mann, DM, and others ...... Hospital-based community service for the mentally subnormal .......... T S Davies, FRCPSYCH ...... More thought for the elderly C Roberts, MD ........... ............. Rubella vaccination in independent schools T W Hoskins, MB;J F Wood, MB ........ Stillbirth, grief, and medical education ........... S Bourne, FRCPSYCH ....... Localised airway obstruction I W B Grant, FRCPED .................. Tourist hepatitis ................ F W Best, MRCP ...... Orthopaedic services in Lincoln
1155 1156 1156 1156
1157 1157
1158
HRWLunt,MCHORTH;JAScott,FFCM.. 1158 Responsibility and management in pathology laboratories 1158 J A Macdougall, FRCS ...............
Immunisation and brain damage G Schoenewald, MD .................. Diet and serum cholesterol H J Tagnon, MD ...................... Dextropropoxyphene overdosage and naloxone M J Wiseman, MRCS, and others ........ Monitoring adverse reactions to drugs R M Pearson, MRCP .................. Can cockroaches cause asthma? P B Cornwell, PHD .................... Differentiation of streptococci from diphtheroids Mair E M Thomas, FRCPATH .......... Use of ritodrine in pregnant diabetics C J Chandler, MB .................... Increased serum growth hormone levels in the absence of acromegaly A H Ghodse, MD .................... Truncal vagotomy and cholelithiasis: plea for a controlled study V Torrealba, MD ......................
1159 1159 1159
1159 1159
1159
1159 1160
1160
Correspondenits are urged to write briefly so that readers may be offered as wide a selection of letters as possible. So many are being received that the omission of some is inevitable. Letters should be signed personally by all their authors. Diet and coronary heart disease
SIR,-Professor A G Shaper and Ms Jean W Marr (2 April, p 867) are suggesting that the whole community should be subjected to dietary fat manipulation to reduce the risk of coronary heart disease (CHD). Even the report from the Royal College of Physicians of London and the British Cardiac Society' spared those over the age of 60. The evidence they quote is largely epidemiological. They give not a single reference to modern scientific direct appraisal of the problem or to conclusions from trials which contradict their views. Ten years ago various professional groups and organisations began reporting that, in view of the association of high blood cholesterol values with later onset of coronary symptoms, it might be advisable to take measures to reduce this. In general all reporting groups (except one2) followed by supporting this fashionable view, including the RCP/BCS 1976 Joint Working Party (containing some committed enthusiasts), which was itself chaired by Professor Shaper. Correlation does not signify cause and effect. When this snowball of opinions was set rolling in 1968 some highly relevant evidence was not available, but as time went on such evidence was not allowed to interfere with the growing fashion for polyunsaturated fat, in which commercial interests were now involved. The relevant and more recent evidence is briefly as follows: (1) Two carefully conducted British trials on patients at risk on low fat3 and soya bean oil4 (polyunsaturated) diets clearly showed no effect on coronary recurrences or mortality. These trials involved over 600 patients in all, and the latter trial reduced blood cholesterol by as much as 59 mg. These trials were much superior in statistical design, patient matching, and continuity of observations over five years to the
