Study linking regular tooth-brushing with reduced risk of heart disease should remind us of why cholesterol is unlikely to be the ‘killer’ it’s made out to be

A study published last week in the British Medical Journal has linked irregular toothbrushing with an increased risk of heart disease: individuals who rarely or never brushed their teeth were found to be at a 70 per cent increased risk of ‘cardiovascular events’ (e.g. heart attacks and strokes) compared to regular brushers [1]. Why? Well, it’s possible that those who do not appear to care much for the dental health might not care so much about the rest of their bodies either, and perhaps have other lifestyle habits that harm the heart and circulatory system. However, the association between irregular toothbrushing and cardiovascular disease was after relevant factors such as smoking, body mass index and history of high blood pressure had been taken into account.

Such adjustments are never perfect, but the results support the idea that it’s something about infrequent teeth-cleaning that might increased disease risk. Looking more deeply, the researchers found that those not so assiduous about their oral hygiene had, generally speaking, higher levels of two substances: C-reactive protein and fibrinogen. C-reactive protein (CRP) is an inflammatory substance, and inflammation has emerged as a key underlying process in the development of cardiovascular disease (as well as other chronic diseases). And higher levels of fibrinogen encourage clotting or ‘stickiness’ in the blood, which would also be expected to increase cardiovascular disease risk.

This study’s findings reminded me of the research which suggests that cholesterol-reduction (either through diet or drugs) is not the life-saver some would have us believe it to be. Many doctors and scientists maintain that we have ‘proof’ that cholesterol is a killer in the form of studies which show that cholesterol-reducing drugs known as statins do reduce heart disease risk. However, this would only hold up if the only thing statins do in the body is to reduce cholesterol levels.

The reality, though, is that statins have several effects in the body which include (but are not limited to) an ability to reduce CRP levels and ‘thin’ the blood.

Interesting, even in people without raised cholesterol levels, statins reduce the risk of cardiovascular disease. However, the benefits have in previous studies been found to be pinned more to a reduction in CRP rather than cholesterol levels. Also, there is other evidence which shows that the degree of clinical benefit from statins does not mirror the extent of cholesterol reduction. For more about this, see here.

Another way to prove the benefit of cholesterol reduction would be to assess the effectiveness of other cholesterol reducing measures. In 2005, some Swiss researchers decided to review the evidence regarding cholesterol-reduction and overall risk of death [2].

They found that statin use was associated with a reduced risk of death, particularly in those who already had had a heart attack or stroke.


Resin (another cholesterol-reducing agent) use was not found to reduce risk of death, even in high-risk individuals

Fibrate (also a cholesterol-reducing agent) use was not found to reduce risk of death, even in high-risk individuals

In generally low-risk individuals, fibrate use actually increased risk of death (by 25 per cent)

Diets designed to reduce cholesterol did not reduce the risk of death either.

In more recent years, another cholesterol-reducing drug has hit the market by the name of ezetimibe. Yet, there is no good evidence that ezetimibe prevents disease or death. In fact, the reverse may be true. For more on this, see here and here.

Once someone is aware of these facts about cholesterol reduction I generally find they become much more relaxed regarding the role of cholesterol in health and longevity. But, of course, there’s always going to be people who will cling to this theory no matter what the science shows. These may include doctors who are given financial incentives to reduce their patients’ cholesterol levels, as well as doctors and scientists paid by drug companies to remind us all of the miraculous, death-defying benefits of cholesterol reduction.


1. de Oliveira C, et al. Toothbrushing, inflammation, and risk of cardiovascular disease: results from Scottish Health Survey. BMJ 2010;340:c2451

2. Studer M, et al. Effect of different antilipidemic agents and diets on mortality. Archives of Internal Medicine. 2005;165:725-730

9 Responses to Study linking regular tooth-brushing with reduced risk of heart disease should remind us of why cholesterol is unlikely to be the ‘killer’ it’s made out to be

  1. Jennifer 4 June 2010 at 4:18 pm #

    I read that higher inflammation is more of a problem when high cholesterol is also present. The high cholesterol means the body is making more to plaster the walls of the vessels where inflammation is occurring – i.e. to fix the problem. Gum disease is implicated in inflammation and, therefore, the connection again with dental health. The bacteria from the mouth have been found and implicated in inflammation.

    Anyone with an autoimmune disease going on will also naturally have more inflammation. Correct? I think so.

