* In June 2014, the UK Scientific Advisory Committee on Nutrition (SACN) was tasked with reviewing the role of fats in health in the general UK population. The final report has just been published.
* The SACN did not examine total fat. The total fat guidelines were issued decades ago completely without evidence base and are now conspicuous in their non-mention.
* The SACN has re-issued the recommendation from the 1980s/90s that saturated fat should comprise no more than 10% of total calorie intake. There was no evidence for this recommendation at the time. (There is no more now.)
* The SACN found no evidence for reducing saturated fat, or replacing saturated with unsaturated fat, for the vast majority of conditions that they reviewed including cardiovascular (CVD) mortality and coronary heart disease (CHD) mortality. They did not present these as the key findings. Instead, they claimed that the UK population should reduce saturated fat, and replace saturated fat with polyunsaturated fat, in the name of CVD events and CHD events.
* A number of individuals and organisations responded to the draft SACN report (2018). I was one of them. I submitted in detail why the SACN preliminary findings for CVD and CHD events were not robust. I have done the same again in this note. Some of my inputs were taken on board, most were not, and the original SACN claims were either unchanged or strengthened from the draft report.
* Recommendations to reduce saturated fat (which is in every real food) and to replace saturated fat with polyunsaturated fat show real ignorance as to what fat is, where it is found and what the real issue is. Pizza, biscuits, buns, cakes, pastries, pies, puddings, ice cream, spreads, chips and confectionery deliver almost 30% of saturated fat intake for UK adults (19-64). Ditch these and health will improve, but don’t damn saturated fat because of the fake food it is in and don’t damn highly nutritious foods (meat, eggs and dairy) in the name of saturated fat.
* One third of the committee had conflicts with Unilever (makers of spreads higher in polyunsaturated fat and lower in saturated fat). Other conflicts include food and pharmaceutical companies and the International Life Sciences Institute, which is a who’s who of fake food organisations. A number of the committee members also had conflicts with a biotechnology firm, which is trying to reduce the saturated fat content of dairy products. I found the committee to be biased and I detail in this note the ways in which this manifested itself.
In June 2014, the UK Scientific Advisory Committee on Nutrition (SACN) was tasked with reviewing the role of fats in health. The scope of the review was to “consider the relationship between saturated fats, health outcomes and risk factors for non-communicable diseases in the general UK population.” The review did not address total fat. It did not address unsaturated fat – other than as a replacement for saturated fat.
The committee noted that this would be the first review of fats since the Committee on the Medical Aspects of Food Policy (COMA) reports: Dietary Reference Values for Food Energy and Nutrients for the United Kingdom in 1991 and Nutritional Aspects of Cardiovascular Disease in 1994.
The fact that the SACN remit excluded total fat speaks volumes, as restrictions were set on total fat in these 1990s reports. There has been no apology, no admission that restrictions on total fat were wrong, no postmortem to review the epidemics of diabetes and obesity that have occurred since we were told to restrict fat and increase carbohydrate intake. There is now just silence on total fat from public health authorities. And yet we’re expected to believe them in their continued war on saturated fat.
The 1994 COMA report recommended “The average contribution of saturates to dietary energy should be decreased to no more than about 10% (Ref 1). Interestingly, that COMA report cautioned “No further increase [in n-6 polyunsaturates] is recommended because the safety of high levels has not been demonstrated. The proportion of the population already consuming more than 10% of dietary energy as n-6 polyunsaturates should not increase.”
The draft report from the SACN’s review was published in May 2018 and inputs to the consultation were invited until July 3rd, 2018. You can see my review of the draft report here (Ref 2). My response, with George Henderson, to the submission can be seen here (Ref 3) and officially here (Ref 4).
My view of the draft report
I found the SACN report to be biased. I can’t put it any other way. The declarations of interest of the committee members can be seen here (please note the August 2019 update towards the end) (Ref 5). When the first (and highly impactful) article from my PhD was published in 2015 (Ref 6), one of the SACN saturated fat committee members wrote a letter to the editor defending the guidelines and closing with “Given the improvements in both levels of cholesterol and rates of heart disease world-wide in those countries which have introduced measures to reduce intakes of saturated fats, it would seem that an RCT [randomised controlled trial], with corresponding ethical approval for its conduct, would surely be required to reverse existing recommendations?” Does that seem like someone open to impartially reviewing the dietary guidelines on saturated fat?
(By the way, my February 2015 paper was included in the draft SACN report. It was excluded from the final report!)
