As any salesman will tell you, nothing reels in the punters like the personal touch. From personal shopping to personal trainers, we are far more willing to part with our cash for a product or service that gives us exactly what we want - not a lazy or well meaning approximation.
And diets are no exception. In a culture where food is readily available and choice is overwhelming, generic public health advice exhorting you to eat more fruit and veg or run up the stairs instead of taking the lift is infinitely less compelling than a DNA test revealing that you (ie you personally) have a genetic predisposition to a particular disease and can personally reduce your chances of developing it by changing your diet.
Enter the emerging science of nutrigenomics. The marketer's dream, it's the ultimate in personal shopping: foods tailored to your genetic profile.
The extent of the commercial opportunity that it presents to the food industry is not yet clear however. Indeed, not everyone is convinced that specially formulated products are required at all.
If, for example, DNA testing reveals that you should eat more folic acid because you are genetically prone to high homocysteine levels (and therefore have a higher risk of heart disease), you don't need to buy a specially formulated product from Unilever to ensure you get your required dose.
You could take supplements, or eat more leafy green vegetables, oranges and peanuts (which all contain folic acid).
The easy option
Given that we always choose the path of least resistance, however, chances are that we will look to the food industry to come up with ready made solutions, says Dr Rosalynn Gill-Garrison, chief science officer at DNA testing company Sciona.
We have found that personalisation of dietary advice through the use of genetics has provided individuals with considerable incentive to change their dietary habits, she says. However, we have also experienced feedback from consumers who are looking for convenient solutions [ie products] that can help them achieve their nutritional goals, but which are also amenable to their current lifestyle habits.
Given the growing obesity epidemic and the fact that heart disease remains the number one killer in the western world, it is apparent that we need to find solutions that people can incorporate into their daily lives.
As more is understood about the genome, personalised nutrition and personalised medicine will become commonplace, adds Kristine Ashcraft at another testing firm Genelex. Which could mean big bucks for the food industry.
However, the likes of Unilever and Danone are understandably reluctant to link diagnostics to specific products and are therefore unlikely to get directly involved in widespread genetic screening, says Unilever vice president, corporate research, Frans van der Ouderaa. If you give people their DNA test results and then present them with a list of Unilever products they need to eat, people will smell a rat, he says.
Given the success that lobby groups and certain sections of the media have had in hijacking the genetic modification debate in recent years, the industry is also anxious not to raise expectations before the science has proved that it can really deliver, he says.
Frankenfoods: the sequel
There is a lot we still don't know, and companies offering advice to people on the basis of screening a handful of genes are on potentially dangerous ground, says van der Ouderaa.
That's the problem that some of the testing firms have, that for one or two of these genomic differences you can maybe come up with a solution, but for the 999 other ones you cannot yet, because we don't have the data.
These companies are talking about 20 genes. We have more than 20,000, and unless you are Bill Gates, you can't afford to have them all mapped out. The fear I have is that we over promise, and we get a backlash.
Logically, however, there is no reason why the public should not embrace nutrigenomics, he says. Although it is based on an understandingu of genetic difference (something that we cannot personally influence or control), it is actually very empowering in that it uses genetic information to help us manipulate environmental factors that we can all control, such as diet and exercise.
The evidence that sub-groups of the population react differently to the same environmental factors is now overwhelming, he says. The concept is so well established in pharmaceuticals that in Japan, some drugs are now only given to people of a certain genotype, says van der Ouderaa.
It's well known that drugs only work for a certain percentage of the people that take them, and the reasons for this are often genetic. Environmental factors such as urbanisation also affect different ethnic groups differently, he adds.
Bad cholesterol
Some recent research has also revealed dramatic variations in individual responses to food, with some people showing a 40% decrease in low-density lipoprotein (LDL), or bad cholesterol levels, after following a strictly-controlled cholesterol-lowering diet, and others actually seeing a 10% decrease, he says.
While nutrigenomics could potentially address everything from bone health to B vitamine use, the most fertile area for food companies is currently lipid metabolism.
The most common gene affecting LDL cholesterol levels is ApoE, which has three major variations: E2, E3, and E4. Several studies have established that E4 is associated with higher levels of bad cholesterol, says van red Ouderaa. At one time, this probably conferred an evolutionary advantage when food was scarce and we needed to keep hold of all the fat we could lay our hands on, he says. It's not quite so helpful today.
The point is, that knowing which variant you have could help you determinte whether you are more likely than the next person to develop cardiovascular disease, which might just give you the impetus to do something about it, says Food and Health Research director Jack Winkler. You only have to look at people that have survived a heart attack or taken a cholesterol test; there's nothing like a shock to the system to spur you into action.
Testing, testing...
It is too early to speculate as to how the population might be divided up and targeted by food companies, but DNA screening is not necessarily a pre-requisite for doing this, points out van der Ouderaa. It should be possible to categorise people that have a higher than average risk of heart disease, diabetes, obesity or other chronic diseases through a variety of means including family history and ethnic background, and develop off the peg solutions, he says. You don't need an infinite number of variations.
Indeed, the functional food industry is already encouraging this kind of advised self-diagnosis, by targeting people with high cholesterol or osteoporosis, pregnant women or people in specific age bands, he points out.
However, products tailored to population sub-groups on the basis of genetic predispositions are probably still five years away from commercialisation, predicts van der Ouderaa.
The important thing, he stresses, is to ensure that products that do get to market offer a genuine and compelling benefit to the consumer, and that cowboys trying to make a fast buck do not undermine the good work that is being done.
Enter the cowboys
While Unilever has studiously avoided making wild claims about the potential of nutrigenomics, others have been rather less circumspect, with a swathe of firms now offering punters the benefits of their expertise in personalised nutrition and DNA diets.
Not surprisingly, this is making some food policy experts and civil liberties groups nervous not least because there is no simple means of proving whether we are being taken for a ride, says Food Ethics Council executive director Dr Tom MacMillan.
While consumers might be able to see the impact of a new diet on their cholesterol levels within weeks, it could take decades before they can determine whether it has helped them avoid chronic disease, and even then, a host of other environmental factors could have been responsible, he says.
Basically, you have to take all of this on trust. There really is on way of knowing if you are being ripped off.
The prospect of insurers, employers or mortgage lenders knowing your most intimate genetic secrets is also making some people distinctly uncomfortable, and data protection and proper regulation will be critical if public confidence in nutrigenomics and genetic testing in particular is to be maintained, he adds.
For other people, a more pressing question is whether public money should be spent on nutrigenomics at all, which in the short-term at least, will probably remain the preserve of the affluent, worried well.
However, the argument that all available resources should be pumped into generic public health campaigns encouraging us to eat a more healthy diet and exercise more just doesn't wash, says Dr Siân Astley, European communications manager for the European Nutrigenomics Organisation.
There is growing evidence to suggest that generic messages just don't work anymore. Personalising a message gives consumers control. It makes them sit up and listen. FM