Anyone over 40 may remember schooldays when young people played entire sports matches with nothing more to drink than a slice of orange at half time. Back then, athletes were often careful not to drink water before competing, for fear it would harm their performance. How things have changed.

Nowadays, keeping ‘hydrated’ is taken seriously at all levels. Indeed, you’d be hard pressed to find any place of physical activity without those ever-present water containers and bottles of sports drinks.

But how important is it for our performance and our health to keep hydrated? And how much benefit do sports drinks actually bring us?

A fine piece of investigative journalism by the British Medical Journal has looked at just these questions, scrutinising the science behind the claims. The article (see the link below*) is, for the most part, nontechnical and easy to read, and we recommend it to anyone interested in sport or physical activity.

Their conclusions: The claims for the importance of keeping hydrated during activity and for the benefits of sports drinks are not backed up by strong scientific studies. In fact, they found that much of the science had been financed by the sports drink industry itself. (This does not make the science invalid.)

Take hydration. Evolution has favoured us humans with effective ways to regulate the amount of water in our bodies needed to keep our physical and chemical processes going smoothly in a wide variety of different environments. In general, we know we need to top up on water by the feeling of thirst we get. But in recent years the idea has emerged that we should abandon this feeling of thirst as an indicator and instead simply drink often. To avoid the dangers of ‘dehydration’, we are expected to prime ourselves by drinking before exercise, continue drinking while exercising and then drink substantial amounts after it.

The article challenges the need for this behaviour. What scientific evidence exists is often based on studies that involved relatively small numbers of selected individuals in artificial lab conditions and is not necessarily applicable to everyone or to real-life situations. For children there’s very little evidence indeed. The risks of dehydration during normal exercise are probable overstated: we are able to endure periods of mild dehydration without harm.

(There is, however, evidence that some elderly people lose some of their sensitivity to feeling thirsty and so should drink a little more often than they feel they need to.)

A huge sports drinks industry has grown up marketed on the basis that these drinks help boost performance for us all. Sports drinks certainly have the right balance of minerals and sugar for rehydrating us quickly, and they replace things like the sodium lost in sweat and the sugar burned in our muscles. But how important is this?

The actual evidence underpinning the claimed performance benefits of sports drinks proved difficult to obtain from a couple of the manufacturers, but the authors scrutinised all the evidence that was supplied to them and concluded that it was fairly weak and may not apply to most of us.

There will be situations where people who are exercising very hard or working in high temperatures may need to replace quickly not only water but also the sodium lost in their sweat. But these are not the everyday situations most of us encounter (and many people consume far too much sodium anyway due to the salt in their food).

A bottle of sports drink typically contains 4 to 5 teaspoons of sugar. The authors of the article did not find any good evidence that this is a better way for athletes to get their energy than from their food. For most of us who are keeping an eye on our waistlines, it’s questionable whether consuming sports drinks containing sugars is a sensible strategy.

Sports drinks are classed as ‘foods’ rather than ‘medicines’. Claims made about the benefits of foods do not need to undergo scrutiny in the same way as those about medicines. But that shouldn’t mean there is any less of a need for good evidence, particularly where claims relate to aspects of health.

Until there is strong evidence, you’ll need to make up your own mind about sports drinks. If you are an elite athlete, do what works well for you and your sport. For everyone else, it’s worth reading the article before coming to a judgement. In particular, if you are exercising to reduce your body fat, be especially sure you are not replacing the calories lost by exercising with calories in your sports drink.

 

*Link to the article: http://www.bmj.com/content/345/bmj.e4737

 

Professor Brian Kirby, co-author of How to Live to 110: Your comprehensive guide to a healthy life.

 

Takeaway food is undeniably popular. It’s convenient, whether eaten at home or when out and about, and it can be tasty. Unfortunately, a recent study* has confirmed what many nutritionists have long suspected: we should all be wary about dangerous amounts of salt in our takeaways.

Researchers analysed more than 400 samples of 23 different takeaway hot meals. The salt content varied in different samples of the same food, but the overall pattern showed that most of these meals contained an alarming amount of salt. For some of them a single portion contained more salt than an adult’s daily recommended intake of 6 grams per day.

Out of the meals analysed, pizza came out worst, averaging over 9g of salt per portion, followed by Chinese food with 8g. Then came kebabs with 6g of salt and Indian meals with nearly 5g.

There was quite a variation in salt levels in each type of food, but for pizzas even the lowest amount was more than an adult should consume in a day, and the worst portion of pizza contained more than two day’s worth of salt!

And remember that this needs to be added to all the rest of the salt consumed with other foods and snacks in the course of the day.

Eating food that contains a lot of salt just once in a while is unlikely to be harmful. But the overwhelming evidence shows high salt consumption is associated with raised blood pressure which in turn increases the risk of heart disease and stroke.

It is possible that some people may be more sensitive than others to the harmful effects of salt but, as there is no simple way of differentiating this, it’s sensible for us all to stick to the recommendations.

And if we all start avoiding high salt content snacks and meals, it won’t be long before those preparing these foods will feel the need to modify their recipes – to the benefit of us all.

 

*Link to the study http://dx.doi.org/10.1016/j.appet.2012.06.018,

 

Professor Brian Kirby, co-author of How to Live to 110: Your comprehensive guide to a healthy life

 

Where is the healthiest place to live?

