An apple a day does (not) keep the doctor away – more bad science
I love the Mail! I would have a fraction of the diet and obesity stories to comment on that I do without it. This blog post comes from today’s Mail on Sunday – from the health section in Review (29/4/2012).
Described as “Why should we eat five a day? And is butter bad? A food writer explores the science and explains why…” the article is supposed to be evidence based and scientific. I tweeted that there is more food science in a packet of cornflakes than in this article. It does, however, serve as a great example of how we must question everything and assume nothing.
Are apples really good for me?
Is the first question asked by Hattie Ellis. She opens by noting that the phrase “’an apple a day keeps the doctor away’ was originally a marketing slogan dreamt up by American apple growers at the start of the 20th century.” This should have raised alarm bells immediately to suggest that it was not based on scientific evidence. However, Ellis seems to have no such worries and post rationalises the value of apples, notwithstanding the origin of the slogan.
“Apples are a good source of fibre” is the first justification for eating apples. Ellis distinguishes between insoluble and soluble fibre. The latter, she claims, can lower cholesterol. She assumes that this is a good thing. I suggest quite the opposite. This blog can explain why cholesterol is a good thing per se and lowering cholesterol is anything but.
The following passage from Dr Uffe Ravnskov, a world expert on cholesterol, explains why having plant sterols compete in the gut for the human cholesterol made by the body is not a good idea:
“It is questionable if a lowering of cholesterol by dietary means is equivalent with a lowering of the risk of coronary heart disease (CHD) because hitherto no unifactorial dietary trial has succeeded in lowering cardiovascular or total mortality.1,2 What the authors also ignore is that an increased intake of plant sterols is associated with an increased cardiovascular risk. In at least four cohort studies a high intake or a high plasma level of plant sterols were independently associated with a higher risk of CHD, and in experiments on mice a dietary supplementation with plant sterol esters equivalent to a commercial spread induced endothelial dysfunction.3 “ (References at the end)
Ellis also unquestioningly accepts “The Department of Health recommends that adults consume 18g of fibre per day”. Why? Notice on the NHS page about “Why is fibre important?” that the page opens with “Fibre is a very important part of our diet…” but makes no attempt to explain why. Why fibre per se? Why 18g of fibre per day? Where is the study that showed any benefit for fibre, let alone the precise number of 18g per day? Where is any evidence? There is none. Instead Ellis just accepts this nutritional myth and proceeds on the basis that fibre is good and apples provide fibre so apples are good. (A former Cambridge University peer of mine is now a UK bowel specialist and he prescribes as little fibre as possible in the diet.)
Ellis suggests a benefit that the NHS page doesn’t – “by hitting the daily recommended fibre intake we may be lowering our risk of colorectal cancer. While diets containing more than 80g of meat per day have been linked to a higher incidence of these tumours, a fibre-rich diet seems to cancel out this effect.” This is all very vague and suggestive and makes the usual error of confusing association with causation. Here is my more scientific take on the red meat and bowel cancer study. There is no mention in this SACN (Scientific Advisory Committee on Nutrition) study of a fibre-rich diet “cancelling out this effect”, let alone apples having anything to do with anything.
We then leap from apples to cider vinegar – more cholesterol lowering claims are made; more assumptions that the utterly life vital substance that is cholesterol is bad; more confusion between association and causation.
The only vitamin mentioned in the “apples are good” section is vitamin C – which is, of course, the only one of the 13 vitamins and c. 16 minerals for which apples are a decent source. In the red meat criticism, Ellis neglected to mention that liver has nearly four times the vitamin C content of an apple – but then not many people know that.
What is the best breakfast?
This section starts with a half hearted attack on sugary cereals – great in principle, weak in execution. Low GI cereals end up being the first recommended breakfast.
“Go to work on an egg” starts the next suggestion, which lifted my heart thinking that we would get an excellent egg breakfast suggestion. Instead Ellis recommends poached egg on glucose (sorry – wholegrain toast) and suggests that the full English breakfast “will keep you full for a long time. However, the calories can be alarmingly high”. Not if you avoid the carbohydrates, which no real food fan would consume as part of a healthy breakfast.
Ellis mentions that the full English breakfast contains protein and fat and that is all that it need contain. Bacon and eggs, without the sugary baked beans and starchy bread, is an excellent source of fat, protein, (including the essential fats and complete range of amino acids), vitamins and minerals. Add a tomato (a bit of carb) and it really does provide the full range of nutrients. Two rashers of bacon, two eggs and a tomato adds up to just under 300 calories – infinitely more nutritious and filling than the cereal that would likely provide more. Far more important than the calories is the very low carb content, which will keep blood glucose stable and protect against diabetes and obesity.
Ellis does rightly correct the British Dietetic Association advice to have a glass of freshly squeezed orange juice, which would give a massive shot of sugar (fructose and glucose) into the body to upset blood glucose levels from the start of the day. Ellis advises that the whole fruit would be better. If one must eat fruit, this is correct, but meat/fish/eggs/veg & salad will always be better than fruit.
Can I eat to avoid heart disease and cancer?
