Understanding Fats - Richard Young
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This document discusses the history of dietary recommendations to reduce saturated fat and consume more vegetable oils. It notes that in the early 20th century, consumers were encouraged to switch from animal fats to vegetable oils and saturated to polyunsaturated fats. However, despite these dietary changes, rates of heart disease, obesity and diabetes have increased. The document questions whether vegetable oils are better for health or the environment than animal fats. It summarizes the evidence that linked saturated fat to heart disease and promoted vegetable oils may have been influenced by the sugar industry.
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Understanding Fats - Richard Young
- 1. Living off: the fat of the land Or the fat of the rainforest? Richard Young, ORFC 2017
- 2. Animal fats vs. vegetable oils • 36% of energy intake today comes from fat1, but over the last century consumers have been encouraged to switch from: • animal fats to vegetable oils. • saturated fat to polyunsaturated fat • visible fats to invisible fats • natural fats to industrially altered fats 2 Type of Fat US data1 1909 Meat/fish 2000 Meat/fish 1909 Vegetable 2000 Vegetable Polyunsaturated 32% 14% 32% 72% Monounsaturated 42% 25% 40% 59% Saturated 33% 26% 40% 44% Trends 107 65 112 175 1. National Diet and Nutrition Survey 2014 2. USDA, 2004. Nutrient Content of the US Food Supply 1909-2000 3. COMA, 1984. Diet and cardiovascular disease pp18-19 UK - Saturated fat fell from 19.9%2 to 12.6%1 energy intake, 1980-2012
- 3. Despite these changes, every day • 515 people have a heart attack, 190 die • A further 245 people will die from other forms of cardiovascular disease (CVD) • 7 million people are living with CVD • Two-thirds of adults and 25% of children overweight or obese • 3.6 million suffering from type-2 diabetes (1.4 million 1996) • Huge increases in dementia, obesity and type-2 diabetes • All this despite: major changes in diets, an average 80% fall in tobacco use per person, 5 million blood pressure prescription and 92,000 coronary heart interventions each year 3 Statistics: British Heart Foundation The Nuffield Trust and Diabetes.co.uk
- 4. Are soya, corn, rape and palm oils – better for the environment than beef fat? Rape oil: decline of pollinating insects due to insecticides, fungicides and summer starvation due to monocultures and grassland loss. Palm oil: rainforest clearance, species extinction, carbon loss, pollution and social impacts. Corn and soya oil: Impacts on LUC, soil degradation and water pollution
- 5. Soyabeans • The massive expansion of soyabean (and sugar cane) in South American Atlantic Forest Ecoregion and virgin Cerrado to supply Europe and China - responsible for huge land use change (LUC), GHGs, pollution, soil erosion, biodiversity loss and displacement of at least 180,000 indigenous Cerrado pastoralists and their families, many of whom had no option but to take their animals into the rainforest. • Only 11-19% of crop by weight becomes oil • 81-89% goes for animal feed • Most studies therefore attribute c.90% of all this to the livestock sector. However, humans use 99% of the oil: • 80% goes into food • 20% used in biodiesel, cosmetics and flyspray • Therefore human demand for soyabean oil is at least as big a driver of LUC as livestock and arguably more so, because without the soyabean oil we would need even more palm oil. 5
- 6. Key drivers of change • The dramatic rise in coronary heart disease and stroke during the 20th century • Ancel Keys’ Lipid Hypothesis, which laid this at the door of fat, and later saturated fat consumption specifically • The sugar industry which put about $1 billion p.a. into proving the lipid hypothesis • Misdirection from the vegetable oils industry keen to deflect attention from the problem caused by trans fats • The rise of vegetarianism and veganism Let’s assess the evidence 6
- 7. CHD Mortality, UK 1931-2000 0 50 100 150 200 250 300 350 1930 1940 1950 1960 1970 1980 1990 2000 Deathsper100,000 7 Source: Office for National Statistics. Rate not age-adjusted.
