Comments on: Should we worry about trans fats?

By: Bill Shrapnel

Bill Shrapnel — Wed, 12 Nov 2014 23:15:54 +0000

Hi Ulyssess. Trans fats from animal sources and industrial sources have the same effects on blood lipids, which is presumably how they increase the risk for heart disease.
It is difficult to determine whether one is better or worse than the other from the type of studies available. In diets, ruminant trans fats are present in small amounts whereas in some countries (e.g. USA) industrial trans fats have been present in quite large amounts. Consequently, the effect of ruminant TFAs may fail to reach statistical significance and the effect of industrial trans fats may reach significance, even if both have exactly the same effect on risk. It’s the higher exposure to industrial trans fats that’s making the difference, not any difference of effect.
The trend for both industrial and animal trans fats is in the same direction – increase in risk.
Replacing saturated and trans fats from animal sources with unsaturated fats lowers heart disease risk without having any known adverse effects. Regards, Bill

By: Ulysses Elias

Ulysses Elias — Mon, 27 Oct 2014 07:43:01 +0000

Hi there. Do you know this study:

Jakobsen,M, Overvad, K, Dyerberg, J and Heitmann, B. 2007 “Intake of ruminant trans fatty acids and risk of coronary heart disease” in International Journal of Epidemiology. Oxford University Press, Oxford. 37:1. pp173-182

Its worth looking at the studies showing that TFAs from animal sources might not increase the risk of CHD at all.

cheers

By: Bill Shrapnel

Bill Shrapnel — Sun, 17 Mar 2013 23:57:54 +0000

Hi David. Elaidic acid is ONE of the ten 18:1 isomers shown in that paper and it appears in both industrially generated trans fats and ruminant trans fats (meat and dairy trans). Similarly, vaccenic acid is also ONE of the ten 18:1 isomers and it also appears in both industrial and ruminant trans fats.
I disagree with your statement that elaidic acid is known to be harmful. What we know is that trans fats, comprising many isomers (including elaidic and vaccenic acid), are harmful to health. Saying that elaidic acid is bad but vaccenic acid is good requires a big leap of faith – it’s not supported by the evidence. Whether CLA really has beneficial effects IN HUMANS has yet to be demonstrated. However, we do know that CLA has adverse effects on blood lipids so any beneficial effect would need to be strong enough to overcome this. Regards, Bill

By: David Brownlea

David Brownlea — Sun, 17 Mar 2013 22:48:55 +0000

Many thanks for the reply Bill. I’ve had a look over both of those references, but I’m not certain they clarify my question in light of your column. The trans isomer of oleic acid that you’re referring to is edilaic acid (the most commonly industrially produced trans fat- known to be harmful as you say). This is only present in negligible quantities (less than 0.1%) in products derived from bovine milk [Alonso L, Fontecha J, Lozada L, Fraga MJ, Juárez M (1999). "Fatty acid composition of caprine milk: major, branched-chain, and trans fatty acids". J. Dairy Sci. 82 (5): 878–84].
I can only find information stating that the predominant natural ruminant trans fats in dairy are VA and the CLAs, and the apparent health benefits of these, which is contary to what you are saying about the health dangers on trans fats in butter, milk etc.
If you can steer me in the right direction it’d be a great help. I’m a fan of your work and columns, but I think I’m missing something in the trans fat debate!
Kind regards, David Brownlea.

By: Bill Shrapnel

Bill Shrapnel — Sun, 17 Mar 2013 05:07:01 +0000

Hello David. There was a supplement on trans fats in the American Journal of Clinical Nutrition in September 1995. The paper to look at is the one called ‘Physicochemical properties, intake and metabolism’ (Am J Clin Nutr 1995;62:659S-69S.)
Figure 2 shows that butter contains 10 trans isomers of 18.1 (oleic acid). The same figure shows that partially hydrogenated fats contain the same 10 trans isomers of 18.1. Not surprisingly, both the trans fats in butter (including CLA) and the trans fats in partially hydrogenated fats have adverse effects on the LDL/HDL ratio in the blood (Brouwer IA, Wanders AJ, Katan MB (2010) Effect of Animal and Industrial Trans Fatty Acids on HDL and LDL Cholesterol Levels in Humans – A Quantitative Review. PLoS ONE 5(3): e9434. doi:10.1371/journal.pone.0009434). Regards, Bill

By: David Brownlea

David Brownlea — Sun, 17 Mar 2013 03:44:38 +0000

Hello Bill,

I’m very interested in reading further about your assertion that all trans fats are “the same chemical and have exactly the same effect on the human body.” I’m having trouble finding such information. Are you able to recommend a reference to extrapolate on this? It’d be greatly appreciated.

