There are a lot of myths and half-truths about health, whether it’s about diet, exercise, alcohol and detoxing, or avoiding bugs while travelling. We look at nine common health beliefs and find most of them don’t stack up.

Body parts

Myth: Regular exercise lets you have your cake and eat it

Exercise contributes a lot to good health, benefiting muscular strength, cardiovascular fitness, blood pressure, cholesterol levels and bone strength. It’s particularly important for maintaining muscle mass if you’re dieting. However, many people overestimate the kilojoule-burning benefits of exercise.

When you consider it takes the average person half an hour of brisk walking just to exercise off a chocolate biscuit, or a one-hour jog for a slice of cake and an iced chocolate, it’s easy to see that the energy intake from more than one or two small treats a day is going to exceed the energy burnt in an average exercise regime. In addition to over-rewarding exercise with treats, studies have found that when people have exercised a lot they tend to compensate by moving less throughout the rest of the day.

Verdict: You can't outrun a bad diet.


Myth: You should brush your teeth straight after drinking fizzy drinks to prevent tooth damage

Acidic drinks such as juice, sports drinks, wine and carbonated soft drinks (including ''diet'' soft drink) temporarily soften the tooth's enamel, as do acidic foods such as vinegar, pickles and many fruits. This is known as dental erosion, and is a different issue from decay or cavities, which are caused by bacteria feeding off sugars in your mouth. The enamel’s hardness is gradually restored with the help of saliva. However, softened enamel may be abraded if you brush your teeth too soon after consuming acidic food and drink, and experts recommend you wait at least an hour before brushing your teeth. Snacking and grazing also makes it difficult for the enamel to recover. Limiting your consumption of acidic foods and drinks to meal times can help, as can swishing water around your mouth, eating a piece of cheese or chewing sugar-free gum.

Verdict: Wait before you brush.


Myth: The appendix is a redundant organ

Commonly thought to be a hangover from our bark-eating days, the appendix is largely regarded as redundant. So much so that routine prophylactic appendectomies are sometimes carried out on people travelling to Antarctica (and in similar long-term circumstances of isolation) to avoid the potential high costs of evacuation and threat to life if they were to contract appendicitis.

However, scientists now think the appendix is a storehouse for beneficial gut bacteria, which the body draws upon to replenish stocks wiped out by gastrointestinal diseases such as cholera and dysentery. Although it's possible for these bacteria to be replenished by contact with other people, in sparsely populated areas, the appendix is or was more important. Even today, in societies where gastrointestinal disease is common, the appendix may still have a valid and important function.

Verdict: While it's not strictly redundant, in modern Australian society your appendix is probably not necessary.


Drinks and detox

Myth: Mixing drinks gives you a worse hangover

If you start the party with a couple of glasses of champagne, followed by red wine and a brandy nightcap, will you be worse off than if you'd just stuck to one type of drink?

All the evidence says no – it's mostly the total amount of alcohol that counts, not the variety. But colour also plays a part.

Dark drinks such as red wine, whisky and brandy will make you feel worse because, in addition to the alcohol, they contain large amounts of substances called congeners – toxic impurities formed during fermentation. On the other hand, drinks like beer which have a high water content will keep you better hydrated, and hence feeling better than you would after an equal amount of alcohol consumed from neat spirits, say. Sticking to light-coloured and fewer drinks, interspersed with plenty of water, is the key to minimising the chances of a hangover.

If the horse has already bolted, you can ease your discomfort with painkillers and rehydrate with plenty of water or sports drinks (which can also help replenish lost electrolytes). There’s anecdotal evidence that eggs (which contain cysteine, a helpful amino acid), toast with Vegemite (which will replace salts, sugars, B vitamins and other lost nutrients) and some coffee or caffeinated beverage (although not too much, because caffeine also dehydrates) can help perk you up.

Verdict: Lighter drinks are better than dark drinks; and prevention is better than cure.