- 8. 1953, Ancel Keys claims link between fat intake, cholesterol and CHD1 Japan Italy England & Wales Australia Canada US 0 1 2 3 4 5 6 7 8 0 5 10 15 20 25 30 35 40 45 CHDdeathsper1,000 % calories from fat 8 1961: Time Magazine promotes Keys’ hypothesis American Heart Association recommends polyunsaturated fat to combat heart disease2 1. Keys A 1953. J. Mount Sinai Hospital, 20:118-139 2. Page H et al., 1961, Dietary fat and its relation to heart attacks and strokes, Circulation 23:133-136
- 9. ‘Six Countries Study,’ with ignored countries included Japan Italy England & Wales Australia Canada US 0 1 2 3 4 5 6 7 8 0 5 10 15 20 25 30 35 40 45 CHDdeathsper1,000 % calories from fat 9Source: Yerushalmy and Hilleboe 1957, cited in Modern Nutrition and Heart Disease, M E Shills Countries selected by Keys Countries ignored by Keys Keys did not consider sugar intake
- 10. Coronary Heart Disease Timeline • 1926 First medical description of a heart attack (in the US) • 1954 WHO called first expert meeting on atherosclerosis (hardening of the arteries) • Keys’ fat and cholesterol hypothesis not accepted by the committee • Key’s returned to the US and started planning his Seven Countries Study • 1954 Fat grading introduced for pigs in the UK • 1961 American Heart Association recommends increased consumption of polyunsaturated fats (essentially vegetable oils) to reduce heart disease 10
- 11. CHD cases per year at the Edinburgh Royal Infirmary 11 Sources: Dr Rae Gilchrist, 1971. ERI, and R. M Marquis, Smith, Kline and French, Cardiovascular Forum (Swann Press 1979), cited by Dr Walter Yellowlees, 1993, A Doctor in the Wilderness 0 12 100 321 0 50 100 150 200 250 300 350 1924-26 (2 years) 1928-30 (2 years) 1939-46 (7 years) 1947-54 (7 years)
- 12. US fat consumption 0 50 100 150 200 250 1905 1915 1925 1935 1945 1955 1965 1975 1985 1995 2005 gpercapitaperday Total fat Monounsaturated fatty acids Polyunsaturated fatty acids Saturated fatty acids 12 Source: USDA CNPP http://www.cnpp.usda.gov/USFoodSupply.htm
- 13. UK CHD v. US fat consumption 0 50 100 150 200 250 300 350 0 50 100 150 200 250 1905 1915 1925 1935 1945 1955 1965 1975 1985 1995 2005 deathsper100,000 gpercapitaperday Total fat Monounsaturated fatty acids Polyunsaturated fatty acids Saturated fatty acids CHD mortality, UK 1931-2000 (right axis) 13
- 14. 14
- 15. Consequences – for humans 15 In 2009, after two years switching to a low fat, high carb diets and from animal fats to vegetable oils, I became part of the morbidity statistics for ‘other’ CVD and almost part of the mortality statistics after an aortic dissection (a split in the main artery leaving the heart).
- 16. UK sugar consumption 16 0 20 40 60 80 100 120 140 160 1850 1870 1890 1910 1930 1950 1970 1990 sugar consumption g/day gpercapitaperday Source: Diet and Coronary Heart Disease (1974), DHSS
- 17. UK sugar consumption v. CHD 17 0 50 100 150 200 250 300 350 0 20 40 60 80 100 120 140 160 1850 1870 1890 1910 1930 1950 1970 1990 sugar consumption g/day CHD crude mortality rate gpercapitaperday deathsper100,000
- 18. Committee on the Medicinal Aspects of Food (COMA) • 1984 – COMA told us to ‘reduce consumption of saturated fatty acids* and total fat’ – the asterisk led to a footnote, which read ‘includes trans fats’, which few people noticed. • Of the 10 members: 3 were paid consultants to the sugar industry, a 4th had received food industry funding1. Two members didn’t endorse the report. An 11th member was turfed off because he was known to be convinced that sugar, not fat, was responsible for the rise in heart disease. The report stated, ‘We all agreed that the evidence falls short of proof.’ • 1989 – COMA gives sugar a clean bill of health 18 1. Cannon G, 1987, The Politics of Food, Century, London
- 19. Japan had low level of CHD but also low sugar consumption 19 Pre-war average 1958 1987 UK 107.8 lbs (134 g/day) 114.4 lbs (142.5 g/day) 83.16* lbs (103.6 g/day) Japan 27 lbs (33.7 g/day 30 lbs 37.5 g/day 48.6 lbs (60.5 g/day) Yellowlees points out that this figure was based on a European average and is probably an under-estimate in relation to the UK Sources: FAO Publications, Rome 1961, Sugar Year Book, London 1987, cited by Yellowlees, ‘A Doctor in the Wilderness, 1993
