By Marika Sboros
It is official: Harvard scientists say butter is not back. Saturated fat will kill you. Fat phobia is back – with a vengeance.
The scientists from Harvard TH Chan School of Public Health and Brigham Women’s Hospital don’t say that in quite so many words. Those are just implications of conclusions in their new study in the JAMA Internal Medicine.
They say the more saturated fat you eat, the shorter you’re likely to live. The more unsaturated fat you eat, the longer your days on this planet. They say you should replace saturated fats, such as butter, lard, and fat in red meat, and trans fats with unsaturated fats from plant-based foods, such as olive oil, canola oil, and soybean oil. They say this should “continue to be a key message in dietary recommendations”.
They say their study is “further support” for the 2015-2020 US dietary guidelines – that are high in carbs and low in saturated fats (HCLF). But is this study really a fatal blow to the science behind low-carb, high-fat (LCHF)?
Does it breathe new life into the failing diet-heart hypothesis, the scaffold that holds the guidelines together?
Also known as the lipid hypothesis, the diet-heart hypothesis is the one that says fat in the diet equals fat in the arteries; that saturated fat clogs your arteries and will give you a heart attack or stroke.
The researchers say eating less saturated and trans fat doesn’t just lower your risk of early death from cardiovascular disease and cancer. It protects you from neurodegenerative diseases such as Parkinson’s and Alzheimer’s.
A study senior author is Dr Frank Hu, professor of nutrition and epidemiology at Harvard Chan School and professor of medicine at Harvard Medical School. On Harvard’s website, Hu says the study shows “the importance of eliminating trans fat and replacing saturated fat with unsaturated fats, including both omega-6 and omega-3 polyunsaturated fatty acids”.
He says in practice, “replacing animal fats with a variety of liquid vegetable oils” achieves this.
Hu also says in a New York Times blog the study shows that low-fat, high-carb diet doesn’t benefit health and longevity”. He says fats from fish and avocados are better than animal fats.
Study lead author Harvard epidemiology and nutrition doctoral student Dong Wang calls the study “the most detailed and powerful examination to date” on how dietary fats impact health.
If that’s the case, the study should already be a knockout blow to critics of the US guidelines. It should quickly silence the vocal support for safety and efficacy of LCHF to treat obesity, diabetes, heart disease, cancer and dementia and other serious diseases.
In the UK it should hand victory on a platter to one side of the “fat wars“. It could effectively answer those nasty enough to say Public Health England’s Eatwell Guide is more like an Eatbadly Guide.
It’s probably not all that surprising that doctors, dietitians and mainstream media globally swallowed the study’s messages whole.
Harvard is one of the world’s most revered research institutions. The world sits up and takes notice when Harvard scientists make declarations about what we should all eat and not eat. More so when Harvard comes out in open support of official dietary advice.
The US guidelines are the world’s most influential source of public dietary advice. Most English-speaking countries have dutifully followed them for the past 35 years.
It’s an understatement to say the guidelines are controversial. Some experts say the guidelines have probably helped to kill millions around the world. They say the guidelines contribute to global epidemics of obesity, diabetes, heart disease and other life-threatening diseases.
Research shows the guidelines were short on science when the US government first launched them on an unsuspecting public four decades ago.
A study by British obesity researcher Dr Zoë Harcombe in the BMJ Open Heart in 2015 reveals just how short. In the British Journal of Sports Medicine in April 2016 she shows why both the US and UK guidelines should not have been introduced.
Research also shows that the guidelines quickly became a licence to print money for powerful vested interests propping them up.
Those interests are not just in medical and scientific nutrition circles. Research points to undue influence of food and drug industries on the guidelines.
It doesn’t take a rocket investigative journalist to work out why these industries are so keen to maintain the status quo. Or why the Harvard researchers have positioned their study clearly as shoring up the US guidelines.
The researchers do admit to some study limitations. Among these is “reverse causation” as a possible explanation for findings, since people with chronic disease and poor health might change dietary habits. However, they believe the study strengths offset any weaknesses. They point to the large sample size, high follow-up rates, and “repeated assessments of dietary and lifestyle variables during a long period”.
