Ja Uffen ja Katanin väittely liittyen suoraan eläinrasva vs. kasvirasva debaattiin.. ite en ota kantaa suuntaan enkä toiseen..
American Journal of Clinical Nutrition, Vol. 84, No. 6, 1550-1551, December 2006
© 2006 American Society for Nutrition
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LETTER TO THE EDITOR
Saturated fat does not affect blood cholesterol
Uffe Ravnskov
Magle Stora Kyrkogata 9
S-22350 Lund
Sweden
E-mail:
ravnskov@tele2.se
Dear Sir:
The most striking observation from the study by Krauss et al (1) is the finding that a diet rich in saturated fatty acids (SFAs) results in a lower or a steady state concentration of total and LDL cholesterol and an increase in the concentration of HDL cholesterol, regardless of whether the diet has a reduced energy content. Similar effects on blood lipids have been observed in 4 weight-reducing trials with high intakes of SFAs (2-5) (Table 1) and in many similar trials with unrestricted intakes of SFAs.
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TABLE 1 Changes in blood lipids in 4 trials of calorie restriction in which a conventional diet was substituted for a low-carbohydrate diet rich in saturated fatty acids (SFAs)1
In 1973, Reiser (6) questioned the effects of SFA intake on serum cholesterol. In a thorough review of the relevant experiments, he noted several methodologic and interpretational errors. The most important errors are probably the attribution of differences between SFAs and polyunsaturated fatty acids to the former, when the effect could have been due to the latter, and the use of vegetable oils saturated by hydrogenation instead of natural SFAs.
A possible reason why the effects were more pronounced before weight reduction than after weight reduction in the study by Krauss et al was the difference in metabolism between the normal-weight and overweight subjects. Cornier et al (7) recently found that total and LDL-cholesterol concentrations decreased more with a low-carbohydrate than with a low-fat, calorie-restricted diet. Interestingly, the overweight subjects with reduced insulin sensitivity, but not those with normal insulin sensitivity, had an increase in cholesterol with the low-fat diet but a decrease with the low-carbohydrate diet. In both groups, the changes in lipids were more beneficial with a low-carbohydrate diet than with a low-fat diet. Therefore, the different lipid responses before and after weight reduction in the study by Krauss et al may have been because the loss of weight may have improved the participants’ insulin sensitivity and thus their lipid response.
Because the main reason for restricting the intake of SFAs in all official guidelines is to change blood lipids, demonizing these nutrients seems inappropriate. In his editorial, Katan (8) claims that high intakes of unsaturated fatty acids reduce the risk of heart attacks, but his evidence is based on a meta-analysis that had ignored 4 unsuccessful trials (9). Two meta-analyses of all controlled clinical trials in which the only intervention was a change in dietary fats found no effect on coronary or total mortality (10).
ACKNOWLEDGMENTS
The author had no vested interest in the subject of this letter.
REFERENCES
Krauss RM, Blanche PJ, Rawlings RS, Fernstrom HS, Williams PT. Separate effects of reduced carbohydrate intake and weight loss on atherogenic dyslipidemia. Am J Clin Nutr 2006;83:1025–31.[Abstract/Free Full Text]
Sondike SB, Copperman N, Jacobson MS. Effects of a low-carbohydrate diet on weight loss and cardiovascular risk factor in overweight adolescents. J Pediatr 2003;142:253–8.[Medline]
Hays JH, DiSabatino A, Gorman RT, Vincent S, Stillabower ME. Effect of a high saturated fat and no-starch diet on serum lipid subfractions in patients with documented atherosclerotic cardiovascular disease. Mayo Clin Proc 2003;78:1331–6.[Medline]
Meckling KA, O’Sullivan C, Saari D. Comparison of a low-fat diet to a low-carbohydrate diet on weight loss, body composition, and risk factors for diabetes and cardiovascular disease in free-living, overweight men and women. J Clin Endocrinol Metab 2004;89:2717–23.[Abstract/Free Full Text]
Sharman MJ, Gomez AL, Kraemer WJ, Volek JS. Very low-carbohydrate and low-fat diets affect fasting lipids and postprandial lipemia differently in overweight men. J Nutr 2004;134:880–5.[Abstract/Free Full Text]
Reiser R. Saturated fat in the diet and serum cholesterol concentration: a critical examination of the literature. Am J Clin Nutr 1973;26:524–55.[Free Full Text]
Cornier MA, Donahoo WT, Pereira R, et al. Insulin sensitivity determines the effectiveness of dietary macronutrient composition on weight loss in obese women. Obes Res 2005;13:703–9.[Abstract/Free Full Text]
Katan MB. Alternatives to low-fat diets. Am J Clin Nutr 2006;83:989–90.[Free Full Text]
Ravnskov U. The diet-heart idea is kept alive by selective citation. Rapid response. BMJ 8. December 2003. Internet:
http://bmj.bmjjournals.com/cgi/eletters/327/7427/1348-c.