People have been suggesting answers to this for hundreds of years. For example, Hippocrates wrote in 400 BC about the importance of choosing somewhere healthy, based on factors such as location, prevailing wind and water supply. And during the Industrial Revolution, people pointed to the healthiness of life in the countryside compared with overcrowded and polluted cities.

In the 19th Century, emphasis was placed on the recuperative and health benefits of coastal air and sea bathing – with the result that many workers took their annual holidays at the seaside. Charities were stimulated to open tuberculosis hospitals and convalescent homes in country and coastal locations.

Even today, many people head to the coast for holidays or to live after retirement. Intuitively, that might seem a healthy idea – but is it?

Recently, a group of researchers looked into this*. They were based in the South-West of England, an area much visited by holiday-makers and which attracts a lot of retirees.

The researchers compared health statistics across England with where people lived, and showed that living near the coast was indeed associated with better health. Interestingly, they found that people who were more socially deprived gained the greatest health benefits. The explanation they suggested for the results was that living near the coast gave greater opportunities for stress reduction and physical activity.

Plainly not everyone can live at the seaside, but the study does show the continuing need for us to think carefully about our built environment and the impact it has on our health.

 

*Link to the study: http://dx.doi.org/10.1016/j.healthplace.2012.06.015

 

Professor Brian Kirby, co-author of How to Live to 110: Your comprehensive guide to a healthy life

 

We all need salt – but in the right amount. Too little or too much makes us ill. Mostly our bodies regulate it well, but in some people it’s less well regulated or over time it gets reset at a higher level than we need.

When salt intake is too high, blood pressure increases, and so does the risk of heart disease, stroke and kidney failure. The British Heart Foundation estimates that too much salt causes 50,000 deaths a year and costs the country £50 billion per year.

To avoid problems, experts recommend that you should consume less than 6 grams of salt a day. That’s about a teaspoon in total, which isn’t much when you consider the amount that is in many manufactured foods (and even some drinks), as well as what people add to their food during cooking or at meal times.

In 1991 the average intake was about 9.5 grams per day – that’s more than 50 per cent too much – and this led to public information campaigns about salt and the government discussing with food manufacturers how they could contribute to reducing intake.

So, how well is this working?

In England, salt intake is monitored year on year. The figures for 2011 have recently been released: on average it’s now 8.1 grams per day.

That’s certainly an improvement compared with 20 years ago, but when you look at it in greater detail it’s not as satisfactory as it sounds, particularly for men. Around 80 per cent of men and 58 per cent of women exceed the recommended level. Men on average are consuming an unhealthy 9.3 grams per day (the overall figure is brought down by women’s lower consumption of 6.8 grams per day). And it looks like the trend for the reduction in salt intake has been slowing down in recent years. There is clearly a long way to go, and this will need continued cooperation from the food and drink industry.

But the release of these statistics is also a timely reminder for us all to check our own salt intake and that of our families.

Unless you cook all your food from scratch, you probably won’t be able to get an exact figure, but it is worth checking the nutrition labels on all the manufactured food you eat during one day to get an idea of how much salt you are consuming. Remember that even desserts and dairy products may have salt in them, and so do some drinks. If a label only lists the sodium content, multiply this by 2.5 to get the equivalent amount of salt.

Are you safely within your 6 grams limit*?

 

Professor Brian Kirby, Author of How to Live to 110: Your comprehensive guide to a healthy life.

 

*You may have seen suggestions that this limit is lower than necessary – but actually it is supported by but the overwhelming balance of scientific evidence.

 

 

‘Low carb’ diets are a popular way to lose weight, and millions of people have used them to shed some unwanted body fat. These diets go under various names, but essentially they involve cutting right back on starchy foods such as potatoes, bread, rice and cereals and instead eating more protein as a source of calories (as well as fats and oils to varying degrees).

Many health professionals have been uneasy about the possible health effects of these diets over the long term. Now a comprehensive study* suggests their concerns may be justified.

The study followed 43,000 Swedish women for nearly 16 years. At the start, they were aged between 30 and 49. The study looked at what they ate and noted who developed coronary heart disease, stroke or other diseases of the arteries. Researchers were particularly careful to rule out alternative explanations of their findings.

They concluded that reducing carbohydrate intake and increasing protein intake was associated with an increase in diseases of the arteries. A 20 g reduction in daily carbohydrate intake and a 5 g increase in daily protein intake corresponded with a 5% increase in the overall risk of cardiovascular disease.

This may be down to two reasons. People on these diets tended to eat less fruit, vegetables, cereals and legumes, all of which have benefits in reducing heart and blood vessel disease. At the same time, many were eating more red meat, associated with increases in these diseases.

The conclusion is these ‘low carb’ diets may result in short-term weight loss, but continuing with them over the longer term carries a risk.

If you choose to follow a ‘low-carb’ diet for any length of time, try to make sure you are still eating a good range of vegetables, fruit and wholegrains. And think about getting your protein from plenty of sources other than red meat – such as beans, soya, fish, chicken and dairy products.

*Link to the study:  http://www.bmj.com/content/344/bmj.e4026

 

Professor Brian Kirby, Author of How to Live to 110: Your comprehensive guide to a healthy life.

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