The study examines associations of specific dietary fats with total and cause-specific mortality in two large ongoing cohort studies involving 126,233 participants. These include 83,349 women from the Nurses’ Health Study, and 42,884 men from the Health Professionals Follow-up Study (February 1, 1986, to January 31, 2012). Participants were free of cardiovascular disease, cancer, and types 1 and 2 diabetes at baseline. They answered “validated food frequency questionnaires (FFQs)” every two to four years on diet, lifestyle and health.
The 35-year follow-up period is similarly impressive numerically: 3,439,954 person-years.
So far, so good – if this were a numbers game. However, nutrition science is not a numbers game. And given human bio-individuality, it’s as much art as science.
The researchers do make it clear their study is epidemiological. Thus it can only show association, not causation. Presumably, they know most scientists consider this kind of evidence weak and unreliable. It’s a far lower class of evidence compared with randomised controlled trials (RCTs, the “gold standard” of scientific research).
That makes the authors’ conclusions that much more surprising. Critics say the study has so many holes in it, it’s lucky it’s not an ocean-going liner.
Weaknesses include the way researchers have analysed and obtained results in this study. The researchers have also ignored the well-documented unreliability of FFQs. In her seminal work, The Big Fat Surprise, US science journalist Nina Teicholz quotes sources showing that Harvard itself has established the unreliability of FFQs.
Another hole is the absence of all the available evidence contradicting the researchers’ hypothesis. Wang has said evidence on specific dietary fat (saturated in this case) and mortality remains “limited and inconsistent”. That’s an understatement at best. At worst, it’s wrong.
Teicholz could direct Wang’s attention to at least 14 systematic reviews and meta-analyses concluding that saturated fats are not associated with CVD or have no effect on CVD mortality. And that’s just over the past five years.
These omissions are all the more surprising on Hu’s part. A responder on JAMA Internal Medicine Pub Peer notes that Hu co-authored two prominent review papers on saturated fat and heart disease in the American Journal of Clinical Nutrition in 2010. These looked at the historical literature. They found “both no association of saturated fats with heart disease (the epi data) and very little evidence of an effect on heart disease (the RCT data)”.
Hu’s obvious enthusiasm for vegetable (seed) oils is also somewhat surprising. He appears oblivious to evidence on health risks of these oils, and not just those that are industrially produced.
In the same Pub Peer report, another critic asks why Hu did not disclose another significant conflict of interest. As a member of the 2015 Dietary Guidelines Advisory Committee, he chaired the controversial review on saturated fats and heart disease. That’s a position his study seeks to support.
Must read: ALL SEED OILS SAFE TO EAT? FAT CHANCE!
The critic says publishing a paper that appears to confirm the controversial policy recommendation that Hu directed could be viewed as an effort to support his policy work. This is an obvious conflict of interest which Hu should have disclosed.
Wang and colleagues also appear at times to conflate saturated and trans fats, as if they are part of the same problem.
In his blog, The Science of Human Potential, New Zealand nutrition professor Dr Grant Schofield eviscerates the study. It’s worth reading what he has to say in full.
Schofield is professor of public health at Auckland University of Technology and director of the university’s Human Potential Centre. He says the trans fats that occur naturally in red meat and dairy “are widely believed to be beneficial” and weren’t the trans fats measured in the Harvard research. Butter, meat and lard contain lots of unsaturated fat – “the unsaturated fat that’s supposed to be good for people in this study”.
As well, he says Americans actually eat very little butter – 4.8% of total fat in 1955, before fat-phobia started. Thus Schofield says the contribution of butter and lard to saturated fat intake in these studies “would have been small”. And in a recent meta-analysis of butter alone, the first ever done, it has “zero correlation with cardiovascular disease”.
Schofield says it is predictable that Harvard is beginning to confirm the benefits of a high-fat diet. “Yes, even in the context of the confounders of this study,” he says.
