By Rob Verkerk PhD
Founder, executive & scientific director
Yesterday marked the close of the UK’s Scientific Advisory Committee on Nutrition’s consultation on saturated fat and health.
The central question asked through its 233 pages is should the UK Government be telling its population to change its current advice to consume no more than 10% of daily energy as saturated fat.
Cutting to the chase, it would appear, given the approach that’s been used in the data synthesis by the SACN, nothing will change. This is regardless of all the criticism that will come from a variety of quarters, including ourselves, the likes of Zoe Harcombe PhD, Diabetes.co.uk and numerous others.
What the SACN found…
Download 7 tables of summary findings.
What we told the SACN…
Download our consultation response.
When you ask the wrong question….
Unfortunately, the likelihood is that the long-drawn out process of this review on saturated fats and health, that follows the SACN’s 2015 report on carbohydrates and health, is likely staged. The consultation appears to have been set up to elicit zero change in dietary saturated fat guidelines. Here are some of the tell-tale signs:
- Inclusion criteria were set so tight that only 46 ‘studies’ made it through the door of SACN’s review process. But because some ‘studies’ were studies of other studies (meta-analyses) the actual number was considerably fewer than this.
- The SACN missed out some key studies that showed no effect – Zoe Harcombe pointed out three such studies, one being her own, in her consultation input
- The SACN specifically ignored the quality of saturated fats (fatty acid profile) being considered indicating this was outside its remit. No explanation was given
- The SACN restricted itself to reviewing just two kinds of studies, randomised controlled trials (RCTs) and Prospective Cohort Studies (PCSs). These have particular challenges in relation to nutrition in the real world, and should not be the exclusive source of evidence in any review of the totality of evidence. The SACN gets around this by referring to the ‘totality of evidence considered’ in the opening line of its Recommendations (Section 16.6, p. 219)
- The SACN used a very weak scientific method that relied largely on looking at the direction of association in RCTs and PCSs to establish trends. But it avoided clarifying what kinds of benefits (or risks) might be conferred and their respective extent. Most of the so-called associations represented tiny effects that are likely to have no relevance to any individual
- The SACN avoided any input from clinicians who have worked with specific types of high fat (and therefore low carbohydrate) diets
- The SACN avoided looking at any data in studies in which the baseline subjects in studies were not ‘healthy’. This is in spite of knowing that 34% of UK adults aged 45-74 are clinically obese and almost 3.7 million Brits have been diagnosed with diabetes
- The SACN approach ignores the effects of the food matrix, including the quality of typical high fat diets based on animal products including processed meats, damaged fats, heat-damaged and contaminated foods, etc.
- The SACN has not sought to establish whether the associations it found were causally related to the presence or absence of saturated fats. Its conclusions however imply a causal relationship
- The SACN ignored the effects of critical micro-nutritional factors such as vitamins, minerals and plant secondary compounds (e.g. polyphenols) that have profound effects on health, directly or via the microbiome
- The SACN ignored the confounding effects of physical activity and other lifestyle factors given that less healthy patterns of diet and lifestyle can be common among those who consume high saturated fat diets (e.g. processed meats, take-aways, dairy, low plant food diversity)
- The SACN draft appears to assume that an association with stronger evidence is biologically more important than one supported by weak evidence. This view is scientifically invalid
- The SACN knows that any increase in its saturated fat guideline will mean people will be encouraged to consume less in the way of carbohydrates
- There are clear conflicts of interest among the SACN’s advisors.
An entirely different approach would have had to be used had the questions the consultation addressed been different. How might it have looked had an unconflicted group of scientists and clinicians been asked to answer one or more of the following questions?
- Can the ‘saturated fat-heart disease’ hypothesis that is implicit throughout SACN’s review be tested? In other words, what evidence, both published and from clinical records, exists to show that healthy outcomes can be found among those who consume greater than 10% of energy from saturated fats with specific fatty acid profiles?
- How much could associations between worse outcomes (such as more heart attacks) as found in some cohort studies or randomised controlled trials be attributed to substituted food types, and not macronutrient groups? Unhealthy foods that can easily be consumed along with diets rich in saturated fats include those containing large amounts of refined or damaged polyunsaturated fats, damaged or contaminated protein-rich foods, refined carbohydrates, low fibre and low plant food diversity.
- How relevant are the studies reviewed by SACN to members of the population who are overweight and sedentary – in other words the majority of the adult UK populaton? As Professor Frank Hu from Harvard said in an editorial in the American Journal of Clinical Nutrition back in 2010, “…refined carbohydrates are likely to cause even greater metabolic damage than saturated fat in a predominantly sedentary and overweight population.”
Bottom line: the question posed doesn’t have a simple answer. Why? Because it’s so easy to have a high saturated fat diet that’s unhealthy. Think take-away burgers, processed meats and milk shakes. So when epidemiological studies are done across large sectors of the population the subjects with high saturated fat diets are often also those who have unhealthy patterns of eating. They also likely have other unhealthy lifestyle habits. In other words, there isn’t sufficient available evidence to determine if most of us would be better off eating more than 10% of our energy quotient from particular types of saturated fat.
What’s more, it’s a scientific no-go to suggest, as the SACN has in its draft report, that people will endure significantly better long-term health if they consume less than this amount.
Food4Health – more than Food4Energy
We don’t have a single Prospective Cohort Study or Randomised Controlled Trial supporting Food4Health. But we do have around 96 studies that support its essential tenets. Most importantly, the Food4Health guidelines have been created over many years working closely with clinicians who are transforming people’s health for the better on a daily basis.
And we think our approach of combining research findings with clinical experience holds more validity for the application of nutrition practice to the real world than the myopic desk-based approach used by the SACN. Fortunately, the choice is in your hands regardless of what we or the SACN say.