Does exercise really explain how those eating a high-animal fat diet can be at low risk of heart disease?

I noticed an interesting article in the British Journal of Sports Medicine (BJSM) recently. It sought to determine the explanation for the ‘paradox’ seen in Masai tribesmen in Kenya can consume relatively large quantities of animal fat (especially in the form of milk, meat and blood), and have stunningly low rates of heart disease. We all know that saturated fat causes heart disease, right, so the question some have asked for decades now is how the Masai can eat so much of this stuff will so little apparent impact on their cardiac health. The explanation has typically been that the Masai are protected from heart disease by certain genetic factors. In this BJSM article, scientists put forward a different theory: that the Masai’s regular and prolonged physical activity (mainly in the form of walking) and low body weight affords them protection from the supposed hazards associated with their high-animal fat diet.

Some of you reading this may find this topic vaguely reminiscent of the so-called ‘French paradox’, whereby some inhabitants of France consume very high levels of animal fat but appear to enjoy, again, really quite low rates of heart disease. If you’re familiar with phenomenon, then you may also know that the oft-quoted explanation for this apparent paradox is the consumption of red wine which, we are told, serves as an antidote to the fat-filled diet of the French.

However, before we go looking for explanation for paradoxes, my suggestion would be first to examine whether there is indeed a paradox to be explained. The paradox seen is both the Masai and the French assumes that animal (and saturated fat, particular) has the ability to clog up our arteries and precipitate heart disease and perhaps other cardiovascular conditions (e.g. stroke) as well. But is this really the case?

From a theoretical perspective one could argue that animal fat should not be the dietary spectre its generally made out to be. Why? Because there is quite a body of evidence which suggests that it’s been in our diet forever, and therefore is something we should be quite well adapted to by now. However, it’s not enough to rely on this sort of common sense, we also need to look to the science too.

Back in February I reviewed the evidence surrounding saturated fat and cholesterol. You can read that blog post here. In summary, what the evidence shows is that:

1. Saturated fat consumption does not have strong links with risk of heart disease

2. There is little (if any) good evidence that eating less saturated fat reduces the risk of cardiovascular disease or overall risk of death

This may seem like nutritional heresy, but it is, remember, utterly in keeping with the theory that the foodstuffs we’ve had for the longest in our diet are the ones we’re best adapted to and are likely to be the most appropriate foodstuffs for our consumption too.

Or course, there’s another side to this coin, in that authors of the BJSM study note that the typical Masai diet is not just high in fat, but low in carbohydrate. I recently wrote about the issue of carbohydrate and cardiovascular health here.

You will read here how certain carbohydrates have the capacity to cause considerable disruption of blood sugar levels, and their consumption may induce changes that would be expected to increase the risk of cardiovascular disease. The review that forms the focus of this blog post concludes that eating a diet rich in highly disruptive carbohydrates (high glycaemic index and/or glycaemic load foods) is associated with a 20 – 100 per cent increased risk of cardiovascular disease.

In other words, not only may the Masai’s low risk of heart disease not be a paradox at as far as animal fat consumption is concerned, it might also be related to the relative paucity of carbohydrate in their diet too. The physical exercise may indeed be helping to reduce their risk of heart disease, of course, but we don’t necessarily need this lifestyle factor to explain how it is that individuals eating a high- fat, low-carb diet are at the same time at relatively low risk of heart disease.

References:

Mbalilaki JA, et al. Daily energy expenditure and cardiovascular risk in Masai, rural and urban Bantu Tanzanians. Br J Sports Med. 2008 Jun 3. [Epub ahead of print]

18 Responses to Does exercise really explain how those eating a high-animal fat diet can be at low risk of heart disease?

  1. SkepTicTacToe 25 July 2008 at 10:43 am #

    The benefits of a paleo diet is the proverbial ‘elephant in the room’. Increasingly we see the benefits of a diet that:

    - avoids refined carbohydrate and grains (basically avoiding any carbohydrate that cannot be eaten in its raw state),
    - limits fruit consumption (to a seasonal basis), and,
    - emphasises the fat that comes with (free range) animal protein – free range food having a favourable fat profile due to the exercise and foraging activities of the animal.

    Somehow the wider medical community REALLY does not want to admit to the benefits of eating this way. Every time the paleo-type diets perform well in trials, the medical establishment rush out to try to defend the status quo and prop up failing predjudice.

    They mumble their way through explaining these ‘shock’ results and end up almost apologising for the fact that the paleo diet came out in a favourable light….and then rush to shroud the result in caveats and well trodden platitudes about ‘saturated fat’, ‘dieting fads’ and inferences that it is not somehow a ‘balanced diet’.

