New urine test can quickly detect whether a person has
a healthy diet
by Kate Wighton, Imperial College of London
The
analysis, developed by researchers from Imperial College London, Newcastle University and Aberystwyth University, also gives an indication
of how much fat, sugar, fibre and protein a person has eaten.
Professor
Gary Frost, study author said, “This test could be the first independent indicator of the quality
of a person's diet - and what they are really eating."
Although
the work is at an early stage, the team hope that with future development the
test will be able to track patients' diets. It could even be used in weight
loss programmes to monitor food intake.
Evidence
suggests people inaccurately record their own diets, and under-report unhealthy
food while over-reporting fruit and vegetable intake - and that the likelihood
of inaccuracies in food diaries increases if a person is overweight or obese.
Developing 'healthy diet' profiles
In
study, published in the journal Lancet Diabetes and Endocrinology and
conducted at the MRC-NIHR
National Phenome Centre, the researchers asked 19 volunteers to
follow four different diets, ranging from very healthy to very unhealthy.
These
were formulated using World Health Organisation dietary guidelines,
which advise on the best diets to prevent conditions such as obesity, diabetes
and heart disease.
The
volunteers strictly followed these diets for three days while in a London
research facility, throughout which the scientists collected urine samples in
the morning, afternoon and evening.
The
research team then assessed the urine for hundreds of compounds, called
metabolites, produced when certain foods are broken down in the body.
These
included compounds that indicate red meat, chicken, fish, fruit and vegetables,
as well as giving a picture of the amount of protein, fat, fibre and sugar
eaten.
They also included compounds that point to specific foods such as citrus
fruits, grapes and green leafy vegetables.
From
this information the researchers were able to develop a urine metabolite
profile that indicated a healthy, balanced diet with a good intake of fruit and
vegetables.
The idea is this 'healthy diet' profile could be compared to the
diet profile from an individual's urine, to provide an instant indicator of
whether they are eating healthily.
The
scientists then tested the accuracy of the test on data from a previous study.
This included 225 UK volunteers as well as 66 people from Denmark.
All of the
volunteers had provided urine samples, and kept information on their daily
diets.
Analysis
of these urine samples enabled the researchers in the current study to
accurately predict the diet of the 291 volunteers.
Objectively assessing
overall healthiness
Professor John Mathers, co-author from the Human Nutrition Research Centre at
Newcastle University, said: "For the first time, this research offers an
objective way of assessing the overall healthiness of people's diets without all
the hassles, biases and errors of recording what they've eaten."
The
team now hope to refine the technology by testing it on larger numbers of
people. They also need to further assess the accuracy of the test on an average
person's diet, outside of a research setting.
Dr Isabel
Garcia-Perez, co-author from the Faculty of Medicine at Imperial
explained: "We need to develop the test further so we can monitor the diet
based on a single urine sample, as well as increase the sensitivity. This will
eventually provide a tool for personalised dietary monitoring to help maintain
a healthy lifestyle. We're not at the stage yet where the test can tell us a
person ate 15 chips yesterday and two sausages, but it's on the
way."
The
team added the technology may one day be used alongside weight loss programmes,
as well as patient rehabilitation, for instance to help heart attack patients
follow a healthy diet.
Professor Elaine Holmes, co-author from the Department of Surgery and Cancer at
Imperial added: "We are hoping to make this test available to the public
within the next two years. The idea would be to collect a urine sample at home
and deliver it to a local centre for analysis. We envisage the tool being used
by dieticians to help guide their patients' dietary needs, or even by
individuals who are interested in finding out more about the relationship
between diet and their health"
Dr
Des Walsh, head of population and systems medicine at the Medical Research Council said: "Though
this research is still in its early stages, it's grappling with essential
methods in food and diet studies where advances are really needed. Measuring
what we eat and drink more accurately will widen the benefits of nutrition
research, developing better evidence-based interventions to improve
individual's health and reduce obesity."
Professor John Draper, co-author from
Aberystwyth University added: "The future challenge is to apply the
technology developed in this laboratory study in a community setting and
objectively monitor diet in the home. The teams in Aberystwyth and Newcastle
have been doing just this and the results are looking very promising."
The
work was funded by the Medical Research Council and the National Institute for Health Research.
"Objective assessment of dietary patterns by use of
metabolic phenotyping: a randomised, controlled, crossover trial"
by I. Garcia-Perez et al is published in the journal Lancet Diabetes and
Endocrinology