When reviewing the draft report, I found that the SACN had done five things to try to make a case against saturated fat:
1) The SACN presented duplicated studies and studies that simply reported other studies, which gave the appearance of there being more evidence supporting their claims than there was;
2) They left out some studies – all of which found evidence of no effect (one of mine (Ref 7); Schwingshackl & Hoffman (Ref 8) and Hamley (Ref 9));
3) They presented non-significant results as if significant;
4) They looked for and reported fixed effects methodology when the random effects methodology concluded that there were no significant findings (Note 10);
5) They ignored evidence that didn’t suit them (paragraphs 8.40-8.47 in the draft report were extraordinary).
All of these five biases have been reiterated in the final report.
The conclusion of the final report
The key conclusions of the 443-page final report were (reported verbatim with the paragraph reference):
– “S.16 New evidence published since 1994 supports and strengthens the COMA conclusion that a reduction in intake of saturated fats from current population average levels would be beneficial.”
– “S.18 The evidence also indicates that reducing saturated fats is unlikely to increase health risks for the general UK population.”
(ZH comment – S.18 is scarily reminiscent of the 1977 Senator McGovern report which said: “Some witnesses have claimed that physical harm could result from the diet modifications recommended in this report… However, after further review, the Select Committee still finds that no physical or mental harm could result from the dietary guidelines recommended for the general public” (p.xxxiii) (Ref 11). It is negligent to recommend dietary change in the hope that it is “unlikely” to increase health risks. First do no harm.)
– “S.19 There were significant relationships between intake of saturated fats and CVD and CHD events, but not CVD and CHD mortality.”
The key recommendations were:
“S.24 It is recommended that:
• the dietary reference value for saturated fats remains unchanged: the [population] average contribution of saturated fatty acids to [total] dietary energy be reduced to no more than about 10%. This recommendation applies to adults and children aged 5 years and older.
• saturated fats are substituted with unsaturated fats. More evidence is available supporting substitution with PUFA than substitution with MUFA.”
The bottom line of the SACN report is that the 1991 and 1994 10% restrictions on saturated fat were correct. What are the chances that a number set in 1977 (US) and 1984 (UK), with no evidence-base, turned out to be correct? The 2019 SACN report has then overturned the 1994 COMA report cautions about n-6 polyunsaturated fats and said that these should be consumed instead of saturated fat.
It is timely at this point to remind ourselves of the nutritional facts about fat: i) all foods that contain fat contain all three fats (saturated, monounsaturated and polyunsaturated), there are no exceptions and ii) dairy is the only food group, which contains more saturated than unsaturated fat. If we consume more meat, eggs, fish, nuts and even lard, we consume more unsaturated than saturated fat. Not that saturated fat is bad and unsaturated fat is good – why would nature try to harm us and help us in the same foods? – but just to state facts. More recently, I have been trying to find a food that does not contain saturated fat. So far, I can find one – sucrose.
Table S1 (pages 23-27) in the 2019 SACN report summarised the evidence for the conditions that were examined. There was no evidence to support either reducing saturated fat, or replacing saturated fat with polyunsaturated fats, for: type 2 diabetes; colorectal cancer; pancreatic cancer; lung cancer; breast cancer; prostate cancer; cognitive decline; mild cognitive impairment; Alzheimer’s disease; dementias; CVD mortality; CHD mortality; strokes; or peripheral vascular disease (Note 12). Those were the vast majority of conditions examined by far. These should have been the headlines.
The evidence for the claims on CVD & CHD events
The SACN should have ignored all evidence related to surrogate end points, as this is irrelevant when outcome evidence is available. The SACN should also have ignored all evidence related to prospective cohort studies, as this is irrelevant when outcome RCT evidence is available.
The report claimed the following from meta-analysis of RCTs:
1) That there is “adequate” evidence that reducing SFA intake reduces CVD events. (This was unchanged from the draft report);
2) That there is “adequate” evidence that replacing SFA with PUFA reduces CVD events (This was unchanged from the draft report);
3) That there is “moderate” evidence that reducing SFA intake reduces CHD events (This was unchanged from the draft report);
4) That there is “moderate” evidence that replacing SFA with PUFA reduces CHD events. (This was upgraded from “limited” evidence in the draft report).
