Category: medicines

Multi-vitamins increase risk of death in some cases

Over the last few decades, people have been more concerned about health. The fitness boom of the 1970s led to a running craze and the 1980s could be described as the supplement decade, where people started taking multivitamins. (We could refer to the 1990s as the bodybuilding age and the noughties as the creatine and steriod age.)

Why do people take supplements? As the term suggests, it is to make up for vitamins that might be missing in your diet. But a report by the Guardian found that not only did supplements not have any positive effect, some vitamins actually have a higher risk of death of poor health.

Researchers at the University of Toronto looked at the effect of various vitamins on the risk of heart disease and stroke. What were the results? There was no significant proof that vitamins prevented heart disease, although folic acid, found in the B vitamins, did reduce the risk of stroke.

However, niacin (vitamin B3) and antioxidants (vitamins A, C and E) were associated with an increased risk of all causes of death, according to the findings published in the Journal of The American College of Cardiology.

Too many people have assumed that multivitamins only have a positive effect, but the levels in the products on sale can be well over the daily recommended limit, sometimes by as much as 1000%.

Vitamin C, in particular, is assumed to be good but too much can be dangerous.

There should be no need to take multivitamins if you are on a balanced diet, and the money spent could turn out to be a waste, or even harmful, if you happen to get supplements that have high levels of certain vitamins.

The pianist Robert Schumann suffered from poor health and even lost the use of his left hand, causing his performing career to be over. While part of it was reportedly due to a device that he used to widen the reach of his handspan, medication he was taking did not help either – which goes to show you must be careful what you put in your body.

Part of the problem is due to what we call anchoring. When we have a fundamental belief in an assumption, subsequent opinions are formed relative to that first opinion. If you believe supplements are good, then successive formulations of opinion are assumed to be good too, even though they may be distorted.

Painkillers may have effect on your baby’s fertility

Nope, you read right.

Scientists have studied data and suggested that the use of painkillers by women during a pregnancy may have effect on their offspring when it comes to future generations’ intent to conceive.

Scientists studied foetal human tissue and the effects that these had under treatment of paracetamol and ibuprofen. Both are common generic medicines used to manage pain, and hence a common feature of them is the management of pain receptors – the dulling of pain to the point that receptors are less responsive so that the body adapts and is less affected. The scientists found that in both cases, when the foetal human tissue was exposed to pain relief drugs, the number of germ cells, which are the ones that develop into sperm and eggs, were reduced after a week.

Hence, the use of painkillers by women during their pregnancy could lead to these effects being transferred to their off spring.

In other words, their children could have difficulty conceiving.

The problem with this research, as with many other similar kinds, is that it was done not on humans but on tissue-compatible cases. Tests were done on mice and tissues grown in laboratory, and while they have similar bearing to humans, we cannot say for definite if this is what would happen. Unfortunately, it is unethical to prescribe high doses of pain-relief to women only to observe the effects on their offspring a generation later. That cannot happen.

Current pregnancy guidelines do state that it is safe to take paracetamol, but only at the lowest dose and for the shortest space of time.

It is best prescribed under the supervision of a doctor, but it is difficult to prevent pregnant women to walk into a supermarket and get some for themselves!

The study was carried out by researchers from the University of Edinburgh and Copenhagen University Hospital. It was funded by the UK Medical Research Council, the Wellcome Trust, and a British Society of Paediatric Endocrinology and Diabetes Research Award. It was published in the peer-reviewed journal Environmental Health Perspectives.

The researchers did say their results suggested that painkillers have an effect on the level of germ cells, which may alter how DNA is formed and so could potentially affect future generations. But these results came from tests that were not performed in humans, and many other factors that contribute to fertility were also not accounted for.

And while these kinds of studies may never be fully conclusive, it is always better to be aware, than sorry!

Going herbal? Switch with caution

Do you use herbal remedies rather than traditional medicines? If you belong to the former group, you may find yourself part of a growing number of individuals who may be increasingly opting for the herbal medicine route in favour of the traditional medicine route.

What makes people resort to traditional medicine? There are many reasons. One may be that they have been on a particular type of medication for a long period of time, and have seen no improvement, and are keen to try something that might bring about change. For example, if you have been suffering from migraines for quite a long time, and the medication does not appear to alleviate the severity of the frequency of the headaches, then would you not be tempted into trying something else that might work? After all, you might think that if you do not try, you might miss out of the potential benefits. Hence, the search for a better treatment might be a motivating reason for going herbal.