- 20. The Sugar Industry ‘There is a hidden agenda in the research support business. Those who accept your support are often perceived to be less likely to give you a bad scientific press. They may come up with results that cause you problems, but they will put them in a context in a way that leaves you happier than had they emanated from someone not receiving your support. It takes a lot to bite the hand that feeds you: a muzzle is a good insurance against unwelcome bites.’ Professor John Reid, 1983 Reid J, 1983. The life cycle of funding committees, and the basis of committee decisions, WSRO Symposium, Durban, cited in Cannon G, 1987. The Politics of Food 20
- 21. The continuing fat controversy • For example, in 2016 the BMJ published a study which found that replacing 1% of energy from saturated fat was estimated to reduce CHD by 6-8%1 • Earlier (2013 and 2016) it had published 2 papers which analysed unpublished data from 2 major intervention studies2 • Sydney Diet Heart Study 1966-73 in middle aged men. Those on low saturated fat diet/increased vegetable oil diet had higher all cause mortality and were more likely to die from CHD • Minnesota Coronary Experiment (1968-1973), randomised, 9,500 men and women aged 20-97. Key data not published at the time. Increased vegetable oil diet reduced cholesterol by 13.8%, but this group had higher incidence of CHD • These don’t disprove the lipid hypothesis on their own, but they do call it into question. 21 1. BMJ 2016;355:i5796 2. Calder, P. A hole in the lipid heart hypothesis? doi:10.1038/nrcardio.2016.78
- 22. Conclusion: we’ve got it almost entirely wrong ‘The total body of evidence suggests that attention should be shifted from the harmful effects of dietary SAFA per se, to the prevention of the accumulation of SAFA in body lipids. This shift would emphasise the importance of reducing dietary carbohydrate, especially carbohydrate with a high glycaemic index, rather than reducing dietary SAFA.’ Kuipers R S et al, 2011 The Journal of Medicine, 69(9):372-378 22
- 23. Pure Golden Oils seen as good 23
- 24. Spoof adverts show confidence of the anti-animal fats lobby 24
- 25. What’s wrong with vegetable oils? • Soyabean oil, rape oil and corn oil contain the essential fatty acids omega-6 and omega-3. So far so good. Omega-6 lowers bad cholesterol. That may be good, but it may be of no value • The ratio between these is unhealthy. Soyabean, olive, corn, cottonseed and sunflower oil contain 8, 10, 54, 58 and 199 times more omega-6 than omega-3, respectively. Rape oil contains equal amounts but as with other vegetable oils the omega-3 is only in the form of alpha-linolenic acid and only 5- 8% of this converts to the important DPA and EPA omega-3 • Palm oil contains omega-6, but no omega-3 • Omega-6 (linoleic acid) converts to arachidonic acid which causes the release of prostaglandins and other substances which cause inflammation in cells unless there is sufficient DPA and EPA to prevent this. This is believed to initiate many diseases, including dementia and rhumatoid arthritis1. 251. Calder, P, 2006. Omega-w polyunsaturated fatty acids and inflammatory processes: nutrition or pharmacology? DOI:10.1111/j.1365-2125.2012.04374.x
- 26. Hardening of vegetable oils • Most vegetable oils are liquid at room temperature and need to be hardened for use in processed foods • Hydrogenation turns polyunsaturated oils into saturated fats, and partial hydrogenation produces intermediate fats including trans fats. • Food industry now using more palm oil due concerns about trans fats, because it is a semi-solid fat at room temperature • Interestestification moves the triglycerides between molecules to create designer fats, but also increases the proportion of saturated fat • Any processed food containing ‘vegetable oil’ will either contain trans fats of interestified fats, traces of the chemical solvents, such as hexane, and byproducts of the catalysts nickel and aluminum • Fractionation – breaking down into fractions - is also frequently used with palm oil to create new variants for processed foods 26