    Quackwatch makes me laugh (http://www.quackwatch.org/06ResearchProjects/lcd.html). Despite their objectives they manage to criticise low carbohydrate diets by a combination of generalisation (low carbing diets seem to be criticised under the umbrella term of ‘the Atkins Diet’), old research, scare stories, mild inference of a conflict of interest (funding of some of the research was by Atkins), repetition of outright inaccuracies and fallacies (“A high intake of saturated fats over time raises great concern about increased cardiovascular risk”) and plainly unsupportable advice (“Following a low-carbohydrate diet under medical supervision may make sense for some people, but a population-wide increase in fat consumption would not.”).

    Despite all this, the guy that wrote the Quachwatch article cannot outright dismiss the value of the Paloe approach and concedes that “My advice to people who are considering a low-carbohydrate diet is not to try it on their own by reading a book, but to seek supervision from a physician who can monitor what they do”. Reasonable enough.

    It seems the best that the critics can do is to warn about ‘unknown long term consequences’ – a scare tactic if ever I heard one. Perhaps, in the interests of fairness, they should wanr about the known long term consequences of the so called ‘balanced diet’ – dieabetes, obesity etc….

    Keep fighting the good fight Dr B.

    Regards,
    Chris

  2. Katrina Woodrow 25 July 2008 at 9:22 pm #

    Sally Fallon’s book ‘Nourishing Traditions’ is essential reading on this subject in which she refers to research carried out by Mary Enig on good and bad fats. There has been too much rubbish written about traditional diets over the years, which too many doctors, nutritionists and scientists have stuck to as if their lives depended on it. (A lot like global warming).

    It irritated me at Slimming World when the organiser, for want of a better word, cited the death of Dr Atkins as justification of the lack of desirability of a low carb diet. She looked stunned when I corrected her that he had actually died as the result of a fall on a New York sidewalk and the weight gain was a result of being on a drip for the last two or three weeks of his life. She talked a lot of other rubbish about there being no proof that aspartame and Splenda can do us any harm as well. Let’s face it, Donald Rumsfeld and the rest of the executives at Searle and the FDA all knew about the holes aspartame caused in rats’ brains before they got approval for it. They haven’t even done that much research on Splenda yet and a report on the http://www.mercola.com website is inaccessible on this side of the Atlantic as Tate & Lyle have somehow managed to censor it. Tells you a lot doesn’t it? But I digress.

    I love carbs but I am not healthy on them and am very prone to the recurrence of candida overgrowth. As long as enough water is consumed to prevent damage to the kidneys, there appears to be nothing wrong with a low carb diet, but ironically they are now trying to rubbish the consumption of water as tragically one woman suffered brain damage as a result of excessive intake and a concurrent reduction of salt in her diet. On the next page of the newspaper was a large article about the importance of getting salt out of the diet. I do wish someone with some clout would take a sensible overview in order to guide the confused masses.

    To digress yet again, I must admit I was thrilled when the article came out about the reduction in sperm count which the regular consumption of tofu can bring about (I bought it twice and it went mouldy twice, it just wasn’t appetising!). I have been warning my patients about the dangers of unfermented soya for a couple of years now in relation to the reduction in testosterone levels and the premature onset of puberty in girls who have consumed a lot of it. It was good to have a headline which confirmed what I have been telling people about this over hyped foodstuff. See Dr Kaayla Daniels book “The Whole Soy Story”.

  3. James H 26 July 2008 at 10:48 am #

    An important message that exercise maybe makes the Paleo diet healthy. One question I have in the back of my mind is how do we feed the worlds population on this diet ? Or isn’t feeding the world the point ?

    Soya contains phytoestrogen. Can you tell me what evidence there is that this is causing premature onset of puberty? A far more likely cause of early onset of puberty in girls is the estrogen present in Cow’s milk. The level of estogen in Cow’s milk has increased over time as farmers have turned to more intensive farming practices.

    Typical dairy farms, cows are milked about 300 days a year. For much of that time, the cows are pregnant. The later in pregnancy a cow is, the more hormones appear in her milk.

    Milk from a cow in the late stage of pregnancy contains up to 33 times as much of a signature estrogen compound (estrone sulfate) than milk from a non-pregnant cow.

    In traditional herding societies like Mongolia, cows are milked for human consumption only five months a year, and, if pregnant, only in the early stages. Consequently, levels of hormones in the milk are much lower.

    So I guess another argument for the Paleo Diet, make sure your milk comes from a “traditional” herd.

  4. Jackie Bushell 26 July 2008 at 1:07 pm #

    Take a look at the (free) Weston Price book at
    http://www.gutenberg.net.au/ebooks02/0200251h.html – full of detail but absolutely fascinating and well worth reading.

    If I wanted to choose two books that explain why the high carb/low fat diet is bad for us, it would be the Weston Price one and Gary Taubes’ ‘The Diet Delusion’.

