Science for Life E-Book

Brian Clegg

• Herausgeber: Icon Books
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch
• Veröffentlichungsjahr: 2015

Seitenzahl: 546

Beschreibung

In Science for Life acclaimed science writer Brian Clegg cuts through the vested interests and confusing contradictory statements that litter the media and the internet, to give a clear picture of what science is telling us right now about changing our lives for the better. Discover the much-advertised antioxidants that aren't good for you, the truth about fat and sugar and why one of the healthiest foods contains carcinogens and 21 E-numbers. Find out what does and what doesn't enhance brainpower – from the failure of playing Mozart to babies to the surprising abilities of caffeine and nicotine. Understand the tools that advertisers use to persuade us and how to turn the psychological pressure back on them. From the shortcomings of the five second rule to the truth about phone masts and nuclear power, kept up-to-date on a partnering website, Science for Life is your guide to surviving and thriving in the modern world.

Leseprobe

SCIENCEFOR LIFE

Also by Brian Clegg Dice World Inflight Science Introducing Infinity: A Graphic Guide Light Years The Quantum Age The Universe Inside You

SCIENCEFOR LIFE

A MANUALFOR BETTER LIVING

BRIAN CLEGG

Published in the UK in 2015 by

Icon Books Ltd, Omnibus Business Centre,

39–41 North Road, London N7 9DP

email: [email protected]

www.iconbooks.com

Sold in the UK, Europe and Asia

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ISBN: 978-184831-818-2

Text copyright © 2015 Brian Clegg

The author has asserted his moral rights.

No part of this book may be reproduced in any form, or by any means, without prior permission in writing from the publisher.

Typeset in Minion by Marie Doherty

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ABOUT THE AUTHOR

Science writer Brian Clegg studied physics at Cambridge University and specialises in making the strangest aspects of the universe – from infinity to time travel and quantum theory – accessible to the general reader. He is editor of www.popularscience.co.uk and a Fellow of the Royal Society of Arts. His previous books include Inflight Science, Build Your Own Time Machine, The Universe Inside You, Dice World, The Quantum Age and Introducing Infinity: A Graphic Guide.

www.brianclegg.net

CONTENTS

Introduction

And there’s more …

Disclaimer

DIET

Alcohol

Antioxidants

Artificial sweeteners

Breakfast

Burned food

Calorie intake

Carbohydrates

Chemicals

Chlorophyll

Chocolate

Cholesterol

Coffee

Dairy

Detox

Diets

E-numbers

Eggs

Enzyme powders

Fat

Fibre

Five a day

Fizzy drinks

Food colouring

Food groups

Fried food

Fruit

Fruit juice

Gi

Gluten

GM foods

Hydration

Monosodium glutamate

Natural products

No added sugar

Nuts

Omega 3

Organic food

Paleo diet

Pesticide residues

Probiotics

Processed meat

Protein

Red meat

Red wine

Salt

Saturated fat

Smoothies

Spices

Spreads

Starch

Storage of food

Sugar

Superfruits

Supplements

Tannins

Trans fats

Vitamins and minerals

Vitamin C

Vitamin D

Weight loss foods

EXERCISE

Aerobic exercise

Afterburn

Breathing and relaxation

Broom and mop efficiency

Cycling

Duration

Frequency and timing

Knuckle cracking

Overload

Recovery

Resistance training

Running

Sitting

Stairs

Stress and exercise

Stretching

Swimming

Walking

Warm-ups

BRAIN

Ageing

Baby brains

Brain-boosting habits

Brain food

Brain Gym

Brain training for fading capabilities

Brain training for intelligence

Drugs for mental performance

Environment for thinking

Exercise and the brain

Finding things

Idea prompting

Left/right brain

Long-term memory

Mind maps and note taking

Music

Oxytocin

Problem solving

Procedural memory

Puzzles

Reading

Remembering lists

Remembering names

Remembering numbers

Serotonin

Short-term memory

Software

TV watching

Video games

Violence on TV and in film

PSYCHOLOGY

Advertising

Air versus road

Assertiveness

Bargaining

Clusters

Free things

Habits

Overvaluing things we own

Price

Procrastination

Risk

Ritual

Scale and understanding numbers

Self-esteem

Smiles and other body language

Standing out

Swearing

Upselling

Using incentives

HEALTH

Acupuncture

Allergies

Antacids

Antibiotics

Aromatherapy

Bacteria

Blind trials

BMI

Breast milk

Cancer

Carbon monoxide

Catching a cold

Chicken washing

Chiropractic

Cold cures

Colonic irrigation

Cough medicine

Deep Vein Thrombosis (DVt)

Deodorant

Drinkable sunscreen

Ear candles

Ear pops

Eyesight

Five-second rule

Hand washing

Hangovers

Herbal medicine

Homeopathy

Hyperactivity and sugar

Immune system

Jet lag

MMR

Obesity

Osteopathy

Painkillers

Panic attacks

Paracetamol and childhood asthma

Placebo effect

Reflexology

Reiki

Screens and eyes

Sunburn

Swimming after eating

Vaccination

Vegetable washing

Viruses

Weight reduction pills

ENVIRONMENT

Carbon dioxide emissions

Carbon neutral

Carbon offsetting

Carrier bags

Electric cars

Fire drill

Food miles

Flying

Greenhouse effect

Hybrid cars

Hydrogen fuel

Keeping cool

Keeping warm

Lightning

Low energy light bulbs

Nappies (diapers)

Natural radiation

Nuclear power

Petrol consumption

Phone masts

Power cuts – computers

Power cuts – fridges

Power cuts – lighting

Spiders

Street violence and architecture

Wi-fi

FUN

Buses come in threes

Crop circles

Digital media

Falling toast

Ghosts

Hyaluronic acid and other wonders of chemistry

Irritatingly itchy

Lottery

Queuing

Recorded music

Toilet roll perforations

Ufos

Weather forecasts

Wine

Yet more

INTRODUCTION

Science plays a fundamental role in everyday lives – improving health, increasing life expectancy, enhancing life experience. Yet it can be difficult to get a practical picture of what is really best for us – what’s needed is a science ‘recipe book’ for you and your family. Science for Life is exactly that – it presents the best of current scientific advice, cutting through the vested interests and confusing, contradictory statements to give a clear picture of what science is telling us right now about changing our lives for the better.