He finds it annoying that the researchers “harp on the evils of the saturated fat found in naturally occurring and nutritious food”. And that they continue to promote industrially refined vegetable oils and spreads (which is how trans fats got in our diet in the first place), based on evidence collected by methods which don’t seem that reliable to begin with”.
Seen from another angle, Hu’s involvement can look suspiciously like another salvo in what Irish investigative journalist Dean Sterling Jones calls “Silencing Science – The War on Nina Teicholz”. In the murky politics of nutrition science, that’s not hyperbole. Jones reveals the unedifying behaviour of those opposed to Teicholz’s research.
That war began in earnest after Teicholz published The Big Fat Surprise (Simon and Schuster, 2014). In a review on the BMJ titled Are some diets mass murder?, former BMJ editor Dr Richard Smith is fulsome in its praise. He says all scientists should read it.
The war intensified after Teicholz wrote a commissioned feature highlighting the shortcomings of the DGAC report which the BMJ published in 2015. Titled The scientific report guiding the US dietary guidelines: is it scientific?, Teicholz concludes that the DGAC report “fails to reflect much relevant scientific literature in its reviews of crucial topics and therefore risks giving a misleading picture”.
The omissions, she says, suggest a distinct reluctance by the report’s committee “to consider any evidence that contradicts the last 35 years of nutritional advice”. The committee used “weak scientific standards, reversing recent efforts by the government to strengthen the scientific review process”.
Teicholz identifies undeclared COIs (conflicts of interest) and procedural errors that have led to “internal bias as well as outside agendas”.
The DGAC report’s authors published a response in the BMJ calling Teicholz’s claims “misleading and unsubstantiated”. They say all their procedures were “expansive, transparent, and thoughtful, with multiple opportunities for public input through open commentary, public meetings, and hearings”.
They see nothing wrong in having a chair from industry, not medicine, science or academia: Barbara Millen. Millen has a doctorate and an academic background in nutrition. However, she is currently founder and president of the US-based start-up Millennium Prevention. The company develops web-based platforms and mobile applications to encourage better lifestyle behaviours, and for corporate, academic, and community wellness initiatives.
The DGAC refers positively to the kind of products her company sells. Millen dismisses criticisms that this constitutes a conflict of interest.
None of the DGAC report authors appears to see anything wrong in the extraordinary lengths to which Hu and Millen have gone to muzzle Teicholz. Just how extraordinary shows up in an intricate cross-posting collaboration between Jones and US investigative journalist Peter Heimlich.
Heimlich writes The Side Bar, an annex to his MedFraud website. He accessed damning emails via public record requests under the US Freedom of Information Act. These document just how far both Hu and Millen went to get the BMJ to retract Teicholz’s feature. Hu lobbied colleagues and professionals, eventually getting around 180 academics at top universities, in the US and Europe to sign a letter to the BMJ requesting retraction of Teicholz’s feature. (Other reports put the number lower at just over 170. Millen signed.)
The letter, which Bonnie Liebman at the Center for Science in the Public Interest (CSPI) organised, could have looked like a blow to Teicholz’s research. On its website, the Washington, DC-based advocacy non-profit group says more than 180 prominent cardiovascular and nutrition scientists from 19 countries signed the letter and called for the BMJ to retract Teicholz’s feature.
The letter alleged that Teicholz’s attack on the DGAC report was itself “riddled with numerous factual errors”. It says these undermine her conclusion that the DGAC report, especially its advice to limit saturated fat, suffers from “an overall lack of sound science”.
British author and speaker Ian Leslie shoots that claim out the water in The sugar conspiracy , a brilliant “Long Read” in The Guardian in April 2016, headlined. Leslie describes the nutrition establishment ‘s reaction to Teicholz’s BMJ piece as “ferocious”. He says 173 scientists, some of whom were on the advisory panel, and many of whose work had been critiqued in Teicholz’s book, signed a letter to the BMJ, demanding it retract the piece.”
