Eat five a day to "live well". Adopt a Mediterranean diet to lower the risk of cancer. Drink cherry juice for insomnia. Eat a handful of almonds daily to tackle high blood pressure. The mountain of advice about what to eat and what not to eat grows taller by the day. Yet though championed by food nutritionists and acres of editorial, many of us still find the idea of food as medicine hard to digest.
"People tend to fall into one of two camps – food faddists and food ignorant – because so much of the food we buy carries messages about salt or fat content in the hope of nudging us towards being more healthy. However labelling foods 'good' and 'bad' has steered us away from understanding what a healthy diet is and how to achieve it," says Catherine Collins, principal dietician at St George's Hospital, London.
"Five a day has only got us half-way," believes Michelin-starred chef Chris Horridge, who develops meals to accelerate hospital patients' recovery. "We need to become more aware of how different foods impact on each other and, indeed, how different people's bodies metabolise vitamins or minerals at different rates."
The link between food and health has underpinned medical practice for generations. The laxative effect of rhubarb has been used for 5,000 years. Sage also has a long medical history, hence its use a stuffing for rich meats. In medieval medicine, physicians used wet foods such as fish to combat fever. "For many years our understanding of the human body tended towards the Victorian in its emphasis on the mechanics. Now, though, we are developing a subtler, molecular understanding of how the body reacts to different, everyday foods," says Dr Gio Miletto, a GP and co-presenter of The Food Hospital, which starts on Channel 4 tonight. "Mainstream medicine is only now coming to terms with the impact the interaction of environmental factors including food have on our health and wellbeing," he adds. So today, thanks to scientific research, we know that our hormones and blood pressure are directly affected by what we eat and particular genes in our DNA may be turned on or off in response to nutrition and the environment. By choosing our foods carefully we can have a lot more control over how well we age, how we resist illnesses and how long we can live an active life, The Food Hospital argues.
Experiences of real patients are charted in each programme in the eight-part series. In each case the programme's team of resident experts developed a scientifically-based food plan and then monitored the results. Harvey, a seven-year-old migraine sufferer with suicidal thoughts, went from having five or six migraines a week to none by avoiding full-fat milk, citrus fruits such as oranges and processed meats and increasing his intake of vitamin B2 and magnesium.
Another patient in the show, Lauren, suffers from polycystic ovaries. Though this is not a condition that can be cured by diet, by including in her diet food chosen to improve her hormone balance – more wholegrain foods, more fruit and vegetables, for example – she lost one and a half stones in weight, experienced a thinning in the excessive hair growth that's a symptom of her condition and her fertility improved. In a later episode, Sophie – a singer suffering from gastro-oesophageal reflux – is prescribed a diet designed to tackle her condition in two ways. The first was to reduce the pressure on the sphincter, which usually holds the top of the stomach closed, but which in sufferers of this disease, allows reflux back into the oesophagus leading back up to the throat. The second was to address some of the damage to her body the condition had already done.
"Different foods move through the body at different speeds – fatty foods, for example, stay in the gut longer," explains Lucy Jones, specialist dietician at north London's Whittington Hospital and The Food Hospital's resident dietician.
"We also explored ways to modify Sophie's diet that would introduce specific nutrients that can repair damage. At the start of this process it looked like she would need surgery to repair her sphincter. After ten to 12 weeks of eating differently, however, there was a marked improvement."
The series also explores how foods "work" and exposing myths, such as whether the blueberry – whose properties are now believed to include preventing cancer, reversing memory loss, reducing cholesterol levels and preventing infections of the urinary tract – really is a superfood. (Answer: no, because other fruit such as blackberries can be just as beneficial and cheaper, too, by not being marketed as a "super").
Viewers will be asked to add a single food to their diet then monitor the medical effect. These will include investigations into whether 50g of chocolate a day has any impact on blood pressure, and the effect (if any) drinking cherry juice has on insomnia. But not all of the diet plans tried in the series are successful. In Lauren's case, though her fertility improved, her testosterone levels remained unchanged. However this, in turn, is another important message. "What we are not trying to do is suggest diet is the only way forward, rather than medicine or surgery. What we do want the audience to take away, however, is that any one of us can make some relatively simple changes to what we eat and achieve significant effect," Jones adds. "As a nation we are eating ourselves to death. Our reliance on pills to protect or cure ourselves from illness, meanwhile, has become the norm. My hope is that The Food Hospital will inspire people to take greater responsibility for their own health by developing a deeper understanding of the implications of the food they eat."
'The Food Hospital' starts tonight on Channel 4. 'The Food Hospital' book is published by Michael Joseph on 10 November
Eat to treat
Acne can be helped by a healthy, balanced diet that includes plenty of multicoloured fruit and vegetables. Reducing intake of dairy products – which may impact on our hormone balance – can help some, but experts advise against cutting it out altogether, as dairy is a rich supply of calcium.
Colds and coughs
Though vitamin C tablets are a common, self-prescribed remedy, it's far better to get that vitamin C from food. Ensuring you are eating enough foods containing zinc – seafood, dairy, Brazil nuts, eggs and poultry – is another worthwhile defensive measure. Garlic has anti-viral properties which may also reduce the number of colds you catch.
Eating a healthy balanced diet, eating regularly – a snack at least every four hours – and avoiding dehydration can all help guard against headaches. With magnesium deficiency a common trigger for migraines, eating enough magnesium-rich foods, such as nuts, bananas, oats and beans, is one tactic experts suggest.Irritable Bowel Syndrome
Adjusting your fibre intake – low-fibre foods during bouts of diarrhoea, high fibre during constipation – can help ease the condition, as can swapping foods high in fructose and lactose for low fructose/lactose alternatives. Oily fish and flaxseed can help ease inflammation due to the omega 3 oils they contain. Live yoghurt and probiotic drinks can improve general gut health.
A high-carb snack at bedtime stimulates the release of insulin which, in turn, can help the body create melatonin, which encourages sleep. A milky drink with high levels of melatonin can help. As magnesium deficiency is one cause of insomnia, eat enough magnesium-rich foods – such as bananas, dried apricots, almonds, peas and beans.
A so-called "Mediterranean diet" – high in fresh fruit and vegetables, olive oil, a moderate proportion of dairy and fish, and a low proportion of meat – is believed to help protect against prostate cancer. Seafood, whole grains, pumpkin seeds and pulses are a good source of zinc, which is important to prostate health. A higher fibre diet may also reduce prostate enlargement.
Only make significant changes to your diet with advice from a qualified dietician