Part of the problem we face is that we are bombarded in the press by claims that a new substance helps us lose weight or reduces the risk of cancer … only to find a few weeks later that the same newspaper or magazine says that the same substance is bad for us. This isn’t scientists being confused, but rather the media misusing information.

The news media are desperate to grab our attention. So even when they are entirely aware that a claim for, say, a new product is worthless, they will typically plaster the headlines with the claim as if it were true and only later reveal that it has no merit. The trouble is that, by then, many of us will have given up reading.

A great example emerged while this book was being written – the ‘drinkable sunscreen’ story (see Drinkable sunscreen in the Health section for more details). Several newspapers in the UK splashed this story. Even the usually responsible Daily Telegraph had an opening paragraph reading: ‘The days of asking a friend to rub suncream on your back or waiting for your lotion to “sink in” to avoid a sandy situation could be numbered, as a US skincare company claim to have created a drinkable suncream.’

After giving us details of the product and the company making it, the article does bring in experts to say that the product doesn’t make sense – but by then it is too late. Admittedly the Telegraph’s headline warns that ‘experts say it is a gimmick’, but we get no such suggestion from the Daily Mail, where a travel reporter (not a science reporter) gives us the headline: ‘World’s first drinkable sun cream goes on sale – and just a teaspoon will offer three hours’ protection.’ Well, no, it won’t – but Mail readers may well be convinced it will.

Beyond this kind of marketing ‘news’, when the results of a scientific trial are published, the newspapers are even more likely to blare out the trial’s findings as fact. But there are two problems with this. One is that not all trials are equal. To be useful, a trial has to be properly managed with a large enough number of participants to iron out any statistical oddities, using sensible techniques and ensuring that neither the participants in the trial nor the testers know who is getting the substance being tried out, and who has a harmless substance with no effect (a placebo) to make a comparison. Such trials are called ‘double blind’ and unless this is done, it has been shown time and again that the expectations of both participants and testers will influence the results.

By comparison, a lot of the ‘trials’ and ‘studies’ reported in the press have very small numbers of participants (say ten to twenty), are often based on participants’ descriptions of how they feel, and are not properly controlled for error. They may also be run by individuals with a vested interest in the outcome.

Another problem is that one trial is hardly ever enough. Even the best of scientists can make errors, and one of the checks and balances of science is that before a theory or treatment is considered worthwhile, the results have to be duplicated by other scientists and laboratories. All the best results are supported by a number of trials, and the best medical and dietary results typically come from a study that pulls together the results of many trials and combines them, giving more weighting to the best studies. Such ‘meta analyses’, like those provided by the Cochrane Collaboration, an organisation that specialises in collecting the best evidence on medical issues, are the gold standards in medicine.

Partly as a result of taking time to undertake a wide range of trials, it is also the case that scientists do sometimes change their minds, as they have, for instance, about the health risks from cholesterol in eggs or the chances of saturated fat in your diet giving you heart disease. This is because real science isn’t the same as the cartoon caricature version most of us have in our minds.

We tend to think of science as a search for the truth that will result in discovering the fundamental laws of nature and absolute results. In reality it is hardly ever like that. It’s just about possible for science to come up with a solid result in a straightforward piece of physics, like Newton’s laws of motion – though even those have had to be modified to deal with Einstein’s special relativity. But it’s quite different when dealing with a complex system like the human body, and how different aspects of life influence it.

One problem is separating out a particular cause. It can be quite difficult, for instance, to say whether people who are obese are more prone to heart attacks because of their diets, because of their lack of exercise or because of the changes to their bodies brought about by obesity.

So what science usually provides us with is the best current agreed position, given the data we have at the moment. That position may, and sometimes will, change when we have better data – as it did over saturated fat. But there is no sensible reason for going with anything other than the best current agreed position until we have further information.

Unfortunately the media often ignore this, which is why, for instance, they made such a huge mistake in publicising Andrew Wakefield’s notoriously bad results linking the MMR vaccination to autism in the UK. Wakefield was a single voice, not particularly well-qualified for the task, and based his assertion on a tiny amount of data from a very small, badly selected group of children. Ranked against him was practically every medical expert, with vast numbers of trials showing the opposite conclusion – and yet the media ran with the Wakefield scare story, many parents stopped their children having MMR and the result was large-scale measles outbreaks, causing serious illness and deaths.

Occasionally there will be high-level confrontations, such as the one over statins, the cholesterol-lowering medication, where there is a considerable argument among experts over the exact balance between a definite reduction in risk of heart attack and stroke, and the side effects associated with the drug. But even here, no one with expertise in the field is suggesting we abandon statins – the discussion is over exactly what level of risk makes it worth taking them.

Just to add to the confusion, many of us expect to get information quickly and accurately from the internet – and often the web can be a good source. But there are all too many websites out there that peddle half-truths or downright lies in order to sell a product.

When I was researching one of the topics in this book, Raspberry ketones (see page 117), I came across a web page that seemed to give academic credibility to this weight loss remedy, much touted on the internet. The site, which had the look of a glossy women’s magazine, and a name that suggested it was run by a newspaper, said: ‘We asked the National Centre for Biotechnology at the University of Reading. They confirmed that raspberry ketones fight obesity and increase metabolism.’ I thought this was worth checking.

A quick search online suggested there was no ‘National Centre for Biotechnology’ at the university, but there was a ‘National Centre for Biotechnology Education’. Their response was simple: this has nothing to do with us and we will be contacting our legal team. As it happened, in a perhaps unusual burst of honesty, this particular website had the most hilarious disclaimer I have ever seen. At the bottom of the page it said:

I UNDERSTAND THIS WEBSITE IS ONLY ILLUSTRATIVE OF WHAT MIGHT BE ACHIEVABLE FROM USING THIS/THESE PRODUCTS, AND THAT THE STORY/COMMENTS DEPICTED ABOVE IS NOT TO BE TAKEN LITERALLY AND SHOULD NOT BE TREATED AS NON-FICTION.

No, your eyes don’t deceive you. It was saying that its advice should be considered fictional. But how many of us check at the bottom for such a disclaimer? And it is all too easy for sellers of mumbo jumbo and quack remedies to make fictional references to universities, which we don’t have time to follow up. I have spent hours sifting through online claims for health products and all too often they resort to tricks like these.