1) Relies entirely on one paper – Hooper et al 2015. In my response to the draft report, I pointed out the limitations of Hooper et al (these have been published in a peer-review paper (Ref 13)): i) It included non-peer reviewed information, solicited by Hooper et al, from 4 small studies, involving 646 people with other conditions (skin cancer, diabetes, etc). This was the single difference between Hooper et al finding something and other authors not finding anything and ii) when sensitivity tests were undertaken for studies that actually reduced saturated fat (as opposed to studies that set out to achieve this), the single finding for CVD events ceased to be significant.
I also pointed out that a paper had been excluded in this section – Schwingshackl and Hoffmann, which found no impact on CVD events of reducing saturated fat (from meta-analysis of RCTs) (Ref 14).
The SACN rejected all my inputs – dismissing a glaring error in one of the studies used only by Hooper et al as “most likely to be a typographical error.” The SACN justified excluding Schwingshackl and Hoffmann by saying “it was only looking at secondary prevention of CHD rather than looking at risk of CHD in the general population.“ i) Schwingshackl and Hoffmann looked at CVD, not CHD and ii) every study pooled by Hooper et al included, or was exclusively undertaken on, sick people (mostly male) and thus the same exclusion should have applied to Hooper et al. The one RCT conducted on men and women (ostensibly generalisable to whole populations, but conducted in mental and other institutions and thus not so) (Ref 15) was excluded by Hooper et al. (I made the point about no findings being applicable to general populations in my submission to the SACN. It was rejected.)
2) Relies entirely on two papers – Hooper et al 2015 and Ramsden 2013. Hooper et al 2015 was entitled “Reduction in saturated fat intake for cardiovascular disease.” It wasn’t about replacement of saturated fat. The strongest conclusion on this subject was: “Replacing the energy from saturated fat with polyunsaturated fat appears to be a useful strategy…” (my emphasis). Hooper et al 2015 didn’t specify whether n-3 or n-6 polyunsaturated fats should replace saturated fats. As was noted in paragraph 8.14 of the final SACN report “It was reported that there was no effect from substituting saturated fat with n-6 PUFA alone (Ramsden et al, 2013).“ Schwingshackl and Hoffmann, which found nothing related to replacement of saturated fat and CVD events, was also wrongly excluded from this section.
3) Is a great example of the bias of the SACN. It relies again on the same one paper, Hooper et al 2015. But this time, it relies on an abuse of Hooper et al 2015. Hooper et al found no effect of reduced saturated fat on CHD (mortality or events) using the “random effects model” of meta-analysis, which is the correct one to use. (Technical point – a fixed effects model cannot be used given the heterogeneity of dietary fat trials. The I² of 66% confirms this.) The SACN used the fixed effects model (which Hooper et al reported merely as a sensitivity test) to claim evidence for reducing saturated fat on CHD events. At no time have Hooper et al made a claim for a significant finding for CHD events.
4) Again, shows the bias of the SACN. It relies on a) claiming non-significant results as significant, b) including a biased paper (with Unilever conflicts) and c) the exclusion of a paper that didn’t support their view.
a) The SACN claim that replacing SFA with PUFA reduces CHD events was based on two non-significant results (Skeaff & Miller 2009 and Hooper et al 2015). I pointed both out in my submission as follows:
“Skeaff & Miller (2009) has been wrongly and disingenuously reported. The SACN report claimed that high PUFA and lower saturated fats “reduced the risk for CHD events (RR 0.83, 95% CI 0.69 to 1.00; p=0.05; I2 =44.2%; 8 RCTs; 4528 participants, 284 events…” This is not statistically significant, as it includes the line of no effect.”
“Hooper et al (2015) has been wrongly and disingenuously reported. The claim that “there was a 24% reduction in CHD events (RR 0.76, 95% CI 0.57 to 1.00; >3000 participants, 737 events)” is misleading. This is not statistically significant, as it includes the line of no effect. Hooper et al have never made such a claim for CHD events.”
b) The SACN also relied on a paper by Mozaffarian et al (2010): I addressed this in my submission as follows:
“Mozaffarian et al (2010)(Ref 16) should be excluded for its study selection, as was explained in this peer reviewed critique paper (Ref 17). Mozaffarian et al (2010) omitted two studies that cautioned about the potential harm/toxicity of PUFAs and it included the non-randomised, non-controlled Finnish Mental Hospital cross-over trial, which all other respectable researchers, including Cochrane, omitted.”
c) A paper by Hamley (2017) was flagged as missing by Forouhi’s and my submission (Ref 18). This found “when pooling results from only the adequately controlled trials there was no effect for major CHD events.” The SACN excluded Hamley as follows: “Due to lack of detailed description of criteria for ‘adequately’ controlled trials, SACN agreed that Hamley (2017b) could not be considered in drawing the conclusions.”
