Common sense dictates that fats found naturally in the diet that we’ve been eating for hundreds of thousands of years and have therefore evolved to eat and unlikely to be detrimental to health. For instance, saturated fat (a primal foodstuff if there ever was one) turns out not to have the heart-stopping properties we’ve been warned over for about for several decades. I wrote most recently about this here. Some naturally-occurring fats, such as omega-3 and monounsaturated fats appear to have health-giving properties.
One class of fats I recommend that people do avoid, however, is industrially-produced ‘trans fatty acids’. These are a by-product of what are known as ‘partially hydrogenated’ fats. These fats are unknown in nature, and have only made their way into our mouths since the processing of vegetable oils got underway in a big way very recently. The hydrogenation of fats allows vegetable oils (such as sunflower and safflower oil) to be solidified, which is obviously critical in the manufacturing of solid fats such as margarine. The other ‘benefit’ of hydrogenation is that it makes fats less liable to turn rancid (go off), which extends their shelf life.
The polyunsaturated fats that are the raw material for industrially produced partially hydrogenated and trans fats are ‘kinked’ and even coiled in shape. This physical form of fats is referred to as ‘cis’ (pronounced ‘siss’) configuration. However, in the processing of these fats not only adds hydrogen, but can also cause ‘cis’ fats to straighten out, forming what is known as the ‘trans’ configuration.
As expected, the research suggests that industrially-produced trans fats have the potential for wide-ranging unwanted effects on health. Trans fats have been linked with having adverse effects on heart health. For instance, in one study, individuals who had suffered a heart attack were found to have significantly higher levels of trans fats in their bodies compared to health individuals [1]. Those with the highest concentrations of trans fat were found to be, on average, more than 2½ times more likely to suffer from a heart attack than those with the lowest levels. A number of other studies also support the concept that trans fats are bad for the heart. Of four studies that have examined this potential association over time, three found that consuming just 2 per cent of our calories from trans fat is associated with an increased risk of heart disease of 28-93 per cent [2-4].
Trans fats seem to have the ability to impair the function of the hormone insulin, something that would be expected to increase the risk of developing type 2 diabetes [5,6]. Other research has found that, in women, a higher intake of trans fat is associated with an increased risk of diabetes [7].
All-in-all, the evidence suggests, as we would expect from primal theory, that industrially-produced trans fats are thoroughly unhealthy. In the UK, we consume an average of about 2.5-3.0 grams of trans fats per person each day [8]. This may not sound like much, except that studies show even very small amounts of these fats are associated with an increased risk of disease. In 2002, the Food and Nutrition Board of the Institute of Medicine in the USA published a report on the role of trans fats on health and made recommendations regarding safe levels of intake [9]. In the summary of this report, its authors suggest that the: “tolerable upper intake level of zero”. In normal language, this translates as “the safest amount of trans fats to consume is none at all.”
The adverse effects of trans fats, and the benefits of removing them from the diet was recently highlighted in an editorial published in the British Medical Journal [10]. In response to this article, a letter was published today in the BMJ that makes interesting reading I think [11]. It refers to the fact that the addition of trans fats to food (a widespread practice in food processing) is injurious to health. Here is the letter:
In many jurisdictions it is unlawful to render food injurious to health. For example, the UK Food Safety Act section 7 states: “Rendering food injurious to health: (1) Any person who renders any food injurious to health by means of any of the following operations, namely-(a) adding any article or substance to the food; (b) using any article or substance as an ingredient in the preparation of the food; . . . (2) In determining . . . whether any food is injurious to health, regard shall be had-(a) not only to the probable effect of that food on the health of a person consuming it; but (b) also to the probable cumulative effect of food of substantially the same composition on the health of a person consuming it in ordinary quantities.”
Note the emphasis in section 7(2)(b) on probable cumulative effects when consumed in ordinary quantities.
If it is the case that people on poor diets consume considerable amounts of industrial trans fatty acids, even where the average is quite low, it seems that using industrial trans fatty acids as food ingredients,1 in any foods that some consumers would eat regularly and frequently, may be unlawful in the United Kingdom.
The idea that the production of foods containing damaging trans fats is unlawful is an interesting concept I think. It does open up the possibility that legal action could be taken against food companies who manufacture these foods. Who might take such legal action? The Food Standards Agency? Don’t hold your breath: for some inconceivable reason the FSA has not even made it mandatory for food companies to declare the trans fats on product labels. However, a class action by some rightly disgruntled consumers is a distinct possibility and may have legs.