Other sites (and plenty of celebrity nutritionists’ books) have stacks of references, linking their products and ideas to real scientific research. And these look impressive. But what some of them are relying on is that readers are not going to have the time or inclination to check up on these references. When I have done so, many such references are fictional or, where they do refer to a real piece of research, the conclusions of the research are totally different to those claimed in the article. One of the benefits of this book is that I have checked out the truth behind these claims so you don’t have to.

Life is too short to always be confused by the latest fads and misdirection from those who are trying to sell you something. The whole point of Science for Life is to make the picture clear and simple for you, improving your life choices without compromising the message of the latest scientific research.

AND THERE’S MORE …

Science for Life isn’t complete. There’s an important reason for that. Science (and for that matter, life) is ever-changing, and there will always be new and interesting items to add. To make this possible we have set up www.scienceforlife.info – this site features both updates for existing articles and new posts on the latest science information that impacts our lives.

There’s also the opportunity to drop us an email with new topics that you would like covered. Take a look at www.scienceforlife.info.

Disclaimer

The contents of this book are based on the best information available to the author at the time of writing. The book does not constitute medical or professional advice – always consult a doctor or appropriate professional where necessary. Neither the author nor the publisher shall be liable or responsible for any loss or damage allegedly arising from any information or suggestion in this book.

DIET

Anyone writing a diet book (and that seems to be every celebrity and nutritionist you can name) faces a problem – there is absolutely no rocket science involved. In the case of some diet books, there’s no science at all. The embarrassing fact is that all the dietary advice you ever need could be fitted comfortably into a single paragraph. Here we go:

Don’t eat too much – if you are putting on weight, eat less. Eat plenty of fruit and vegetables (and don’t make them into smoothies as this ruins the valuable fibre). Make around one third of your diet starchy foods, preferably wholegrain. Don’t eat too much processed meat. Drink alcohol moderately, if you must. Avoid sugar and salt as much as possible and don’t go overboard on fats, avoiding trans fats entirely. It’s not strictly part of a diet, but add ‘don’t smoke’ and ‘take sensible exercise’ and you’ve got an instant health plan.

That’s it – that’s what you pay hard-earned cash to get a diet book for. Every other page in such a book is padding. If you write a diet book you have to find some way to make yours different from the rest. Some do this by straying away from what is most beneficial to include mystical mumbo jumbo. Others find different ways to expand those basics to fill a whole volume by adding lots of rules, or filling it out with healthy recipes (which is fair enough). But that single paragraph is all the diet book you’ll ever need.

The problem is that it is very natural to want a quick fix, to hope for a magic wand we can wave to improve our health. But there is very strong evidence that short-term diets do no good whatsoever. It’s far better to make small changes that you carry through from year to year than to go on a crash diet, returning to overdoing it a few weeks later.

In part because of this desire for a quick fix, there are always new miracle foods and dietary wonders that are splashed across the newspapers. The reason this section is a lot more than just that single paragraph is partly to clarify the value of all these different suggested wonder foods and drinks. Some are just nonsense. Others have a grain of truth behind them and are worth considering – but even these aren’t magic bullets. Keep coming back to my core paragraph and you can’t go too far wrong.

A major problem that we all face in trying to work out what’s good for our health is that it is very difficult to spot whether eating a particular thing is good or bad for you. This is why we get so many reports in newspapers telling us that something is good or bad for our health. This is also why we were told for so long that saturated fats were worse for us than unsaturated fats, where this no longer seems to be the case.

The problem is that, unlike testing a medication, it is very difficult to do a proper, scientific blind-controlled trial on what we eat. Most dietary studies are observational – they tell us, for instance, that people in the Mediterranean suffer from less heart disease than people in Glasgow. We can also observe that these people have a different kind of diet. But it’s hard to say for certain that it is the diet that is giving the benefit – and even harder to identify a particular aspect of the diet, like olive oil or tomatoes – because there are so many other differences between life in the Mediterranean and life in Glasgow, and we don’t know what the actual cause is, merely that people in one environment, with their typical lifestyle, are healthier in this aspect than people in the other.

For instance, in 2001 an Australian study was portrayed in the media as showing that people who consume more olive oil get fewer wrinkles. So journalists (often without a science background) got all excited, telling us that consuming olive oil is good for your skin. But the study was not done by taking two similar groups of people and feeding one olive oil while the other received another oil, with neither the people involved nor the scientists knowing which was which, as would be the case in a proper double blind trial. Such a trial on a big enough sample of people over a long enough period would, indeed, show whether eating olive oil helps reduce wrinkles.

Instead, what the trial did was to bring together information on different groups of people from widely varying backgrounds – Australians, Swedes and Greeks, for instance – and find that the level of wrinkling they experienced corresponded reasonably well to the level of olive oil in their diets. But to deduce that the oil reduced wrinkles is to fall for the oldest statistical error in the book – that correlation (where two things vary in a similar fashion) is the same as causation (saying that one causes the other). See the section on Paracetamol and childhood asthma, which explores causality and correlation (page 313), for more on this.

In practice, all manner of other differences were likely to be common in the olive oil and wrinkles study. For instance, dietary variations often relate to levels of income, education, living conditions, environment, stress levels, moisturiser use, sleeping patterns and many other things that could have been responsible for the lower levels of wrinkles. To make the assumption that the consumption of olive oil caused the reduction in wrinkles makes no sense. You could almost certainly find some other factor (say reading newspapers) that also varied with the wrinkle levels.

A lot of the media stories seem to be about a particular food or drink (red wine, say, as this is the favourite substance) causing or preventing cancer. It can seem baffling that the same thing potentially has both effects, and it’s easy to think that science has got it wrong. But in reality it is the interpretation put on the science by journalists and nutritionists (who often don’t have proper scientific training) that is at fault. We’ve already seen one way this can be the case with observational studies. Comparing populations who do and don’t drink red wine is fraught with difficulties in determining what causes differences in health. But there’s another problem.

When it’s claimed that something causes or cures cancer, for instance, what is often the case is that someone has either tested the substance on cells in a laboratory or fed it in large doses to rats and observed the outcome. This can contribute to very valuable research, leading to proper testing of the active chemicals in a way that will see if there are real benefits. But almost all the trials quoted this way don’t show that the substance being tested, when consumed, will have that effect on cells in the human body. As Bad Science author Ben Goldacre points out: ‘Fairy Liquid will kill cells in a test tube, but you don’t take it to cure cancer.’

