A fat chance
Pondering the Eskimo Diet, this intrepid wonderer turns his sights on the truth about fats.
There are many opinions on fat, and many of these strike me as senseless and illogical – but not all, since the media, some past questionable science and recent research are joint causes for a lot of the current confusion on the matter.
The recent spate of news items about the new- found health benefits of saturated fats is an obvious example – and my last series about the various kinds of fats should have explained that it is probably not saturated fats that directly cause heart disease, but that all kinds of fats can certainly be a contributory factor. This is especially if you have arterial wall damage ( which is a common consequence of modern lifestyles).
As several people have asked, I will return to the health aspects of saturated fats a little later.
But let’s start with another wellknown fallacy – that somehow, the Eskimos ( part of the Inuit tribes) have a significantly lower incidence of coronary artery disease ( CAD) compared to other populations, due to the heavy dependency on seal and whale blubber in their diet.
This became known as the “Eskimo Diet”, which went against all known dietary theories at the time, especially as the Inuit also consume very few green vegetables or fruits. The two Danish researchers – Hans Olaf Bang and Jorn Dyerberg – who studied this diet in the 1970s received a lot of positive attention for their findings.
Some 5,000 research papers have since been dedicated to Omega- 3 fats, which were thought to be the contributory factor to this low incidence of CAD. One thing arising from this research is that no ascertainable toxicity has been associated with consuming large amounts of Omega- 3 fats. However, more detailed, rigorous research on Omega- 3 fats in recent years have also found no significant benefits in terms of the incidence of CAD – apart from one study which indicated that the mortality rate was 25% lower in the subjects taking Omega- 3 supplements for over 8 years. However, the same study also found that the incidence of CAD was practically the same – just that death was 25% less likely for people on Omega- 3 during the research period.
So how did the Eskimo Diet gain such prominence, to the point that even the nutritional guidelines from many developed countries actively promote the consumption of fish fats as a preventive measure against CAD? It would appear to be a case of something called confirmation bias, or an error in the way statistics have been gathered, which suited a pre- determined hypothesis.
Bang and Dyerberg were originally told that the Eskimos have a much lower incidence of CAD than other populations and they set out to find out why – but they forgot to rigorously check if the statement was valid in the first place.
They gathered data about the Eskimos’ diet – and also did a check that deaths from CADrelated diseases were indeed within their expected low ranges. And the death statistics in the 1970s did initially seem to bear out the hypothesis.
However, they did not validate that the data was consistent – ie. they just accepted the available death statistics and did not realise that only one in seven deaths happened in hospitals or medical stations, and that most were dying in remote locations, where there was little proper analysis of the cause of death.
Fully 30% of the Eskimo population also lived in communities without any medical services – therefore the causes of death would have been certified by the nearest medical officer based on second- hand information, and not via an autopsy or diagnosis. Hence, the Eskimo death rate reported for CAD- related diseases in the 1970s was probably around one- fifth what it should have been.
Bang and Dyerberg also quoted from a 1974 paper by Dr. Bent Harvald, which stated that myocardial infarctions ( MI, more commonly known as heart attacks) “does not occur in the Eskimo population” according to available statistical data. However, Harvald also called this a “mystery” as “records in those older than 50 years of age show numerous abnormalities compatible with history of MI at least as frequent as in many Western populations”.
Subsequent research has established that the reason behind the mystery is simply that Eskimos suffering from severe heart attacks seldom receive medical help in time – globally, 20% of all MI victims die suddenly without any prior warning; even in the United States, only 40% of people suffering from MI in the 1990s got to reach a hospital in time, and in Europe some 25% of such patients used to die within 2 hours regardless. So it is not surprising that statistics in 1974 did not properly cover MI mortality – however more recent data definitely does report MI as a common cause of death in Eskimos.
What is much more surprising – and indefensible – is that the old, flawed statistics are still used today to promote the fallacy that Eskimos have a lower incidence of CAD.
This is despite new studies, for example, from Bjerregaard in 2003, and countless other researchers, which were summed up by George Fodor in 2013 as follows: “The totality of reviewed evidence leads us to the conclusion that Eskimos have a similar prevalence of CAD as non- Eskimo populations, they have excessive mortality due to cerebrovascular strokes, their overall mortality is twice as high as that of non- Eskimo populations and their life expectancy is approximately 10 years shorter than the Danish population.”
Other research released in 2010 has also confirmed that the incidence of CAD in Eskimos is at least as high – potentially higher – than for non- Eskimo populations.
So how come this somewhat baneful diet remains the basis for health recommendations for much of the developed world? Well, there may be several reasons. Although the Eskimo Diet is clearly not a leading factor in the reduction of CAD, there have been studies which show that Omega- 3 fats can somewhat mitigate the modern trend for overconsuming Omega- 6 fats, which have been known to promote tissue inflammation in the body – hence the comment earlier that there is no significant toxicity associated with the ingestion of Omega- 3 fats ( which is also an essential fatty acid).
Basically, Omega- 3 is safe, even if it does not fully protect anyone from CAD – and this is relevant to the multi- billion dollar food industry which sells fish oils, fish oil emulsions, fish oil capsules and fish, snug in the knowledge that at least these products do no harm to humans. Also, these health supplements are often made from free or low- cost by- products, such as fish livers. And they can rely on mountains of old research to justify the “health benefits” of ingesting such products.
As an aside, there has been some research that suggests that taurine, a complex organic molecule found in fish and animal tissue, may actually have some benefit against CAD.
Taurine is quite unusual for a biological molecule, for it is an organosulfur- based acid which is rather more acidic than the usual amino acids ( which are based on carboxylic acids). So although taurine is often classified as an amino acid, in reality it has rather different and peculiarly interesting characteristics, for example, as an antioxidant, and its ability to cross the blood- brain barrier.
Maybe taurine is a subject which I can revisit later, especially as some Japanese research in 2010 has made some very intriguing ( and positive) observations about its effectiveness against CAD.
Many people have recently read that saturated fats are now not necessarily the leading causes of CAD and obesity – so the media angle is that all is well again with stuffing your face with butter, eggs and fatty chops. The earlier series on fats identified that it is improbable that saturated fats by themselves cause CAD – it is more likely that a combination of arterial wall damage and the overabundance of low- density lipoproteins ( LDL) are the likely causes of CAD. And it also mentioned the pointlessness of ingesting low- fat products, which tend to be made up of various chemicals, heavily- processed foods and sugars.
However, the seismic shift in the media towards extolling the virtues of saturated fats may be a step too far – or at least too early.
Certainly, it appears that all the facts are not being explained clearly to the public. For example, there are some stories about how saturated fats don’t make people fat. Excuse me – but they do, and it is simply a function of ( a) how much you eat, and ( b) what you eat with your slabs of fatty meat.
One common explanation of why foods with a lot of saturated fat won’t make people overweight is because of such foods’ rather high Thermic Effect of Food ( TEF, also known as Dietary Induced Thermogenesis or DIT). This was explained in an earlier article about dieting – note that the TEF is often affected by how much food has been cooked.
Many meats have a high TEF of between 65% to 75%, which means that for a rare rib- eye steak containing 400 calories, only about 280 to 300 calories will actually get absorbed by the body after digestion.
But, keep eating more fatty meats, and the calories will build up and then you are easily on the road to being overweight or worse,