Myth: A detox regime can rid your body of dietary excesses

''Detox'' [link to Do diet detox products work] or ''liver-cleansing'' diets and kits that promise to purge your body of toxins can seem an appealing antidote to indulging in too much alcohol and rich food – a fast track to the new trimmer, glowing you. However, our bodies are already well equipped with self-cleansing mechanisms – the lungs, kidneys, liver, gastrointestinal tract, skin and immune system all playing a part in effectively removing or eliminating toxins. Symptoms such as bloating and fatigue may be an indication of an unhealthy lifestyle, or a lack of vital nutrients due to poor eating habits – not of toxin build-up.

There’s no sound evidence that we need to ‘detox’, or that following a detox program will increase the elimination of toxins from your body. Detox supplements provide little or no known benefit over a healthy diet - we suggest you save your money.

Verdict: A week or two on a detox program won’t absolve you from all your health sins.

 

Healthy diet

Myth: Antioxidant supplements can replace fruit and vegetables

Popping a few antioxidant vitamins and drinking loads of fresh juice [link to Juicers buying guide] will make up for unhealthy eating habits ... or will it? There’s strong evidence that a diet high in fruit, vegetables, whole grains and tea can help protect against cancer, heart disease, diabetes and other health problems. These plant-based foods are a rich source of antioxidants. Supplement manufacturers would have you believe that by extracting the antioxidants and putting them in a pill, you can obtain the same benefits as eating a healthy diet. However, evidence suggests that antioxidant pills offer no health benefits, and juice will not give you the same antioxidant effect as the equivalent whole fruit or vegetables.

Possible reasons include that antioxidants in whole foods are digested differently to pills and juice, there may be synergistic effects with other nutrients in the plant, and that behaviour of antioxidants in a test tube is completely different from that in the body.

Verdict: Popping antioxidant pills or guzzling juice does not replace a diet rich in fruit, vegetables and wholegrains.

 

Myth: Popcorn is a healthy snack food

You may have heard recent claims that popcorn, which is a wholegrain, is one of the richest cereal sources of polyphenols – antioxidants that offer numerous health benefits. However, not all popcorn is created equal, and it’s what’s added to the grain – the salt and “butter” – that rings alarm bells.

A small serving of movie popcorn at one cinema chain contains a quarter of your daily saturated fat allowance, and the sodium is about 13%. Granted, it’s a better choice than a choc-top – one of those heart-stoppers will give you more than half of your recommended daily saturated fat intake. Home-cooked popcorn (even the microwave packs) is a healthier option.

Verdict: Popcorn can be a healthy snack food, but movie popcorn should be regarded as a treat – just stick to the smallest size and have it with water.

 

Healthy travel

Myth: Recirculated cabin air on planes will make you sick

If you’re worried about getting sick from breathing recirculated air on planes, you’re not alone. However, studies have shown it’s not a reasonable concern. People who travel on planes may be more likely to get sick than non-travellers, but this is likely due to dry air and a proliferation of germs in a small space (such as being coughed on by the person next to you or touching things sick people have touched), rather than germs being spread through the air supply. Jetlag, stress, poor diet while travelling and fatigue can also affect health. The low humidity can lead to a dry throat and cough, making people think they’ve picked up a bug when they haven’t. Using a hand sanitiser and drinking plenty of fluids while onboard is a good idea.

Verdict: Recirculated cabin air alone doesn’t make passengers sick.


Myth: Bottled water is a safe alternative to tap water when you’re travelling

In some countries, especially developing countries, travellers are advised not to drink tap water and stick to bottled water [link to Bottled water] instead. However, in some cases bottled water may simply be untreated tap water. Even ''filtered'' water may not have had all the baddies removed. Buying a well-known brand of imported water is the best bet, but check the seal carefully for tampering – sometimes empty bottles are refilled with tap water and sold to unwitting tourists. You might also consider carrying disinfection tablets and a couple of bottles if you’re venturing off the beaten track – ask for advice at a hiking and camping store.

Verdict: Not all bottled drinking water is safe.