This section jumps all over the place and sadly not from fact to fact:
1) “Eating too many calories can lead to you becoming overweight, which raises risk of heart disease and cancer.” Wrong. I have written 135,000 words on this topic “The Obesity Epidemic: What caused it? How can we stop it?” The evidence supports the fact that carbohydrates – which we have been instructed to ensure form 55-60% of our dietary intake – are together responsible for obesity, heart disease and cancer (and diabetes, Alzheimers and all modern illness). Obesity is not a cause of heart disease and cancer – it is another condition alongside, caused by our appalling diet. (Additionally smoking, lack of activity, stress and many other causal factors apply in the case of heart disease and chemicals, sugar, pollution etc are key causal factors for cancer.)
2) Ellis then quotes Walter Willett of Harvard Medical School who openly declared war on red meat some time ago – giving me the opportunity to expose the bias and lack of science in the Harvard studies – Part 1 and Part 2.
Whole grains are promoted instead, as Ellis quotes Willett: “They provide fibre and micronutrients such as folic acid, magnesium and vitamin E”. Fibre we’ve already established has no evidence base (and we should investigate the rise in bowel disease, from IBS to cancer, which has accompanied our rise in fibre intake). The evidence confirms that liver has over 13 times the folic acid of whole wheat flour and that’s gram for gram. Given that liver has approximately one third of the calories of whole wheat flour, calorie for calorie, liver has nearer 40 times the folic acid. Cocoa powder has nearly four times the magnesium of the same flour, gram for gram, and again is substantially lower in calories. Sardines have two and a half times the vitamin E for a fraction of the calories. Better still, sunflower seeds are the ultimate vitamin E super food – with 42 times the vitamin E content of the flour – albeit for just over one and a half times the calories. We rave about whole grains and then try to justify telling people to consume them. If we really were trying to explore the food science, with evidence, the facts would speak for themselves.
3) Ellis then quotes Professor Corder from Barts on red wine – why quote random different people on random different foods and drink? Ellis is the food science writer – how would she answer the question heading up this section: Can I eat to avoid heart disease and cancer?
My answer would be “You cannot guarantee avoidance of any illness, but you can minimise your chances of heart disease by eating naturally farmed meat/fish/eggs/dairy products/vegetables/salads and seeds and minimising your carbohydrate intake to ensure weight and blood glucose level control. Additionally don’t smoke, moderate your stress and do something active that you enjoy each day. To minimise your risk of cancer, which is a modern illness, minimise your exposure to modern life. The diet advice is the same, but particularly avoid sugar (sucrose) like the plague. Let not one grain pass your lips if you really want to minimise your risk of cancer. Additionally minimise exposure to chemicals, toiletries, pollution and other modern unnatural substances.”
How should I eat my five a day?
This is completely the wrong question! A food science writer doing an investigative article should ask – why five a day? Not how should I eat my five a day?! She would then find, as I did when I asked this question, that it originated in the same way as the “apple a day keeps the doctor away” nonsense. It was “dreamt up” by the fruit and veg companies in 1991 to sell more fruit and veg. Here are the facts on this nutritional myth Even worse is that Ellis heads in this direction but gets it wrong and writes that five a day was created by a state nutritionist in 1998. Even knowing this, the alarm bells should have been ringing again and warning that this is a nutritional myth and not an evidence based nutritional message.
The 2011 study in the European Heart Journal is quoted. Here is the level of analysis that Ellis should have done before accepting this as fact. This blog post takes the origin of the data used by the 2011 study (the European Prospective Investigation into Cancer study) and what the EPIC study concluded about fruit and veg consumption and what the heart team then did to try to find a positive benefit for fruit and veg. As Einstein said – if you know what you’re looking for, it’s not research!
We at last have two statements with which I would agree – 1) eat vegetables rather than fruit because they have more micronutrients and less sugar and 2) vitamin C is destroyed in cooking – so try to eat your vegetables raw or lightly steamed.
The closing line is close to common sense, but it still doesn’t get to the heart of the matter – the fat soluble vitamins in vegetables are only of use to the body if delivered in/with fat. However, an even better way to get the fat soluble vitamins, A, D, E and K is to eat the meat/fish/eggs and dairy foods in which they are abundant. Additionally retinol (the form in which the body requires vitamin A), D3 and K2 are only found in animal foods, not vegetables.
This is not a scientific article and there is little evidence of investigation and questioning undertaken to make it so. This is not intended as a personal attack on the author who is likely a very decent person with good intentions. However, the world is full of nutritional fairy stories that desperately need exposing for the health and weight of our fellow humans. It is bad enough seeing yet another article perpetuating the myths, rather than exposing them. It is even worse when the article claims to be doing the exact opposite.
(p.s. On the same day that this article was published “The Sun on Sunday” reported: “A third of kids believe that eating an apple a day means they will never have to see a doctor, a poll found.” That’s how serious bad science is).
References for the Uffe Ravnskov extract:
1. Ravnskov U. The questionable role of saturated and polyunsaturated fatty acids in cardiovascular disease. J Clin Epidemiol. 1998;51(6):443-460.
2. Hooper L, Summerbell CD, Higgins JP et al. Dietary fat intake and prevention of cardiovascular disease: systematic review. BMJ. 2001;322(7289):757-763.
3. Weingärtner O, Böhm M, Laufs U. Controversial role of plant sterol esters in the management of hypercholesterolaemia. Eur Heart J. 2009;30(4):404-409.