What do you eat for your vagina?
By Isabel Erreygers, University of Antwerp
Imagine you can keep your vaginal microbes happy by ‘eating healthy’. It sounds like a peculiar thought, no? However, recent data suggest some potential truth to that, so this thought does not fully come out of the blue. Every day, a wealth of dietary and nutritional advice to maintain a 'healthy' gut microbiome is available to women. On the contrary, much less is known about the link between nutrition and the vaginal ecosystem. In my research, I refer to this as the gut-vagina axis: vaginal health starts, at least partially, on our plates. Moreover, it is probably mediated via the gut and the gut microbiome. Currently, with our Isala project (https://isala.be/en/), we are trying to bridge the knowledge gaps on the gut-vagina-axis, by mapping the impact of dietary habits and other lifestyle and environmental factors on the vaginal microbiome of healthy women in Belgium and beyond. 😊
This Isala project was launched in March 2020 as a citizen-science project by the team of Prof. Sarah Lebeer (head of the Lab of Applied Microbiology and Biotechnology and academic board member of ISAPP) with the overarching goal of better understanding the vaginal microbiome of women outside the hospital. The call for participation set up and lead by Prof. Sarah Lebeer, Dr. Sarah Ahannach and Dr. Eline Oerlemans and other Isala team members was followed by overwhelming enthusiasm, with more than 3345 women providing a vaginal swab. In the survey data answered by these women, it became evident that women are eager to know more about their vaginal microbiome. Not too surprising since the vagina has a crucial role in their general and sexual health, reproduction, and overall well-being. Women are interested in more knowledge and evidence-based lifestyle and dietary advice. When visiting their general practitioner or gynaecologist with specific vaginal complaints, women do not always want or need an antibiotic or antimycotic treatment. These survey data and feedback provided by the Isala participants formed an important inspiration for the project to generate scientific data and design experiments that can ultimately result in advice on what women can do themselves to prevent vaginal complaints by beneficially modulating their vaginal microbiome, including how they are filling their plates.
As a first step, the Isala team decided to look for associations between lifestyle, life course, environment, and diet in the Isala surveys on the one hand and the vaginal microbiome profiles of the participants on the other hand. This analysis needed months of complex statistical analyses, but revealed that dietary habits do influence the vaginal microbiome composition, in a modest but statistically significant way. What appears daily on your plate can have an impact on the community of bacteria living together in your vagina and I am very happy to further explore this during my PhD.
Figure 1: Infographic of the large-scale citizen-science project Isala of the team of Prof. Sarah Lebeer. Major topics related to women’s health that are worth further exploration (according to participants) are shown, including the impact of lifestyle and diet.
In more detail, several significant associations between the consumption of certain food products and the vaginal microbiome composition of the Isala participants were found. First, it should be noted that 43.2% of the participating women had a vaginal microbiome that was dominated by Lactobacillus crispatus. This bacterium is best documented with a healthy vaginal environment because of its extensive lactic acid production and low inflammatory potential. These factors, among others, protect against certain invading pathogenic microorganisms and infections and inflammation. Although these lactic acid bacteria may be invisible to the naked eye, I do not question their beneficial effect on both your and my health. But why am I telling this information? Well, join me for a walk through our results. 😊
On the one hand, consuming sugary beverages, such as soda and fruit juice, appeared to have a negative impact on L. crispatus and the co-occurring taxa Limosilactobacillus and Lactobacillus jensenii. As mentioned above, such a drop in L. crispatus is not great news since this bacterium is mostly associated with a healthy vaginal ecosystem. Our Isala team has found the same trend for L. crispatus and meat consumption, while noticing an increase in the presence of Prevotella in that case. Prevotella generally produces limited amounts of lactic acid and is associated with irritation and (chronic) inflammation in literature, so its presence is considered less beneficial. Now that I am talking about meat, you may wonder about the situation for fish. Women solely eating fish (as part of a certain lifestyle including a pescatarian diet) seemed to have more L. crispatus and related bacteria. Moreover, eating a lot of vegetables also seems to be associated with an increase in L. crispatus, possibly due to the fibres present in these vegetables. This is also a very cool finding: imagine that prebiotics and fibres benefit not only your gut but also your vagina. 😊
Figure 2: What appears daily on your plate seems to have an impact on your vaginal microbiome. I am happy to explore this further with the entire Isala team.
Why am I so careful in the vocabulary I use? Because all of these associations do not (yet) mean that you can really change your vaginal microbiome through food consumption. Hereto, we would need to do dietary intervention studies in sufficiently large cohorts and study the vaginal microbiome before, during and after the intervention, while keeping all other lifestyle factors constant. Needless to say, such intervention studies are complex and expensive. We are currently planning such trials but need to prioritise and look for funding. 😊
Therefore, we have thought of other ways to study the possible existence of a food-gut-vagina axis. One thing I am currently working on is looking for food-derived metabolites in the vaginal metabolomic profiles we determined together with our fantastic colleagues of EMBL (Dr. Michael Zimmermann & Dr. Denise Medeiros Selegato). Surprisingly, we could already detect way more signals from food origin than expected. For example, we could detect theobromine, a metabolite associated with chocolate consumption. These findings suggest that food compounds do not only impact the vaginal microbiome indirectly but could also end up in the vaginal environment via a food-gut-vagina axis, although we currently do not exactly know how. Still, a lot of fascinating things to explore which makes me really excited. 😊
In conclusion, this was a short trip to illustrate the importance of nutrition and diet in vaginal microbiome research, but we certainly have not landed yet. Once again, we are faced with numerous challenges in and outside the lab and we are far from having a bellyful. Luckily! 😉 Altogether, the results mentioned above create a future perspective on improving vaginal health through (personalized) dietary advice, thereby empowering women to take their health into their own hands!