My challenges were all rejected. The SACNs conclusion to this section was: “SACN graded the evidence for CHD events as moderate, based on an adequate number of studies and events, consistency with the outcome of Mozaffarian et al, (2010), and upper confidence interval from Hooper et al, (2015) of 1.00.”
With the words “Upper confidence interval of 1.00”, the SACN has just redefined statistical significance to suit their own agenda.
And that’s it. The entire case against saturated fat – which was started with no evidence in the name of heart disease, now continues with contrived evidence against CVD and CHD events.
The SACN has been negligent and irresponsible in endorsing a recommendation to replace saturated fat with polyunsaturated fat a) in the absence of strong evidence and b) without serious cautions about n-6 being the replacement. But then one third of the SACN committee had Unilever conflicts and one, David Mela, was Unilever’s Senior Scientist.
What the SACN should have done
1) Open by apologising on behalf of all public health advisors since 1984 (the first UK dietary fat guidelines) that total fat was ever restricted, as there has never been any evidence against this. Continue to apologise that there was never any evidence against saturated fat when restrictions were introduced and admit that this current report is an attempt to retrospectively justify recommendations for which there was no evidence.
2) Present the non-findings as the key messages. Ensure that the general population knows that nothing has been found against saturated fat for most conditions examined. Stress that there was no evidence to support either reducing saturated fat, or replacing saturated fat with polyunsaturated fats, for almost every condition examined: type 2 diabetes; colorectal cancer; pancreatic cancer; lung cancer; breast cancer; prostate cancer; cognitive decline; mild cognitive impairment; Alzheimer’s disease; dementias; CVD mortality; CHD mortality; strokes; or peripheral vascular disease. Make those the headlines. Reassure the public that you really don’t need to worry about a substance found ubiquitously in natural food.
3) Include CHD events in non-findings – to try to claim findings that were not claimed by the authors is a demonstration of bias and an abuse of power. Then critique Hooper et al (2015) properly (as shown in (1) above) and this finding also ceases to exist.
4) IF the SACN insists on maintaining that findings for CVD (or CHD) events should be taken seriously, they need to clarify the following:
i) No findings apply to the general UK population, which was the population that SACN was tasked with working for. No findings apply to any general population for that matter. None of the dietary fat RCTs, pooled in meta-analysis, have been undertaken in the general population.
ii) No study recommended change. A number cautioned about the potential harm of their (vegetable oil/n-6) interventions (Ref 19). The SACN should warn the public that increases in n-6 have not been shown to be safe.
iii) There might/might not be a benefit from eating more oily fish. If you choose mackerel, for example, over steak, you will consume more total and saturated fat, and you will consume more n-3 essential fatty acids (Ref 20). The original (1989) DART study found this to be a benefit, but the finding could not be replicated by the same team (Ref 21).
iv) A lot of fake food is rich in saturated fat. Don’t eat pizza, biscuits, buns, cakes, pastries, pies, puddings, ice cream, spreads, chips and confectionery etc (Note 22). Your saturated fat intake will reduce by about a third, but that’s an aside – the health benefit will come from not eating junk.
5) The SACN could have done the UK population a genuine favour by concluding that we should cease the demonisation of saturated fat – something that they may not realise is in every food other than sucrose – and advise populations to consume healthy whole diets instead. The SACN should have said “our best advice to the UK population is to eat real food, which provides the macro and micro nutrients needed for optimal health. These are found in meat (especially red), fish (especially oily), eggs (especially yolks), and dairy products (especially full fat). Vegetables, legumes, nuts and seeds can also provide nutrients of value.”
Oh and “we’re really sorry about the carbohydrate-metabolic consequences of making dietary fat recommendations 35 years ago with no evidence.”
Ref 1: Committee on Medical Aspects of Food Policy (COMA). Nutritional Aspects of Cardiovascular Disease. In: Authority HE, ed. Nutrition briefing paper. London: Health Education Authority, 1994
Ref 2: http://www.zoeharcombe.com/2018/05/sacn-report-on-saturated-fat/
Ref 3: http://www.zoeharcombe.com/2018/07/saturated-fat-consultation-sacn-my-response/
Ref 4: https://www.gov.uk/government/consultations/saturated-fats-and-health-draft-sacn-report
Ref 5: http://www.zoeharcombe.com/2018/06/scientific-advisory-committee-nutrition-sacn-declarations-of-interest/
Ref 6: Harcombe Z, Baker JS, Cooper SM, Davies B, Sculthorpe N, DiNicolantonio JJ, et al. Evidence from randomised controlled trials did not support the introduction of dietary fat guidelines in 1977 and 1983: a systematic review and meta-analysis. Open Heart. 2015.