But seeking products that might work better because they are more naturally occurring and possibly more readily adopted by the body may only be one reason for switching to or trying herbal remedies. Traditional medicine also carries risks of adaptation and addiction, which is why some individuals consider switching.

Take for example pain relief medicines such as ibuprofen. If taken consistently for a long period of time, the body adapts to this increased level and the benefit of ibuprofen is gradually neutralised and minimised. It does not bring pain relief if taken on a prolonged basis because the body has adapted. But because the body has acclimatised or become accustomed to this, it now depends on this level of ibuprofen. The medicine has now bred dependency, and an individual is now addicted to it. It is possible that something more potent in terms of pain relief may be prescribed by doctors but again with prolonged use there is the danger of adaptation and addiction, but this time to a higher dose.

Medicines also produce side effects if used for long term. We have already examined for example the effect of aspirin in the elderly – it can cause bleeding and other complications.

Hence it is unsurprising that individuals look to the herbal medicine route as a means of avoiding greater dependency on drugs, to avoid tampering with the body’s natural ability to heal itself, and in the hope that herbal remedies could provide a quick alternative resolution to medical issues that they have had long term treatment for.

The herbal medicine world is not as regulated as the traditional medicine world although there is increasingly a tightening on the controls, especially on the advertising and promotion of products to make sure that products cannot make claims to curing certain illnesses.

While some may protest into the regulation of the herbal medicine market as the clamping down on civic liberties by an over protectionist nanny state, there are actually valid medical reasons for these interventions.

Herbal remedies may interact with traditional medicines and cause conflicts. They may either neutralise the potency of the traditional drug, or enhance it to dangerous levels above recommended limits.

The most often reported drugs that can come into conflict with traditional drugs include the blood-thinning drug warfarin, cholesterol-lowering statins, anti-cancer drugs, antidepressants, immunosuppressant drugs for organ transplants and antiretroviral drugs for people with HIV. The most common result of a drug herb interference was that of cardiovascular disease, involving medicine such as statins and warfarin. Other unwanted spheres of influence include cancer, kidney transplants, depression, schizophrenia, anxiety disorders and seizures.

The most commonly used herbal remedies included ginkgo biloba, St John’s wort, ginseng, sage, flaxseed, cranberry, goji juice, green tea, chamomile and turmeric, while those most likely to cause interactions with drugs appear to be sage, flaxseed, St John’s wort, cranberry, goji juice, green tea and chamomile.

In some cases herbal remedies can lead to death or secondary death. One man died after a herbal remedy prevented his anti-seizure medication from working properly, resulting in him drowning.

These facts highlight the need for patients to inform their doctors if they are taking other forms of herbal medication apart from the medication that the doctors are prescribing, so that the doctors can examine if there might be interference in the interactions. This need is particularly important if among the drugs are those that have been identified as being likely to be affected by herbal remedies.

But what stops people from mentioning they are trying herbal remedies? One main reason is embarrassment. Alternative remedies still have a reputation for being outside the periphery of the mainstream and carry with them the stigma of being unconventional, flaky and based on superstitious beliefs. Some might question their unscientific basis as a whole load of quackery, akin to snake oil or elephant powder. Subscribing to herbal remedies in some circles in seen as being illogical. And no one wants to be perceived as a nutter.

There is also the perception of owning up to being a failure for whom traditional medicine has not worked for.

The crossover group is the one most at risk as they are most likely to continue taking the doctor’s medication while trying herbal remedies at their prescribed doseages. In other words, they are most likely to take double of what is recommended in a bid to get the best of both worlds.

Herbal remedies may prove their worth in time. But in the meantime, while we move towards a scientific study, regulation and understanding of non-pharmaceutical medicines, it is best to be cautious of interference and their crossover effect.

Ibuprofen and the fertile imagination

There is an astounding variety of painkillers available for purchase both in supermarkets, chemists, and corner shops. Just take a look at the shelf of your nearest Tesco or Sainsbury. You have various types of paracetamol, both made by pharmaceutical companies as well as in house versions of the supermarkets.

What is the difference between them and why are there so many varieties?