Finnish Mental Hospitals and Los Angeles trials quoted by Shaper and Marr. (2) Cholesterol-lowering drugs (clofibrate and niacin) were tried out on 8141 patients in the USA' with no benefit, although cholesterol levels were significantly reduced. (3) Dr W B Kannel6 (of Framringham) admitted that there was no evidence that dietetic measures had any influence on coronary mortality. Dr E H Ahrens,7 of Rockefeller University, and Dr Michael Oliver,8 of Edinburgh, who have both devoted decades of study to the cholesterol problem, now feel that "any advice to the general public to make large dietary changes is now premature" (EHA) and the view "that raised plasma cholesterol is a cause per se of coronary heart disease is untenable" (MO). (4) Fuster et al' at the Mayo Medical School have shown by the detailed study of 300 angiograms that the severity and extent of coronary disease is unrelated to high or low cholesterol levels. (5) The fatty streaks often seen in childhood are distributed differently from atheroma (Mitchell and Schwartz10), and Dr Elspeth Smith and R H Smith" confirm that they are morphologically and chemically different from atheroma. She also notes that the atheroma lesion begins as a gelatinous deposit without visible fat in the earliest stages. She concludes, "To think of atherosclerosis only in terms of lipoproteins or cholesterol uptake seems to be a serious oversimplification." The Finland death rates quoted by Shaper and Marr are from two populations. The East Finns have approximately the same level of blood cholesterol as the West Finns but double the coronary incidence and mortality. They lead strenuous lives as lumberjacks, and exercise does not save them."2 Much coronary trouble can develop during strenuous effort,
"T}he cholecystogram is normal" but... P B Cotton, MD, and J R Croker, MRCP; D Gordon, MB ..... ........ 1160 Administrative staff in the NHS N H N Mils, MRCPSYCH; A C Faulkner.. 1160 Differentials in payment of hospital staff P J E Wilson, FRCS ............. 1161 Whole-time consultants and the contract 1161 SIJacobs,MD .................. Medical Academic Staff Committee J P Quilliam, FRCP ............. 1162 Points from letters Medical assistants in developing countries (H de Glanville); Burst abdomen-a preventable condition? (B Williams); The magic puff-ball (C P Petch); Prevention of backache (C F J Cropper); Seat belts (A M Ross); Cascade of paper (A D M Bryceson; C Brun); Diet and heart disease (A A Lewis); Oxygen enrichment for mouth-to-mouth respiration (C M French); Aids to administration (H B Devlin).... 1162
so even current fashionable advice may need reconsideration. We have got to be very sure of our grounds before altering the nation's diet. Mere repetition of the anticholesterol chorus does not make it true.
JOHN MCMICHAEL London NW11
Joint Working Party of the Royal College of Physicians of London and the British Cardiac Society, Journal of the Royal College of Physicians of London, 1976,
10, 213. 'Diet and Coronary Heart Disease. London, HMSO, 1974. ' Research Committee Report, Lancet, 1965, 2, 501. ' Medical Research Council, Lancet, 1968, 2, 693. 'Coronary Drug Project, Journal of the American Medical Association, 1975, 231, 360. Kannel, W B, Journal of the American Medical Association, 1974, 227, 338. 7 Ahrens, E H, Annals of Internal Medicine, 1976, 85, 87. ' Oliver, M, British Heart Journal, 1976, 38, 214. * Fuster, V, et al, British Heart journal, 1975, 37, 1250. o0 Mitchell, J R A, and Schwartz, C J, Arterial Disease. Oxford, Blackwell Scientific Publications, 1965. Smith, E B, and Smith, R H, Atherosclerosis Reviews, 1976, 1, 119. 3Punsar, S, and Karvonen, M J, Physical Activity and Coronary Heart Disease, in Advances in Cardiology, Vol 18, p 196. Basel, S Karger, 1976.