    Did you know tiny amounts of doxycycline per day (not enough to cause any problems in the gut but do eat yogurt) – maybe 25 mg (1/4 of 100 mg tablet) reduces inflammation (CRP levels) by almost 40% over 6 months? There was an obscure study on the internet that stated this, however, it has since been removed. Some dentists do know about this. I know of a person who had quadruple bypass surgery who says doxycycline makes all the difference in how he feels. If you have any access to research or studies on this, I’d be keenly interested to hear what you have to say on the subject. My own CRP levels dropped 33% using doxycycline in tiny doses over 1 year. Some people with Hashimoto’s Thyroiditis (about 70%) have a mycoplasma infection ( I thought I might be one of those and coincidentally my CRP levels dropped. However, I was taking such a tiny dose – 25 mg per day for a year. Maybe had I taken a larger dose it could have affected the mycoplasma infection if there was such a thing going on in my case. However, 25 mg doxycycline for treatment of Hashi’s in my case was a failure. Happily my CRP levels did respond though as was borne out by that obscure study. I would love to hear of anything that links that treatment to reduction in inflammation. Thank you, Dr. Briffa, for all you do!

  2. Claire 4 June 2010 at 4:23 pm #

    On the whole business of cholesterol reduction, what are your thoughts on the margarines that allegedly have benefits? My elderly mother, who has very mild heart problems and angina but reasonable blood pressure, normal body weight and an active lifestyle insists on eating the special margarines over butter which she feels would kill her. I’m totally unconvinced – I see most margarines as unnatural and potentially harmful but don’t want to distress her. Is there any evidence that the margarines could be harmful? If there’s no need to lower cholersterol what’s the point? Or do their plant sterols add anything beneficial to her diet?


  3. Terry 4 June 2010 at 4:58 pm #

    Dr Briffa

    Here’s a link to a recent open letter from an American heart surgeon that supports all the points you make a thousand fold: –

  4. Radiant Lux 4 June 2010 at 11:21 pm #

    Jimmy Moore just had a dentist on his podcast discussing oral health and its relationship to heart disease.

  5. simona 5 June 2010 at 2:36 pm #

    I wish somebody could link oral health with diet in a way that would show that tooth brushing the way it is expected of us nowadays (with fluoride tooth paste, for two minutes, plus flossing, twice a day at least, if after eating one hour later) is not really necessary if eating a nutrient dense diet. Many bone remains show that paleo man had perfect teeth and they weren’t flossing. There is an inverse link between high processed carb and dental health, and regarding gum disease, vit C metabolism (dependent on sugar consumption too) is very important, but not even mentioned by hygienists. I had chronic periodontal disease for years and the only thing my dentist would do was to clean them of calculus and threaten me that I would lose my teeth in a few years.
    My point is that it’s not only tooth brushing that leads to gum disease and possibly to heart disease.

  6. Chris 7 June 2010 at 6:16 pm #

    One fairly well accepted proposition (to agree with Simona) is that dental caries appear more common in the archeological record around the time that cereal grains are adopted into the evolving human diet. The argument may be that the starches we ingest with cereal grains are really not that different to sugars and so have a similar effect within the mouth and upon the teeth.
    Certainly the effect upon digestion is very similar; sugars and denatured cereal carbohydrates (bread, pasta, etc.) are rapidly digested to become glucose in the blood, this is acknowledged in the metrics of GI and GL (glycemic index; glycemic load). The GI of glucose and bread are both high. Eating them can promote an insulin spike in response to, and to regulate, levels of glucose in the blood. (High) Insulin is cited as being one of the pro-inflammatory agents.

    I think the relatively recent notion of GL is a powerful concept. The principal difference between a chimp diet and that of a typical modern western human is that the modern human diet has a far higher aggregate GL, yet our progenitors of four million years ago or more existed on diets broadly similar to that of a chimp. If the chimp spends circa 85% of its waking hours gathering, masticating, and digesting its’ food the diet is surely low in energy density. That modern humans have so much time free for other enterprising behaviours is entirely attributable to the diet being far more energy dense.

    Chewing raw cale gives an idea of the difference. It takes a lot of chewing, and after chewing there remains a resistant bolus; it is fibrous material that chewing will not appreciably reduce, but while chewing the bolus the soft scouring and cleansing action upon the teeth can be sensed from the feel in the mouth. I think modern flossing mimics something that was once a fairly common and natural effect for our distant ancestors, and in chewing a stalk, such as celery, the ‘stringy’ fibers do physically ‘floss’ between the incisors. Cook cale, or any vegetable matter, and the persistence of the bolus during chewing is reduced. Cooking breaks down the structural integrity of the fibrous components of plant matter that make it easy to chew and easier to digest.