- 27. 27 In 1954, the UK introduced punative fat grading on pigs. It became impossible to produce British free-range breeds profitably due to their high level of back fat. My father was forced to slaughter his whole herd. By 1960 very few traditional British pig herds remained in the UK. ‘From August 1954, most bacon factories purchased pigs from the Fatstock Marketing Corporation, a company established by the NFU. …It established large differentials between the different grades in an effort to encourage rapid improvements in the quality of bacon pigs. … Grading was done on the basis of back fat measurements .’1 Me in 1953, with some of my father’s 7 pedigree Wessex Saddleback sows. Consequences for farming 1. Report of the advisory committee on the development of pig production in Britain. Parliamentary Papers 1955-56 cmnd 9588, p 14
- 28. From breeds bred to thrive on grass to those needing grain or more grain 28
- 29. Polyunsaturated fats ‘Replacing a combination of SAFA and trans-fatty acids with n-6 PUFA (notably linoleic acid) in controlled trials showed no indication of benefit and a signal toward increased coronary heart disease risk, suggesting that n-3 PUFA may be responsible for the protective association between total PUFA and CVD.’ Kuipers R S et al, 2011 The Journal of Medicine, 69(9):372-378 ‘Total cholesterol, LDL cholesterol and triglycerides are all lowered by n-3 fatty acids.’ Oliver M F, 2012 Personal communication 29
- 30. Fat in US food, rise of trans fats 0 20 40 60 80 100 120 1909 1919 1929 1939 1949 1959 1969 1979 1989 1999 Unhydrogenated soybean oil Hydrogenated soybean oil Margarine Vegetable shortening Animal shortening Butter Other animal fats 30 Note: Shortening is any type of fat solid at room temperature used to make crumbly pastry and other food products. Source: USDA CNPP http://www.cnpp.usda.gov/USFoodSupply.htm gpercapitaperday
- 31. Omega-3 to Omega-6 ratio in 7 grass-fed vs. grain-fed beef studies 1.8 2.8 1.7 2.0 2.0 3.7 1.4 9.0 13.6 10.4 3.6 8.3 5.7 3.0 0 2 4 6 8 10 12 14 16 Alfaia Leheska Garcia Ponnampalam Nuernberg Descalzo Realini Grass-fed Grain-fed Daley et al: A review of fatty acid profiles and antioxidant content in grass-fed and grain-fed beef. Nutrition Journal 9:10 31 Healthy range
- 32. Switch from beef to chicken 0 50 100 150 200 250 300 1940 1950 1960 1970 1980 1990 2000 2010 Beef Chicken Source: National Food Survey 1950-2000, Defra 32 Gramspercapitaperweek Note: since this data was published it has become clear that national data was not, and still is not, collected on the types of meat being consumed in restaurants, ready meals or some fast foods. As such, while these trends are still likely to be broadly accurate, the number of grams per person for both chicken and beef may not be entirely accurate.
- 33. Intensive chicken • Chicken has less saturated fat than beef • Chicken has twice as much omega- 3 fatty acids as beef • Chicken also has vastly more omega-6 fatty than beef • A study in the UK found that the Omega-6 to omega 3 ratio of chicken was up to 9:11 • A study in Brazil (from where we import chicken) found an omega-6 to omega-3 ratio of 14:12 • Significantly higher levels of PUFA are found in drumstick meat c/w breast, but levels of omega-3, including DHA and EPA vary according to breed and production method3,4 33 1. Wang et al, 2010. Modern organic and broiler chickens sold for human consumption provide more energy from fat than protein, 2. Carnevale de Almeida J et al, 2006. Fatty acid composition and cholesterol content of beef and chicken meat in Southern Brazil, 3. Cortinas et al, 2004, Fatty Acid content of chicken thigh & breast.. 4. Del Bosco et al. 2012. Fatty acid composition of meat and…..