Ravnskov U. Diet-heart disease hypothesis is wishful thinking. BMJ 2002;324:238.[Free Full Text]
American Journal of Clinical Nutrition, Vol. 84, No. 6, 1551-1552, December 2006
© 2006 American Society for Nutrition
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LETTER TO THE EDITOR
Reply to U Ravnskov
Martijn B Katan
Vrije Universiteit
Faculty of Earth and Life Sciences Institute of Health Sciences
De Boelelaan 1085
1081 HV Amsterdam
Netherlands
E-mail:
katan99@falw.vu.nl
Dear Sir:
Ravnskov’s suggestion that a reduction in the intake of saturated fat does not lower cholesterol is wrong. At constant body weight, the replacement of saturated fat with other nutrients unequivocally lowers cholesterol concentrations; all meta-analyses of controlled trials agree on this.
As for the effects of saturated fatty acids on heart disease, Ravnskov rightly notes that some clinical trials have failed to show that the replacement of saturated fat with unsaturated fat reduces heart disease. However, most clinical trials have shown a benefit. In addition, evidence from epidemiologic, metabolic, and laboratory studies confirms that high intakes of saturated fat do cause heart disease. Ignoring this evidence leads to absurd consequences. For instance, our knowledge of the ill effects of cigarette smoking rests purely on epidemiologic, metabolic, and laboratory studies, whereas evidence from clinical trials is largely lacking. The same holds true for the ill effects of physical inactivity, the failure to use seat belts, the consumption of toxic chemicals in foods, and asbestos exposure. None of these conditions has been proven to be unhealthy in clinical trials performed according to the standards for pharmaceutical drugs. I believe that, in all of these cases, we should consider the totality of the evidence, and the totality of the evidence overwhelmingly indicts saturated fat as a cause of heart disease, just as it indicts cigarettes.
Ravnskov has now published approximately 58 Letters to the Editor (1-58) that address publications about lipids and heart disease. His letters have been published in the Journal of the American Medical Association, the New England Journal of Medicine, the British Medical Journal, the Lancet, Science, Annals of Internal Medicine, the Journal of Clinical Epidemiology, the Quarterly Journal of Medicine, and several Scandinavian medical journals. All his letters have argued essentially the same point, namely that lowering blood cholesterol concentrations is of unproven value. I agree with the dozens of scientists who have carefully replied to his letters and who have shown that, by and large, his arguments are faulty.
ACKNOWLEDGMENTS
The author had no conflict of interest.