    Dr Briffa, have you read the Weston Price book? An article from you on it’s implications for the way we approach health today would be excellent…

    Jackie

  5. Lindy 26 July 2008 at 5:33 pm #

    In the 60s, the advice then, if you wanted to lose weight, was to reduce starches and sugars. So people would cut down or stop eating potatoes, bread, cakes and biscuits etc. Fat was described as needed by your body. It was in the mid 70s that the ‘new’ idea of low fat was started, which erroneously seemed to make sense i.e. the less fat you ate, the less fat you put on. This belief has now become a cult belief that everyone accepts and refuses to question or even wish to change. People don’t like to change things they have believed in as it tends to neutralise their intellect and credentials to others.

  6. Pauline 26 July 2008 at 6:55 pm #

    I suggest that anyone wishing to know more on this fascinating subject goes to http://www.second-opinions.co.uk. The writer, a researcher and author by the name of Barry Groves, will indeed give you food for thought.

  7. James H 26 July 2008 at 8:38 pm #

    Jackie, the book link you posted looks very interesting, esp as the author had access to people eating primitive diets to compare against those that were on modern diets. I will definitely be reading it.

    Pauline, sorry I can’t say the same for “your second opinions” website. e.g is his section – “Healthy” fruit and veg don’t reduce cardiovascular risk – for real ?

  8. Stephan 27 July 2008 at 12:35 am #

    I posted on this study a while back as well. I think it’s worth mentioning that due to the exceptionally high fat content of Masai milk, they traditionally have a higher consumption of saturated fat than perhaps any other population on earth, about 33% of calories! The most parsimonious explanation of the data is that saturated fat doesn’t cause heart disease! Here are a few of my posts on the Masai if you’re interested. I got my hands on some great old research for the second two:

    http://wholehealthsource.blogspot.com/2008/06/what-to-do-if-your-study-contradicts.html

    http://wholehealthsource.blogspot.com/2008/06/masai-and-atherosclerosis.html

    http://wholehealthsource.blogspot.com/2008/06/more-masai.html

  9. Pauline 27 July 2008 at 6:58 pm #

    I don’t wish to detract from the main thrust of Dr Briffa’s article but I do think that James H is being somewhat unfair in his dismissive criticism of Barry Groves and his second-opinions website. In the article to which James refers Barry Groves was commenting on a 2002 study by the Division of Nutrition, University of Helsinki and others that came to the conclusion that in healthy volunteers diets that differed markedly in the amounts of linoleic, oleic acid,vegetables, berries and apples showed little difference in lipid peroxidation or lipid metabolism. In his commentary Barry states that this was the first of several studies which looked into the claim that 5 portions of fruit and vegetables a day reduced the risk of CHD and cancer and in effect was found wanting.
    In a subsequent article he refers to a Greek 2003 study that seemed to show that 2 or more servings per week, as opposed to the nutritional mantra of 5 per day, were associated with some reduction in risk whilst also highlighting a 2004 US study that found that increased fruit and vegetable consumption was associated with a modest although not statistically significant reduction in the development of major chronic disease.. Further analysis of different groups of fruit and vegetables revealed that the consumption of green leafy vegetables, such as spinach and kale appeared to offer the strongest protection against cardiovascular disease, although a mere 2 rather than 5 servings per day sufficed and presumably still not in any statistically significant way. As an addendum he made the point that there exist many people on earth who eat no vegetables or fruit at all and yet where heart disease and cancer are virtually unknown.
    Personally I find his writings to be interesting,incisive, intelligent, forthright and all the more refreshing because they possess a healthy measure of scepticism and are happily devoid of any pseudo-academic hyperbole.
    Perhaps, should I appear to eulogise, I should hasten to add that I have no personal axe to grind.

  10. Reina Powlison 27 July 2008 at 11:55 pm #

    It is such a breath of fresh air to see you people putting honest data up for the public. One question I have is, are there studies showing the difference between the natural, God-designed fats (milk-fat, fat in meat, and olive oil) as opposed to the processed vegetable oil (margarine, etc.)?
    I will be searching and hoping for some confirmations of some serious suspicions I have about the man-made fats.

  11. James H 28 July 2008 at 7:46 pm #

    Pauline. I am sorry to detract from the main point on this page. However in reply to your lengthy post, One of the main issues I have with Barry Groves is summed up with this quote “People are turning to vegetarianism because, they believe, it is healthier, or kinder to animals, or the planet. . . The fact is that vegetarianism is less healthy; and if we all became vegetarians, we would starve.” One of his main arguments is “Animal farming is an efficient use of land”. I dispute this argument totally. For example, In the US 70% of the grain produced is fed to livestock. So not only do you need the land to hold the animals you have to feed the majority of the grain you produce to feed them. In the war we survived in Britain by reducing the amount of animal products we ate and increased the amount of vegetables as this was the most efficent use of our resources and land.