Editor's Notes
- Note age-adjusting allows you to properly compare death rates across populations with changing numbers in each age group – for example, as the proportion of people over 80 increases, the death rate will increase, but this does not mean that the likelihood of any one person dying has changed! This adjustment has not been performed on these figures, so actual rise would have been less steep. Also note that many of the deaths from CHD from 1920 to 1960 partly related to the increase in smoking during the First World War when cigarettes were made freely available to millions of British soldiers (this was explained to me by retired Professor Michael Oliver). What about smoking in 2nd WW? Probably the same but I don’t know. Data since 2000 shows a further fall. Decline in CHD since mid-1970s. Official view this is partly due to lower sat fat consumption. But might it just be decline in smoking – 75% less tobacco sold today than in 1961, better blood pressure medication and preventative surgery such as heart bypass operations?
- Shills M E in Modern Nutrition and Disease, In 1957, Yerushalmy and Hilleboe, using the same data set from which Keys had shown the strong relationship between dietary fats and artherosclerosis, pointed out an even stronger positive correlation between animal protein intake and the incidence of coronary heart disease’. However, we can see that there is still a general association between increased fat intake and increased levels of CHD. Of note that this often in the diet in processed food in combination with sugar. Keys did not consider sugar in 1953 or even in is major 7 countries study in 1970s (according to Dr Robert Lutzig. I have yet to check this point. Keys 1970 is over 300 pages and difficult to obtain.
- Shills M E in Modern Nutrition and Disease, In 1957, Yerushalmy and Hilleboe, using the same data set from which Keys had shown the strong relationship between dietary fats and artherosclerosis, pointed out an even stronger positive correlation between animal protein intake and the incidence of coronary heart disease’. However, we can see that there is still a general association between increased fat intake and increased levels of CHD. Of note that this often in the diet in processed food in combination with sugar. Keys did not consider sugar in 1953 or even in is major 7 countries study in 1970s (according to Dr Robert Lutzig. I have yet to check this point. Keys 1970 is over 300 pages and difficult to obtain.
- In his carefully referenced book, ‘The Great Cholesterol Con’, Anthony Colpo argues that there was no actual increase in CHD during the 20th century, simply a succession of redefinitions of heart disease by the WHO which gave the impression of an increase. It is true that the WHO didn’t call its first meeting on CHD until the 1950s and there ther are no completely reliable statistics for the incidence of CHD in either the UK or US throughout the 20th century. However, this part of the book is vefry much at odds with various accounts from medics of their first encounters with the phenomenon of middle-aged men in particular dropping dead from heart attacks, which they considered to be unexplained and unusual. This said, the lack of reliable information and the need to depend on anecdotal evidence is far from ideal. The late Professor Michael Oliver, a cardiologist from the Edinburgh Royal Infirmary and a member of the 1984 COMA panel, believed that the provision of free cigarettes to 5 million UK servicemen and women during the First World War, plus their the lifetime addiction and free cigarettes also during the Second World War were major factors in the rise of CHD (personal communiction).
- BUT Note no case of CHD at the Edinburgh Royal Infirmary before 1926 . Graph not very clear. Figures shown relate to periods and figures shown are per year. Actual data as presented: 1924-6 No deaths from CHD; 1928-30, 12 deaths from CHD; 1939-46, 100 deaths from CHD; 1947-54, 321 deaths from CHD, By 1970s running at over 500 cases per year. Ernest Shakleton the Antarctic explorer dies from a heart attach in 1922 in his forties during a trip back to Antartica. Could it be significant that Shakleton took a lot of sugar in his tea? In the Victorian era almost all dietary fats were animal fats and people were not dying of CHD – even the idle rich. However, while the testimony
- Difficult to see how the consumption of a commodity which remained flat during the 20th century could be responsible for such a major change in the rate of a human disease. Before 1920s almost all fat in the diet was animal fat. There was some cottonseed oil, but not soyalbean oil, rape oil etc. Yellowlees quotes a Dr Jack henderson (1900-1979) who had a special interest in heart disease and stated in a lecture in 1964, ‘In 1925 coronary thrombosis was a rare disease and I do not recall seeing even one example of it when I was a student’. Yellowlees also points out that Henderson was a student in Glasgow, now regarded as having one of th4e highest incidents of CHD anywhere in the world.
