It seems like only yesterday when being healthy was so easy. Knocking back a glass of fizzy Vitamin C in the morning was all you needed to feel that you were ready to take on the world and all the nasty bugs it might hurl at you. Alas, those days are long gone. There are vitamins and minerals and amino acids out there we've never even heard of that are, apparently, essential to wellbeing. Vitamin K? GHR15? And what about my personal favourite, 5-HTP? The mere knowledge of their existence has an unsettling effect: it forces us to ask whether we are courting disasterforeshortening our lives making ourselves prematurely old and decrepit by not using them.
Of course, we all have our favourite supplements that we turn to for specific ailments. The minute there's a tickle in my throat I'm pouring echinacea down it. And I would not get far without glucosamine and chondroitin for middle-aged creakiness, or calcium and magnesium for my bones.
Considering what fusspots some of us are about each morsel of food that passes our lips, we are happy to know precious little about vitamins. It's as if the mere fact that they come in a little pot that looks pharmaceutical means they must be good for us.
A lot of us suspend disbelief every time we pass shelves crammed with what has come to be known in the industry as "nutraceuticals". Last year, pound;350 million was spent on vitamins by 45 per cent of all British households.
The industry grows healthier as we grow more neurotic about the susceptibilities of our bodies.
Are we deluding ourselves into thinking we can beat nature at her own game? Manufacturers of food supplements say that natural sources of vitamins and minerals are unreliable because of modern methods of food production. The soil is reputedly depleted of its goodness and contaminated with pesticides. The oceans are brimming with fish containing important oils for our health - but they are also brimming with toxins such as mercury. So we either have to ration our consumption of fish or only buy what comes out of "clean" waters.
Unless we have the time to swot up on the status of the world's oceans and the money to buy only organic produce, we are in trouble, as far as the nutraceutical companies are concerned. But don't despair - for no more effort than the gulp of a pill and a few quid, they promise us more youthful looks, more energy, more resistance to disease and more sexual energy. On the other hand, the mantra of health promoters is that if we eat five helpings of fruit and veg every day alongside a varied low-fat diet, and take 30 minutes of moderate exercise five times a week, we will feel and look healthy and will reduce the risk of heart disease and some cancers.
In fact, there is hardly an area of human existence that attracts as many conflicting views as the question of whether supplements are beneficial. We get pronouncements like those of Rory Collins, professor of medicine and epidemiology at Oxford university, who has concluded that "vitamin pills are safe but useless". He speaks with authority, having led a five-year study on the effectiveness of Vitamins C and E and beta-carotene in the prevention of cancer, cardiovascular and other potentially deadly diseases.
But his study was looking at those vitamins' ability to prevent serious disease, not at their effectiveness in promoting good health generally. This was the response to the Oxford study's findings by the Health Supplements Information Service: "Supplements are not intended for the treatment or prevention of serious illnesses such as heart disease or cancer in these circumstances. Vitamins, including antioxidants, play a general preventative role with health." Now, you may think that HSIS would say that, being an industry-backed organisation with vested interests in selling expensive supplements. But what they are saying is irrefutable: vitamins and minerals do make us healthy and can stave off conditions such as anaemia and congenital conditions like spina bifida. But whether supplements containing vitamins and minerals enhance our health generally is less clear.
One problem with interpreting the evidence is the complex set of variables that come into play when scientists look at diets as one element of lifestyle. Numerous studies have shown lower cancer rates among people who have a diet which includes fresh fruit and vegetables. Since we know that they contain vitamins and that some (such as C and E) function as antioxidants which attack damaging free radicals, it is possible that they protect against cancer. But does this mean that taking them as nutritional supplements is the same thing?
According to the American Cancer Society, the jury is still out on whether the benefits of a "healthy" diet are due to the vitamins that fresh produce contains, or to the range of chemicals that they are made up of, or to one or the other combined with the lifestyle that go with healthy eating.