Three weeks ago, one of my blogs focused on the presumed benefits of food products containing plant substances known as stanols or sterols. These partially block absorption of cholesterol from the gut and therefore can reduce blood cholesterol levels. The point I made in that blog, though, was that the impact these foods products have on cholesterol is quite irrelevant, it’s the impact they have on health that counts. No studies exist which demonstrate that stanols and sterols actually improve health, and this fact has not escaped the National Institute for Health and Care Excellence (NICE) in the UK, which actually advises against the use of stanols and sterols.
The fact is, no published studies have tested the impact of stanols or sterols on human health in the long term. One may argue that this is not an issue because we know that cholesterol reduction is beneficial and, so the benefits are almost assured and, anyway, what harm can they do?
Well, the evidence shows that when we take dietary steps to reduce cholesterol through reducing fat in the diet or substituting saturated fat for ‘healthier’ fats, it does not reduce the risk of heart attack or stroke or overall risk of death [1]. This, obviously, casts some doubt on the validity of the assumption that dietary reduction of cholesterol is necessarily a good thing.
The other issue though concerns safety. How do we know if we do not have the long-term studies of the use of stanols and sterols in humans that are even safe? Again, one may argue what’s the harm, seeing as they’re ‘plant-derived’. Well, it turns out there is quite a body of evidence which suggests far from being the wonder-chemicals we’ve been lead to believe them to be, stanols and sterols may pose real and significant risks to health.
The research was summarized in a 2009 paper published in the European Heart Journal [1].
Several studies link the presence of higher levels of sterols in the blood stream with raised risk of cardiovascular disease [2-7]. This evidence is epidemiological, which means we cannot conclude from it that sterols actually increase the risk of cardiovascular disease (only that the two are associated with each other). However, more incriminating evidence comes of studies in which the effects of sterols have been tested on tissues or animals in the lab.
In one study, feeding animals with sterols increased what is known as ‘endothelial dysfunction’ – unhealthy chances on the inside of blood vessels associated increased cardiovascular disease risk. The sterols also led to animals having strokes bigger in size than when no sterols were consumed [8].
In another study, sterols led to an increased level of damaging oxidation and release of free oxygen radicals (oxidative stress) compared to cholesterol, which suggests a greater capacity to induce chronic disease (including cardiovascular disease) [9]. Sterols have also been shown to induce cell death (what is known as ‘apoptosis’), including in the cells which line human blood vessels (endothelial cells) [10]. In another experiment, giving plant sterols to rats (with high blood pressure and prone to stroke) shortened their life spans [11].
In summary, there is no evidence that stanols and sterols benefit human health, and quite a few lines of evidence that suggest these substances have potential for harm. Yes, this is the stuff that is marketed on the basis of their assumed value for heart health.
The use of stanols and sterols is supported by the British Heart Foundation (as I write about in the blog post I link to above). I have written to this organisation regarding the evidence, and am interested to see what comes back.
References:
1. Weingartner O, et al Controversial role of plant sterol esters in the management of hypercholesterolaemia. Europlean Heart Journal 2009;30:404-409
2. Relationships of serum plant sterols (phytosterols) and cholesterol in 595 hypercholesterolemic subjects, and familial aggregation of phytosterols, cholesterol, and premature coronary heart disease in hyperphytosterolemic probands and their first-degree relatives. Metabolism 1991;40:842–848
3. Independent association of serum squalene and noncholesterol sterols with coronary artery disease in postmenopausal women. J Am Coll Cardiol 2000;35:1185–1191
4. Association of plasma noncholesterol sterol levels with severity of coronary heart disease. Nutr Metab Cardiovasc Dis 1998;8:386–391
5. Baseline serum cholestanol as predictor of recurrent coronary events in subgroup of Scandinavian simvastatin survival study. Finnish 4S Investigators. BMJ 1998;316:1127–1130
6. Plasma sitosterol elevations are associated with an increased incidence of coronary events in men: results of a nested case-control analysis of the Prospective Cardiovascular Munster (PROCAM) study. Nutr Metab Cardiovasc Dis 2006;16:13–21
7. Abstract 4099: elevated campesterol serum levels–a significant predictor of incident myocardial infarction: results of the population-based MONICA/KORA follow-up study 1994–2005. Circulation 2006;114:II_884
8. Vascular effects of diet supplementation with plant sterols. J Am Coll Cardiol 2008;51:1553–1561
9. Oxidized plant sterols in human serum and lipid infusions as measured by combined gas-liquid chromatography-mass spectrometry. J Lipid Res 2001;42:2030–2038
10. Beneficial or harmful influence of phytosterols on human cells? Br J Nutr 2008;100:1183–1191
11. Vegetable oils high in phytosterols make erythrocytes less deformable and shorten the life span of stroke-prone spontaneously hypertensive rats. J Nutr 2000;130:1166–1178
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i am guessing no response will be forthcoming!
as they seem to be run by Flora and these substances are a cash cow for them
I’m sure that plant derived foods are very healthy for those animals designed to eat those type of foods, as are animal derived foods healthy for those animals designed to eat animal meats and fats.