Welcome, then, to the diet section.

A

Alcohol

Alcohol is bad for us – but in moderation, for those without related health issues, the risk is sufficiently low that it’s perfectly reasonable to enjoy a drink.

Most of the things we consume have pros and cons as far as a contribution to a healthy diet goes. For alcohol, though, the only thing to be said is that in moderation its risks are relatively low, so tolerable.

You may have seen newspaper articles saying that, for instance, red wine is good for you. This is a rather mixed assessment, as we’ll explore in the Red wine section, but this is a result of the many other constituents of red wine. Alcohol itself, a simple organic compound, is a poison, pure and simple – but one that we can tolerate in low doses and that has sufficient pleasurable effects to make it worth tolerating.

Similarly, there was a lot of coverage in 2014 of a claim that anything up to a bottle of wine a day is fine. This came from a retired professor who did not present any evidence to back up his claim, when there is a huge amount of evidence for the harmful nature of drinking more than recommended amounts. In any science you will get mavericks coming up with an alternative view in good faith, but the only sensible approach is to go with the view held by the majority unless there is remarkable new evidence to suggest otherwise. No such evidence was provided here.

One myth is worth dismissing immediately. Alcohol is alcohol, and it doesn’t matter what type of drink it is in. Mixing drinks makes no difference. There are some drinks, like whisky, that contain a range of other chemicals that are likely to make a hangover worse, but in terms of the impact on the body of alcohol itself, there is no difference. Some people think the mixing effect in cocktails somehow makes them more potent – it doesn’t. But because many cocktails combine a high alcohol content with enough sweetness to conceal its potency, it can be easy to consume more alcohol than you realise when drinking cocktails.

The risks from moderate consumption – beyond a hangover – are usually due to inappropriate or illegal behaviour when we’ve had a couple too many, whether it is driving a car or simply doing things we wouldn’t normally do and may regret afterwards. However, for heavier drinkers there are a number of concerns.

Most alcoholic drinks contain significant calories. Heavy beer drinkers, particularly, will tend to pile on the weight, as a pint of beer has as many calories as a packet of crisps, while the average wine drinker will consume around 2,000 kcal (see Calorie intake, page 17) a month from alcohol. This isn’t a huge daily calorie consumption, but it is significant.

Alcohol is also a carcinogen – it causes cancer. In fact, alcohol is by far the biggest direct cancer-causing substance in our diets. It also increases blood pressure and risk of heart attack. And then there is the impact of the alcohol on the systems that take alcohol out of the body. The liver particularly can suffer with excess alcohol consumption, in the extreme case failing altogether.

Typical recommendations are that men do not regularly drink more than three or four units a day, and women do not regularly drink more than two or three units a day. We should know what units are by now, but they still cause confusion. Half a pint of 4 per cent alcohol beer is around one unit, a small glass of wine (125ml) is 1.5 units, and a single spirit is one unit. It is also recommended that you go at least two days a week without any alcohol.

To get a feel for the impact, if you go over the recommended limits to between five and eight units (men) or four and six units (women), you are 1.8–2.5 times (men) or 1.2–1.7 times as likely to get cancer of the mouth, neck and throat. Women are 1.2 times as likely to get breast cancer. Men are twice as likely to develop liver cirrhosis, and women are 1.7 times as likely. And men are 1.8 times as likely to develop high blood pressure, where women are 1.3 times as likely. Go beyond those limits into the higher risk zone and you can at least double those risks.

The best advice is still that pregnant women, or those trying to conceive, do not drink alcohol at all, and certainly don’t exceed one to two units a week.

LINKS:

Calorie intake – page 17Hangovers – page 291Red wine – page 87

Antioxidants

Antioxidants are vital chemicals used by the body to combat dangerous free radicals. But all the evidence is that consuming antioxidants has no benefit and could have some negative effects.

If you were to believe the advertising for some products, particularly those making use of the ‘superfruits’ tag that are rich in antioxidants, you would think that antioxidants were an ideal nutrient that provides huge benefits to make your body healthier. In fact, the picture is far less clear.

Antioxidants are naturally occurring chemicals that the body uses to counter the impact of free radicals, which are highly reactive substances that can damage DNA and cells, leading to cancer, cardiovascular problems and diabetes. Some free radicals play important roles in the body, but in the wrong place at the wrong time they are dangerous, and antioxidants are there to mop them up.

It seems reasonable, then, that tucking into products that are rich in antioxidants or taking antioxidant supplements would be a good thing. But it is often the case that just because something has an effect within the body does not mean that consuming it will have any direct impact. And even when it does, once you have enough of anything, adding more and more does not provide a benefit. At best the excess will be excreted and at worst it can have negative effects itself.

We get plenty of antioxidants from a normal diet, plus the antioxidants such as glutathione that the body manufactures itself. It might at first seem reasonable that ‘if some antioxidants are good, lots of antioxidants are better. The more you take in, the better.’ But think of applying that to eating in general. It’s pretty obvious that ‘if some food is good, lots of food is better. The more you eat, the better,’ is wrong – and the same goes for antioxidants.

What is sometimes forgotten is that almost everything is damaging to the body or poisonous in excess. Toxicity is all about dosage. Water, for instance, does damage and can even kill if drunk to excessive levels. The antioxidant levels in foods – even superfruits – are sufficiently low that it would be difficult to overdose dangerously, and fruit has other benefits (though even fruit should not be taken in excess as it is high in sugar), but the real danger with antioxidants is when taken in supplements, where it is easy to exceed recommended daily amounts.

There is now good evidence that those taking antioxidant supplements on a regular basis are more likely to die prematurely than those who don’t. (Specifically this seems to apply to vitamin A, vitamin E and beta-carotene supplements.) One reason for this seems to be that the supplements encourage growth in cancer cells, and so result in a greater likelihood of death for those already suffering from the disease. Another possibility is that increasing consumption of antioxidants means that our bodies’ natural production of them tends to decrease – and those internally produced antioxidants have a much more significant impact. So, supplements could actually reduce our antioxidant defences.