SIR,-Professor A G Shaper and Miss Jean W Marr conclude their excellent review (2 April, p 867) with the advice that dietary recommendations to the public aimed at reducing the risk of coronary heart disease (CHD) should be specific, clear, and brief. These should not, in their opinion, be confounded by other dietary recommendations which may be of general health value but are not specifically aimed at reducing the incidence of CHD. Their basic advice to the community should be a reduction in saturated fat intake and partial substitution by polyunsaturated fat. Their arguments are sound if the sole concern is an attempt to reduce the frequency of premature CHD. There is, however, an appreciable amount of evidence that the health of a Westernised community may be improved by certain other dietary changes. Many nutritionists interested in preventive medicine might feel that there is a case to be made for
1155
30 APRIL 1977
CORRESPONDENCE Diet and coronary heart disease Sir John McMichael, FRCP, FRS; J I .......... Mann, DM, and others ...... Hospital-based community service for the mentally subnormal .......... T S Davies, FRCPSYCH ...... More thought for the elderly C Roberts, MD ........... ............. Rubella vaccination in independent schools T W Hoskins, MB;J F Wood, MB ........ Stillbirth, grief, and medical education ........... S Bourne, FRCPSYCH ....... Localised airway obstruction I W B Grant, FRCPED .................. Tourist hepatitis ................ F W Best, MRCP ...... Orthopaedic services in Lincoln
1155 1156 1156 1156
1157 1157
1158
HRWLunt,MCHORTH;JAScott,FFCM.. 1158 Responsibility and management in pathology laboratories 1158 J A Macdougall, FRCS ...............
Immunisation and brain damage G Schoenewald, MD .................. Diet and serum cholesterol H J Tagnon, MD ...................... Dextropropoxyphene overdosage and naloxone M J Wiseman, MRCS, and others ........ Monitoring adverse reactions to drugs R M Pearson, MRCP .................. Can cockroaches cause asthma? P B Cornwell, PHD .................... Differentiation of streptococci from diphtheroids Mair E M Thomas, FRCPATH .......... Use of ritodrine in pregnant diabetics C J Chandler, MB .................... Increased serum growth hormone levels in the absence of acromegaly A H Ghodse, MD .................... Truncal vagotomy and cholelithiasis: plea for a controlled study V Torrealba, MD ......................
1159 1159 1159
1159 1159
1159
1159 1160
1160
Correspondenits are urged to write briefly so that readers may be offered as wide a selection of letters as possible. So many are being received that the omission of some is inevitable. Letters should be signed personally by all their authors. Diet and coronary heart disease
SIR,-Professor A G Shaper and Ms Jean W Marr (2 April, p 867) are suggesting that the whole community should be subjected to dietary fat manipulation to reduce the risk of coronary heart disease (CHD). Even the report from the Royal College of Physicians of London and the British Cardiac Society' spared those over the age of 60. The evidence they quote is largely epidemiological. They give not a single reference to modern scientific direct appraisal of the problem or to conclusions from trials which contradict their views. Ten years ago various professional groups and organisations began reporting that, in view of the association of high blood cholesterol values with later onset of coronary symptoms, it might be advisable to take measures to reduce this. In general all reporting groups (except one2) followed by supporting this fashionable view, including the RCP/BCS 1976 Joint Working Party (containing some committed enthusiasts), which was itself chaired by Professor Shaper. Correlation does not signify cause and effect. When this snowball of opinions was set rolling in 1968 some highly relevant evidence was not available, but as time went on such evidence was not allowed to interfere with the growing fashion for polyunsaturated fat, in which commercial interests were now involved. The relevant and more recent evidence is briefly as follows: (1) Two carefully conducted British trials on patients at risk on low fat3 and soya bean oil4 (polyunsaturated) diets clearly showed no effect on coronary recurrences or mortality. These trials involved over 600 patients in all, and the latter trial reduced blood cholesterol by as much as 59 mg. These trials were much superior in statistical design, patient matching, and continuity of observations over five years to the
