Gluten-free diet MAY be unhealthy and MAY increase risk of heart attack (or not)

OK, so I made up the quote above, but it captures a certain zeitgeist that’s in the air right now. The media is all too keen to uncritically give gluten-free and clean diets a kicking at the moment, wagging fingers at all those ‘silly people’ who fell for the anti-gluten message even though they don’t have coeliac disease – what fools!

Except, as we have explained in multiple articles on this site, gluten has a far greater reach than that 1% who have classic coeliac disease. Non coeliac gluten sensitivity (NCGS) is a recognised and studied condition, with an estimated prevalence of up to 6% of the population.

And even a cursory look behind these dismissive headlines shows that the studies they are based on add almost nothing to our understanding of gluten pathology, and indeed contradict themselves. Continue reading

Heart disease trials: Low-fat diet fails. Nuts and olive oil succeed.

nuts-olive-oil

In brief

  • This post focuses on two of the largest intervention trials ever undertaken to assess the effects of diet on heart disease. Together they cover 1.5 million person-years of follow up and show that fats from high quality foods can be protective, whilst low fat diets failed to change heart disease outcomes. 
  • In the first study, The Women’s Health Initiative, an intensive decade long trial of a low fat diet failed to produce any difference in heart disease between the control and intervention arms, despite participants reducing their calories from fat by 10%
  • A second large scale intervention trial, PREDIMED, compared the standard low fat diet to an energy-unrestricted Mediterranean diet supplemented with nuts or olive oil. Despite an increase in fat consumption of 4.5% a distinct benefit was identified with 30% fewer cases of heart disease or death compared to the control group.
  • Between them they demonstrate the futility of low-fat diets and point to the importance of including sources of high quality fats, from unprocessed food in the diet, such as nuts, extra virgin olive oil and oily fish. 

Read time: 7 minutes (1400 words)

1. The WHI (Women’s Health Initiative) – low fat diet and heart disease

In 1991 the US National Institutes of Health (NIH) initiated The Women’s Health Initiative (WHI). It was the largest intervention study ever undertaken, focusing on 160,000 postmenopausal women aged 50–79 years over 15 years. The study included three large scale clinical trials and one observation study covering cardiovascular disease, cancer, and osteoporosis.

The Dietary Modification Eating Pattern is the trial we are interested in here, as it aimed to determine the effect of a low-fat eating pattern on coronary heart disease incidence. The question it was tasked with answering was “can a low-fat diet reduce heart disease?”

The diet group consisted of 19541 women who underwent intensive intervention consisting of:

  • initial training in eating a low-fat diet
  • ongoing group meetings and consultations to keep participants on track
  • dietary fat target of 20% of daily caloric intake
  • Increasing the consumption of fruits, vegetables, and grains

The control group (29294) were given no advice and left to eat their habitual diets. The trial lasted eight years, meaning that this was a very large, long, expensive intervention. Trials like this only come along once in a lifetime. To ensure the participants stuck to the diet the ongoing support and monitoring was unusually thorough.

The study group achieved a reduction in fat intake of 10.7% in the first year, compared to the control group. By year 6 the difference had only dropped slightly to 8.2% so long-term compliance was good. They also increased

Yet for all the success of the study design, there was no significant reduction in coronary heart disease, stroke or cardiovascular disease events as the graph below shows:

womens-health-initiative

Along with the failure to affect heart disease there was also no significant reduction in colorectal or breast cancer incidence which were secondary outcomes of the trial.

Despite all of these failures to affect disease progression, the intervention group did have significant improvements in biomarkers. This is an important point as biomarkers are usually treated as surrogates for disease risk. The logic is that if A causes B and B is associated with C then A causes C. You can see this in the following advice from the NHS:

Eat less Saturated fat… Eating a diet that is high in saturated fat can raise the level of cholesterol in the blood. Having high cholesterol increases the risk of heart disease. NHS Choices, Nov 2016

Saturated fat (A) raises cholesterol (B) and high cholesterol (B) is associated with increased risk of heart disease (C). Implying that saturated fat (A) causes heart disease (C). It’s a compelling argument. It seems so rational. But… it’s wrong.

The Women’s Health Initiative showed that this logic does not hold. The women on the low fat diet did reduce saturated fat, they did have improved cholesterol, but damn them they had just as much heart disease as ever. What were they playing at? Didn’t anyone tell them what was supposed to happen?

The complete failure of a low-fat diet to modify disease progression should have been the nail in the coffin for low fat diets. These results were published at the turn of the century, yet we are still waiting for government recommendations to catch up. In deed, instead of relaxing the recommendations on dietary fat restrictions, the UK government in its latest revisions have doubled down on

Likewise the The World Health Organisation advocate a diet with less than 30% calories from fat overall. The NHS pages on fats states “Current UK government guidelines advise cutting down on all fats” Then goes on to explain how to eat a low fat diet. They say “If you want to cut your risk of heart disease, it’s best to reduce your overall fat intake and swap saturated fats for unsaturated fats.” yet this is not what the highly expensive and extensive WHI study showed.

