Saturated fat is converted into blood cholesterol by the liver.

[TheAwfulToad]

Prompted by a recent posting here, I was browsing the British Dietetic Association website (bda.uk.com). As the regulars here will know, I don't hold dietitians in high regard, and what I read didn't help matters.

Of all the many scientifically-dubious statements on that website, the assertion in the title sent my blood pressure up by a few Torr. The exact quote is this:

"When you eat saturated fat it is converted into blood cholesterol by the liver. Saturated fat also slows down how quickly cholesterol is removed from your body."

Which you can find here under "Cholesterol":

bda.uk.com/foodfacts/home

The other papers are equally amusing (at least if you have a sick sense of humour), but I thought I'd focus on this one for the moment.

Let's start with the most glaringly obvious problem here: cholesterol is synthesized from acetyl coenzyme A, which is a sort of general-purpose Lego block that crops up in all sorts of metabolic processes. The pathway from acetyl-CoA to cholesterol is a long and winding road, but it has nothing whatsoever to do with saturated fats. To be clear: saturated fats are not converted to cholesterol, in the liver or anywhere else.

As for the second part of the sentence, it's hard to be sure what it even means. "Removed from your body?". Why would your body want to remove a critical substrate that it diverted energy and materials into synthesizing? What's the mechanism by which saturated fatty acids might purportedly slow down such "removal"?

Now it could be that they're referring to the balance between LDL-C and HDL-C, HDL-C being a scavenger lipoprotein that mops up unused cholesterol and returns it to the liver for recycling, and offsets the inflammatory effects of LDL-C. However, since saturated fats have little or nothing to do with LDL/HDL balance (except inasmuch as low-fat diets tend to promote a low level of HDL) this interpretation doesn't make much sense either.

It's worth reminding ourselves what a saturated fatty acid actually is (there's no such thing as a "saturated fat" - I'm using that term here simply because people are familiar with it). The difference between a saturated fatty acid and a monounsaturated fatty acid is a missing proton. A polyunsaturated fat is missing more than one. A proton is a very very small thing. Yes, that missing proton has some surprisingly noticeable chemical effects: the bond where the proton is missing becomes 'kinked', which makes it more susceptible to certain chemical reactions; it changes the nature of the electrostatic bonds between fat molecules, which changes their melting point. However, your body pays very little attention to this. Saturated fats, by and large, are treated the same as unsaturated ones: they are burned for energy.

But the BDA does not believe any of this.

When you eat saturated fat it is converted into blood cholesterol by the liver.

If you were to read statements like this on a private blog or a YouTube comment, you could laugh it off as the product of ignorance. It wouldn't matter one way or the other. But the BDA does matter. Their pronouncements are repeated in NHS advice, in the press, and in Government statements. So when the BDA says something inaccurate (otherwise known as "making stuff up"), it gets accepted as fact. The average man in the street does not have enough knowledge to do anything except take the statement at face value.

So I have a little advice for the BDA: get your act together, and fix some of that semi-literate rambling that you present as 'food facts' on your website. It does not matter if you, as individuals, believe privately in unicorns, aliens, or that when you eat saturated fat it is converted into blood cholesterol by the liver. However, when you spread your beliefs beyond the confines of your own ill-informed echo chamber, people suffer and die. No doubt it will take some time for you to sort yourselves out. In the meantime, please: primum non nocere.

Note for the pedants: I'm aware that 'nocere' is the infinitive, not the imperative. But that's the traditional phrasing, so I didn't fiddle with it.

[Jints1]

Thanks for this TheAwfuToad. I'm learning so much on this site and at last eating my fat guilt free - whilst losing weight and feeling energised in the process. I can't believe how the system has been feeding me rubbish information for so many years and how gullible I've been . Keep up the good fight xx

[Climbing67 in reply to Jints1]

Fantastic article I agree. As an osteopath with a strong nutrition and healthy lifestyle focus I find it appalling some of the so called advice that is trundled out time and time again. I've lost count of the times GPs and others tell people not to avocado or coconut butter etc but eat more carbs. It's prompted me to start a book and get more vocal

[TheAwfulToad in reply to Jints1]

>> I can't believe how the system has been feeding me rubbish information for so many years and how gullible I've been

I had the same reaction once I started studying this seriously.

I honestly don't understand what's going on here. It seems to be one of those episodes of collective madness that humans get caught up in now and then.

[Climbing67]

Great article keep up the good work. Just found this page and surprised it's part of the NHS site!!

