Factchecker: 'De Belg is steeds minder resistent tegen bacteriën'

‘Belg is steeds minder resistent tegen bacteriën’

Jan Jagers Uit Knack van 16/08/17

Ondernemer Kurt Van Tendeloo (Hygieia), Gazet van Antwerpen

De afgelopen weken hadden opvallend veel jongeren op bivak te kampen met maag- en darmproblemen. ‘In deze periode woekeren bacteriën meer dan anders’, zei Kurt Van Tendeloo daarover in Gazet van Antwerpen. Zijn bedrijf Hygieia geeft advies over voedselveiligheid en allergenenbeheer, en gaf dat ook al aan jeugdverenigingen specifiek voor op kamp, lazen we in de krant. ‘De dioxinecrisis heeft van België een land met extreme aandacht voor voedselveiligheid gemaakt’, zei Van Tendeloo. ‘Positief, maar hierdoor is de Belg minder resistent geworden omdat we zo weinig met bacteriën in aanraking komen. Vroeger werden kinderen ook ziek op kamp, maar niet met twintig tegelijk.’

Dat ons overmatig antibioticagebruik bacteriën doet muteren waardoor die geneesmiddelen almaar minder goed werken, is een gekend probleem. Wat Van Tendeloo zegt, gaat evenwel niet over antibioticaresistentie, maar over ons immuunsysteem. Is de ‘Belg steeds minder resistent tegen bacteriën’, zoals Gazet van Antwerpen kopte? Waarop steunt die uitspraak?

‘Niet op wetenschap’, zegt aan de telefoon Van Tendeloo, die kok is van opleiding. ‘Maar ik sta al meer dan twintig jaar in het vak, in grootkeukens, en zetel met actuele kennis van zaken in commissies die de voedselveiligheid daar bewaken. Voedselveiligheid is van levensbelang, in het bijzonder bij kwetsbare groepen zoals kinderen of senioren. Maar de appel die vroeger thuis op de grond viel, werd afgewassen en toch opgegeten. Vandaag niet meer. En dat breekt ons zuur op.’

Leert dat ook de wetenschap? We komen inderdaad minder in aanraking met bacteriën en allergenen, allerhande stoffen en microben die ons afweersysteem prikkelen, zegt viroloog Marc Van Ranst (KU Leuven). ‘Het aantal keizersneden is gestegen, moeders geven meer flessenvoeding dan vroeger, en we groeien meer op in stadsomgevingen dan op de boerderij’, zegt hij. ‘Het aantal allergieën is de afgelopen twintig jaar verdubbeld. Dat verklaren een aantal wetenschappers – er is discussie – met de zogeheten hygiënehypothese, die zegt dat contact met allergenen in onze jeugd cruciaal is, om later allergieën te voorkomen.’ Maar een maagdarminfectie is geen allergie, beklemtoont Van Ranst. ‘Vandaag halen die opgebroken jeugdkampen de media, maar niets wijst erop dat er meer incidenten zouden zijn dan vroeger. Die jongeren zijn hoogstwaarschijnlijk geteisterd door een norovirus. Een derde van alle mensen is daartegen genetisch resistent, twee derde wordt er ziek van. Dat is de grootte van zo’n epidemie als je die z’n gang laat gaan. Honderd jaar geleden was dat zo. En dat is vandaag niet anders.’

We zijn meer gevaccineerd tegen aandoeningen waaraan kinderen vroeger stierven – denk aan polio, mazelen, rode hond – en in die zin net weerbaarder, voert Van Ranst nog aan.

Maar ook als we die kinderziektes buiten beschouwing laten, is er meer tegen dan voor Van Tendeloo’s claim. ‘Het aantal bacteriële doden stijgt niet’, zegt immunoloog Adrian Liston (KU Leuven). ‘Wel is er een verschuiving bezig. Het klopt dat ons afweersysteem het moeilijk heeft met uitdagingen die het niet vaak tegenkomt. Aangezien we almaar meer in steden wonen en minder op het platteland, worden we gemiddeld minder goed in het neerslaan van rurale infecties – tegen grondbacteriën zoals Legionella, bijvoorbeeld – en beter in het afweren van infecties die mensen op elkaar overdragen. Maar in slotsom zijn we sterker dan ooit tevoren.’

