Another blast on the trans-fat trumpet

For many years, the received wisdom in the medical literature was that eating saturated fat was bad for you and likely to give you heart attacks.  That was always nonsense and, in one of those 180 degree turns so common in the medical literature, has recently been abandoned.  Such fats are good for you these days.

Greenies and food freaks (largely overlapping categories, it would seem) hopped on the bandwagon a decade or so ago and began their usual coercive strategies.  They pressured food manufacturers to stop using such fats.  Vegetable oils were the thing.  And, like a lot of their products, the food manufacturers crumbled.

But vegetable oils were not really very suitable for making cakes and cookies.  But if you added some extra hydrogen atoms to the vegetable oils, you could get a suitable result.  The hydrogenated oils became known as trans fats.

But just as there is no such thing as a happy Greenie so there is no such thing as a happy food freak.  Various claims supported by problematical research appeared which said that trans fats were bad for you too.  They also could damage your heart.

So the food manufacturers again mostly crumbled and now use a lot of palm oil instead of saturated fats and trans fats. The cake you buy has had an adventurous past.

So now palm oils are under attack.  To produce enough palm oil, lots of new trees have to be planted and to plant those trees you have to chop down lots of other trees that were already there --  and that will not do at all!  So the limited supply of palm oil drives up its price and makes it too expensive for some food manufacturers -- who have therefore stuck with their good ol' trans fats.  So the shriekers still have a satisfying campaign to wage.  And below (below the chevrons) is the latest shot in the war.

It features work by the hyperactive and normally skeptical Beatrice Golomb but does her no credit.  The research has not yet been published in the journals so I have not been able to look closely at it but it clearly has one large problem:  It is based on self-reports, which are very susceptible to biases of various sorts.  In particular, self-reporters tend to tell you either what they think you want to hear or what they think will make themselves look good.

And that is a very obvious contaminant in the research below.  Because people are always being told how evil cakes and cookies are, consumption of them is unprestigious so many of those answering a self-report questionnaire will under-report how many of such evil products that they consume -- while people less influenced by popular fads will be little bothered by admitting to their actual diets.  So who are the cake and biscuit gourmands?  Fatties and the poor most likely.  And what do we know about the poor?  As Charles Murray showed long ago, they have lower IQs.  Shocking of me to mention it, I know, but facts are chiels that winna ding, as the Scots say.  

And the memory task used by the gorgeous Dr Golomb (pic below) is IQ-related.  So the wicked eaters probably had lower IQs.   So it seems likely that Dr Golomb's finding is entirely artifactual  -- a product of her research methodology rather than information about the world.

I note that she did control for education but education and income are only weakly correlated, as many recent college graduates have found to their dismay.

Other research:  For one summary of the weak science behind the "trans-fat" hysteria, see here. Trans fats have only a temporary effect on blood chemistry and the evidence of lasting harm from them is dubious. By taking extreme groups in trans fats intake, some weak association with coronary heart disease has at times been shown in some sub-populations but extreme group studies are inherently at risk of confounding with other factors and are intrinsically of little interest to the average person.

Food manufacturers should of course revert to using saturated fats, now that medical opinion is in their favour -- JR


I was pleased to receive a prompt and scholarly reply from Dr Golomb about my post.  Some scientists can get very defensive and snarky if their work is criticized but she did not. It says much for her character. I reproduce the reply below:

Dear John Ray,

 It is true that the findings are based on a food frequency questionnaire, and observational data are *always* subject to potential unmeasured confounding. That is why we never use(d) the word "cause" but only describe higher trans fat consumption as "associated" with worse memory. (I can't exactly say higher "reported" trans fat consumption because it wasn't actually trans fat consumption they reported.)

On the plus side, though, the data from which the analysis was done were collected in 1999-2004, a privileged time window vis a vis trans fat assessment --  after trans fat abstraction from foods was added to analysis of the Fred Hutchinson Food Frequency Questionnaire, but before the FDA trans fat labeling requirement that made it easy for people who were health conscious to more readily limit trans fats. 