- Data is not available for fat consumption trends in the UK throughout the 20th century. However, tends in heart disease in US very similar to UK. Difficult to see how the consumption of a commodity which remained flat during the 20th century could be responsible for such a major change in the rate of a human disease. Before 1920s almost all fat in the diet was animal fat. There was some cottonseed oil, but not soyabean oil, rape oil, palm oil etc. Yellowlees quotes a Dr Jack Henderson (1900-1979) who had a special interest in heart disease and stated in a lecture in 1964, ‘In 1925 coronary thrombosis was a rare disease and I do not recall seeing even one example of it when I was a student’. Yellowlees also points out that Henderson was a student in Glasgow, now regarded as having one of the highest levels of CHD anywhere in the world.
- A selection of the books published over the last 43 years presenting evidence that the lipid hypothesis is flawed and/or that the main dietary causes of CHD and/or obesity are high consumption of refined carbohydrates, especially sugar and/or the substitution of saturated fat with polyunsaturated fats. The hypothesis links saturated fat consumption to raised levels of ‘bad’ cholesterol and this to increased risk of coronary heart disease. Despite billions spent trying to prove it and a number of false claims that this had been done, the hypothesis remains unproven. It remains widely supported despite an steadily increasing number of research papers, books and articles which call it into question.
- October 28 I became part of the morbidity statistics for ‘other’ CVD and almost part of the mortality statistics Aortic dissection Possible reasons: Taking diclofenac a NSAID for arthritic knee – now known to increase risk of CVD 8-fold Very short of sleep as nursing invalid mother and working through the night 3 days in a row to meet a publication deadline But had also moved to a ‘healthy diet’ due to weight gain two years, earlier - cutting out red meat and all animal fat, and eating more carbohydrate and vegetable oils instead. Should I have changed sooner, or was this also a factor? It made my minor weight problem very much worse.
- Rather better fit that fat or saturated fat. Using data from graph in grams (which is in the 1974 COMA report, but also in similar form but more directly sourced in Cleave’s ‘The Saccharine Disease 1974) current dietary guidelines recommend that men should eat no more than 120 g of sugar and women no more than 90 g a day. Young children should obviously eat proportionally less. So if we assume that taking babies and childen into account total sugar consumption per head of the population should not exceed 90 g per day, it is clear that this had happened by 1890. Given the range of consumption masked by average figures it is also likely that some individuals were consuming more than this by 1880. It takes 40 to 50 years of consuming a bad diet before most people start dying from CHD which fits very well with the beginnings of the epidemic in the late 1920s. Also perhaps of note that soldiers during WW! Had a very poor diet also high in refined sugar as in ‘Tinkers Jam’ which was universally disliked but served up on a daily basis. One of my grandfathers was sure they included wood shavings in it to bulk it out! Arguably current sugar recommendations too high anyway. Humans did not evolve to eat refined sugar. Cleave argues that we evolved to have a sweet tooth because wild fuits and berries a high in vitamins and minerals, the consumption of which made primitive people healthier and helped them to live longer.
- Rather better fit that fat or saturated fat. Using data from graph in grams (which is in the 1974 COMA report, but also in similar form but more directly sourced in Cleave’s ‘The Saccharine Disease 1974) current dietary guidelines recommend that men should eat no more than 120 g of sugar and women no more than 90 g a day. Young children should obviously eat proportionally less. So if we assume that taking babies and childen into account total sugar consumption per head of the population should not exceed 90 g per day, it is clear that this had happened by 1890. Given the range of consumption masked by average figures it is also likely that some individuals were consuming more than this by 1880. It takes 40 to 50 years of consuming a bad diet before most people start dying from CHD which fits very well with the beginnings of the epidemic in the late 1920s. Also perhaps of note that soldiers during WW! Had a very poor diet also high in refined sugar as in ‘Tinkers Jam’ which was universally disliked but served up on a daily basis. One of my grandfathers was sure they included wood shavings in it to bulk it out! Arguably current sugar recommendations too high anyway. Humans did not evolve to eat refined sugar. Cleave argues that we evolved to have a sweet tooth because wild fuits and berries a high in vitamins and minerals, the consumption of which made primitive people healthier and helped them to live longer.