Conclusie:

Omdat we volgens wetenschappers geen systematisch probleem hebben met neerslaan van bacteriën, beoordeelt Knack de stelling als grotendeels onwaar.  

Congratulations Dr Franckaert!

Congratulations to Dr Dean Franckaert, for successfully defending his PhD! Dean has been in the lab almost since the start, first as a job student running genotyping PCRs, then a Masters student and finally a PhD. We will surely miss such an amazing scientist, and amazing person, in our lab.

Journal club: smell drives obesity

A fascinating study has just come out in Cell Metabolism. Two groups looked at the role of the sense of smell in altering metabolism.

In one set of experiments, mice were depleted of their sense of smell and then put on a high-fat diet. Unlike their smelling-competent peers, the smelling-defective mice did not put on as much weight. In fact, if mice were first made obese, removing the sense of smell resulted in weight loss. This was not due to altered food consumption, which was equal in both mouse strains. 

In a second set of experiments, a strain of mice were generated which were "super-sniffers", with an enhanced ability to smell. When these mice were put on a high fat diet, they gained weight at a faster level then their wildtype siblings, the reverse effect of knocking out the sense of smell. Again, this was not due to any change in the amount of food eaten - the conclusion is that smelling fatty foods acts in an independent circuit to eating fatty foods, and reprogrammes the adipocytes into a high storage setting.

These studies should be the end of the silly "physics model" of obesity, which postulates that humans are essentially perfect machines where weight is driven only by calories in (diet) and calories out (exercise). This model has been proven over and over again to be incorrect in essentially every aspect. Adipose tissue is not an inert storage for extra calories, it is an active tissue that can be programmed and reprogrammed to increase or decrease. This adipocyte program is altered by genetics, epigenetics, microbiomics, immunology and the environment, as well as the diet and exercise postulated in the physics model. Unfortunately I doubt very much that this study, or future studies, will throw off the allure of the "physics model" to replace it with a biological model - victim blaming is too well entrenched in both the public and medical spheres.

Read the paper here: Riera et al, "The sense of smell impacts metabolic health and obesity", Cell Metabolism 2017. 26(1) p198.

Quote of the week

Research hall of fame

"Hey, whatever happened to that really good tech you had?"

"Sad story, really, she got married".

Getting married as a woman in the 1940s - literally equivalent to career death.

Oxford sabbatical

Thanks to the Guy Newton Research Fund I am currently enjoying a sabbatical at the Sir William Dunn School of Pathology, which today hosted an exceptional graduate school symposium. An impressive job by the PhD students here!

Congratulations to Dr Emanuela Pasciuto

Dr Emanuela Pasciuto was successful in obtaining a highly competitive FWO post-doctoral fellowship to continue her neuroimmunology research in our laboratory.

She is a wonderful role model as a young mother who is a highly successful scientist. Congratulations Manu!

Good luck to our Masters class of 2017!

Work-life balance interview

The interview below was with Jorg Stange, the manager of the "equality4success" program at the Babraham Institute.

Why did you want to achieve a good work-life balance?

I don’t really think that I have achieved a good work-life balance. I work a lot more than I probably should, and I don’t have much time or hobbies or the like. I would love to have the time to learn a language and spend every weekend and evening work-free. On the other hand, I really like my work. Working 9 to 5 doesn’t sound appealing to me, and I don’t really make an attempt to firewall work and life.

The one place where I would say that I achieved a good work-life balance was in parenting duties. Many fathers automatically step into the part-time parenting role, happy for the mother to take most of the parenting duties. For me this is ideologically incompatible with having an equal relationship. I am a passionate feminist, so I actively seek not to replicate the typical mistakes of fatherhood. Equality in my relationship with my wife is a must, and I want to be a good example to my son.

But that doesn’t mean I have work-life balance – sometimes I have too much work AND too much parenting. When decisions on priority need to be made, I make sure that the most important facets of life come first, but the less important parts of both work and life sometimes get sacrificed.