The message, then, is that it is not a good idea to take antioxidant supplements, and while there is no harm in eating blueberries or cranberries or other fruits that are sources of antioxidants, they are unlikely to be giving any benefit. Just eat them to enjoy them!

LINKS:

Superfruits – page 104Water excess – see Hydration – page 63

Artificial sweeteners

Artificial sweeteners are important in the fight to reduce sugar in our diets and have been shown to be safe.

Although aspartame (appearing under the brand name Nutrasweet) has been in use since the 1970s as a sugar substitute, there are still many who regard it with suspicion and claim that it is responsible for many health issues. A typical website I discovered researching this article claimed: ‘Artificial sweeteners can actually be far worse for you than sugar and fructose, and scientific evidence backs up that conclusion.’ This is just not true. It is important that we clarify this as, for health reasons, we are all being encouraged to consume fewer sugary products, and it can often be easier to switch to an artificial sweetener than to give up the sweet product altogether.

The European Food Safety Authority (EFSA) has come to a clear scientific consensus that aspartame is entirely safe. There are a number of reasons for this. First and foremost, numerous studies have shown that aspartame never makes it into the bloodstream. It is very quickly broken down to constituents that are found in almost all animal and plant protein.

Despite the claims of conspiracy theory websites, there is no scientific evidence of aspartame having any carcinogenic effect or of causing any genetic faults. Another frequent assertion is that consumption of aspartame during pregnancy results in an increase in asthma and allergic rhinitis in children; so this has specifically been studied, and once again there was no evidence. The link is fictional.

Like all substances, aspartame should not be consumed to excess. The potential harmful dose, however, would require you to consume several hundred cans of a diet drink a day. On a precautionary level, the EFSA suggests not consuming more than 40mg of aspartame per day for each kilogram of body weight. However, that still means that it’s fine to drink more than is sensible. For a ten year old this is around seven cans a day, while adult women would be allowed fifteen cans and adult men nineteen. If you are drinking this many cans of fizzy drink, your diet is in need of a serious overhaul. Similarly, if you are using aspartame to sweeten your tea or coffee, the equivalent limits are around 36 spoonfuls/tablets per day for a ten year old, 77 for a woman and 98 for a man.

There are other artificial sweeteners. You will sometimes still see saccharin (brand name Sweet’N Low). A 1980s cancer scare pushed this out of favour, though the problem seems only to be with rats. Most consumers find the taste of aspartame more acceptable than saccharin. Some products use an extract of the stevia plant (brand names include Truvia and Rebiana), which is technically not an artificial sweetener, but a substitute, natural low-calorie sweetener instead. Stevia has a ‘generally regarded as safe’ status but has not had anywhere near the level of testing that aspartame has, and has produced some mixed lab results. So it may be worth treating with caution until more information is available, although it is used more and more widely. The most popular alternative is sucralose (brand name Splenda), which outsells aspartame in the UK. All studies have shown it to be safe, though it has had nowhere near as much scrutiny as aspartame. It has the advantage of not being sensitive to heat, so can be used in baking.

Whatever the sweetener, be wary of the ‘seatbelts cause accidents’ effect. There is reasonably good evidence that the more safety features a car has, the more careless our driving is likely to be, as we feel safer and so take more risks. Similarly, it can be tempting if you are ‘being good’ and cutting out sugar in your drinks to feel that you can now get away with more sugary or high-calorie treats. It’s important to detach the two in your mind. If you can substitute, say, a sugar-free drink for the sugary equivalent but not change your diet otherwise, you are on the right track.

Research published in September 2014 suggested that artificial sweeteners could cause glucose intolerance in mice by altering the balance of gut bacteria. This could increase the risk of diabetes. As yet this is a single trial, and it is often the case that an effect in mice is not replicated in humans. This certainly does not make artificial sweeteners worse than sugar, and more research is needed – but it adds more weight to the ideal being to avoid all sweeteners if possible.

Artificial sweeteners are certainly not always the best solution. Rather than go from sugar to sweeteners in my coffee, I went to using no sweetener at all. For two weeks it tasted foul, but once I got used it, there was no problem, and now sweetened coffee tastes horribly over-sweet. There are plenty of circumstances where you can reduce or cut out sugar entirely. But in something like a can of cola the choice is really only sugar or sweetener, and it’s worth going for the diet version if you can. (Again, it can take a few weeks to get used to the different taste, but for most it will grow on you.)

LINKS:

Sugar – page 102

B

Breakfast

There are probably more sayings about breakfast than any other meal – but do they make sense?

Breakfast, we are told, is the most important meal of the day. But is this true? And if so, what should we be looking for in a breakfast? Is it best to go for a spartan muesli or the full English fry-up with all the trimmings?

Certainly, breakfast is a good thing. It sets you up for the day, making you more alert and productive, and research suggests that those who breakfast regularly tend to eat less (and snack less) later on. Those who regularly skip breakfast tend to have higher risk of heart problems. In part this is because extended fasting can result in increased blood pressure and raised cholesterol, and in part because of that tendency to substitute unhealthy snacks through the day. Though, as always with observational studies, it could also be that people who skip breakfast also tend to have more stress in their life, sleep less or have other factors that could have a negative effect on health. The lack of breakfast itself is not necessarily the cause.

In health terms, there seem to be benefits from having a relatively small number of meals – two or three – a day rather than snacking throughout the day. This seems to run counter to a frequently heard suggestion that frequent mini-meals are better for your digestion, but the problem with the grazing approach is that it is very difficult to keep on top of calorie intake when snacking, and all too easy to overdo intake of sugar, salt and fat.

It’s best to avoid high-sugar foods for breakfast, as the result will typically be a dip in blood sugar a couple of hours later, just when the potential to go for a sugary snack is at its highest. It’s particularly important to keep an eye on sugary children’s cereals, which some of us continue to enjoy well into adulthood.

But what about the full English (or Scottish, Welsh or Irish) in all its fatty goodness? The positive news is that the recent discovery that saturated fat is not particularly worse than unsaturated fat for heart disease risks makes the traditional breakfast slightly less terrifying from a nutritional standpoint. However, it is still a very high-calorie, high-fat meal with a lot of processed meat. It came into being when workers were undertaking heavy manual labour and could easily burn up 5–6,000 calories a day, so could cope with the circa 1,500 calories provided by a typical fry up. But most of us don’t work like that any more.