[TheAwfulToad in reply to Climbing67]

Yeah, it's quite incredible what the NHS feel duty-bound to repeat as fact. It's odd, because I'm sure their medically-qualified members know it's mostly nonsense.

[Alisongold in reply to TheAwfulToad]

Thank you for your worrying message, these pages on the BDA site have been designed for public use and should be based on sound biochemistry. Have you written to the BDA, please let us know their response , if any?

[TheAwfulToad in reply to Alisongold]

I did write to the NHS once about this sort of thing. They just sent me back a document quoting "evidence" from a think-tank. I do intend to write to the BDA, and I'll certainly post on here if I get a response.

[alchemilla12 in reply to TheAwfulToad]

really clear put down of what the BDA article says AwfulToad! I do hope you take them to task overthis -I too despair when people talk about what a "state registered dietician" has told them and am always amazed at how slow they are in keeping up to date with current research ( but thats pretty much on par for the british medical system anyway as far as Im concerned )

[Zest]

Hi TheAwfulToad

Thanks for this. I like the explanation from Dr Malcolm Kendrick about this - as well - who puts it very clearly in his blog post:

drmalcolmkendrick.org/2018/...

I hope you have a good weekend, and I was wondering if you've had time to try out the Omelette tip yet, and whether you found it worked better?

Zest

[TheAwfulToad in reply to Zest]

That's a very good article. I like Kendrick's writing and that one outlines the biochemistry very clearly. The only bit I'd take issue with is his remark about all ingested fats going straight into storage. This is true enough when there are high levels of circulating insulin, but generally speaking, chylomicrons are unpacked during transit through capillaries and most cells (notably, your heart and skeletal muscle) are capable of burning the glycerol and fatty acids released during this process. Some fat also ends up going back to the liver where it is converted into ketone bodies, which will be used by those few cells that can't utilize fatty acids directly. On a low-carb diet, this is the fate of a good fraction of consumed dietary fat.

You know what - I just made an omelette an hour ago and completely forgot the egg-white separation thing. I'll give it a go next time!

[Cooper27 Administrator]

I was going to do a related post on this actually, so thanks!

I was listening to something the other day, on the craziness of dietary advice. Doctors tell us to cut back on red meat, like steak and pork, that we should eat lots of oily fish and salad with olive oil instead. Oh, and swap lard for healthier fats, like coconut oil.

A sirloin steak has 2.1g of saturated fat, while mackerel has 3.3g. 2tbsp of olive oil on your salad will give you 3.8g of saturated fat, yet we're given the impression we can free-pour the stuff!

Lard is apparently only 39% saturated fat, while coconut oil is 96%.

I also heard the original study saying food cholesterol was bad, was based on an animal study (rabbits). They wanted to see what happens if you feed an animal that eats no cholesterol, food based cholesterol. Not surprisingly, feeding rabbits a diet of meat and eggs,made them very sick, so they concluded it must make humans sick too!

I start to lose faith in dietary associations, when I hear things like that!

[TheAwfulToad in reply to Cooper27]

They'll usually tell you to swap lard for "low fat" spreads, which drives me nuts. All fats have to be disassembled into fatty acids and a monoglyceride so that they can pass out of the small intestine; on the "other side", they're reassembled into triglycerides. Low-fat spreads and lard both contain a similar ratio of saturated and unsaturated fatty acids (that's why low-fat spreads have about the same texture as lard). At the point they enter your bloodstream, they've been transformed into very similar things. So the question is ... why not just eat lard? Is it really likely that a synthetic fat is more healthful than a natural one? I think Sagan's Law applies here: extraordinary claims demand extraordinary evidence.

But yeah .. the rabbit study. I know that one. Absolutely incredible that anyone took it seriously.

EDIT: here's the numbers for Stork margarine:

SFAs 27%

MUFAs 50%

PUFAs 23%

and for lard:

SFAs 40%

MUFAs 50%

PUFAs 10%

[Cooper27 Administrator in reply to TheAwfulToad]

Just daft, isn't it?

They also explained that plant sterols artificially lower cholesterol in the body. The body treats sterols like it treats cholesterol, so your body can have quite high cholesterol as far as it's concerned (as a combo of cholesterol and sterols), but plant sterols aren't detected by the blood test, so on paper, your cholesterol looks good.

[Redspot]

Wow......

You certainly deserve.......

First to do no harm!

This is frightening stuff from a respected body.

Thanks