  12. James H 28 July 2008 at 7:55 pm #

    P.s I also except that some land can not be used to grow crops and is more efficient for keeping livestock. I respect peoples wishes to eat meat if they want to. As I would hope they respect my wish to be a vegetarian. :-)

  13. Rarest1 29 July 2008 at 3:53 am #

    Might it be useful to know if the Masai food is riddled with pesticides, herbicides, hormones, antibiotics and other drugs and the water the animals drink … is it a chemical soup of every drug sold by Big Pharma and does it also contain animal and human excrement? Like our food and water?

    If it is NOT like our (contaminated) food and water, might that mean that (our) additives are the culprits rather than the food?

  14. superburger 29 July 2008 at 7:37 pm #

    Dr Briffa says

    “1. Saturated fat consumption does not have strong links with risk of heart disease

    2. There is little (if any) good evidence that eating less saturated fat reduces the risk of cardiovascular disease or overall risk of death”

    However, the following reviews have been published in the peer-reviewed literature

    Mead et al, J Hum Nutr Diet. 2006 Dec;19(6):401-19.

    This review concludes

    “There remains good evidence that reducing saturated fat reduces morbidity in patients with CVD.”

    Khan et al, Can J Cardiol. 2008 Jun;24(6):465-75

    recommendations

    “……follow a diet that is reduced in saturated fat and cholesterol, and one that emphasizes fruits, vegetables and low-fat dairy products, dietary and soluble fibre, whole grains and protein from plant sources; and consider stress management in selected individuals with hypertension.”

    Hu et al, JAMA. 2002 Nov 27;288(20):2569-78

    review concludes

    “Substantial evidence indicates that diets using nonhydrogenated unsaturated fats as the predominant form of dietary fat, whole grains as the main form of carbohydrates, an abundance of fruits and vegetables, and adequate omega-3 fatty acids can offer significant protection against CHD.”

    Hooper et al, Cochrane Database Syst Rev. 2000;(2):CD002137

    Plain Language Summary

    “Cutting down how much fat we eat or replacing some saturated (animal) fats by plant oils and unsaturated spreads may reduce risk of heart disease, probably including fatal heart disease. Heart disease includes heart attacks, chest pain, strokes and the need for heart surgery.”

    Temple, Biomed Pharmacother. 1996;50(6-7):261-8.

    “The prevention and treatment of coronary heart disease (CHD) necessitates vigorous dietary intervention……..The critical dietary change is the reduction in intake of saturated fat and cholesterol.”

  15. Pauline 29 July 2008 at 8:43 pm #

    I confess, James, that I am invariably drawn to a paradox for what often appears an unreasonable anomaly often invites a reasoned debate. The particular paradox highlighted by DR Briffa becomes all the more interesting in that it is not unreasonable to infer from this and other studies that a main plank of Western allopathic medicine might possibly be resting on shaky foundations. It is certainly not a quantum leap to infer that a major cause of CHD could be rather different from the one that big pharma earn billions in attempting to cure.

    As to the second-opinions web site, I have no hesitation in recommending anyone who possesses an open mind to take a look at what it’s creator, Barry Groves, has to say on this and many other diseases that he believes are the result of an inappropriate diet. There is a compelling clarity to many of his well researched, if forceful assertions, but I can quite understand if some find his certainties hard to swallow. Personally for me that is not an issue and that may indeed surprise you for since my early teens I have eschewed the eating of flesh and have kept strictly to a lacto-ovo vegetarian diet. But then as he rightly says I am leaving the burden of the harsh reality of dairy farming to others.

  16. Liz Clarke 6 August 2008 at 2:47 pm #

    If Couch Potatoing was an Olympic Sport I’d be a contender!

    I’m extremely overweight (like 40%+) and have had “Body size problems”since childhood.

    I do know, however, that when I’m fat and unfit I feel awful but when I’m fat and fit I’m terrific.

    I can’t be the only one who “listens to their body” and has noticed that their circulation feels so much better after something like 10 minutes hard pedalling on a bike or (for me) an energetic swim. It just feels as though the veins and arteries have had a good toning session and been declogged.

  17. Fat to Fit Review 27 December 2008 at 6:43 pm #

    Reading your post this goes against a lot of the conventional wisdom that is still out there in the public domain. I studied Bsc Sports Development at University in Portsmouth and my disseration was on the incidence of obesity, granted this was a few years ago, but I myself like so many out there when looking at the studies pertaining to cardiac mortality and morbidity rates always interpreted the data as being correlated with exercise and diet namely saturated fats.

    It will be very interesting if it is conclusively proven that carbohydrates can have that significant of an effect on the incidence of heart attacks as proposed.

    Olly

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