You may have seen in the newspapers that ‘a fry-up for breakfast could be the healthiest start to the day’. Like most of these stories, this was based on a study that really doesn’t tell us a lot about people. It was done on mice, which weren’t, as you might expect, fed a full English, but rather high-fat mouse food. What the study does suggest is that it might be easier (for mice) to metabolise fat in the morning than later in the day, but that certainly isn’t enough to suggest that a heavy fried meal makes the best breakfast.

Like pretty well any other dietary restriction, the fry-up is something that we shouldn’t worry too much about enjoying occasionally, but if you have it more than once a week (one in four in the UK have it at least twice at a weekend), it would be a good idea to consider a change of diet.

LINKS:

Processed meats – page 82Saturated fat – page 82Sugar – page 102

Burned food

Although the risk is relatively low, there is evidence that some over-cooked foods can increase cancer risks.

We’ve all burned the toast before, and have probably come up with that old chestnut: ‘It’s charcoal – good for your digestion.’ However, very little of the blackened toast actually is charcoal, and the substance that is used medically to absorb poisons and quieten the digestive system is activated charcoal, which has been treated to fill it with little holes and bumps, vastly increasing its surface area to enable it to act effectively. It is not just a lump of burned wood. In fact burned food – or even just some of the over-cooked variety – does seem to present us with a health risk.

When we grill, toast, roast or fry foods that are high in carbohydrates, we increase the quantity of acrylamides in them. Acrylamides are relatively simple organic compounds, chemicals that are poisonous in high doses and seem to present a cancer risk. The more coloured a food is by the cooking, particularly in a highcarbohydrate food, the more acrylamides it is likely to contain. So, for instance, burned toast or deep brown, over-fried chips do have an increased risk factor. A continued diet heavy in acrylamides could double the risk of some cancers, though this may well only be an increased risk of under half a per cent.

Another slightly surprising source is potatoes that have been kept in the fridge. This can increase the amount of acrylamide that forms when they are cooked (particularly if they are fried or roasted). The best place to keep your potatoes is in a cool, dark place – but out of the fridge.

There is also some acrylamide formation in coffee, but there’s not a lot we can do about this, as it occurs when the beans are roasted. Again, the risk is very low – best to grin and bear it.

We can’t totally avoid acrylamides. They occur in most cooked foods – and we get far greater benefits from cooking than we do problems. And eating the odd bit of burned toast or chargrilled potatoes will have a negligible impact. But by avoiding overdoing it, particularly avoiding food that has been fried, roasted or grilled until dark, you are certainly minimising the risk.

LINKS:

Coffee – page 29

C

Calorie intake

Calories measure the energy content of food and can give us a good, quick measure of just how much we are consuming.

We are used to seeing food packaging that shows a measurement of the calories it contains. Even some restaurants, notably the fast food chains, now show the calorie content of their products on their menus. This is a good thing, because keeping an eye on calories is one of the easiest ways to avoid overeating and to keep your diet healthy. It’s not enough – you need to watch your sugar and salt levels too, for instance – but it’s a good starting point.

Note that calories and fat content aren’t the same thing. Fat is a major contributor to the calorie content of a food, but even a fat-free product is likely to have calories from other food groups. A typical fat-free yoghurt, for instance, has around 100 calories.

Another potentially confusing aspect of calories is the unit they are measured in. You will see both ‘calories’ and ‘kcal’ or ‘kilocalories’ on labels. A kilocalorie is 1,000 calories. All dietary measurement is in kilocalories, but dieticians originally thought their clients couldn’t cope with that complicated ‘kilo’ bit, so shortened kilocalorie to ‘Calorie’ with a capital C. So a Calorie is 1,000 calories. This is very confusing, particularly as ‘Calorie’ is often written without the capital letter. Increasingly the standard is to have all labelling as kilocalories (kcal), and that’s what we’ll use here. Worse still, the calorie is an outdated unit – it was replaced in the scientific world by the joule a good 50 years ago, but the dietary world is slow to catch up.

Calories provide a measure of energy. They show how much energy content there is in a food. There is then a simple balance. If you burn off more energy through exercise than your body absorbs from your food (not all the calories you eat will be retained – some will pass through), you will lose weight. If your body takes up more calories than you burn, you will gain weight.

The rule of thumb is that an average man needs around 2,500 kcal a day and an average woman around 2,000 kcal. If you don’t do much exercise, reduce those to 2,000 and 1,700. This is where those menu boards in fast food restaurants can be quite scary. Go for KFC’s ‘Big Daddy box meal’ with regular Pepsi, for instance, and you are consuming 1,615 kcal in a single meal. Even for a man undergoing a reasonable level of exercise that’s 65 per cent of his daily calories gone in one go. And British fast food meals are skimpy when compared with American portions.

That’s really all you need to know to diet successfully. Reduce calorie intake and increase exercise and you will lose weight. The difficulty is managing this consistently, as most dieters follow the diet for a relatively short period of time, then binge and, if anything, put on weight. It is also very difficult to lose weight by exercise alone. Time and again, studies have shown surprisingly low weight loss when overweight people tried to reduce weight with an exercise regime. This seems to be because they compensated for the extra work they were doing by eating more and by moving less at other times than the specific exercise period.

What seems to be one of the most reliable and easiest diets to stick to is the 5:2 diet, where two days a week you eat a significantly reduced calorie intake, while the rest of the week you eat normally. (This is sometimes described as ‘whatever you like’, but the idea is not that you can pig out on piles of fatty food five days a week, just that there is no specific food restricted.) The reduced calorie days should be between half and one third of the usual daily intake. This sounds like a tiny amount, but it’s easily done with a light breakfast, a sandwich for lunch and a low-calorie meal for dinner. What’s important is to keep an eye on the extras like drinks and snacks that can easily push you over the top.

LINKS:

Fat – page 44

Carbohydrates

Fads come and go as to whether carbohydrates are a great way to fill up without fat or are to be avoided at all costs. But what’s the reality?

A carbohydrate is a relatively simple organic compound, made up of just carbon, oxygen and hydrogen, with the hydrogen and oxygen usually in the same 2:1 ratio as water. Technically sugars are carbohydrates, as is the fibre that is so good for our digestion, but the term is usually used in food to refer to the long-chain or polymer versions of carbohydrates, sometimes called polysaccharides, of which a typical example is starch. Such molecules are energy stores.