    Richard Wrangham (author of ‘Catching Fire; How cooking made us human’) asserts that cooking is a major ratchet point (my choice of word) in the evolution of the human species. It is an improving caloric economy that permits opportunity for behavioural mutations, that some such adaptations would reap advantage, and further assist the growth in the volume of the brain and an increasing intellect. Cooking makes food easier to chew and to digest, Wrangham clearly argues that cooking improves digestive economy, but cooking (coupled at times with leaching) also opened up new dietary opportunities. While almost certainly raw bulbous roots had been a novel introduction to a distant and evolving ancestral diet many such potential raw foods were off limits either for being indigestible or toxic by degree. Cooking can destroy toxins and cooking breaks down the fibrous ‘membrane’ of starch granules releasing starch. In a BBC Horizon program largely based upon Wranghams’ hypothesis potatoes and carrots were used to demonstrate these effects.

    It is a fairly recent innovation, the ability to fire a flash of laser light at tooth enamel and analyse chemical isotopes in the gases given off, that can reveal insight into the composition of the diets of ancient ancestors. It is a technique that adds to insight that can be gleaned from the scant archeological record of human evolution; it helps distinguish between prominently plant based diets and prominently meat based diets.

    The evolving insight into the the evolution of the human diet seems to meld well with the evolving and advancing theories upon inflammation and the promotion of chronic disease. The more people rely upon ‘fast foods’ ( term used in a broader context) that involve pre-consumptive processing and cooking (even precooking by third parties) the greater seems the incidence of chronic disease.
    However, it is not just the nature of carbohydrates that reveal contrasts. There have been major trends in the type of, and manner, that oils enter the diet. The modern diet, particularly the convenience component, is as reliant, arguably more so, upon denatured oils as it is denatured carbohydrates. Certain oils, the ones that originate from vegetable oils and find their way into many industrially prepared ‘foodstuffs’ including the margarines that Claire is sceptical of, are increasingly understood to have pro-inflammatory effects. However, our Food Standards Agency seemingly willfully would have people consume more of these pro-inflammatory oils via an implicit suggestion to migrate from consumption of saturated to polyunsaturated fats and oils. Such a migration has economic expediency for the corporatised and industrialised product provision chain but, reconciled against a emergent and counter-orthodoxy, has no (beneficial) expediency for human health, possibly quite the reverse.

    On Thursday 20th May 2010 (not entirely certain of date) Dr Phil Hammond addressed a delegation of Dentists in Liverpool. He asked delegates to entertain a challenge to the ‘plaque hypothesis’. It has been a long established view that plaque and plaque acids cause gum disease (gingivitis). Dr Hammonds’ presentation was a discussion upon inflammation and the role it may have in advancing gingivitis. My friend was present and she knew I would be interested. Unfortunately my friend could not cast light upon what may have been suggested, if indeed anything was, as promoting the inflammation. Nonetheless, I did wonder if the applicability of inflammation hypotheses to dentistry might help advance theories that seem slow to influence applied public health policy. Teeth seem to say a lot about us and contemporary health risks.

  7. Jackie Bushell 8 June 2010 at 9:49 pm #

    On the subject of tooth health and nutrition, dentist Weston Price’s ‘Nutrition and Physical Degeneration’ is a must-read if you haven’t already.

  8. simona 9 June 2010 at 1:14 am #

    Thank you Chris for the very interesting and detailed post.
    Dentists talk about the anaerobic bacteria in the pockets as causing the inflammation, I’m sure you know. There must be an imbalance in the oral flora that gradually gets more serious as the ‘bad’ bacteria multiply. That can be influenced by many factors, acidic environment, due to sugars or high GI foods eg bread, even mouth washes with alcohol or toothpastes with triclosan (just guessing)

    You need to convince your mother to give it up.
    You might want to visit Stephan’s site. Have a look at the comments too.

  9. Chris 9 June 2010 at 6:05 pm #

    simona, I’m sure your remark about dietary inputs and imbalance in oral flora is quite right. Dietary choices, the persistent lack of ‘good choices’, almost certainly has a parallel effect in the gut, denuding the balance of gut flora. I chanced upon a recent feature that discussed a cross generational consequence of poor diet and poor gut flora. The detail and the source escape my memory but it was an interesting essay about the immediacy of consequence of a poor maternal diet for offspring.

    Claire, your concerns are important, but if your mother is stubborn or can’t be directed to understand, then don’t let it spoil a healthy relationship, the relationship is far more important.

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