understanding fats - richard young
TRANSCRIPT
Living off: the fat of the landOr the fat of the rainforest?
Richard Young,ORFC 2017
grass
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 FatUS data1
1909Meat/fish
2000Meat/fish
1909Vegetable
2000Vegetable
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 20142. USDA, 2004. Nutrient Content of the US Food Supply
1909-20003. COMA, 1984. Diet and cardiovascular disease pp18-19
UK - Saturated fat fell from 19.9%2 to 12.6%1 energy intake, 1980-2012
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
3Statistics: British Heart FoundationThe Nuffield Trust and Diabetes.co.uk
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
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
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
CHD Mortality, UK 1931-2000
1930 1940 1950 1960 1970 1980 1990 20000
50
100
150
200
250
300
350
Dea
ths p
er 1
00,0
00
7Source: Office for National Statistics. Rate not age-adjusted.
1953, Ancel Keys claims link between fat intake, cholesterol and CHD1
5 10 15 20 25 30 35 40 450
1
2
3
4
5
6
7
8
US
CanadaAustralia
England & Wales
Italy
Japan
% calories from fat
CHD
dea
ths p
er 1
,000
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, 20:118-1392. Page H et al., 1961, Dietary fat and its relation to heart attacks
and strokes, Circulation 23:133-136
‘Six Countries Study,’ with ignored countries included
5 10 15 20 25 30 35 40 450
1
2
3
4
5
6
7
8
% calories from fat
CHD
dea
ths p
er 1
,000
9Source: Yerushalmy and Hilleboe 1957,cited in Modern Nutrition and Heart Disease, M E Shills
Countries selected by KeysCountries ignored by Keys
Keys did not consider sugar intake
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
CHD cases per year at the Edinburgh Royal Infirmary
11Sources: 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
1924-26 (2 years) 1928-30 (2 years) 1939-46 (7 years) 1947-54 (7 years)0
50
100
150
200
250
300
350
012
100
321
US fat consumption
1905 1912 1919 1926 1933 1940 1947 1954 1961 1968 1975 1982 1989 1996 20030
50
100
150
200
250Total fatMonounsaturated fatty acidsPolyunsaturated fatty acidsSaturated fatty acids
g pe
r cap
ita p
er d
ay
12Source: USDA CNPP http://www.cnpp.usda.gov/USFoodSupply.htm
UK CHD v. US fat consumption
1905 1912 1919 1926 1933 1940 1947 1954 1961 1968 1975 1982 1989 1996 20030
50
100
150
200
250
0
50
100
150
200
250
300
350Total fatMonounsaturated fatty acidsPolyunsaturated fatty acidsSaturated fatty acidsCHD mortality, UK 1931-2000 (right axis)
g pe
r cap
ita p
er d
ay
deat
hs p
er 1
00,0
00
13
14
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).
UK sugar consumption
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1850 1870 1890 1910 1930 1950 1970 19900
20
40
60
80
100
120
140
160sugar consumption g/day
g pe
r cap
ita p
er d
ay
Source: Diet and Coronary Heart Disease (1974), DHSS
UK sugar consumption v. CHD
17
1850 1870 1890 1910 1930 1950 1970 19900
20
40
60
80
100
120
140
160
0
50
100
150
200
250
300
350sugar consumption g/dayCHD crude mortality rate
g pe
r cap
ita p
er d
ay
deat
hs p
er 1
00,0
00
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
181. Cannon G, 1987, The Politics of Food, Century, London
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 lbs37.5 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
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
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.
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1. BMJ 2016;355:i57962. Calder, P. A hole in the lipid heart hypothesis?
doi:10.1038/nrcardio.2016.78
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, 2011The Journal of Medicine, 69(9):372-378
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Pure Golden Oils seen as good
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Spoof adverts show confidence of the anti-animal fats lobby
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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
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
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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
From breeds bred to thrive on grass to those needing grain or more grain
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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, 2011The Journal of Medicine, 69(9):372-378
‘Total cholesterol, LDL cholesterol and triglycerides are all lowered by n-3 fatty acids.’
Oliver M F, 2012Personal communication
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Fat in US food, rise of trans fats
19091913
19171921
19251929
19331937
19411945
19491953
19571961
19651969
19731977
19811985
19891993
19972001
20050
20
40
60
80
100
120
Unhydrogenated soybean oilHydrogenated soybean oilMargarineVegetable shorteningAnimal shorteningButterOther animal fats
30Note: 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
g pe
r cap
ita p
er d
ay
Omega-3 to Omega-6 ratio in 7 grass-fed vs. grain-fed beef studies
Alfaia Leheska Garcia Ponnampalam Nuernberg Descalzo Realini0
2
4
6
8
10
12
14
16
1.82.8
1.7 2.0 2.0
3.7
1.4
9.0
13.6
10.4
3.6
8.3
5.7
3.0
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
Switch from beef to chicken
1940 1950 1960 1970 1980 1990 2000 20100
50
100
150
200
250
300Beef Chicken
Source: National Food Survey 1950-2000, Defra32
Gram
s per
cap
ita p
er w
eek
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.
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
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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…..