When pharmaceutical companies take on the decision to manufacture a new drug, they are given a twenty-year patent which covers the research into the product, testing and manufacturing, and sales. The period of twenty years, a monopoly as such, is to reward them for the time invested into the research. In the course of the research into the product, pharmaceutical companies must publish various forms of medical evidence and put it into public domain, so that if there is any medical evidence that points to the contrary, these can be debated both by the medical community and the pharmaceutical world.

The problem, if we can call it that, is that business is a very competitive world, and if research is put out in the open without any form of intellectual protection, any manufacturer can pounce on the research undertaken by someone else who has taken the effort and trouble to do it, and produce their product off the back of it. They would have saved the time and cost investment.

Imagine if a writer has taken the time to research a topic, organise his thoughts succinctly, and find a publisher. And when his book is published, someone else photocopies it, binds the copied pages and subsequently peddles it as their own.

Within the period of twenty years, a pharmaceutical company has to research, market and sell enough of the product to recoup the investment costs and profit. It is after the twenty period has expired that the other sharks enter the fray. This is where you get the supermarket brands of the product, which are cheaper because they don’t need to pay for research.

What is the difference between brand names and generics? They essentially do the same thing. But if the original company has done a good job in making the product synonymous with its own brand, then you might think they are better. If you take Neurofen for headaches, then you might think it better than Tesco ibuprofen, even though they both contain the same active ingredient.

But pharmaceutical companies have to reinvent themselves, to make varieties of the same product, otherwise they will lose their market share and eventually die out. If you realise that Neurofen is matched in ability by the cheaper Tesco ibuprofen, you would buy the latter, unless you are persuaded that Neurofen for Flus and Colds, or Neurofen Muscle Pain has something clinically formulated for that specific purpose.

So the shelves of supermarkets are stacked with different priced products with the same active ingredient, as well as different varieties of the same product.

Painkillers are a common medicine because there will always be a demand for pain management.

The availability of pain relief medicine means it is easy for the average individual to obtain them. There is the possibility of overdose, and while this may be a rarity, there is a higher likelihood that the greater availability may mean individuals are taking more doses than they should.

What are the long term health impacts of taking ibuprofen for prolonged periods?

One problem is that the body adapts and so the long-term resistance is affected. In certain groups such as the elderly, aspirin also increased the risks of stomach bleeding.

A clinical trial seemed to suggest it may impact on testosterone production and hence affect fertility.

Test subjects were administered 2 x 600mg doses of ibuprofen daily for six weeks, much higher than the average dose. The sample size was only a small group of 30, and half received ibuprofen, while the others received a placebo. It would have been better if the subject group had been greater, so that there could be more confidence in the test results, but because a test of such nature is to examine human resistance to what is essentially toxicity, it would have been unethical to involve a large group of participants. The research findings found that there was no impact on testosterone already in the body, but the pain relieving nature of ibuprofen, as a relaxant of sorts, had impact on the production of testosterone and appeared to slow down production.

How did these reports end up in the media? The tabloids had a field day, and you would undoubtedly have found one with the usual wisecracks about balls and other man-related genitalia, along the lines of “Ibuprofen shrinks your balls” or “Ibuprofen smalls your balls”.

Maybe instead of Ibuprofen for colds or fast relief, we need Ibuprofen for Dummies.

A short history of non-medical prescribing

It had long been recognised that nurses spent a significant amount of time visiting general practitioner (GP) surgeries and/ or waiting to see the doctor in order to get a prescription for their patients. Although this practice produced the desired result of a prescription being written, it was not an efficient use of either the nurses’or the GPs’time. Furthermore, it was an equally inefficient use of their skills, exacerbated by the fact that the nurse had usually themselves assessed and diagnosed the patient and decided on an appropriate treatment plan.

The situation was formally acknowledged in the Cumberlege Report (Department of Health and Social Security 1986), which initiated the call for nurse prescribing and recommended that community nurses should be able to prescribe from a limited list, or formulary. Progress was somewhat measured, but The Crown Report of 1989 (Department of Health (DH) 1989) considered the implications of nurse prescribing and recommended suitably qualified registered nurses (district nurses (DN) or health visitors (HV)) should be authorised to prescribe from a limited list, namely, the nurse prescribers’formulary (NPF). Although a case for nurse prescribing had been established, progress relied on legislative changes to permit nurses to prescribe.