REFERENCES
Ravnskov U, Rosch PJ, Sutter MC, Houston MC. Should we lower cholesterol as much as possible? BMJ 2006;332:1330–2.[Free Full Text]
Ravnskov U, Rosch PJ, Sutter MC. High-dose statins and the IDEAL study. JAMA 2006;295:2476, 2478–9.[Free Full Text]
Ravnskov U. [Misleading advice on cholesterol reduction.] Lakartidningen 2006;103:568, 569 (discussion).[Medline]
Ravnskov U. [Treatment of hypercholesterolemia—lower is not better.] Ugeskr Laeger 2006;168:1665.[Medline]
Understrup AG, Ravnskov S, Hansen HC, Fomsgaard IS. Biotransformation of 2-benzoxazolinone to 2-amino-(3H)-phenoxazin-3-one and 2-acetylamino-(3H)-phenoxazin-3-one in soil. J Chem Ecol 2005;31:1205–22.[Medline]
Ravnskov U, Rosch PJ, Sutter MC. Intensive lipid lowering with atorvastatin in coronary disease. N Engl J Med 2005;353:93–6.[Free Full Text]
Ravnskov U. [Should cholesterol levels be reduced more aggressively?] Lakartidningen 2005;102:2583–4.[Medline]
Ravnskov U. Europe in transition: dietary fat is not the villain. BMJ 2005;331:906–7.[Free Full Text]
Ravnskov U, Sutter MC. Aggressive lipid-lowering therapy and regression of coronary atheroma. JAMA 2004;292:38–40.[Free Full Text]
Ravnskov U. Inflammation, cholesterol levels, and risk of mortality among patients receiving dialysis. JAMA 2004;291:1833–5.[Free Full Text]
Ravnskov U. [High cholesterol level may protect against infections and probably also atherosclerosis.] Lakartidningen 2004;101:1215–7, 1218 (discussion), 1221–2.[Medline]
Ravnskov U. [Hasty conclusions on cardiac mortality in Norway.] Tidsskr Nor Laegeforen 2004;124:2153.[Medline]
Ravnskov U. [Karl Popper and the cholesterol hypothesis.] Tidsskr Nor Laegeforen 2004;124:2517.[Medline]
Ravnskov U. ASCOT-LLA: questions about the benefits of atorvastatin. Lancet 2003;361:1986.[Medline]
Ravnskov U. Lipoproteins and cardiovascular risk. Lancet 2003;361:1988–9.[Medline]
Ravnskov U. [Too many calories and too little exercise cause obesity not intake of fat.] Lakartidningen 2003;100:3255–6.[Medline]
Ravnskov U. High cholesterol may protect against infections and atherosclerosis. QJM 2003;96:927–34.[Free Full Text]
Ravnskov U. Dietary fat intake and risk of stroke: allegations about dietary fat are unfounded. BMJ 2003;327:1348.[Free Full Text]
Ravnskov U, Allen C, Atrens D, et al. Studies of dietary fat and heart disease. Science 2002;295:1464–6.[Medline]
Ravnskov U. Diet-heart disease hypothesis is wishful thinking. BMJ 2002;324:238.[Free Full Text]
Ravnskov U. [Surrogate research on heart disease and risk factors.] Lakartidningen 2002;99:1507.[Medline]
Ravnskov U. Is atherosclerosis caused by high cholesterol? QJM 2002;95:397–403.[Free Full Text]
Ravnskov U. [The debate in science: dietary guidelines against myocardial infarction are defended by wrong citations.] Lakartidningen 2002;99:2673.[Medline]
Ravnskov U. A hypothesis out-of-date. the diet-heart idea. J Clin Epidemiol 2002;55:1057–63.[Medline]
Ravnskov U. [Millions of healthy people can be considered ill because of the American cholesterol policy.] Lakartidningen 2001;98:4574–7.[Medline]
Ravnskov U. [Lipid lowering doesn’t affect the development of atherosclerosis in peripheral artery disease.] Lakartidningen 2001;98:4897–8.[Medline]
Ravnskov U. Cholesterol and all-cause mortality in Honolulu. Lancet 2001;358:1907.[Medline]
Ravnskov U. VAT and fat. Evidence is contradictory. BMJ 2000;320:1470.[Free Full Text]
