Detox and gluten-free products are big business at the moment, all designed to help you live longer and be healthier. But what if most of it was based on nonsense science, designed to sell you a quick-fix idea that doesn't actually work?
HuffPost UK Lifestyle asked science writer Brian Clegg who wrote Science For Life: A Manual For Better Living to name five things that we tend to get wrong when it comes to health. As he says, there's no magic bullet...
We are told that our bodies build up nasty stuff, and the only way to get rid of this is an extreme detox diet or eating a wonder substance to flush it out. Of course, overeating and drinking, or partying all night, will leave us worse for wear. This will be improved by returning to a normal lifestyle.
But there is no ‘detox’ process, like flushing gunge out of a radiator. Your body recovers from the misuse perfectly naturally. As the toxicologist John Hoskins points out: "The only thing that loses weight on a detox is your wallet."
One legitimate concern is that unpleasant substances – PCBs, dioxins and pesticides particularly – can accumulate in fatty tissue.
The detox approach to this is to greatly reduce solid intake. Unfortunately, not only is this a slow process – you would have to fast for years to remove a typical build-up – the main impact of the ‘detox’ is to move the contaminants from fat, where they are harmless in small quantities, to the blood, where they can do more damage.
The attempt doesn’t so much flush out contaminants as make them more active.
Detoxing is fictional. Just switch to a good, balanced diet with limited alcohol intake and plenty of exercise. It’s boring – and doesn’t sell detox products – but it’s the best you can do.
You’d think from the way some companies push their special drinks that water was alien to us. But keeping hydrated is not difficult.
It’s often said that you should drink eight glasses of water a day, a persistent myth that may have came from a 1945 US National Research Council recommendation that adults should consume a millilitre of water for each calorie of food. But we don’t need to drink this.
We get about half from our food. As for the rest, Heinz Valtin, a kidney specialist from the Dartmouth Medical School in New Hampshire has reviewed the available evidence and shown that there is no need for this to be pure water. Tea and coffee, for instance, are fine if not taken to excess.
Sports drinks work fine too, but research in the British Medical Journal showed that, despite manufacturers’ claims, thirst is a fine guide for hydration. There is no need to ‘stay ahead’ of your thirst. And there is no evidence we need to provide electrolytes, the substances that support the body’s electro-chemical mechanisms, in our drinks – these are replaced naturally from food.
Between 1 and 2% of the population is gluten or wheat intolerant. They get stomach pains, constipation and diarrhoea, usually because they have coeliac disease, a genetic disorder of the small intestine.
If a GP finds genuine gluten intolerance, your diet should be gluten-free, easy now with a wide range of gluten-free products available. But there has been a celebrity-driven fad of avoiding gluten by those without an intolerance, presumably on the assumption that there’s something toxic in gluten. In reality, it’s the reverse – people who are gluten intolerant have a mutation that makes them react badly to a harmless substance.
Supermarkets use ‘gluten-free’ to add an extra mark-up. There is no obvious health benefit from a gluten-free diet for those who aren’t intolerant – quite the reverse. It makes it harder to get the fibre (and some vitamins) we need. What’s more, many gluten-free products are higher in fat than normal equivalents to restore the texture. Don’t go gluten free without a medical reason.
Many of us receive spam emails with offers for weight loss products, notably, green coffee beans and raspberry ketones. But are they any good?
Green coffee beans are standard coffee beans before roasting. Coffee has a range of impacts on the human body, but not weight loss. This might seem strange when the emails mention that this is proven by a study. And there is one. But it is a single poor study with sixteen participants that doesn’t tell us anything of statistical significance.
As for raspberry ketones, the intense chemicals that give raspberries their distinctive smell, there is also poor evidence to back up advertising claims. A study did show weight loss in rats with a diet of around 2 per cent raspberry ketones – but other studies contradicted this.
That 2% is far more ketone than weight loss pills provide, and an effect in rats does not mean it is effective in humans. There have been no human trials, nor testing to determine safe levels. Raspberry ketones are not authorised for sale in the UK.
Most of us want to know: ‘How little exercise can I get away with?’
In the US, expert advice is that we should undertake a minimum of 150 minutes of brisk walking or 75 minutes of jogging per week. This fits with a big 2015 European study reporting that 20 minutes brisk walking a day made a big difference.
There is some benefit to going further, but the biggest health gains come from the difference between no exercise at all and that minimum level. Just the minimum brings your risk of dying prematurely down by about 20 per cent. After that, the benefit is small. Tripling the exercise only drops premature death risk another 4 per cent. There is some benefit from doing more – but you’ll work a lot harder.
• John Hoskins/Detox - http://www.senseaboutscience.org/data/files/resources/154/MakingSenseofChemicalStories2.pdf (page 5)
• 1945 water recommendation: Food and Nutrition Board. Recommended Dietary Allowances. National Research Council, 1945.
• Heinz Valtin critique of ‘8 glasses’: http://www.ncbi.nlm.nih.gov/pubmed/12376390
• BMJ on sports drinks: http://www.bmj.com/content/345/bmj.e4737
• Green coffee beans study: http://www.dovepress.com/randomized-double-blind-placebo-controlled-linear-dose-crossover-study-peer-reviewed-article-DMSO
• Raspberry ketone study showing weight loss: http://www.ncbi.nlm.nih.gov/pubmed/15862604
• Raspberry ketones studies showing no weight loss: http://www.ncbi.nlm.nih.gov/pubmed/5489397
• Food Standards Agency, unauthorised novel foods: https://www.food.gov.uk/science/novel/unauthorised
• US exercise recommendations: http://www.health.gov/paguidelines/guidelines/summary.aspx
• 2015 inactivity and obesity study: http://ajcn.nutrition.org/content/early/2015/01/14/ajcn.114.100065.full.pdf+html