Friday, 31 January 2014

Australian Nutritional Guidelines 2013...ha

This blog is not going to be one of the several thousand that bang on and on about my particular beliefs on nutrition. I might occasionally, but there are already many people smarter than me who can do that already, and do it very well. I don't usually give a rat's arse what people eat and don't eat. What I do give a flying duck about is certain authorities that tell the great unwashed exactly that; what they should be eating. When clearly, they have no clue. 

I have a particular disdain for nutritional guidelines - the same old boring twaddle that is trotted out every few years, like some octogenarian relative that no-one particularly likes, but for reasons not quite clear, holds sway over the whole family. I hate that old prick with a passion, and in this post I tell him to get stuffed. Him and his bullshit stories about what it was like in his day. No one gives a shit, you old bastard.

I first put this together for a close friend who was having a hard time accepting what I was putting in to my body. A fair amount of time and wading through shit went in to it, so I figure there may be someone else who gets a kick out of as well. It's by no means a take-down worthy of a glossy cover and sale on Amazon (or even a post on a half-decent blog for that matter), however it hopefully points out at least some of the madness that many people accept as truth.

To start with, the 2013 release, in all its 226 page glory is here -  http://www.nhmrc.gov.au/guidelines/publications/n55
Hold on to your pants, 'cause here we go:
From page vi (Guideline 3):
“Limit intake of foods containing saturated fat, added salt, added sugars and alcohol.
  •  Limit intake of foods high in saturated fat such as many biscuits, cakes, pastries, pies, processed meats, commercial burgers, pizza, fried foods, potato chips, crisps and other savoury snacks. (underlining, mine).
  • Replace high fat foods which contain predominantly saturated fats such as butter, cream, cooking margarine, coconut and palm oil with foods which contain predominantly polyunsaturated and monounsaturated fats such as oils, spreads, nut butters/pastes and avocado.
  • Low fat diets are not suitable for children under the age of 2 years.
Firstly, it should be obvious to anyone with half a brain that the foods they listed as high in saturated fat in the first dot point are all foods that are just as high, if not higher, in refined carbohydrates (flour and sugar) than they are in fat.

Skipping to the last dot point, I'll comment on the idiocy of infant guidelines further down.

Going back to the second dot point - this pushes the idea that polyunsaturated (PUFAs) and monounsaturated fats are healthier than saturated fats. This is a whole other blog post, but briefly, one study done on this issue was the Sydney Diet Heart Study. From 1966 to '73 they tracked a few thousand middle aged men and told half of them to replace saturated fat with PUFAs (safflower oil and margarine). The men who were consuming more PUFAs had lower cholesterol but a higher death rate from all causes.

Taken from a review of the Sydney Diet Heart Study - “Conclusions  - Advice to substitute polyunsaturated fats for saturated fats is a key component of worldwide dietary guidelines for coronary heart disease risk reduction. However, clinical benefits of the most abundant polyunsaturated fatty acid, omega 6 linoleic acid, have not been established. In this cohort, substituting dietary linoleic acid in place of saturated fats increased the rates of death from all causes, coronary heart disease, and cardiovascular disease. An updated meta-analysis of linoleic acid intervention trials showed no evidence of cardiovascular benefit.”

taken from Sydney Diet Heart Study

So, call me deluded, but I think one could reasonably conclude from the Sydney Diet study – if you want to lower your cholesterol, eat lots of polyunsaturated fat. If you want to live longer, err...don’t.

From page 69 of the Nutritional Guidelines - “The early work on dietary fats and heart disease focused on the type of fat in the overall diet, with the fat being contributed by a wide range of foods. The evidence that replacing saturated fats with polyunsaturated fats affects serum cholesterol levels has been accumulating for the last 60 years,(36,666) and the relationship has been confirmed in a recent review of human intervention trials and other studies. (94,667-670)”

Firstly, you have to ignore the big "so what?" in your head when you read the bit about serum cholesterol levels. But once you have:

Their evidence for this statement
Reference 36 = National Health and Medical Research Council. Dietary Guidelines for Australian Adults. Canberra;Commonwealth of Australia; 2003b.

Here they are using their own 2003 guidelines as proof of their argument. Brilliant.

