Psychobiotics are of interest also in the treatment of anorexia nervosa
There is still plenty of research to be done when it comes to the link between the diet, gut microbes and mental health. For example, researchers have found that the gut microbiome of patients with anorexia nervosa is different to that of healthy individuals, but it is not yet known whether this is the cause or the consequence.
“Different studies have reported different changes in the microbiome of people with anorexia nervosa. For instance, their microbiome have bacteria that are rare in healthy individuals, and they also have fewer bacteria that produce important short-chain fatty acids. This is not surprising because the diet is known to affect the composition of the gut microbiome, and we know how altered the eating behaviour of people with anorexia often is.”
Ruusunen is interested in how gut microbes affect recovery from anorexia nervosa, and how this could be taken into account in nutritional therapy. This is being examined in the ReGut project carried out in collaboration with Australian partners.
“There are considerable differences in the uptake of energy and nutrition between people with anorexia nervosa, and this could theoretically be explained by different strains of microbes. For example, when two patients get the same amount of energy from their diet in a hospital setting, one of them might get their weight restored easier, while the other’s weight might be very difficult to recover. Microbes may also be a link to the gastrointestinal problems and mood, anxiety and behavioural symptoms typical of anorexia nervosa.”
“We are keen to learn whether the composition of the gut microbiota could predict recovery, and also whether recovery could be promoted by modifying the gut microbiome.”
In a recent review article, the research group examined the potential benefits of fermented foods in the treatment of anorexia nervosa. Fermented foods, such as fermented milk products, kombucha, fermented vegetables and soya products, contain probiotics, i.e., bacteria that are beneficial to the gut, or prebiotics, i.e., compounds that promote the function of beneficial gut bacteria.
“These have not been studied much in anorexia nervosa, but based on our review, they really should.”
“In nutritional therapy for anorexia nervosa, regular meals, sufficient intake of energy to restore the nutritional status and weight, eating diverse foods, learning flexible eating, and challenging anorexic thoughts, play a key role. Research will eventually show whether food that supports the well-being of the gut should also be recommended to support recovery.”
Speaking volumes of the growing interest in the topic is the fact that a new term has been coined for probiotics and prebiotics that have a beneficial effect on mental health via the gut: psychobiotics.
“Some research into probiotic products in the treatment of depression has already been conducted, with some reported benefits, too. However, more evidence is needed. In principle, a diet that is rich fibre, colourful veggies and fermented foods may be psychobiotic as such.”
Developing and teaching nutritional therapy for mental health disorders
Ruusunen stresses that food is only one of many pillars of mental health and can complement the treatment of mental health disorders.
“Pharmacotherapy is essential for many, and many find psychotherapy and counselling indispensable. Besides the diet, other lifestyles, such as sleep, stress management and physical activity, are important. These are also discussed during an appointment with a dietitian.”
In addition to doing research, Ruusunen has also been involved in the development of nutritional therapy for people with mental health disorders, and she has been teaching it to future dietitians and nutritionists.
“It was like winning the lottery to be recruited for a newly established nutritionist position at Kuopio University Hospital right after my PhD. Working with patients has helped me to better understand people’s different circumstances and challenges of treatment, also from the perspective of research.”
“In my teaching, I aim to provide students of dietetics and nutrition with skills to address this theme. Back when I myself was a student, the nutritional challenges of people with mental health disorders, and how to solve them, were not talked about very much.”