The influence of genes turns out to be more complex than was believed.
Commercial genetic nutritional advice: charlatans.
Ten years ago you wrote that personalized diets were 'still a long way off'. Was your cautiousness justified?
'Definitely, and I still see it the same way. Although we have come a long way in the science since then.'
'We now know that, although the genome is fixed, there is plasticity as well. On our genes there is a regulating 'layer' called the epigenome. And especially during the first thousand days of life, this layer reacts to the environment flexibly: there is a lot of energy or a little, a lot of movement or a little. So you certainly cannot say: show me your genes and I'll tell you what to eat.'
That doesn't make things any easier.
'The day is indeed still far off when we will give people individual advice on what to eat. But we do know that everyone's metabolism has an individual capacity - determined by a large number of genes. If you know that capacity, you can remind people to stay within their safe zone. You don't need to scare them with it or turn them into hypochondriacs. There is a broad range within which people can be healthy.'
On the internet there are companies that offer detailed nutritional advice based on a gene profile. Is there anything to be gained from their advice?
'No, they are charlatans, really. Advice like that is extraordinarily difficult to give and is still only possible for a few aspects. For example, supplements for people who do not easily absorb minerals. And even for that the evidence is very flimsy.'
Nowadays most people have a good general idea of what is healthy. Why should we listen to personalized advice?
'For that we should also communicate with people in individually appropriate ways. One person can be triggered through an app, someone else can be reached through the community, and another person might respond to a healthy cookbook like Sonja Bakker's. Scientists are not always that great at communication and I think there's a lot to be gained in this area.'
In our world it is easier to make unhealthy choices than healthy ones. Isn't it more important to change this environmental factor?
'You can create incentives for companies to produce healthy food and not stuff children full of rubbish. But you shouldn't expect to solve the whole problem like that, considering we live in a free society and economy. I would most like to give people incentives to eat healthily. And to use campaigns that imprint the value of food on children's minds from a young age. People who know more about food are less vulnerable to the temptations of convenience foods.'
Your research is known for its complexity. How do you deal with it?
'That is tricky. We concentrate on a few systems, for example how a sensor in our bodies reacts to fat. We study how organs respond individually. The ultimate ideal is to combine the findings into a systems biology for food. But we never have a simple message saying: this gene or that nutrient did it.'
Wouldn't you sometimes like to have some simple answers?
'Of course, but we are working on complex diseases such as type 2 diabetes. That is just the challenge we face.'
The Science Café on the theme of 'Nature and Nurture in Nutrition will be' takes place on 18 April in Loburg café. Starting at 20.15 (live music from 19.45).