Reference 669 = Siri-Tarino PW, Sun Q, Hu FB, Krauss RM. Meta-analysis of prospective cohort studies evaluating the associatation of saturated fat with cardiovascular disease. The American Journal of Clinical Nutrition 2010.

Quote directly from the Siri-Tarino paper – “Conclusions: A meta-analysis of prospective epidemiologic studies showed that there is no significant evidence for concluding that dietary saturated fat is associated with an increased risk of CHD or CVD.”

Here they have used a paper that concludes saturated fat can’t be blamed for heart disease to argue that saturated fat is bad. ???????? Sneaky bastards didn't expect anyone to actually read that one, I bet.

Reference 666:
Aust N Z J Med. 1994 Feb;24(1):98-106.Review of dietary intervention studies: effect on coronary events and on total mortality.Truswell AS.Source Department of Human Nutrition, University of Sydney, NSW, Australia.

Abstract (full version behind paywall) - “The perfect randomised controlled dietary prevention trial of coronary heart disease has never been done. The best we can do is to look at all the trials together.”

So, right up front they admit that their paper is inconclusive. At least they're partly honest. 

“In all trials plasma cholesterol was effectively lowered and coronary narrowing regressed a little, or progressed less in the diet group but significantly compared with controls. These angiographic trials strongly support the results of the major prevention trials. Lastly, a set of ten trials with fish oil after coronary angioplasty are reviewed. In some there appeared to be lower rates of restenosis, but not in all.”

They say cholesterol was lowered and artery narrowing was slightly less, or perhaps didn’t worsen as much as the standard control person. Sound conclusive? 

Reference 667:
Hooper L, Summerbell CD, Thompson R, Sills D, Roberts FG, Moore H et al. Reduced or modified dietary fats for preventing cardiovascular disease. The Cochrane Library 2011;July 2011
Quotes - “Dietary change to reduce saturated fat and partly replace it with unsaturated fats appears to reduce the incidence of cardiovascular events, but replacing the saturated fat with carbohydrate (creating a low fat diet) was not clearly protective of cardiovascular events” and “Effects on total and cardiovascular mortality are much less clear. No evidence was found on the long term health effects of altering trans fat intake.”

Notice how they say replacing saturated fats with unsaturated fats “appears” to reduce the incidence of cardiovascular events. It either does or it doesn’t. They also say that replacing saturated fat with carbohydrate (creating a low fat diet) “was not clearly protective”.

Ref 668: Skeaff M, Miller J. Dietary fat and coronary heart disease: Summary of evidence from prospective cohort and randomised controlled trials. Annals of nutrition and metabolism 2009;

Quote -“Differences between populations in the amount and type of fat consumed explain much of the  variation in the incidence of cardiovascular diseases [Keys, 1980].”

And references in this paper include:
Keys A: Coronary heart disease in seven countries.Circulation 1980; 41: 1–211.
Keys A, Anderson J, et al: Serum cholesterol response to changes in the diet. IV. Particular saturated fatty acids in the diet. Metabolism1965; 14: 776–787.
Keys A, Menotti A, et al: The diet and 15-year death rate in the Seven Countries Study. Am J Epidemiol 1986; 124: 903–915.

Ancel Keys (the author of  these references) is widely known to be the father of the lipid hypothesis (that suggests saturated fats cause heart disease) and his “seven countries” study is a deceitful paper with the clear intention to show fat being evil. 

Ancel Keys is revered in some circles, despised in many others, so if you want to find out more about why I think the use of his studies is laughable, there are probably a million blogs who can elaborate. This is just one -  Moving on...
From page 71 – “Raised LDL cholesterol has been found to be a significant risk factor in at least 50 prospective cohort studies involving more than 600,000 subjects in 18 countries.712

That sounds impressive, so it must be true. But it gets really weird when you see where they got that wording from. Their reference (712) is - Baghurst K. Dietary fats, marbling and human health. Australian Journal of Experimental Agriculture 2004;44:635-44.
If you’re confused, so was I. The paper is one written by some bloke at CSIRO (The Commonwealth Scientific and Industrial Research Organisation) on fat in cows (marbling referring to the marbling in beef). The quote above is taken directly from the paper and the references they use to support the statement are….well, they don’t give any. Putting the quote into a well-known search engine didn't produce any useful results either. 
In the paper, the quote follows with a statement that “Saturated fat is the strongest dietary determinant of plasma LDL-concentration”. The reference they use for this is “Keys et all, 1957”. Thank goodness for dependable Mr Keys. 