Ref 7: This was excluded from the draft document and included in the final: Harcombe Z, Baker JS, Davies B. Evidence from prospective cohort studies did not support the introduction of dietary fat guidelines in 1977 and 1983: a systematic review. Br J Sports Med. 2016.
This was included in the draft document and excluded from the final: Harcombe Z, Baker JS, Cooper SM, Davies B, Sculthorpe N, DiNicolantonio JJ, et al. Evidence from randomised controlled trials did not support the introduction of dietary fat guidelines in 1977 and 1983: a systematic review and meta-analysis. Open Heart. 2015.
Ref 8: Schwingshackl L, Hoffmann G. Dietary fatty acids in the secondary prevention of coronary heart disease: a systematic review, meta-analysis and meta-regression. BMJ Open. 2014.
Ref 9: Hamley S. The effect of replacing saturated fat with mostly n-6 polyunsaturated fat on coronary heart disease: a meta-analysis of randomised controlled trials. Nutrition journal. 2017.
Note 10: This is a technical aspect of meta-analysis, which is the methodology for pooling data from RCTs or PCSs. There are virtually no circumstances when using fixed effects methodology is the correct methodology. The pooled trials and cohort studies need to be virtually identical for that to be appropriate and this rarely, if ever, is the case. There were a number of occasions when the correct methodology – the random effects method – was reported in a paper as showing that there was no effect and yet the committee searched the paper for mentions of fixed effects tests, usually done as sensitivity tests, and reported the fixed effects outcome if it showed that there was an effect. I reported this as bias when I saw it.
Ref 11: Select Committee on Nutrition and Human Needs. Dietary goals for the United States. Second ed. Washington: U.S. Govt. Print. Off. December 1977
Note 12: This means that there was either no evidence or evidence of no relationship.
Ref 13: Harcombe Z. Dietary fat guidelines have no evidence base: where next for public health nutritional advice? Br J Sports Med 2016
Ref 14: Schwingshackl L, Hoffmann G. Dietary fatty acids in the secondary prevention of coronary heart disease: a systematic review, meta-analysis and meta-regression. BMJ Open 2014
Ref 15: Frantz ID, Dawson EA, Ashman PL, et al. Test of effect of lipid lowering by diet on cardiovascular risk. The Minnesota Coronary Survey. Arteriosclerosis 1989
Ref 16: Mozaffarian D, Micha R, Wallace S. Effects on coronary heart disease of increasing polyunsaturated fat in place of saturated fat: a systematic review and meta-analysis of randomized controlled trials. PLoS Med 2010.
Ref 17: Ravnskov U, DiNicolantonio JJ, Harcombe Z, et al. The Questionable Benefits of Exchanging Saturated Fat with Polyunsaturated Fat. Mayo Clinic proceedings Mayo Clinic 2014.
Ref 18: Hamley S. The effect of replacing saturated fat with mostly n-6 polyunsaturated fat on coronary heart disease: a meta-analysis of randomised controlled trials. Nutrition journal 2017.
Ref 19: Rose GA, Thomson WB, Williams RT. Corn Oil in Treatment of Ischaemic Heart Disease. BMJ 1965.
Woodhill JM, Palmer AJ, Leelarthaepin B, et al. Low fat, low cholesterol diet in secondary prevention of coronary heart disease. Advances in experimental medicine and biology 1978.
Ref 20: http://www.zoeharcombe.com/2018/01/saturated-fat/
Ref 21: Burr ML, Fehily AM, Gilbert JF, et al. Effects of changes in fat, fish, and fibre intakes on death and myocardial reinfarction: diet and reinfarction trial (DART). The Lancet 1989.
Burr ML. Secondary prevention of CHD in UK men: the Diet and Reinfarction Trial and its sequel. Proc Nutr Soc 2007.
Note 22: Table A3.2 in the full report listed sources of saturated fat. I took intakes of Pasta, rice, pizza and other miscellaneous cereals (6%), biscuits (5%), Buns, cakes, pastries and fruit pies (4%), puddings (1%), ice-cream (1%), reduced fat spreads (2%), meat pies and pastries (3%), chips (3%) and confectionery (4%) for the 19-64 age group.