2. The PREDIMED trial (Prevención con Dieta Mediterránea) – an unrestricted Mediterranean diet with increased fat from olive oil or walnuts

The PREDIMED trial began in 2003. The 7447 participants were men (55 to 80 years of age) and women (60 to 80 years of age) with no cardiovascular disease at enrollment, who had either type 2 diabetes mellitus or at least three of the following major risk factors: smoking, hypertension, elevated low-density lipoprotein cholesterol levels, low high-density lipoprotein cholesterol levels, overweight or obesity, or a family history of premature coronary heart disease.

They were split into three groups: A control group who received the standard of care advice to eat a low-fat diet. The other two groups were advised to eat a Mediterranean dietary pattern: moderate consumption of ethanol (mostly from wine), low consumption of meat and meat products, and high consumption of vegetables, fruits, nuts, legumes, fish, and olive oil. These two groups were then provided with either extra-virgin olive oil or nuts (walnuts, hazelnuts and almonds) as regular, free food items.

PREDIMED Table S6

Supplementary table S2 from the PREDIMED trial showing the main changes in dietary patterns between the control and Mediterranean diet groups (click image to enlarge)

Despite regular counselling to eat a Mediterranean dietary pattern the only significant differences with the control group (apart from a rather obvious increase in consumption of  extra virgin olive oil and nuts), was a modest increase in fish and legume consumption amounting to aproximately half a portion per week. The main difference in macronutrients was an average 4.5% increase in consumption of calories from fat mainly due to the olive oil and nuts. This additional fat would be primarily monounsaturated and polyunsaturated.

What is remarkable, when compared to the Women’s Health Initiaive is the clear benefits of these high-fat foods. On average there were 30% fewer cases of heart disease or death among those eating the extra virgin olive oil or nuts. The graph below shows the distinct and increasing separation between the mortality lines of the control and intervention groups.

predimed-trial

Considering the relatively modest dietary changes involved the size of the protective effect is quite remarkable.

Conclusions

  1. High Fats v Low Fat
    The PREDIMED intervention clearly produced cardiovascular benefits despite being higher in fat, whereas the low fat WHI failed to produce any such benefits.
  2. Plant v Animal fats
    The main source of the additional fats in the PREDIMED diet was from plants (olive oil and nuts). However, there would have been a small contribution from animal fats via moderatly increased fish consumption. The benefits observed were not from reduced meat consumption, as these remained similar between both control and intervention groups.
  3. Type of Fatty acids
    The types of fat in the PREDIMED diet varied between the two intervention groups: In the olive oil group the main increase came from monounsaturated fatty acids (MUFAs) whilst in the nut group the main increase came from polyunsaturated (PUFAs). As both groups benefitted equally it seems unlikely that either MUFAs or PUFAs are uniquely beneficial. Saturated fat decreased slightly across all groups (including the control group), so cannot account for the observed benefits. Omega 3 PUFAs (α- linolenic acid or marine long chain fatty acids) are considered cardio protective, but these varied little between the groups, and were most different between the nut and olive oil groups. Overall it seems unlikely that changes in individual fatty acids accounts for the benefits. This suggests that other factors in nuts and olive oil are significant. Interestingly, the trial used extra virgin olive oil, as this contains a range of micronutrients and phytochemical not found in more refined and heat treated oils. 
  4. Diet Quality
    In a 2016 comprehensive review in Circulation, the journal of the American Heart Association, Dariush Mozaffarian suggests that it is time to move away from considering diet in terms of isolated nutrients as they appear to behave differently depending on the particular food matrix they are found in as well as the other foods they are eaten with. He suggests that the benefits observed in the PREDIMED diet come not from individual nutrients, but rather differences in overall foods across the diet as a whole. The Mediterranean diet pattern includes more fish, legumes, nuts and whole foods generally, and it may be this that contributed most to the improvements seen in this trial.I think he is right: don’t avoid fats and aim to include low or minimally processed foods like these:

high-fat-real-foods

References

Howard BV et al, Low-fat dietary pattern and risk of cardiovascular disease: the Women’s Health Initiative Randomized Controlled Dietary Modification Trial. JAMA, 2006 [Full Text, PubMed]

Ramón Estruch, et al, Primary Prevention of Cardiovascular Disease with a Mediterranean Diet. 2013 [Full Text, PubMed]

Dariush Mozaffarian. Dietary and Policy Priorities for Cardiovascular Disease, Diabetes, and Obesity. Circulation, Jan 2016 [Full text, PubMed]

April News Round-Up

In_the_News_AprilCheese and Heart Disease

The Daily Mail reported that cheese in the French diet may explain their very low levels of heart attack despite eating high levels of saturated fat – the so called ‘French Paradox’.