It should probably strike people odd that even if "Keys et al 1957" had any credibility, surely there would have been better and more convincing studies in the last 50+ years. 
To be clear, I personally believe saturated fat does increase plasma LDL concentration in a lot of people. But, so what? They just assume that higher LDL concentration = oh shit. Sadly, so do the majority of readers. LDL is synonymous with 'you're a dead duck'. 

Back to the "on your 2nd birthday, your brain is fully developed and doesn't require fat" bit:

From page 56 of the guidelines - "It should be noted that reduced fat varieties of milks and/or plant-based drinks are not suitable as a drink for children under the age of 2 years due to energy requirements for growth."
Page 60 -  "As children under 2 years are growing rapidly and have relatively high energy (kilojoule) needs, reduced fat milks are not recommended as a main milk food for this age, but are suitable after 2 years of age."
Page 73 -"Neurological development is particularly rapid in the first 2 years of life and restriction of the fat intake during that time may interfere with optimal energy intake and reduce the supply of essential fatty acids, particularly omega-3 LCPUFAs needed by developing nervous tissue, adversely affecting growth and development.

A few comments here; it strikes me odd that they continue to use this magical age of 2, at which point the kids' brains don't require the "neurological development" that they receive from eating fat. It seems to me that these people know fat is good for the brain, however they are that shit-scared of recommending that kids eat fat - and that convinced of the cholesterol-heart hypothesis, that brain development slips down the ladder of priorities. 

Seriously, does that sound logical to you? Do you really think that it is acceptable to risk your kids' neurological development because some dickhead with a white coat says there is some vague chance you'll be setting them up for a heart attack in 40+ years time?

On what planet is that sensible?  

"Even at a young age, a diet high in saturated fats may predispose children and adolescents to the development of cardiovascular disease later in life and the evidence supports this advice on fat intake for children from 2 years of age.35,719" 

Reference 35 is the 2003 Australian guidelines for kids - http://www.nhmrc.gov.au/_files_nhmrc/publications/attachments/n34.pdf

It basically mimics the adult guidelines and I found this gem particularly perplexing - "Restriction of the fat intake of children aged up to 2 years may interfere with optimal energy intake and reduce the supply of essential fatty acids needed by developing nervous tissue, thus adversely affecting growth and development". 

But again, this seems to be unimportant on the day they blow out 2 candles on a cake. Maybe that is because Mum made a low fat cake. It was full of sugar of course, but the experts say kids need that for energy so...carry on.

"A high-fat diet is likely to be energy-dense, contributing to excess energy intake and the development of obesity." I could be reading too much into this, but the fact that they've completely ignored the role of, say, sugar and refined carbohydrates, speaks volumes as to whether or not they are biased. 

Reference 719 is a paper written by the American Academy of Pediatrics in 2008 - http://www.ncbi.nlm.nih.gov/pubmed/18596007

Essentially this is one big "cholesterol will kill your kids, mmm'kay" paper, which includes the fascinating proposal to put your 8 year old on cholesterol lowering meds if their LDL plasma concentration is what they consider 'high' (over 160 mg/dl or 130 if they have diabetes). 

I'll be honest, I stopped reading after that point because it was simply too depressing. 

To wrap up

Even if you still believe the nutritional guidelines work to reduce your risk of obesity, cardiovascular disease and/or diabetes, the evidence they have used to back up their recommendations are at best, feeble, at worst, downright pathetic and misleading. 

If you want to avoid saturated fat in your diet, fine, just don't use the nutritional guidelines as an excuse, because it's not a good one. 

Conflicts of interest declared: I think the lipid hypothesis is bullshit. I think saturated fat is good for you. But I eat lots of it and have high cholesterol, so I would say that, wouldnt I? 


Bessie is hoping you take the guidelines very seriously


2 comments:

  1. Thank you for all this. Very interesting. It's a shame that doctors get most of their drug prescribing guidelines from drug company sales reps. Wish I could find a doctor who actually knew something about the relationship between the modern crappy diet and chronic disease.

    ReplyDelete
  2. No problem, Lisa. The last doctor I thought might be knowledgeable enough to share my dietary habits with, responded "oh, I've heard of that, so you basically eat lots of bacon?"

    All the best.

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