Let food be your medicine - Hippocrates
You are what you eat - anonymous
There has long been an intimate relationship between food, health and disease. Chicken broth is a traditional pick-me-up in the convalescent phase of many illnesses. Yogurt has been used as a treatment for thrush in the bowel and vagina, and recent scientific evidence has endorsed the use of cranberry juice in cystitis. For centuries, garlic has had a reputation for protection against colds and flu, although this may be as much from a desire to enlarge one's personal space as from any intrinsic antibacterial activity. In addition, many people take large amounts of vitamins, calcium, zinc and other supplements for dietary deficiencies, more often imagined than real in Western society.
On the negative side, sensitivity to peanuts and shellfish can provoke very nasty, occasionally fatal side effects. Too much dietary roughage may lead to loose bowel motions and, possibly, poor absorption of important nutrients.
Colouring agents and food additives can cause rashes, and a host of other symptoms have, rightly or wrongly, been blamed on "food allergies". To add to the confusion, there is often little consensus among medical researchers about nutrition. Coffee has been implicated in conditions as diverse as breast cancer and pancreatitis, but, as often happens, other research will downplay such associations.
There is also the area of "food poisoning", which usually occurs following bacterial or viral contamination of food that has been inadequately prepared, cleaned or cooked. Most cases are mild, unpleasant and self-limiting, lasting a day or two, but occasionally food poisoning can be more serious, especially in the elderly and debilitated and in institutions. Salmonella can be contracted by eating foods such as chicken or eggs that have not been fully cooked, and listeria, which can contaminate soft cheese and pΓtΘ, can be hazardous in pregnancy.
It is now widely accepted that high blood cholesterol is one of the many factors in the development of coronary arterial disease. High cholesterol levels can be reduced by eating less animal fat and more vegetable fat, and by using drugs known as statins. One of these, Lipobay, has recently been withdrawn due to a rare but fatal side effect involving muscle destruction, but none of the others have been implicated so far.
The recent introduction of "functional foods" - foodstuffs with added ingredients that allegedly bestow an extra health benefit - has added to the mist of confusion surrounding the cholesterol debate. Margarines such as Benecol and Flora pro.activ contain chemicals known as sterols and stanols, which block cholesterol absorption from the gut, leading to a fall in blood levels. There is some evidence that these products can reduce the levels of LDL, or "bad", cholesterol and be useful in patients with established heart disease or who are at risk of heart disease, but they are of no value in healthy people.
Other functional foods include cereal bars and energy drinks such as Red Bull and Lucozade, which was originally found at the bedside of almost every hospital patient and has now been reinvented as a trendy, sporty drink. Such products are often high in caffeine and sugar, and can increase alertness transiently, but they may not fit in with healthy-eating advice. In Japan, absurd creations such as red-wine-flavoured chocolate, containing heart-protecting phenols, are all the rage. Which?, the UK consumer magazine, has examined the products critically, but it does not endorse them enthusiastically, as nutrition experts have yet to accept many of the claims. The products can be quite costly, and their benefits can be obtained by eating less meat and more fruit and vegetables, and by exercise.
The term "functional food" is almost meaningless anyway, as food is not just an inert substance that satisfies hunger by filling the stomach: it is full of biochemical activity that can be good or bad for the body, so in a sense all food is functional.
How best can one achieve a healthy diet in the midst of this minefield of information, disinformation and confusion? As the Ten Commandments can be reduced to the two great commandments - love God and love thy neighbour - similarly, the key to good health can be condensed to the four suggestions of Sir Raymond Hoffenberg, a former president of the Royal College of Physicians:
Don't smoke
Drink moderately
Eat a varied diet
Take regular exercise.
This is common sense; you do not need a degree in food science to live well by healthy eating.
Muiris Houston is on leave