This will come as no ‘Quelle surprise!’ to anyone who attended our Malcolm Kendrick talk where he showed that for just about every country in Europe that deaths from heart disease is inversely associated with saturated fat intake! See the graphs yourself on our video here (forward to 21 minutes).

Eggs and Diabetes

Meanwhile, the Telegraph was one of many papers reporting on a study showing that eating four eggs per week ‘can reduce risk of diabetes’. Only four per week? I eat two per day!

Vitamin-D and Sunlight

Many papers, including The Independent, reported that NICE is considering a proposal that all children under 4 should be given free vitamin D supplements “as lack of direct sunlight causes rise in rickets cases”.

In response to these proposals, Alastair Sutcliffe, one of Britain’s leading experts on vitamin D deficiency and a consultant paediatrician at University College London Hospitals, is quoted in the Huffington Post as saying:

“Sunblock is so powerful, it does work but you end up with no exposure to the sun. People are perhaps overdoing it. They are putting all of this stuff on in our climate. The outcome is that you are blocking out sunshine and you have a secondary effect of reduced exposure to sunshine which the human race needs.”

[I will write a post on sunblocks shortly as there is growing evidence that they do far more harm than simply reducing vitamin D production.]

Exercise, Diet and Obesity

For editorial variety, lets turn to Medpage Today for their take on the report that “Obesity epidemic can’t be stemmed by exercise alone”. Which came from an editorial opinion piece in the British Journal of Sports Medicine which slammed the idea that you can get away with eating high-carb junk food and sweetened drinks as long as you are physically active. It is interesting to see how the contributors to the Medpage piece react to the ‘low carb’ message inherent in the original editorial.

Iodine deficiency widespread

Next up, Iodine – a trace mineral essential for infant brain development and IQ – is increasing in public awareness, making the news three times this month:

  • In the UK there are warnings that organic and UHT milk contains less iodine than regular milk which may affect infant IQ. (Daily Mail)
  • Whilst in India iodine impregnated bindis are helping fight deficiencies (The Times of India)
  • In the USA iodine status has fallen 20% due to use of non-iodised salt – according to the Houston Chronicle.

Livestock and carbon sequestration

Finally, “Organic farming can reverse agriculture from a carbon source to sink” – the use of livestock and manure on crops instead of artificial fertilisers has been shown to sequester large amounts of carbon – just as we have been saying in our posts on food and the environment!

Why we pass on the semi-skimmed and low-fat dairy

Full_Fat_Dairy

If you take a look at the recipes, articles and health issues discussed on this site you will see that we love full-fat dairy products, (see here, here and here). Of course, not everyone can tolerate cow’s milk (or sheep’s or goat’s for that matter), but for those that can full-fat is the way to go.

Continue reading

Autumn Seminar 2014 (post 2) – Dr Malcolm Kendrick video pt1 Ten Key Contradictions

Here, at last, is the video of Malcolm Kendrick’s first presentation: ten key contradictions that show why the cholesterol hypothesis is wrong.

This talk was originally recorded on 27th September 2014, 7:40pm at the Assembly Rooms Chichester, West Sussex, England in front of an audience of over 100 people. It was organised, hosted and promoted by Rosemary Cottage Clinic Education Trust. The video was recorded and edited by Keir Watson.

Dr Malcolm Kendrick – Autumn Seminar – Tickets now available

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Cholesterol: why it does not and cannot cause heart disease

For our 2014 Autumn Seminar we are very pleased to present Dr Malcolm Kendrick, author, speaker and blogger, who will expose the myths and misunderstanding around cholesterol and heart disease.

This talk is not to be missed whether you simply wish to understand your own health better, are wanting to become more informed about the current national health debate, or are concerned about politics and corruption in the medical establishment.

Dr Kendrick will also be signing copies of his book The Great Cholesterol Con
during the break.

Date: Saturday September 27th 2014 7:30pm-10:00pm (doors open 7:00 pm)
Venue: The Assembly Room, North St, Chichester, PO19 1LQ
Parking
Northgate (Festival Theatre) Car Park – download directions (pdf)

Tickets

  • Online booking: . . . . .  from £ 8.50 . . . click here for secure online booking
  • Telephone booking: . . . . . . £10.00 . . . 0333 666 3366 (national landline rate)
  • On the door: . . . . . . . . . . . . £10.00 . . . subject to availability on the night

For further information or assistance contact Afifah on 01243 868108
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