Finnish Mental Hospitals and Los Angeles trials quoted by Shaper and Marr. (2) Cholesterol-lowering drugs (clofibrate and niacin) were tried out on 8141 patients in the USA' with no benefit, although cholesterol levels were significantly reduced. (3) Dr W B Kannel6 (of Framringham) admitted that there was no evidence that dietetic measures had any influence on coronary mortality. Dr E H Ahrens,7 of Rockefeller University, and Dr Michael Oliver,8 of Edinburgh, who have both devoted decades of study to the cholesterol problem, now feel that "any advice to the general public to make large dietary changes is now premature" (EHA) and the view "that raised plasma cholesterol is a cause per se of coronary heart disease is untenable" (MO). (4) Fuster et al' at the Mayo Medical School have shown by the detailed study of 300 angiograms that the severity and extent of coronary disease is unrelated to high or low cholesterol levels. (5) The fatty streaks often seen in childhood are distributed differently from atheroma (Mitchell and Schwartz10), and Dr Elspeth Smith and R H Smith" confirm that they are morphologically and chemically different from atheroma. She also notes that the atheroma lesion begins as a gelatinous deposit without visible fat in the earliest stages. She concludes, "To think of atherosclerosis only in terms of lipoproteins or cholesterol uptake seems to be a serious oversimplification." The Finland death rates quoted by Shaper and Marr are from two populations. The East Finns have approximately the same level of blood cholesterol as the West Finns but double the coronary incidence and mortality. They lead strenuous lives as lumberjacks, and exercise does not save them."2 Much coronary trouble can develop during strenuous effort,
"T}he cholecystogram is normal" but... P B Cotton, MD, and J R Croker, MRCP; D Gordon, MB ..... ........ 1160 Administrative staff in the NHS N H N Mils, MRCPSYCH; A C Faulkner.. 1160 Differentials in payment of hospital staff P J E Wilson, FRCS ............. 1161 Whole-time consultants and the contract 1161 SIJacobs,MD .................. Medical Academic Staff Committee J P Quilliam, FRCP ............. 1162 Points from letters Medical assistants in developing countries (H de Glanville); Burst abdomen-a preventable condition? (B Williams); The magic puff-ball (C P Petch); Prevention of backache (C F J Cropper); Seat belts (A M Ross); Cascade of paper (A D M Bryceson; C Brun); Diet and heart disease (A A Lewis); Oxygen enrichment for mouth-to-mouth respiration (C M French); Aids to administration (H B Devlin).... 1162
so even current fashionable advice may need reconsideration. We have got to be very sure of our grounds before altering the nation's diet. Mere repetition of the anticholesterol chorus does not make it true.
JOHN MCMICHAEL London NW11
Joint Working Party of the Royal College of Physicians of London and the British Cardiac Society, Journal of the Royal College of Physicians of London, 1976,
10, 213. 'Diet and Coronary Heart Disease. London, HMSO, 1974. ' Research Committee Report, Lancet, 1965, 2, 501. ' Medical Research Council, Lancet, 1968, 2, 693. 'Coronary Drug Project, Journal of the American Medical Association, 1975, 231, 360. Kannel, W B, Journal of the American Medical Association, 1974, 227, 338. 7 Ahrens, E H, Annals of Internal Medicine, 1976, 85, 87. ' Oliver, M, British Heart Journal, 1976, 38, 214. * Fuster, V, et al, British Heart journal, 1975, 37, 1250. o0 Mitchell, J R A, and Schwartz, C J, Arterial Disease. Oxford, Blackwell Scientific Publications, 1965. Smith, E B, and Smith, R H, Atherosclerosis Reviews, 1976, 1, 119. 3Punsar, S, and Karvonen, M J, Physical Activity and Coronary Heart Disease, in Advances in Cardiology, Vol 18, p 196. Basel, S Karger, 1976.
SIR,-Professor A G Shaper and Miss Jean W Marr conclude their excellent review (2 April, p 867) with the advice that dietary recommendations to the public aimed at reducing the risk of coronary heart disease (CHD) should be specific, clear, and brief. These should not, in their opinion, be confounded by other dietary recommendations which may be of general health value but are not specifically aimed at reducing the incidence of CHD. Their basic advice to the community should be a reduction in saturated fat intake and partial substitution by polyunsaturated fat. Their arguments are sound if the sole concern is an attempt to reduce the frequency of premature CHD. There is, however, an appreciable amount of evidence that the health of a Westernised community may be improved by certain other dietary changes. Many nutritionists interested in preventive medicine might feel that there is a case to be made for
