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UPDATED with with new comment and link to BMJ study
By Marika Sboros
It’s a message scientists are giving more often these days. It’s one Big Pharma and Big Food still hate to hear: stop worrying and start loving saturated fat because it isn’t linked to a greater risk of death and heart disease.
A higher intake of trans fats, on the other hand, is linked in Canadian research in the British Medical Journal (BMJ).
The research findings will likely also stick deep in the throats of die-hard critics of low-carb, high-fat (LCHF) eating regimens – and critics of University of Cape Town emeritus professor Tim Noakes, who has pioneered LCHF in South Africa. Still, critics’ voices are growing dimmer as the evidence grows more compelling that Noakes is not a dangerous nutter out to kill people after all.
As Noakes, US science journalists Gary Taubes and Nina Teicholz, and other researchers internationally have noted ad nauseum, the diet-heart hypothesis was built on a shaky scientific foundation, saturated fat is so far not proven to be the enemy of heart health after all.
Taubes, author of Why We Get Fat, and Teicholz, author of The Big Fat Surprise, are among those who say the science is there to show that LCHF is looking good to prevent or even treat heart disease and diabetes.
The problem is that these messages seem to be taking an awfully long time to permeate through medical and dietetic professional circles.
LCHF experts, including Noakes, say the consequences for health and longevity are nothing short of catastrophic. If you doubt it, they say that all you need to do is just look at the effects on health of current dietary advice doctors and dietitians regularly dish out: global epidemics of obesity, diabetes, and related medical conditions.
Treating metabolic syndrome and type 2 db with a low-carb diet? Discussion and a case report in the BMJ today: http://t.co/Z2uzOGUWsL
— gary taubes (@garytaubes) August 4, 2015
A BMJ press release (to read it in full, scroll down below) gives provisos of the Canadian research – results are based on observational studies, so no definitive conclusions can be drawn about cause and effect. However, the analysis “confirms the findings of five previous systematic reviews of saturated and trans fats and CHD”. It concludes that “dietary guidelines must carefully consider the health effects of recommendations for alternative macronutrients to replace trans fats and saturated fats”.
Just as importantly, though, the researchers look at implications for current official dietary guidelines. A recent and groundbreaking study by British obesity researcher Zoe Harcombe showed that US and UK dietary guidelines were without any scientific foundation whatsoever when they were imposed on an unsuspecting public close to 40 years ago, and spread to other parts of the globe.
(You can listen here to a podcast of Harcombe explaining why official dietary guidelines may have caused the unnecessary deaths of millions globally in the interim).
Interestingly, in late 2013 Sweden was widely reported by the country’s own and leading international media to be about to change its official dietary guidelines in favour of LCHF on its own committee’s expert advice.
Yet when health push came to shove, the Swedish government baled, and did a spectacular backflip: it missed a golden opportunity to be the world leader experts were predicting it would, and ignored its own expert committee’s views and the growing scientific evidence on fat and carbohydrate intake. The only inference to be drawn is that it bowed to vested interests – or at the very least, bad science – by sticking to conventional, unscientific, dietary dogma in its latest guidelines that promote high-carb, low-saturated-fat eating.
It is yet another example of the damaging effects that the politics of food wreak on people’s health.
Predictably, the guidelines encourage ‘lots of fruits and vegetables’ – presumably based on the 5-a-day recommendation. Harcombe has effectively demolished the science – or lack thereof – on that one.
Here’s what the Canadian researchers have to say:
From the British Medical Journal
Saturated fats are not associated with an increased risk of death, heart disease, stroke, or type 2 diabetes, finds a study published in The BMJ this week. However, the findings show that trans fats are associated with greater risk of death and coronary heart disease.
The study confirms previous suggestions that industrially produced trans fats might increase the risk of coronary heart disease and calls for a careful review of dietary guidelines for these nutrients.
Guidelines currently recommend that saturated fats are limited to less than 10%, and trans fats to less than 1% of energy to reduce risk of heart disease and stroke.
Saturated fats come mainly from animal products, such as butter, cows’ milk, meat, salmon and egg yolks, and some plant products such as chocolate and palm oils. (Editor’s note: coconut oil is by far the best source, with a high content of saturated fat.)
Trans unsaturated fats (trans fats) are mainly produced industrially from plant oils (a process known as hydrogenation) for use in margarine, snack foods and packaged baked goods.
Much more that a “must read”. If you haven’t read it shouldn’t be allowed to practice medicine or nutrition https://t.co/OlDF1elQtM
— Tim Noakes (@ProfTimNoakes) August 8, 2015
Contrary to prevailing dietary advice, a recent evidence review found no excess cardiovascular risk associated with intake of saturated fat. In contrast, research suggests that industrial trans fats may increase the risk of coronary heart disease.
To help clarify these controversies, researchers in Canada analysed the results of observational studies assessing the association between saturated and/or trans fats and health outcomes in adults.
Study design and quality were taken into account to minimise bias, and the certainty of associations were assessed using a recognised scoring method.
The team found no clear association between higher intake of saturated fats and all cause mortality, coronary heart disease (CHD), cardiovascular disease (CVD), ischemic stroke or type 2 diabetes, but could not, with confidence, rule out increased risk for CHD death. They did not find evidence that diets higher in saturated fat reduce cardiovascular risk.
Trans fat intake
However, consumption of industrial trans fats was associated with a 34% increase in all cause mortality, a 28% increased risk of CHD mortality, and a 21% increase in the risk of CHD.
Inconsistencies in the included studies meant that the researchers could not confirm an association between trans fats and type 2 diabetes. And they found no clear association between trans fats and ischemic stroke.
The researchers point out that the certainty of associations between saturated fat and all outcomes was “very low,” which means that further research is very likely to have an important impact on our understanding of the association of saturated fats with disease. The certainty of associations of trans fat with CHD outcomes was “moderate” and “very low” to “low” for other associations.
They also stress that their results are based on observational studies, so no definitive conclusions can be drawn about cause and effect. However, they say their analysis “confirms the findings of five previous systematic reviews of saturated and trans fats and CHD.”
And they conclude that dietary guidelines for saturated and trans fatty acids “must carefully consider the effect of replacement nutrients”.
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