Leslie says that “publishing a rejoinder to an article is one thing; requesting its erasure is another, conventionally reserved for cases involving fraudulent data”. He quotes NHS consultant oncologist Dr Santhanam Sundar in a response to the letter on the BMJ website: “Scientific discussion helps to advance science. Calls for retraction, particularly from those in eminent positions, are unscientific and frankly disturbing.”
The BMJ has put the issue to an outside panel of reviewers where it currently remains.
The action of those experts raises the question of why, with such a significant numerical advantage over Teicholz, did they not prevail?
Probably because Teicholz responded with a powerful blood-letting salvo of her own. On The Big Fat Surprise website, she shows how the scientists who signed the letter were practically haemorrhaging undeclared COIs.
She points to common factors among the signatories. Most are researchers who have promoted the diet-heart hypothesis which Dr Ancel Keys first proposed way back in the 1950s. In fact, Teicholz points out that the signers include “all the remaining authors of the Seven Countries Study and their intellectual offspring at the American Heart Association and Harvard”.
It’s probably strategic rather than mere coincidence then that the CSPI retraction request has disappeared from its website. Here’s what you get when you look for it:
The DGAC report authors are clearly still out to get Teicholz. Heimlich used another FOIA request to show how Millen intervened to remove Teicholz as a speaker on a National Food Policy Conference panel earlier this year.
In emails to Angie Tagtow, executive director the US Department of Agriculture Center for Nutrition Policy and Promotion, Millen issues an ultimatum: It’s Teicholz or me. What is even more astonishing is the person Tagtow suggests in place of Teicholz, who attended Yale and graduated from Stanford: Philippe Caradec from Danone. Tagtow she says Caradec has a “compelling story on product reformulation”. (Caradec didn’t make it onto the panel.)
But back to Hu and the Harvard study.
University of Cape Town emeritus professor Dr Tim Noakes dismisses it simply as “dishonest science”.
In an email to me, Noakes says ”Harvard know that the gold standard research method RCTs have disproved the low-fat diet-heart hypothesis. There is no evidence that saturated fats are harmful – there never was.”
“(Harvard) should stop doing endless associational studies that cannot prove causation in any attempt to “pull this particular rabbit out of the hat again”.
Noakes says most of the evidence from the Harvard study supports exactly what LCHF theory proposes: no trans fats; fewer carbs; more healthy mono-unsaturated fats; healthy polyunsaturated fats (omega 3s); no vegetable oils.
“Because Harvard School of Public Health is so committed to the value of vegetable oils, (the scientists) must also ignore the evidence for harm (or lack of benefit) of vegetable oils. So they say less saturated fats and more polyunsaturated fats without warning about the dangers of omega 6 polyunsaturated fats.”
US specialist Dr Richard Feinman is similarly dismissive. Feinman is professor of biochemistry and medical researcher at the State University of New York Health Science Center at Brooklyn, better known as SUNY Downstate Medical Center. He studies nutrition and metabolism and is a world authority on LCHF.
In an email to me and on the Pub Peer site, Feinman is critical of Hu’s research and the journal for publishing it. He says the Harvard study has not undergone proper peer-review. “Editors should recognize when a manuscript is controversial. They should sensibly solicit reviews from experts on both sides of the controversy.”
Failure to do this for whatever reason could be considered “de facto bias”.
Feinman suggests a “New Rule” that’s really just common sense. “In a controversial subject, journal editors should solicit reviews from both sides of the controversy.” Journalists should also challenge editors to show that both sides have evaluated the issue, he says.
What’s the best public health message overall on nutrition? Schofield has the last word: “Just eat real food with a mixture of fatty acids.
“Avoid trans-fats and advocate for more funding for intervention research, where cause and effect is more easily determined and confounding exists less because of randomisation.”
Author’s note: I emailed Dr Frank Hu and Dr Dong Wang for comment on criticisms of their research. Hu replied asking what I wanted the information for. I told him it was for a post on this website. I did not hear from him again, despite follow-up requests. Wong has also not replied. All Harvard researchers and those mentioned by name in this report have right of reply. If they choose to take it up, Foodmed.net will publish their responses.