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Eating for science

25 April 2022
Anouk Willems
Anouk Willems

Symptoms such as headaches, stomach ache, stress, and fatigue can be a precursor for so-called ‘diseases of affluence’ and depression. But can you reduce the symptoms and prevent serious illness by changing your diet? Anouk Willems spent a month studying the effects of a vegetarian, gluten-free, low-carbohydrate, or high animal-based diet on a large group of test subjects.

‘Wanted: volunteers willing to spend four weeks following a diet that is different from what they are used to.’ This appeal, which was published in several northern newspapers in 2019, generated over 500 test subjects for Anouk Willems. Last January, she was awarded a PhD for her thesis entitled Eating for Science, The effect of lifestyle on prevention of non-communicable diseases.

What type of people applied to take part in your study?

‘It was a very diverse group: young, old, fat, thin. Some of them wanted to lose weight, while others wanted to feel more energetic. There were people with and without an official diagnosis, as well as people who were simply interested, and wanted to do their bit for science. The participants were free to choose which particular diet they wanted to try for a month. The diets varied from vegetarian to gluten-free or low-carbohydrate. There were also people who just wanted to eat animal products for four weeks.’

Five hundred completely different people on very diverse diets. How do you manage that?

‘The most practical way was to organize everything online. Information about the various diets was posted on the ‘Eating for science’ website, which unfortunately is no longer online. We tried to help people to choose a diet that appealed to them, and which they thought they would be able to sustain. We used questionnaires to gather information about the participants, such as their weight and waist measurement, current eating habits, and physical and mental health but also about how often and intensively they exercised. During the study, the participants recorded data about everything they ate and their sense of physical and mental well-being. At the start and end of the study, around half of the participants were asked to provide a faeces sample, which we examined to analyse the composition of their gut bacteria.’

'Can't identify the ingredients of a product? Leave it be' (Photo: Jasper Bolderdijk)
'Can't identify the ingredients of a product? Leave it be' (Photo: Jasper Bolderdijk)

Why were you interested in those gut bacteria?

‘The more varied someone’s diet, the more varied and balanced the population of their gut bacteria. This variation and balance are important for an efficient immune system; people with a disturbed gut bacteria population tend to be ill more often. In addition, there is a connection between gut bacteria and the brain. There are even indications of a link between gut bacteria and mental health. It seems that a disturbed gut bacteria population makes you more susceptible to depression. At the same time, depression and a poor diet go hand-in-hand. It’s a chicken and egg situation.’

What are the results of your research?

‘I identified a number of eating patterns among the participants, based on the questionnaires. I looked at frequent combinations of foods, and at products that test subjects did not eat. One of these eating patterns was the so-called Western diet, which contains lots of processed products such as biscuits, soft drinks, and crisps, and which commonly lacks fruit and vegetables. Another eating pattern involved people eating large amounts of animal products: people who eat a lot of meat every week also tend to eat lots of eggs and fish. And then there are people who eat a lot of grain products, such as bread, pasta and rice. These people usually also eat a lot of potatoes.

Once we had identified these eating patterns, we gave people a score for the extent to which they complied with them. After four weeks of the experiment, we made an inventory of the participants who had drastically changed their eating pattern, and linked this to any changes in symptoms such as headaches, stomach ache, or stress. Participants who scored high on the Western diet in their normal life reported relatively large numbers of physical and mental symptoms before the experiment. The symptoms were considerably milder after four weeks of eating fewer processed food products.

Then there were the people who ate large amounts of animal products, compared with those who chose a vegetarian or vegan diet. Despite the better image attached to a vegetarian diet, in our results, we did not find that participants felt better for cutting meat out of their diets. This could be explained by the fact that many of them switched from animal products to processed plant-based products: vegetarian sausages or burgers. Research into the Western diet had already showed that these processed products cause more symptoms and are possibly more harmful to people’s health than meat.’

What is the problem with processed food?

‘Aside from the obvious benefits, such as a longer shelf-life and convenience, processed food is problematic to our health in several ways. It tends to contain large amounts of sugar and salt. The process of heating and grinding destroys many of the nutrients and fibres, and changes the structure of fats and proteins. In addition, as processed food is more easily digestible, the nutrients that remain do not reach the final stages of digestion in the colon, so the gut bacteria there starve. The processing itself converts many healthy fats (both animal and plant-based) into harmful trans fats. I could go on... So my advice is: if the ingredients in a product do not sound familiar, don’t eat it!’

What about the gut bacteria measurements?

‘That’s still a work in progress. The huge range of data I gathered was too complex to interpret for my thesis. Based on the first measurement at the start of the four weeks, we saw a clear link between symptoms, diet, and the presence of certain gut bacteria. We could not, however, prove that they change when the symptoms change.’

S o you’re still working on this subject?

‘Yes, I’m glad to say! During my PhD research, I realized how much I enjoy giving lectures on this subject. And I was involved in the Bloeizone project in Bakkeveen, where an impassioned GP did everything in her power to persuade her villagers to change their diet so that they could enjoy a long and healthy life. All of these experiences inspired me to set up my own business: AnoukWeten. This will allow me to continue developing my knowledge of food and gut bacteria, but more importantly, I’ll be able to keep sharing it. After all, everyone has the right to knowledge that will help them to lead a longer, healthier life.’

This article has been taken from our alumni magazine Broerstraat 5. Text: Kirsten Otten

Last modified:16 June 2022 11.33 a.m.
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