- The sugar industry consultants were: Professor Harry Keen, Dr Jim Mann and Professor John Durnin. Professor Philip James had received funding from Nestlé, as had Professor Durnin. He had also received funding from the Rank Prize Fund. Professor Tony Mtchell, refused to agree the key recommendation, saying that the evidence did not support it. Professo Michael Oliver reluctantly agreed to endorse the full report but later publicly withdrew his support. I spent half a day with Professor Oliver in 2012. Professor John Yudkin, Author of ‘Pure, White and Deadly’ was on the COMA Panel which considered ‘Diet and Coronary Heart Disease’ in 1974 along with Oliver, Mitchell and Keen. He complained that he should have been on the panel which produced the 1984 but this was not heeded, suggesting that DHSS and Defra had decided in advance to blame saturated fat not sugar The recommendations of the 1984 panel were endorsed and extended in a 1994 COMA report (No 46). In 1989 Professor Keen, a paid consultant to the suar industry at multiple levels chaired the COMA panel which gave sugar a clean bill of health except in relation to ooth disease which it pointed out could easily be controlled by regular brushing.
- Ancel Keys and many others since have pointed to low consumption of saturated fat in Japan as the reason for their low level of heart disease. He also noted that the US had the highest consumption of fat and the highest levels of CHD. This was the basis of his 1953 study, where he found 4 other countries with intermediate levels of fat consumption and intermediate levels of CHD, which when plotted on a graph appeared to show a straight line association between fat consumption and CHD. However, as Yellowlees points out, Japan also had a very low consumption of sugar. Given the extent to which sugar and fa are both included in many processed foods it also seems likely that the US, at this time, had very high consumption of sugar, yet this was not even considered as a possible factor by Keys. This may simply have been an oversight rather than bias, but it is worth noting that Keys developed the K-ration (presumably named after him) for the US military in 1941. This was a high energy low weight ration containing a lot of sugar which provided 2,800 to 3,000 calories per day for military personnel in action.
- The BMJ is a particularly useful source of papers, analysis and comment on the lipid hypothesis, having published a large number of studies in recent years some which appear to support the hypothesis, others which clearly do not. Points to note are that in general none of the studies consider the fact that there are 14 different types of saturated fat and they do not all have the same effect. In addition, little consideration is given to the source of the fats or the total balance of different fats present in the diet, in the foods containing the saturated fat, or elsewhere. It is of potential significance that today an increasing proportion of saturated fat in the diet comes from vegetable oils (see slide 2) c/w 50 or 100 years ago, and some of those oils, such as palm oil, contain more saturated fat than beef tallow and much less, or in some cases no omega-3. Of further significance is the fact that vegetable oils contain no long chain omega-3 fatty acid and only 5-8% of the omega-3 in vegetable oils converts to EPA or DHA in the body.
- It has become axiomatic in our society that animals fats are harmful and vegetable oils healthy, yet the evidence tells a very different story. Before the 20th Century most fat in the diet was animal fat: butter, lard, suet and beef dripping. Yet almost no one died or CHD. This applies equally to the idle rich who took little exercise. Today a high incidence of CHD is often amongst manual labourers. Humans evolved to digest animal fats over tens of thousands of years. We have not had time to evolve to cope with many of the vegetable oils which have been used in food often partially hydrogenated and now instead interestified.
