TWO FOOD PANICS DEBUNKED

Bad diets costing the British taxpayer billions?

Panic: 'NHS picks up 6 billion pounds a year bill for our bad diet', reports today's Daily Telegraph. Researchers working in the British Heart Foundation (BHF)'s Health Promotion Group at Oxford University brought together figures on NHS costs broken down by disease, and compared them with figures from the World Health Organisation (WHO) which attribute percentages of each disease by cause. The main claim is that 'food-related ill health is responsible for about 10 per cent of morbidity and mortality in the UK and costs the NHS about 6 billion pounds annually'.

Don't panic: Even the researchers accept that their results are 'crude estimates', although they think they are probably reasonable. They are, nonetheless, estimates based on other estimates.

The headline figure sounds incredible until you realise that the NHS spent around 70 billion pounds in 2002, increasing to around 88 billion pounds in the current financial year. So while 6 billion pounds seems like a lot of money, it actually reflects the huge sums now spent on healthcare as much as it might be an indictment of our diets.

The figures still need to be treated with caution. They are based on WHO figures suggesting that diet contributes about 15 per cent of all life-years lost to death and disability. However, such estimates are prone to re-evaluation, as the embarrassingly massive downward revision in US obesity-related deaths earlier this year demonstrated. US health authorities produced a figure of 400,000 obesity-related deaths in 2004, but now the accepted figure is in the region of 75,000.

It's also worth noting that the category of '15 per cent' who die of 'bad diet' includes not just those who are overweight and obese (6.9 per cent) but also those who have a low fruit and vegetable intake (2.3 per cent) and consume a lot of saturated fats (6.4 per cent). Yet the links between ill-health and all three of these factors is much more controversial than is suggested by such bald estimates. All estimates of deaths from any lifestyle cause (smoking, eating, alcohol and so on) are produced by extrapolating risk factors from small studies, each with their own methodological problems, to whole populations. There is plenty of room for error in such an exercise.

Above all, it is laughable to suggest that all this death and illness would disappear if we all just switched to eating fruit and salads and avoided burger bars. But such news reports help groups like the British Heart Foundation to bang the drum in favour of greater levels of spending on their particular concerns.

The wickedness of salt

Panic: A report published this week suggests that people in Britain consume too much salt, and that reductions in salt intake could cause a significant reduction in cardiovascular disease. Why 6g? A Summary of the Scientific Evidence for the Salt Intake Target, produced by the UK Medical Research Council (MRC), argues that a reduction in salt intake from current average levels of about 9.5g per day to the government's 6g per day target would lead to a predicted 13 per cent reduction in stroke and a 10 per cent reduction in coronary heart disease.

One of the report's authors, Dr Susan Jebb of the MRC, said: 'It is important for people to understand the links between salt and high blood pressure and to recognise the importance of reducing salt intake as part of broader lifestyle changes to decrease the risk of heart disease and stroke.'

Don't panic: While a link between salt intake and cardiovascular disease seems plausible, there is little direct evidence to support this report's assertion. High blood pressure is a well-known risk factor for heart disease and strokes. Reducing salt intake seems to lower blood pressure for many people, although for some people it has no effect whatsoever - and for a few, leads to an increase in blood pressure.

However, little research has been done into the direct effect of salt intake on the risk of ill health. What we do know is that the human body is very adept at regulating salt levels in the blood so that excess salt is excreted. This capacity to adjust salt levels has been crucial to our ability to cope with changes in temperature and diet, and our ability to adapt to living in a very wide range of different climates. It seems that the government and medical researchers would prefer to downplay this sophisticated mechanism in favour of salt regulation by guideline.

Moreover, blanket advice to cut salt intake may even cause harm. Sudden changes in temperature, due to a heatwave, exercise or travel to a hot country, can cause those accustomed to milder temperatures to suffer sodium deficiency. The current obsession with cutting salt intake may increase this risk.

The data linking salt intake with health is contradictory - and if there is a positive benefit, it is likely to be small. Reducing salt may help the seriously hypertense, for whom any means of reducing blood pressure is beneficial. For the rest of us, reducing salt in our diet is more likely to lead to bland food than better health.

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