Ravnskov U. [Misleading cholesterol statistics.] Lakartidningen 1999;96:1947.[Medline]
Ravnskov U. Why heart disease mortality is low in France. Authors’ hypothesis is wrong. BMJ 1999;319:255–6.[Free Full Text]
Ravnskov U. [Experts ask for priorities when it comes to interpretation. Ravnskov answers in the debate on dietary fats.] Lakartidningen 1998;95:1022–3.[Medline]
Ravnskov U. The questionable role of saturated and polyunsaturated fatty acids in cardiovascular disease. J Clin Epidemiol 1998;51:443–60.[Medline]
Ravnskov U. [Excellence of the "Mediterranean diet" is a myth. There is no evidence that monounsaturated fats prevent myocardial infarction.] Lakartidningen 1998;95:4749–50.[Medline]
Ravnskov U. [On honesty and monounsaturated fat.] Lakartidningen 1998;95:4966.[Medline]
Ravnskov U. [Do cholesterol-lowering drugs cause cancer?] Lakartidningen 1996;93:2040.[Medline]
Ravnskov U. American College of Physicians guidelines on cholesterol screening. Ann Intern Med 1996;125:1010–1.[Free Full Text]
Ravnskov U. [Fatty acids and confusing signals.] Ugeskr Laeger 1995;157:1534–5.[Medline]
Ravnskov U. Quotation bias in reviews of the diet-heart idea. J Clin Epidemiol 1995;48:713–9.[Medline]
Ravnskov U. Implications of 4S evidence on baseline lipid levels. Lancet 1995;346:181.[Medline]
Ravnskov U. Beneficial effects of simvastatin may be due to non-lipid actions. BMJ 1995;311:1436–7.[Free Full Text]
Ravnskov U. Hypercholesterolemia does not cause coronary heart disease–evidence from the nephrotic syndrome. Nephron 1994;66:356–9.[Medline]
Ravnskov U. Ischaemic heart disease and cholesterol. Optimism about drug treatment is unjustified. BMJ 1994;308:103.
Ravnskov U. [Do polyunsaturated fats cause male sterility?] Lakartidningen 1994;91:2308.[Medline]
Ravnskov U. [Uncritical review of articles on cholesterol.] Ugeskr Laeger 1994;156:4479–80.[Medline]
Ravnskov U. Is intake of trans-fatty acids and saturated fat causal in coronary heart disease? Circulation 1994;90:2568–9.[Medline]
Ravnskov U. Doing the right thing: stop worrying about cholesterol. Circulation 1994;90:2572–3.[Free Full Text]
Ravnskov U. What do angiographic changes after cholesterol lowering mean? Lancet 1994;344:1297.[Medline]
Ravnskov U. [Doubtful advices on cholesterol screening in children.] Ugeskr Laeger 1993;155:1886–7.[Medline]
Ravnskov U. Reducing serum cholesterol. Lower cholesterol of doubtful benefit to anyone. BMJ 1993;307:125.[Medline]
Ravnskov U. [New trends from the USA. The cholesterol campaign is questioned.] Lakartidningen 1993;90:2528–9.[Medline]
Ravnskov U. Coronary atherosclerosis on angiography—progress or regress, and why? Circulation 1993;88:1358–60.[Free Full Text]
Ravnskov U. [Decreased cholesterol level shortens life.] Ugeskr Laeger 1993;155:3679–80.[Medline]
Ravnskov U. [Stop the cholesterol campaign!] Lakartidningen 1993;90:4587–8, 4589–90 (discussion).[Medline]
Ravnskov U. [What is the correct answer in the cholesterol debate?] Ugeskr Laeger 1992;154:1716–8.[Medline]
Ravnskov U. Cholesterol lowering trials in coronary heart disease: frequency of citation and outcome. BMJ 1992;305:15–9.[Medline]
Ravnskov U. Frequency of citation and outcome of cholesterol lowering trials. BMJ 1992;305:717.[Medline]
Ravnskov U. [Are polyunsaturated fats useful?] Lakartidningen 1991;88:1058.[Medline]
Ravnskov U. An elevated serum cholesterol level is secondary, not causal, in coronary heart disease. Med Hypotheses 1991;36:238–41.[Medline]