- 1954 introduction of fat grading. NFU pushing to modernise British agriculture in tandem with the government. At the time two out of every three farms in Britain kept pigs, mostly free-range. Fat grading got rid of most traditional breeds over the next few years and most outdoor production. Large Whites and Landrace came to predominate. While they can be kept outdoors, especially today as winters generally milder, the traditional breeds were unsuitable for intensive production as they would get too hot in indoors. The lipid hypothesis linking fat (note at this stage just fat, not saturated fat) to heart disease first hinted at in a textbook by Paul Dudley-White in 1947 and first postulated by Keys in a paper in 1952 (in a paper published in 1953), played into the hands of those wishing to get rid of free-range production and plough up more grassland from grain production. The Small Farm Business Grant also played a role. In order to qualify for a one-off grant of £900 (farm worker’s wage at the time was £2.50 per week, company managers typically earned £600 a year) farmers were forced to specialise in just one enterprise and either start using, or increase their use of, subsidised nitrogen fertiliser. The government also introduced a ploughing grant of £5 per acre for those ploughing up grassland. The intensification of pig production was also only made possible by the innappropriately named 1953 Penicillin (Prevention of Misuse) Act, which first permitted the routine use of antibiotics (initially just penicillin and tetracyclines) for growth promotion, something which also helped to suppress the diseases of intensification. While it is easy to criticise the modernisation of farming being promoted in the post-war period it is also important not to see agriculture prior to this period as a golden era when everything was fine. As Astor and Rowntree make clear in their book, ‘British Agriculture’, published in 1939, there were high levels of disease in British farm animals, high levels of mortality and low levels of productivity. It’s not that better agricultural education and some new techniques were not needed, in my view, it is fundamentally that the model chosen was specialisation and the removal and diversity and integration, rather than the improvement of mixed and integrated farming systems.
- British farmers responded to the requirement to produce leaner animals by switching from traditional British breeds of cattle, such as Herefords, Beef Shorthorns and Lincoln Reds to leaner breeds, most of which came from continental Europe. However, most of these breeds require grain to bring them to slaughter specifications. Farmers are also pushed to slaughter cattle at younger ages before much fat has accumulated by fat grading which imposes severe price penalties on farmers producing cattle with additional fat on the carcase. Today, most beef fat is turned into biofuel, while we turn to rain forests for the fat in our diets.
- This is the amount of fat meal expressed in grams per person per day in the US food supply. It will not be quite the same as the amount people actually eat because it doesn’t, for example, allow for fat trimmed from meat, the amount of fat discarded after cooking, or the amount of fat left on plates after a meal expressed in grams per person per day. Considering that vegetable oils are the largest source of saturated fat (contrary to popular belief) and that during the 20th century there was a trend towards discarding visible animal fats, the fact that total levels of saturated fat remained flat during the 20th century illustrates just how significant the move away from animal fats was. ‘Shortening’ (a largely US term) refers to fats used to make crumbly pastry and some other products. In the past lard (pig fat) was the major source of shortening, today vegetable oils have largely replaced lard.
- The blue shaded area marks the recognised ‘healthy’ limit– a ratio of n-6/n-3 of between 1:1 and 4:1. Oily fish have traditionally been the main source of omega-3 fatty acids in the diet, but there are not enough oily fish to go round and there are also concerns about levels of mercury, PCBs, dioxins and other pollutants in oily fish. A significant proportion of the population consume no oily fish at all, despite the recommedndation. For those people who consume less than the recommended 140g of oily fish a week, meat is an important source. However, the type of meat may be important. Grass-fed beef and lamb contain much more omega-3 than grain-fed beef and lamb; and while chicken contains significant amounts of omega-3 it also contains very high levels of omega-6 and a ration of between 8:1 and 14:1. While the consumption of 100g of grass-fed meat only provides about 10% of the recommended daily intake of DHA and EPA, the consumption of 30g of fat from the cooked beef would increase this to 60% of the 500 mg level recommended by some authorities which is many times more than many people consume.
- In 1950 the average consumption of chicken per person per week (calculated by family) was just 19 grams. Most people only ate chicken a few times a year. In contrast, the consumption of beef was almost 250 grams per person per week. However, with the dramatic rise in intensive poultry production, made possible by the routine use of antibiotics for growth promotion and the further availability of prophylactic medication with other antibiotics on veterinary prescription, as well as other technological developments, and the the increased availability of feed grain from the ploughing of grassland, poultry production increased exponentially as did consumption, encouraged as it has been by ‘healthy eating campaigns which claimed that chicken is healthier than beef due to its lower saturated fat and higher omega-3 content. In comparision, beef production fell, initially due to its high levels of saturated fat and more recently, due to claims that high meat consumption increases the risk of colorectal cancer. What is often overlooked however, is that chicken has a vefry high omega-6 to omega-3 ration of between 8:1 and 14:1