I’m currently researching the benefits of vaccenic acid and conjugated linoleic acids in the human diet (both naturally occurring trans-fats as you’re aware).

Thanks for your column, an interesting read as usual.

Kind Regards, David Brownlea BPharm

By: Bill Shrapnel

Bill Shrapnel — Fri, 20 Jul 2012 05:40:25 +0000

Hello Roxanne
In my article I said that ruminant and industrial trans fats were basically different combinations of the same substances. For example, there are about ten 18:1 trans isomers in industrial trans fats and all ten also appear in dairy fat. They are the same chemicals and have exactly the same effect on the human body.
CLA is an exception of course – a trans fatty acid that occurs in dairy fat but is not present in industrial trans fats. But studies show that it affects LDL-cholesterol and HDL-cholesterol similarly to other trans fats.
Epidemiology will never be able to demonstrate that ruminant trans fats are associated with increased risk for heart disease because the amount in the diet is too small. However, lack of evidence due to the limitations of the experimental tool is not evidence of a lack of effect ruminant trans fats on risk.
Personally, I am not concerned about having 0.5% of the energy in a typical diet coming from trans fats – it’s a very low level. However, if people are concerned and want to reduce their intake of trans fats further, they should be aware that about three-quarters of the typical intake is coming from dairy and meat fat, and one-quarter from industrial trans fats. Regards, Bill

By: Dr Roxanne Portolesi

Dr Roxanne Portolesi — Fri, 20 Jul 2012 05:02:40 +0000

Hi Bill,
Thank you for your post on trans fats. It’s great to know our current intakes of industrial produced trans fats are low with limited supply in the foods we eat. You might also be aware of WHO’s recent review of trans fats (http://www.who.int/nutrition/topics/trans_fatty_acids/en/index.html) presenting the evidence on the impact of industrial produced trans fats and ‘natural’ trans fats, (or the more correct term, ruminant trans fats) on health. The review notes the intake of ruminant trans fats in most societies is low and concludes the current evidence does not support an adverse effect of these fats on the risk of cardiovascular disease. It’s also worth noting the evidence statements in the NHMRC draft Dietary Guidelines (http://www.eatforhealth.gov.au/page/public-consultation) demonstrate the consumption of dairy foods, such as milk, cheese and yogurt, is associated with reduced risk of chronic diseases including CVD, stroke, hypertension and type 2 diabetes.
Kind regards,
Dr Roxanne Portolesi, Nutrition Science Manager, Dairy Australia

By: Bill Shrapnel

Bill Shrapnel — Tue, 17 Jul 2012 01:13:03 +0000

Hi Nicole. Ah, inter-sectoral collaboration – so much potential, so little of it realised. Why is so much effort in public health nutrition invested in fighting with those we should be collaborating with? Regards, Bill

By: Bill Shrapnel

Bill Shrapnel — Tue, 17 Jul 2012 01:08:50 +0000

Hi Paul. As long as people eat meat and dairy products we will always have trans fats in our diet. I guess the point is, at what level do we say trans fat intake is acceptable. The WHO recommendation is less that 1% of energy. Our intake is half that, so we have already minimised our trans fat intake. Should we really focus in on the one-eight of 1% of energy coming from ‘artificial’ trans fats? Saturated fat intake is 25 times higher than trans fat intake – shouldn’t that be our priority now?

Believe me, the food industry does not need any incentive to lower trans fat use. They have been doing it for the last 17 years and very successfully. I was working on it in 1995!

The issue is often raised that an individual may choose to eat a lot of pies, chocolate, etc containing trans fats and their intake may be higher than desirable. That a problem for the individual but it’s not a public health problem. If mean population intake of trans fats is very low the public health players have done their job. Regards, Bill