References:
1. Pedersen JI, et al. Adipose tissue fatty acids and risk of myocardial infarction – A case-control study. Eur J Clin Nutr 2000:54:618-625
2. Ascherio A, et al. Dietary fat and risk of coronary heart disease in men: Cohort follow up study in the United States. BMJ 1996:313:84-90
3. Hu FB, et al. Dietary fat intake and the risk of coronary heart disease in women. N EngI J Med 1997:337:1491-1499
4. Oomen CM, et al. Association between trans fatty acid intake and 10-year risk of coronary heart disease in the Zutphen Elderly Study: A prospective population-based study. Lancet 2001357:746751
5. Christiansen E, et al. Intake of a diet high in trans monounsaturated fatty acids or saturated fatty acids. Effects on postprandial insulinemia and glycemia in obese patients with NIDDM. Diabetes Care l997;20:88l-887
6. Alstrup KK, et al. Differential effects of cis and trans fatty acids on insulin release from isolated mouse islets. Metabolism I 999:48:22-29
7. Salmeron J, et al. Dietary fat intake and risk of type 2 diabetes in women. Am J Clin Nutr 2001;73:1019-1026
8. Hulshof KF. Intake of fatty acids in western Europe with emphasis on trans fatty acids: the TRANSFAIR Study. Eur J Clin Nutr 1999 53(2):143-57
9. Letter Report on Dietary Reference Intakes for Trans Fatty Acids Food and Nutrition Board, Institute of Medicine 10th July 2002
10. Mozaffarian D, et al. Removing industrial trans fat from foods. BMJ 2010; 340: c1826
11. Brock S N. Rendering food injurious to health. BMJ 340: c2981-c2981
John,
Read your book and above article with great interest. What is your view on the difference between natural accuring trans-fatty acids and man-made trans fatty acids? Don’t believe there is a difference from a chemical/moleclar point of view. Most (if not all) margarines in the UK are zero-percent trans nowadays. They are made from blends of Palm Oil fractions and interesterified fats, emulsified with up to 70% water. Butter however contains around 3% trans fat. Sometimes more. Would you advise to stay away from butter as well in a healthy diet and move to for example olive oil? Thanks. Leon
” .. .. Who might take such legal action? The Food Standards Agency? Don’t hold your breath..”
I’m very much in agreement, Dr Briffa, we simply do not get satisfactory regulatory protection from the agencies that are set up ostensibly to protect public interest.
My own indignation began as double-barreled. I felt that the banking crisis as began with the sub-prime home loans crisis was a failure of comprehension and regulation of market activity by those institutions and agencies charged with policing it. For much of 2009 I carried intuitive conviction that the food-health paradigm had much in common with the shortcomings of financial regulation. My own intuition is fast giving way to conviction, just as there appeared to be an adherence to a convenient orthodoxy in economic academia that failed in cognition and failed to heed any warnings or counter-orthodox dissent, so it is with food, and accordingly we seem to be careering headlong to a crisis of morbidity and funding within the health service. This is something that has not escaped the notice of contributors to the BMJ.
I can certainly class myself as a disgruntled consumer. The catalyst was being alerted to the unhealthy aspects of the edible oils industry. I have given much time over to studying the implications of dietary fats and oils and have no more than scratched the surface, but complicated though the topic is it does not take much study or contemplation to grasp that a modern western diet (can) involve(s) ingestion and exposure to a whole load of ‘edible’ oils that didn’t ought to be there. There is good literature available for anyone motivated to grasp deeper comprehension of oils.
The mechanisms that ought to protect us are in place. DEFRA, the Food Standards Agency (FSA), the Advertising Standards Authority (ASA), European Food Safety Authority (EFSA), and WHO. But the mechanisms look increasingly like they fail to deliver their promise. EFSA has been in the news in the last twelve months receiving criticism over a lack of satisfactory consultation prior to rule making on functional health claims for foods. You’ve brought it to our attention about conflict of interest and lack of transparency within the WHO.