Progress continued to be cautious with the decision made to pilot nurse prescribing in eight demonstration sites in eight NHS regions. In 1999, The Crown Report II (DH 1999) reviewed more widely the prescribing, supply and administration of medicines and, in recognition of the success of the nurse prescribing pilots, recommended that prescribing rights be extended to include other groups of nurses and health professionals. By 2001, DNs and HVs had completed education programmes through which they gained V100 prescribing status, enabling them to prescribe from the NPF. The progress being made in prescribing reflected the reforms highlighted in The NHS Plan (DH 2000), which called for changes in the delivery of healthcare throughout the NHS, with nurses, pharmacists and allied health professionals being among those professionals vital to its success.

The publication of Investment and Reform for NHS Staff –Taking Forward the NHS Plan (DH 2001) stated clearly that working in new ways was essential to the successful delivery of the changes. One of these new ways of working was to give specified health professionals the authority to prescribe, building on the original proposals of The Crown Report (DH 1999). Indeed, The NHS Plan (DH 2000) endorsed this recommendation and envisaged that, by 2004, most nurses should be able to prescribe medicines (either independently or supplementary) or supply medicines under patient group directions (PGDs) (DH 2004). After consultation in 2000, on the potential to extend nurse prescribing, changes were made to the Health and Social Care Act 2001.

The then Health Minister, Lord Philip Hunt, provided detail when he announced that nurse prescribing was to include further groups of nurses. He also detailed that the NPF was to be extended to enable independent nurse prescribers to prescribe all general sales list and pharmacy medicines prescribable by doctors under the NHS. This was together with a list of prescription-only medicines (POMs) for specified medical conditions within the areas of minor illness, minor injury, health promotion and palliative care. In November 2002, proposals were announced by Lord Hunt, concerning ‘supplementary’prescribing (DH 2002).

The proposals were to enable nurses and pharmacists to prescribe for chronic illness management using clinical management plans. The success of these developments prompted further regulation changes, enabling specified allied health professionals to train and qualify as supplementary prescribers (DH 2005). From May 2006, the nurse prescribers’extended formulary was discontinued, and qualified nurse independent prescribers (formerly known as extended formulary nurse prescribers) were able to prescribe any licensed medicine for any medical condition within their competence, including some controlled drugs.

Further legislative changes allowed pharmacists to train as independent prescribers (DH 2006) with optometrists gaining independent prescribing rights in 2007. The momentum of non-medical prescribing continued, with 2009 seeing a scoping project of allied health professional prescribing, recommending the extension of prescribing to other professional groups within the allied health professions and the introduction of independent prescribing for existing allied health professional supplementary prescribing groups, particularly physiotherapists and podiatrists (DH 2009).

In 2013, legislative changes enabled independent prescribing for physiotherapists and podiatrists. As the benefits of non-medical prescribing are demonstrated in the everyday practice of different professional groups, the potential to expand this continues, with consultation currently under way to consider the potential for enabling other disciplines to prescribe.

The financial considerations of investing in medicine and medical research

BBC News reports that a drug that would reduce the risk of HIV infection would result in cost savings of over £1bn over 80 years. Pre-exposure prophylaxis, or Prep, would reduce infection and hence lower the treatment costs for patients in the long term.

The catch? There is one. It’s the long term.

The cost of the treatment and prevention is such that its provision for the first twenty years – bundling together the cost of medical research and production of medicine – would result in a financial loss, and parity would only be achieved after a period of about thirty to forty years; this period is hard to define because it is dependent on what the drug would cost in the future.

Prep combines two anti-HIV drugs, emtricitabine and tenofovir. The medical trials behind it have concluded it has an effective rate of over one in five when it comes to protecting men who have unprotected sex with men from HIV infection. The exact figure is close to 86%.

Prep can be used either on a daily basis, or on what has been termed a sexual event basis – using it for two days before, during and after periods of unprotected sex.

The research model analysed the potential impact of Prep and found that it could reduce infection rates by over a quarter. The cost of the treatment itself, comparative to the cost of treating infection, would result in a saving over one billion pounds over eight years.