Shame Ancel Keys didn’t tell his rabbits…
Feeding species a diet for which they are not adapted is asking for trouble.
I picked up a leaflet in my local Boots store today called ‘Healthy Heart Support – Lets Show Your Heart Some Love’ which claims to be giving information on how to look after your heart and reduce your risk of CHD.
High cholesterol is one of the highlighted risk factors along with the claim that a diet high in saturated fat is one of the main causes along with all the usual advice not to eat butter, cheese meat etc and to use reduced fat spreads. You know, the usual advice based on the unproven link between saturated fat and heart disease.
If you get prescribed statins by your doctor you can get advice from Boots about this. The leaflet also lets us know that we can purchase Boots Pharmaceuticals Plant Sterols – ‘proven to reduce cholesterol levels and help support a healthy heart when taken with a healthy diet.’ The leaflet even includes a handy coupon to get £2 off the Boots Plant Sterols.
As you state in this post, there is no evidence that stanols and sterols benefit human health so how can Boots make these claims?
Just curious, what are your thoughts on plant sterols to modulate autoimmune disease.
http://www.ncbi.nlm.nih.gov/pubmed/10383481
Does this apply to “beta sitosterol” being touted for over-the-counter treatment for enlarged prostate and the frequent urination that often accompanies BPH?
It seems that whenever we start mucking around with out food to “improve” it, we end up doing the opposite. I think you could put all the PhD’s in nutrition in a rocket and send them to mars and our health would be better for it. That’s saying a lot since my youngest son is getting his PhD in nutrition!
Nutritional science gave us the Twinkie, low fat eating, Snackwell treats and a long list of toxic food products. Should we be surprised that plant sterols should be any different?
(a) I will not take/touch/consider using plant stanols as they are not natural for the human gut they way they are being pushed contained in another non natural substance – margarine…. They are yet another money making scheme. Basically I do not subscribe to the cholesterol theory of heart disease – so why do I need to take a foreign (to my body) substance to reduce it?
(b) I was fortunate to be passed this “on line” article today our of The National Geographic which I BELIEVE explains the health care crisis very well. If you agree, perhaps you would pass it along.
http://ngm.nationalgeographic.com/2013/08/sugar/cohen-text
(c) I have recently been diagnosed T2DM after ten years of having blocked artery issues. I was on statins many years ago, but believed they were doing worse damage to me. I am a great believer in working ‘backwards’ to see if I can find the cause – and fix that, rather than taking prescribed medications which may, at best treat the symptoms, and at worst cause other medical problems.
I asked my cardiologist two years ago what caused inflammation – he said he had no idea so I better take the statins and let them deal with the problem! NO WAY MATE……. However since a lifestyle change incorporating eating higher fat and lower carbohydrate, my BGL are back into the ‘normal range’ I am, slowly loosing weight each week, and I will not even considering taking doctor prescribed drugs for a condition that can be handled in a very simple natural way. I just wish I lived closer to Dr. Briffa and I would adopt him 🙂
I thought this book was closed. Everybody knows cholesterol is healthy – when you have the right type. So stay off the carbs and cholesterol will be fine.
It is just a billion dollar market, with a billion reasons to maintain the scare tactics.
It is so simple; you can’t make money on those weird people that don’t need anything, that enjoy natural foods and the sun. Even shoes make you sick!
So now you are working in the marketing department of a food or health company. What can you do? Scare the hell out of them! Skin cancer! Bowel cancer! Heart disease! And smile all the way to the bank. (p.s. Vitamin D – the stuff that protects against cancer – is made from ……cholesterol! So what happens if you lower cholesterol? You lower… And you’ll get…)
Even Ancel Keys admitted in his lifetime that his study was garbage. But nobody wanted to know.
@ JustMEinT
“I just wish I lived closer to Dr. Briffa and I would adopt him”
So funny : D
Andre said “I thought this book was closed.”
every day i meet people who show that this is simply not the case.
you get looked at as if you have two heads when you say something like
“if cholesterol is so bad for us, why do we make so much of the damn stuff?”
Oh, not that is likely matters a terrible amount but In light of Dr. Andreas Eenfeldt’s recent heart disease writings, it reminded when i work with sterols. I worked for a company that used some plant sterols in products. We were a small player in the market overall. And at the time sterols were a throw away product. Sterols are a byproduct from natural vitamin E production. During that time most sterols I believe were thrown away.
One day we received a call from the natural vitamin E producer that we purchased from that it was no longer possible for us to purchase sterols from them. All sterols were to be sold to a Swedish margarine company. I guess some firm in the nordic countries had begun to add sterols to their margarine. As a result, nearly over night, what had been a byproduct of natural E production and was sold for next to nothing, became worth more than natural E.