From the start ALSPAC has included data collections on diet. The first collection was in the mothers during their pregnancy, and it's been repeated three other times with them. We've also got a wealth of information on the diets of the children from birth into teenage years. This has been an incredibly rich source of data for us on changing patterns on diet during childhood and is still on constant use today, mainly to study the effects of diet in pregnancy and in childhood on markers of health in later years. This type of long-term data on diet is very unusual in the UK so we are fortunate to have this in ALSPAC.

It's been some time since we've able to collect new information on diet in ALSPAC in the children, but we have an opportunity to do this in some upcoming questionnaires. This will add to our existing long-term data and add greatly to the potential for future scientific work linking diet and health.

As previously we are using a method called a 'food frequency questionnaire' (FFQ) in which participants are asked how often they usually eat particular foods. The FFQ is very similar to that used before in ALSPAC, but we have updated it for changes in the types of food people eat nowadays. In order to sure that the FFQ is correctly reflecting what participants actually eat, we need to do an additional 'validation' study in which we ask some of the participants to record their diet in another way.

For this validation study, we'll be asking some of the participants who fill in the FFQ to access an electronic platform on their smartphones or other device to record one day's food and drink intake in detail (food diary). We'll then ask them to repeat this twice at monthly intervals (so on three separate days in all). We can then compare the two ways and see how well the FFQ is performing against the electronic food diary and whether we get similar data from the two methods. If they are similar, we have can confidence in the data collected from the FFQ and can use it state this in our scientific publications so that others will know we have accurate data.