However, it does raise a few ethical questions. If the National Health Service is aiming to be a sustainable one – and one of the aims of sustainability is to empower citizens to take responsibility for their own health –  shouldn’t it be considering less about how it will balance the books, but spend more on education for prevention in the first place? The cost of producing Prep on the NHS would be £19.6 billion over 80 years; while the estimated savings from treatment would be £20.6 billion over the same period. Educating people not to have unprotected sex with those at the risk of HIV arguably would result in a higher saving over a lower time period. Perhaps the NHS should consider ways of reducing cost more significantly, rather than latching on to a cheaper prevention drug immediately. If consumer behaviour is not going to change, symptoms are still going to surface, and the provision of Prep on the NHS may only encourage less self-regulation and awareness.

Media’s Marvellous Medicine

When it comes to our health, the media wields enormous influence over what we think. They tell us what’s good, what’s bad, what’s right and wrong, what we should and shouldn’t eat. When you think about it, that’s quite some responsibility. But do you really think that a sense of philanthropic duty is the driving force behind most of the health ‘news’ stories that you read? Who are we kidding? It’s all about sales, of course, and all too often that means the science plays second fiddle. Who wants boring old science getting in the way of a sensation-making headline?

When it comes to research – especially the parts we’re interested in, namely food, diet and nutrients – there’s a snag. The thing is, these matters are rarely, if ever, clear-cut. Let’s say there are findings from some new research that suggest a component of our diet is good for our health. Now academics and scientists are generally a pretty cautious bunch – they respect the limitations of their work and don’t stretch their conclusions beyond their actual findings. Not that you’ll think this when you hear about it in the media. News headlines are in your face and hard hitting. Fluffy uncertainties just won’t cut it. An attention-grabbing headline is mandatory; relevance to the research is optional. Throw in a few random quotes from experts – as the author Peter McWilliams stated, the problem with ‘experts’ is you can always find one ‘who will say something hopelessly hopeless about anything’ – and boom! You’ve got the formula for some seriously media-friendly scientific sex appeal, or as we prefer to call it, ‘textual garbage’. The reality is that a lot of the very good research into diet and health ends up lost in translation. Somewhere between its publication in a respected scientific journal and the moment it enters our brains via the media, the message gets a tweak here, a twist there and a dash of sensationalism thrown in for good measure, which leaves us floundering in a sea of half-truths and misinformation. Most of it should come with the warning: ‘does nothing like it says in the print’. Don’t get us wrong: we’re not just talking about newspapers and magazines here, the problem runs much deeper. Even the so-called nutrition ‘experts’, the health gurus who sell books by the millions, are implicated. We’re saturated in health misinformation.

Quite frankly, many of us are sick of this contagion of nutritional nonsense. So, before launching headlong into the rest of the book, take a step back and see how research is actually conducted, what it all means and what to watch out for when the media deliver their less-than-perfect messages. Get your head around these and you’ll probably be able to make more sense of nutritional research than most of our cherished health ‘gurus’.

Rule #1: Humans are different from cells in a test tube
At the very basic level, researchers use in-vitro testing, in which they isolate cells or tissues of interest and study them outside a living organism in a kind of ‘chemical soup’. This allows substances of interest (for example, a vitamin or a component of food) to be added to the soup to see what happens. So they might, for example, add vitamin C to some cancer cells and observe its effect. We’re stating the obvious now when we say that what happens here is NOT the same as what happens inside human beings. First, the substance is added directly to the cells, so they are often exposed to concentrations far higher than would normally be seen in the body. Second, humans are highly complex organisms, with intricately interwoven systems of almost infinite processes and reactions. What goes on within a few cells in a test tube or Petri dish is a far cry from what would happen in the body. This type of research is an important part of science, but scientists know its place in the pecking order – as an indispensable starting point of scientific research. It can give us valuable clues about how stuff works deep inside us, what we might call the mechanisms, before going on to be more rigorously tested in animals, and ultimately, humans. But that’s all it is, a starting point.

Rule #2: Humans are different from animals
The next logical step usually involves animal testing. Studying the effects of a dietary component in a living organism, not just a bunch of cells, is a big step closer to what might happen in humans. Mice are often used, due to convenience, consistency, a short lifespan, fast reproduction rates and a closely shared genome and biology to humans. In fact, some pretty amazing stuff has been shown in mice. We can manipulate a hormone and extend life by as much as 30%1. We can increase muscle mass by 60% in two weeks. And we have shown that certain mice can even regrow damaged tissues and organs.