What happens when a disgruntled consumer tries to take action via established mechanisms? The most likely way a consumer may express concern is to submit a complaint to advertising. This it does to the ASA. The voice of experience can attest this is not a consumer centric process. You might think that the ASA may recognize the imbalance of power, knowledge and access to resources between complainant (read disgruntled consumer) and advertiser, but you would be mistaken. The complainant has to be every bit as ‘professional’ in constructing his/her argument as is the advertiser.
The ASA will do it’s level best to reply that the complainants ‘case’ has been tested before, but if the complainant manages to overcome such a hurdle the next one is one of time. Nothing in the advisory process conveys to the complainant just how robust the argument must be, and time constraints do contribute to the challenge.
I should think complaints in opposition to functional health claims made in a TV advert for a brand of margarine are just about as challenging as things get. The biggest hurdle to be overcome is that the ASA will not actually investigate nor adjudicate upon matters nutritional, instead if the case rests upon a point of nutritional import, it will refer the question to the FSA. It matters not one jot whether the answer that is returned from the FSA may be worthy of contention. It is simply beyond the remit of the ASA to question advice originating from the FSA. The disgruntled consumer has been ‘systemically stonewalled’ and may as well be impotent.
Our FSA has received media attention for conflicts of interest within steering committees and GM. The nature and timing of margarine advertising in proximity to the launch of the FSA anti-saturated fat campaign made at least one person suspicious to the possibility of collusion between FSA and stakeholder (read brand leading margarine manufacturer).
I think the WHO is to report following investigation of health and edible oils. Can we hope they will heed warnings from leading research figures whose work is less obviously tainted by conflicts of interest? Will they, in the light of Parkinson and Langley [1] be wary of the corporate agenda and bias in the knowledge economy, or will they simply fudge it like EFSA?
1, Parkinson and Langley; Science and the Corporate Agenda.
http://bit.ly/bu9IST
Interesting, I had considered this concept with regard to HFCS after watching Rob Lustigs Sugar the Bitter Truth.
Allowing a food product to be made illegal starts us down a slippery slope that doesn’t bode well for those of us who believe in the value of saturated fat, etc. The “food police” would be only too happy to ban high-sat-fat foods, replacing them, no doubt, with industrial oils and tons of carbs.
Dr. Briffa,
I hope you wil comment on Leon’s (first entry) question about trans fat in butter.
……….
On a different subject: the clinical laboratory I go to in San Francisco has just raised its desirable range for vitamin D 25 OH from 18-72 ng/ml to 30-100 ng/ml. The word is getting out.
I agree with Cathy on the subject of food regulation. Regulatory agencies are by their nature incompetent and destructive. All they accomplish is brainwashing and abandonment of personal responsibility on the part of the brainwashed. If the FSA, or some other agency, had the power to ban trans-fats, why not also saturated fats, salt, chocolate, etc? Individuals should be left free to choose their food, health care, and investments for themselves, based on their own best judgement of the evidence available.
Leon/Donald
Industrially-produced TFAs and those found naturally in food have different chemical structures: industrially-produced trans fats are predominantly monounsaturated trans fats of which something known as elaidic acid is a major component. Trans fats found naturally in food, on the other hand, are mainly to be found in the form of very different fats known as trans vaccenic acid and conjugated linoleic acids.
Studies suggest that it is the consumption of industrially produced partially-hydrogenated vegetable fat, rather than trans fat found naturally in food, that is associated with adverse health effects such as increased risk of heart disease.
Pietinen P, et al, Intake of fatty acids and risk of coronary heart disease in a cohort of Finnish men. The alpha-tocopherol, beta-carotene cancer prevention trial. Am J Epidemiol. 1997;145:876-887
Willett WC, et al. Intake of fatty acids and risk of coronary heart diseases among women. Lancet 1993;341:581-585
The same could be said of adding Fluoride to our water supplies – but maybe it’s okay if our governments poison us???
John,
Thanks for your explanation on the differences between ‘natural’ and ‘industrial’ trans-fats.
Co-incidentally NHS watchdog NICE has called for a ban on trans-fats in foods yesterday. Link: http://news.bbc.co.uk/1/hi/health/10369198.stm
NICE is also pressing for further reductions in salt and saturated fats, to help prevent deaths from cardiovascular disease.
Not much left to eat but proteins and poly-unsaturated fats in the future…. although I am sure you wouldn’t agree on a ban on sat-fat.
Leon