Academics at Exeter University have challenged firms that offer personalised dietary advice to consumers based on screening just a handful of their genes.
While there was growing evidence that diet affected the expression of genes associated with certain health problems - the basic premise of nutrigenomics - the proliferation of firms offering diet plans on the back of such research was a real concern, said lead researcher Paula Saukko.
"In the US, there are claims that you can make your children more intelligent by tailoring their diets according to genetic makeup. These tests are available over the internet so there is nothing stopping the British from buying them also."
A study at Exeter, funded by medical research charity the Wellcome Trust, would look at claims by firms selling personalised nutrition services and decide whether regulation was required, said Saukko.
While a lot of the media coverage of nutrigenomics had focused on identifying genetic variations between individuals, current research was more concerned with things we have in common, insisted Catherine Segal, vice president, business development, at US nutrigenomics firm Wellgen.
"We're talking about how foods can alter the expression of known genes associated with well-known health conditions. By contrast, genuinely personalised nutrition is still a long way off."
The issue of whether genetic variations affected how individuals responded to foods was nevertheless worth exploring, said British Nutrition Foundation science director, Dr Judith Buttriss.
A human study exploring how such differences influenced responses to fats had just been completed by the European Lipgene project, said Buttriss. The study explored how the food industry could help tackle metabolic syndrome through developing healthier fats.
"We are getting a lot closer to understanding how people with different genotypes respond to dietary interventions."
Meanwhile, US firm Genelex, which offers clients dietary advice on the basis of DNA screening, rejected suggestions that it was not able to provide credible dietary advice.
A spokeswoman said: "We have strict selection criteria that demand that each genetic marker that we choose has a well-documented effect on health together with a well-validated nutritional or lifestyle intervention that can help to ameliorate any risk associated with a particular genetic marker."