So, can we achieve all of that in humans? The answer is a big ‘no’ (unless you happen to believe the X-Men are real). Animal testing might be a move up from test tubes in the credibility ratings, but it’s still a long stretch from what happens in humans. You’d be pretty foolish to make a lot of wild claims based on animal studies alone.

To prove that, all we need to do is take a look at pharmaceutical drugs. Vast sums of money (we’re talking hundreds of millions) are spent trying to get a single drug to market. But the success rate is low. Of all the drugs that pass in-vitro and animal testing to make it into human testing, only 11% will prove to be safe and effective enough to hit the shelves5. For cancer drugs the rate of success is only 5%5. In 2003, the President of Research and Development at pharmaceutical giant Pfizer, John La Mattina, stated that ‘only one in 25 early candidates survives to become a prescribed medicine’. You don’t need to be a betting person to see these are seriously slim odds.

Strip it down and we can say that this sort of pre-clinical testing never, ever, constitutes evidence that a substance is safe and effective. These are research tools to try and find the best candidates to improve our health, which can then be rigorously tested for efficacy in humans. Alas, the media and our nutrition gurus don’t appear to care too much for this. Taking research carried out in labs and extrapolating the results to humans sounds like a lot more fun. In fact, it’s the very stuff of many a hard-hitting newspaper headline and bestselling health book. To put all of this into context, let’s take just one example of a classic media misinterpretation, and you’ll see what we mean.

Rule #3: Treat headlines with scepticism
Haven’t you heard? The humble curry is right up there in the oncology arsenal – a culinary delight capable of curing the big ‘C’. At least that’s what the papers have been telling us. ‘The Spice Of Life! Curry Fights Cancer’ decreed the New York Daily News. ‘How curry can help keep cancer at bay’ and ‘Curry is a “cure for cancer”’ reported the Daily Mail and The Sun in the UK. Could we be witnessing the medical breakthrough of the decade? Best we take a closer look at the actual science behind the headlines.

The spice turmeric, which gives some Indian dishes a distinctive yellow colour, contains relatively large quantities of curcumin, which has purported benefit in Alzheimer’s disease, infections, liver disease, inflammatory conditions and cancer. Impressive stuff. But there’s a hitch when it comes to curcumin. It has what is known as ‘poor bioavailability’. What that means is, even if you take large doses of curcumin, only tiny amounts of it get into your body, and what does get in is got rid of quickly. From a curry, the amount absorbed is so miniscule that it is not even detectable in the body.

So what were those sensational headlines all about? If you had the time to track down the academic papers being referred to, you would see it was all early stage research. Two of the articles were actually referring to in-vitro studies (basically, tipping some curcumin onto cancer cells in a dish and seeing what effect it had).

Suffice to say, this is hardly the same as what happens when you eat a curry. The other article referred to an animal study, where mice with breast cancer were given a diet containing curcumin. Even allowing for the obvious differences between mice and humans, surely that was better evidence? The mice ate curcumin-containing food and absorbed enough for it to have a beneficial effect on their cancer. Sounds promising, until we see the mice had a diet that was 2% curcumin by weight. With the average person eating just over 2kg of food a day, 2% is a hefty 40g of curcumin. Then there’s the issue that the curcumin content of the average curry/turmeric powder used in curry is a mere 2%. Now, whoever’s out there conjuring up a curry containing 2kg of curry powder, please don’t invite us over for dinner anytime soon.

This isn’t a criticism of the science. Curcumin is a highly bio-active plant compound that could possibly be formulated into an effective medical treatment one day. This is exactly why these initial stages of research are being conducted. But take this basic stage science and start translating it into public health advice and you can easily come up with some far-fetched conclusions. Let us proffer our own equally absurd headline: ‘Curry is a Cause of Cancer’. Abiding by the same rules of reporting used by the media, we’ve taken the same type of in-vitro and animal-testing evidence and conjured up a completely different headline. We can do this because some studies of curcumin have found that it actually causes damage to our DNA, and in so doing could potentially induce cancer.

As well as this, concerns about diarrhoea, anaemia and interactions with drug-metabolizing enzymes have also been raised. You see how easy it is to pick the bits you want in order to make your headline? Unfortunately, the problem is much bigger than just curcumin. It could just as easily be resveratrol from red wine, omega-3 from flaxseeds, or any number of other components of foods you care to mention that make headline news.