In the stuff we eat, most of the carbohydrates come from the ‘staples’ like potatoes, bread, rice, pasta and cereals. It is generally recommended that for a balanced diet, around one third of the food we eat should be carbohydrates. Often there are different versions of the carbohydrate foods, some of which are better nutritionally – usually where they contain extra fibre. So potatoes are better skinon, and the ‘brown’, wholegrain versions of most other carbohydrate sources tend to be healthier.

Going on dietary surveys, a fair proportion of the population don’t have enough starchy foods in their diets. For some this is because they have adopted a low-carb diet – but there is no good evidence that these are beneficial, and they can result in poor nutrition. In fact, cutting carbs isn’t a great way to reduce calories as carbohydrates contain less than half the calories of the same weight of fat. Studies suggest that a healthy, balanced diet gives just as much weight loss as low-carb diets, but typically has a better fibre and mineral content.

It’s not a great thing to miss out on starchy foods, as they combine a good source of energy with the main source we have of fibre, calcium, iron and B vitamins. Don’t, for instance, dismiss the humble potato. We tend to look down on it because of its familiarity, but it gives us energy, fibre (if skin-on), potassium, B vitamins and a fair amount of vitamin C.

When cooking starchy foods, try not to overcook them when toasting, roasting, baking, grilling or frying, as this can result in an increase in levels of acrylamides, which are poisonous in large quantities and may carry a cancer risk. It’s also worth storing your potatoes outside the fridge (ideally in a cool, dark place), as low temperatures can result in sugar forming, which then encourages acrylamides to form. Cut off green parts of potatoes too – these tasty tubers are of the nightshade family, and the green parts have the family tendency to be poisonous.

LINKS:

5:2 diet – see Calorie intake – page 17Acrylamides – see Burned food – page 15Fat – page 44Starch – page 99

Chemicals

All foods are made up of chemicals, so beware of claims that a product is ‘chemical free’, and don’t be put off by a scary looking contents list.

The contents list that manufacturers are required to put on many foods can look scary – and there are things to keep an eye out for – but the mere presence of a long string of E-numbers and other nasty sounding chemicals is not in itself a problem.

Let’s take a specific content list and see what we should look out for:

Aqua 84%, sugars 10% (of which fructose 48%, glucose 40%, sucrose 2%), fibre 2.4% (E460, E461, E462, E464, E466, E467), amino acids (glutamic acid 23%, aspartic acid 18%, leucine 17%, arginine 8%, alanine 4%, valine 4%, glycine 4%, proline 4%, isoleucine 4%, serine 4%, threonine 3%, phenylalanine 2%, lysine 2%, methionine 2%, tyrosine 1%, histidine 1%, cysteine 1%, tryptophan <1%), fatty acids <1% (linoleic acid 30%, linolenic acid 19%, oleic acid 18%, palmitic acid 6%, stearic acid 2%, palmitoleic acid <1%), ash <1%, phytosterols, oxalic acid, E300, E306, thiamine, colours (E163a, E163b, E163e, E163f, E160), flavours (ethyl ethanoate, 4-methyl butyraldehyde, 2-methyl butyraldehyde, pentanal, methylbutyrate, octene, hexanal, styrene, nonane, non-1-ene, linalool, citral, benzaldehyde, butylated hydroxytoluene (E321), methylparaben, E1510, E300, E440, E421, aeris (E941, E948, E290)

It’s a scary looking list, and any concerned parent or anyone worried about E-numbers would be inclined to steer well clear. The good news is that by far the biggest content is water (usually called ‘aqua’ in contents lists, particularly in cosmetics, so it sounds more impressive). Unfortunately, though, a 10 per cent sugar content is not great, there are both poisons and carcinogens in there, and there are enough E-numbers to imagine it would send the average hyperactive child into overdrive.

The interesting thing, though, is that this is not a highlyprocessed food; it is the contents list of that most revered of superfruits, the blueberry. Not some sugary blueberry concoction, but the actual fruit itself. We don’t usually see the chemical contents lists of fruit and veg, but it would make a useful comparison with the products that really worry us if we did.

The level of sugar in fruit is fine as long we don’t overdose on it. As for the poisons, pretty well every food has poisons in it. Most plants, for instance, contain a range of natural pesticides that are deadly in large enough proportions, but, as is always the case with poisons, it is the quantity that matters, and here the volumes are far too low to have any significant impact.

As for those E-numbers, it is a sobering reminder that pretty well everything natural has an E-number, and the presence of E-numbers in a food is not a problem per se. E-numbers are simply a European Union labelling standard for all food additives; they are not intended to say whether those additives are good, bad or indifferent.

So let’s be clear. Whether we are talking about diet, health or any other products, there is no such thing as a chemical-free substance or object. Light is chemical free, but that’s about all you can get. If someone claims a product is chemical free, they are either ignorant or lying. And there is no way you can avoid chemicals by having a particular diet or buying particular products. There is no difference whatsoever between a synthetic and a natural chemical – how can there be, when a chemical is just a compound of elements? It doesn’t know where it came from. But, often, natural sources of chemicals are more dangerous, as they are far more likely to be impure, with all kinds of nasty substances coming along for the ride.

What’s more, we are far safer now than our ancestors were, as we have greater protection against the misuse of chemicals. In the old days, people happily plastered toxic lead oxide on their skin to whiten it, and used wallpaper coloured green by deadly arsenic, which gave off poisonous fumes. Though things go wrong sometimes, the picture that ‘back to nature’ activists paint of a world where we are increasingly subject to dire chemicals gets reality back to front.

Greenpeace comments on the ‘Chemicals out of control’ section of its international website:

If someone came into your house, mixed you a cocktail of unknown chemicals – and offered you a drink – would you take it? Of course not. You wouldn’t want untested chemicals in your home, your drink, or your body. You don’t want them – but shockingly – they’re already there.

But actually most of the cocktails of unknown and untested chemicals we come across are in natural substances. A new synthetic product has to be extensively tested, but only a tiny handful of the ‘chemical cocktails’ that make up tea and coffee have ever been tested (and many of those have proved to be dangerous in large quantities). That Greenpeace comment is a triumph of hype over reality.