Why do you think you have achieved a good WLB?

To the extent that I have, it is because I have amazing people in my life. My wife is an inspiring example of being successful at both work and at home, the people I work with are both amazing colleagues and wonderful friends. It is the support network for when things get tough that is most important. The other really important trick is being able to say no. Sometimes that means saying no to parts of work that are not critical (to keep up the parts that are most important), sometimes it means choosing to say no to parts of home life that are less important (but always preserving the important moments).

What actions did you take to maintain / improve WLB?

The big decisions need to always include both work and life. Where will you live on both the macro (which country/city) and micro (neighbourhood) needs to consider both aspects. Does the country have good healthcare and parental support? Will that city provide good career options for both people, or is someone going to become a trailing spouse? Does this neighbourhood provide an easy way to enjoy weekends, and a minimal commute during the week? If you make the big decisions deliberately friendly to both work and life, then the everyday decisions tend to fall in the right direction. For example, when I was working in the US, everyone around me worked late every evening and the lab was full every weekend. I had to make an effort to notice the time and leave before everyone else just to be home before 10pm. In Belgium, if I leave at 7pm I am often one of the last in the building: one work environment promotes long hours, the other discourages it.

What was the rationale behind these decisions?

I only see one good reason for life choices: being happy. My ideal work-life balance is going to be different from someone else’s. You would think that optimal happiness is something that we automatically drift towards, but actually (for me at least, and, I suspect, many others) it takes an awareness and an effort to arrange your life to be happy.

How did the working environment (attitudes of leaders and colleagues, policies in place, general culture, etc.) impact on your plans to achieve a better WLB?

Like many research institutes, my institute is a negative impact on work-life balance. Pressure is high, and I suspect it is physically impossible to achieve the required objectives within a normal working week. To do anything other than put work first constantly is to be an outlier.

On the other hand, Belgium as a country is very positive on my work-life balance. The culture is generally built around assumptions of normal working hours, and we picked key aspects of our life (where we life, where we work, where our son goes to school) to make healthy choices easier. Doesn’t mean that we always make them, but to a certain extent it counteracts the work pressure.

What support did you receive (from employer / national system / family)?        

The Belgian system is very good for young families – full day crèche from three months of age, great support from in-home nurse care during days when the child is sick, high quality schools everywhere so we can pick based on convenience and not feel guilty.

From my family, my wife and I took equal parenting very seriously, and so we both sacrificed either personal time or work success at various points. Our extended family are in Australia, so we were entirely reliant on each other and external support.

How did you benefit professionally from your solution to integrate life and work (e.g. increased motivation / creativity / focus)?

When I delegated work tasks to senior people in my laboratory, they stepped up to a much higher level than I expected, and things were soon being done better than I had been doing! When you give the right person responsibility you can be very pleasantly surprised, and they also get an opportunity to grow that they otherwise might not have.

How have your decisions for achieving WLB impacted on your career progression?

In the short term, it has probably been mildly negative. There are certainly meetings I should have attended that I didn’t, dinner that would have been good for my career that I skipped, grants I might have got that I didn’t write. On the other hand, I kept up all the really important career goals, so my career has been advancing better than I could have asked for. I certainly don't regret my choices for work-life-balance.

Journal club: the origin of menopause

Menopause is, at face value, evolutionarily perplexing. Why select for the inability to breed, considering natural selection works only on the success of having offspring? Despite several claims, menopause is actually exceptionally rare - only humans and resident orcas (killer whales) have a systematic post-reproductive menopause state. It is rather hard to dissect the why in humans, but this study gives a good explanation of the demographic situation needed to evolve menopause. In short:

* Demographic situations where the offspring of mothers and daughters are in competition, plus where the offspring of daughters have an advantage (if the offspring of mothers have an advantage, breeding suppression in the young is observed)

* Social groups where the "grandmother" effect can aid the survival of the group (food sharing)

The implication is that these were key factors during human evolution, which would have molded our behaviour as well as our biology to maximise fitness.