It’s rare to pick up a newspaper or nutrition book without seeing some new ‘superfood’ or nutritional supplement being promoted on the basis of less than rigorous evidence. The net result of this shambles is that the real science gets sucked into the media vortex and spat out in a mishmash of dumbed-down soundbites, while the nutritional messages we really should be taking more seriously get lost in a kaleidoscope of pseudoscientific claptrap, peddled by a media with about as much authority to advise on health as the owner of the local pâtisserie.

Rule #4: Know the difference between association and causation
If nothing else, we hope we have shown that jumping to conclusions based on laboratory experiments is unscientific, and probably won’t benefit your long-term health. To acquire proof, we need to carry out research that involves actual humans, and this is where one of the greatest crimes against scientific research is committed in the name of a good story, or to sell a product.

A lot of nutritional research comes in the form of epidemiological studies. These involve looking at populations of people and observing how much disease they get and seeing if it can be linked to a risk factor (for example, smoking) or some protective factor (for example, eating fruit and veggies). And one of the most spectacular ways to manipulate the scientific literature is to blur the boundary between ‘association’ and ‘causation’. This might all sound very academic, but it’s actually pretty simple.

Confusing association with causation means you can easily arrive at the wrong conclusion. For example, a far higher percentage of visually impaired people have Labradors compared to the rest of the population, so you might jump to the conclusion that Labradors cause sight problems. Of course we know better, that if you are visually impaired then you will probably have a Labrador as a guide dog. To think otherwise is ridiculous.

But apply the same scenario to the complex human body and it is not always so transparent. Consequently, much of the debate about diet and nutrition is of the ‘chicken versus egg’ variety. Is a low or high amount of a nutrient a cause of a disease, a consequence of the disease, or simply irrelevant?

To try and limit this confusion, researchers often use what’s known as a cohort study. Say you’re interested in studying the effects of diet on cancer risk. You’d begin by taking a large population that are free of the disease at the outset and collect detailed data on their diet. You’d then follow this population over time, let’s say ten years, and see how many people were diagnosed with cancer during this period. You could then start to analyse the relationship between people’s diet and their risk of cancer, and ask a whole lot of interesting questions. Did people who ate a lot of fruit and veggies have less cancer? Did eating a lot of red meat increase cancer? What effect did drinking alcohol have on cancer risk? And so on.

The European Prospective Investigation into Cancer and Nutrition (EPIC), which we refer to often in this book, is an example of a powerfully designed cohort study, involving more than half a million people in ten countries. These studies are a gold mine of useful information because they help us piece together dietary factors that could influence our risk of disease.

But, however big and impressive these studies are, they’re still observational. As such they can only show us associations, they cannot prove causality. So if we’re not careful about the way we interpret this kind of research, we run the risk of drawing some whacky conclusions, just like we did with the Labradors. Let’s get back to some more news headlines, like this one we spotted: ‘Every hour per day watching TV increases risk of heart disease death by a fifth’.

When it comes to observational studies, you have to ask whether the association makes sense. Does it have ‘biological plausibility’? Are there harmful rays coming from the TV that damage our arteries or is it that the more time we spend on the couch watching TV, the less time we spend being active and improving our heart health. The latter is true, of course, and there’s an ‘association’ between TV watching and heart disease, not ‘causation’.

So even with cohorts, the champions of the epidemiological studies, we can’t prove causation, and that’s all down to what’s called ‘confounding’. This means there could be another variable at play that causes the disease being studied, at the same time as being associated with the risk factor being investigated. In our example, it’s the lack of physical activity that increases heart disease and is also linked to watching more TV.

This issue of confounding variables is just about the biggest banana skin of the lot. Time and time again you’ll find nutritional advice promoted on the basis of the findings of observational studies, as though this type of research gives us stone cold facts. It doesn’t. Any scientist will tell you that. This type of research is extremely useful for generating hypotheses, but it can’t prove them.

Rule #5: Be on the lookout for RCTs (randomized controlled trials)
An epidemiological study can only form a hypothesis, and when it offers up some encouraging findings, these then need to be tested in what’s known as an intervention, or clinical, trial before we can talk about causality. Intervention trials aim to test the hypothesis by taking a population that are as similar to each other as possible, testing an intervention on a proportion of them over a period of time and observing how it influences your measured outcome.