{Of note, this was also before most of the positive press about chocolate, when chocolate consumption was still widely viewed as a vice (hard to imagine that time was so recent). Yet, despite this, more frequent chocolate consumption was linked favorably to memory, and to body mass index. (We presented the former finding a couple years ago -- someone else's findings connecting the two got a lot of attention in the NY Times, I understand, last week; the latter finding has been replicated, e.g.,  in a study of European adolescents, and according to a Principal Investigator who contacted us, was also found in a randomized study, supporting causality; and a study in rodents found that cocoa-derived epicatechin led to reduced fat mass with calorie consumption unchanged). Meanwhile, trans fats emerged as adversely associated with both outcomes. This makes sense given that chocolate is rich in antioxidants and has compounds that support cell energy (e.g. via mitochondrial biogenesis and vascularity), while trans fats are prooxidant (and proinflammatory), and adverse to cell energy.  (The hippocampus, a brain area important in memory, is especially vulnerable to cell death in settings of inadequate energy.)

We are encouraged by the fact that, so far, our findings based on the dietary data have almost to a one been replicated, and/or have experimental support from animal research (adding the element of causality). For instance we previously found that, even adjusted for calories and exercise, trans fat consumption was linked to higher BMI and waist circumference. (By the way, I will mention since we have discovered that some scientists -- i.e. peer reviewers! -- are confused on this point, there is no violation of the second law of thermodynamics in that statement. Calories are disposed of in a range of ways -- heat generation, fat deposition, creating blood vessels and mitochondria -- and just what is done with them is subject to modulation by signaling pathways, in turn influenced by dietary factors.) Consistent with this, primate data show that incorporating trans fats, without changing calories, leads to increased deposition of abdominal/visceral fat. 

Anyhow, thanks for sending, and thanks for your interest!



I replied:


Thank you for that interesting reply

I think you should have a closer look at the recent literature on anti-oxidants.  I think we are midway through an 180 degree turn there.  The latest thinking is that antioxidants are actually bad for us.  The body needs plenty of oxidants. So pro-oxidants could be a GOOD thing!



Eating cookies and cakes could damage your memory -  regardless of your age

Fats found in some biscuits, cakes and processed foods could have a harmful effect on memory, researchers have warned.

The fats, known as trans fats, are used both in processed food and in restaurants, often to improve the texture, shelf life or flavour.

They are created when hydrogen is added to vegetable oil to make it more solid, which is why they are often called partially hydrogenated oils.

Now, a study of 1,000 healthy men aged under 45 found those who ate the most trans fat had worse scores in a word memory test.

The link remained after taking account of age, education and depression.

Study leader Dr Beatrice Golomb, of the University of California, San Diego School of Medicine, said: ‘Trans fats were most strongly linked to worse memory, in young and middle-aged men, during their working and career building years.

‘From a health standpoint, trans fat consumption has been linked to higher body weight, more aggression and heart disease.

‘As I tell my patients, while trans fats increase the shelf life of foods, they reduce the shelf life of people.’

The research team studied adults who had not been diagnosed with heart disease.  They were asked to complete a dietary questionnaire, from which the researchers estimated participants' trans fat consumption.

To assess memory, researchers presented participants with a series of 104 cards showing words.  Each person had to state whether each word was new or a word duplicated from a previously seen card.

Each additional gram a day of trans fats consumed was associated with an estimated 0.76 fewer words correctly recalled.

For those eating the highest amounts of trans fats, this translated to an estimated 11 fewer words – a reduction of 10 per cent in words recalled compared to adults who ate the least trans fat.

The average number of words correctly recalled was 86, according to research presented at the American heart Association’s Scientific sessions 2014 in Chicago.

Trans fat is widely considered the worst kind for your heart, even worse than saturated fat, which can also contribute to heart disease.

The UK food industry in recent years has reduced or eliminated industrially produced trans fat in foods.

Current dietary surveys suggest consumption levels provide less than one per cent of food energy, below the recommended two per cent maximum – about 5g a day.

The Food and Drug Administration is taking further steps to reduce the amount of artificial trans fats in the US food supply. 

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