A small confession – I made up the name of the final ingredient in the blueberry to give it a name as exotic-sounding as ‘aqua’ is for water. ‘Aeris’ is just common or garden air.

LINKS:

E-numbers – page 40Fruit consumption – see Five a day – page 47Natural products – page 67Pesticides – see Pesticide residues – page 79Sugar – page 102

Chlorophyll

Chlorophyll (as opposed to Cholesterol – see page 28) is the stuff that makes plants green and is used in photosynthesis. Some nutritionists and nutrition websites recommend chlorophyll in a diet, but there are no proven health benefits.

Chlorophyll, the green substance in plants, does a superb job in photosynthesis, where plants gain energy from sunlight and absorb carbon dioxide to build their structure, along the way releasing the oxygen that enables animals like us to breathe. It is sometimes suggested that this means that chlorophyll is also good as part of a human diet, because it somehow enables us to take in the energy of the sun or because it will oxygenate the blood.

In practice, there is no evidence whatsoever of this happening. It would be very strange if it did. Chlorophyll’s role is to enable photosynthesis, which requires light – not something food gets a lot of once you swallow it. Chlorophyll doesn’t carry oxygen, the photosynthesis process produces oxygen as a by-product. Even if the chlorophyll were churning out oxygen in your stomach (which wouldn’t be safe as your stomach contains flammable gas and adding oxygen would make it like the reaction chamber of a rocket), there is no mechanism for the oxygen to get from there to your bloodstream.

As for harnessing the energy of the sun, as if eating our greens turned us into plants, it’s hard to imagine any way this could be possible. Websites often hint that chlorophyll is similar to the haemoglobin that carries oxygen in our blood (and it is). But being similar isn’t good enough in body chemistry. What certainly isn’t true, as I read on one website, is that: ‘According to scientist [sic], the body has the ability to convert chlorophyll to haemoglobin by changing just one little molecule [sic] of magnesium into iron.’ No, I’m sorry, according to scientist, the body has no such ability.

By all means, eat green foodstuffs from spinach to broccoli, which are all packed with plenty of essential nutrients. But their chlorophyll content is not one of those benefits.

Chocolate

For most of us, chocolate is a wonderful treat, and, as long as it’s consumed in moderation, it’s not a bad thing, either.

Chocolatiers will tell you that the reason chocolate is so appealing is because of the tactile sensation of consuming it. It melts at the temperature of your mouth, so the solid turns into a sensuous liquid on your tongue. There is an element of truth in this. It is also the case that there are a range of active chemicals in chocolate that influence our brains, and sugar is certainly part of the attraction of the modern version of chocolate. But there seems little doubt that we also get a kick from a substance called theobromine.

This is a bitter tasting alkaloid, a term we often associate with drugs like morphine and natural poisons. Caffeine, nicotine, quinine and cocaine are all part of the alkaloid family, but none has the appeal of theobromine. A clue might come from the Greek meaning of the name, which is roughly ‘food of the gods’. Theobromine is the compound that makes chocolate special and is found in the cocoa tree. The seeds of this tree (misleadingly called cocoa beans) contain the fatty substance cocoa butter that is the main ingredient of chocolate.

Chocolate has been enjoyed as a drink in Central and South America for at least 3,000 years, and has been popular in Europe since the 17th century. In its original form, the drink was bitter (it often had chillies added to give it extra bite) – it was a European twist to add sugar and milk to make something closer to modern drinking chocolate. The familiar solid form didn’t arrive until the 19th century, which was also when theobromine was discovered. The substance has similar effects on the brain to caffeine, which is probably why you will occasionally see it said (incorrectly) that chocolate contains caffeine. Theobromine can reduce sleepiness and in large quantities produces a jittery sensation. On the positive side, it is a cough suppressant and can help reduce asthma symptoms.

Most of us have heard that chocolate is bad for dogs – it is theobromine that is to blame. The darker the chocolate, the higher the concentration of theobromine, and the more dangerous it becomes. A small dog could be killed by as little as 50g of strong dark chocolate. Smaller doses will cause vomiting. This isn’t a problem limited to dogs; poisoning occurs in all mammals to some degree, though the speed at which theobromine is disposed of by the system differs from species to species. Cats are particularly sensitive to theobromine but rarely eat chocolate because they don’t have sweet taste receptors and so don’t get the kick from sweets that humans (and dogs) do.

Theobromine is also poisonous to humans, though not to the same the degree as it is to dogs, and shouldn’t cause concern. Almost everything is poisonous in a large enough dose (even water, for example), and toxicity is all about dosage. In the case of theobromine, humans have about three times the resistance per kilogram of bodyweight as does a dog and are significantly heavier, so we are much less likely to be damaged by our treats. A dangerous dose for an adult human would involve eating more than 5kg of milk chocolate.

A number of health benefits have been claimed for chocolate, including reducing blood pressure, reducing stress, reducing diabetes risk and giving limited protection against bowel cancer. None of the trials that have come up with these results have been big enough or repeated sufficiently to be sure of the outcome. The effect on blood pressure was slight, the cancer results are only laboratorybased, and the stress test was poorly designed (and sponsored by a chocolate manufacturer).

The diabetes results were based on compounds in chocolate called flavonoids, but the trial could not show if the flavonoids caused the benefits – and chocolate is not the best source of flavonoids anyway (the study focused mainly on berries and wine). And, of course, we know that excess sugar consumption, a major content of most chocolate products, makes diabetes more likely.

Bearing in mind the high fat levels in chocolate, the balance of evidence is that we can’t think of it as a healthy food, but one to enjoy in moderation.

LINKS:

Caffeine – see Coffee – page 29Fat – page 44Sugar – page 102

Cholesterol

There is a lot of confusion about cholesterol. It is certainly far too simplistic to say that cholesterol is bad for us, but raised levels of some types of cholesterol are strong indicators of risk of heart attack and stroke.

The good news about cholesterol is that it is an essential chemical in the body, required for the cell membranes – the outer layers that hold the contents of the cells in our body in place – to allow various chemicals in and out of these complex tiny factories. Broadly, cholesterol comes in two forms, the larger low-density (LDL) form and the smaller high-density (HDL) form. LDL is sometimes called ‘bad cholesterol’ as it can transport fat into artery walls, while HDL is nicknamed ‘good cholesterol’ as it can remove some fat molecules from special cells in the artery walls.