Professor Müller-Werdan, we are conducting this interview in the summer before the presidential elections in the USA. One candidate is 81 years old, the other 78. Is that too old for such a responsible office?
Not necessarily. Before the last presidential election four years ago, a US study asked the same question and confirmed that Joe Biden would have a statistical life expectancy of a good nine years after his inauguration in 2021 and Donald Trump a good eleven years. After analysing representative data sets, this corresponded to the survival probability of white, academically educated people of their age. At the time, Biden’s healthy lifespan was estimated at 87 years and Trump’s at just over 85 years. These are not individual predictions, but average values, and life expectancy would probably be even better today due to the higher age reached. 

Life expectancy is one thing, physical and mental fitness is another. How do you rate the candidates in this respect?
I have to pass. Even if I knew more about their state of health, I wouldn’t allow myself to make a remote diagnosis. But high professional performance is possible even in old age, and there are a number of examples of this. Just think of Konrad Adenauer, who took office as the first Chancellor of the Federal Republic of Germany at the age of 73 and only retired at the age of 87. 

When someone is so productive in old age, this is often attributed to a particularly good genetic make-up. Is that true?
Only in part. Around a third of the ageing process is genetically determined, two thirds have to do with personal lifestyle – this is how the scientific studies can be roughly summarised. We are therefore by no means at the mercy of our inherited dispositions but have a great deal of room for manoeuvre. 

If you want to grow old as healthily as possible, you will receive a lot of advice. Which are the most important?
The eight recommendations of the American Heart Association are a good guideline. If you follow them, you will be on average about six years younger biologically than your chronological age. The recommendations will sound familiar to many: a healthy diet, sufficient exercise and sleep, no tobacco consumption, no severe obesity and normal values for blood pressure, blood sugar and cholesterol. 

We have heard all this many times before, but what exactly does it mean?
Here are three examples: The US Heart Association defines adequate exercise as 150 minutes of moderate physical activity per week, such as walking, or 75 minutes of increased activity, such as jogging. The daily sleeping time should be between seven and nine hours and the body weight should be below the body mass index value of 30. 

At the GDNÄ meeting in Potsdam, you will be talking about facts and myths on the subject of healthy ageing. Which myth is particularly persistent?
The one about a healthy glass of red wine. Alcohol is a neurotoxin, even in small quantities – there’s no way around it. However, there is evidence that alcohol is more harmful to us in the first half of life, i.e. up to around forty, than later. Another myth has to do with frailty in old age, which many believe is inevitable. In my presentation, I will explain how it can be prevented and, in some cases, reversed. 

Unfortunately, it is not yet possible to reverse dementia, another disease of old age.
But a lot can be done to prevent it. More than a third of cases can be prevented or delayed, as large-scale international studies have shown in recent years. It is particularly important to avoid depression and hearing loss and to acquire education as early as possible. Alcohol, concussions and air pollution have been shown to increase the risk of dementia.

© Charité – Universitätsmedizin Berlin

In the Clinic for Geriatrics and Geriatric Medicine on the Benjamin Franklin Campus of the Charité, patients with acute internal, neurological and orthopaedic diseases are treated in the sense of early geriatric rehabilitation.

A lot of research is being carried out worldwide on the subject of ageing. Which approaches are particularly promising?
I find a field of research called geroscience very exciting. It sees ageing as the main risk factor for diseases that are not purely genetically determined, such as cardiovascular diseases and most types of cancer. The idea is to prevent these diseases by slowing down the ageing process at an early stage. So-called senescent cells offer a starting point. These are body cells that have stopped dividing at some point. They no longer function properly but are not completely dead and can damage surrounding cells. The consequences are diseases and frailty. The older the person, the more such zombie cells there are in the tissue. 

Do we stand a chance against the zombies?
We can drive them to suicide and thus halt their age-related decline. This is possible with certain active substances, so-called senolytics, as animal experiments have shown. The first clinical trials have now been carried out on patients with diseases such as pulmonary fibrosis, kidney dysfunction or diabetes. The results so far are very encouraging. 

When will the first drugs be available?
That depends entirely on the further course of the clinical trials. If nothing comes up, we may have the first drugs in fifteen or twenty years. 

Is your institute at the Charité involved in this research?
Yes, one of our research groups is working on this topic as part of translational bio-gerontology. 

What are the other research groups at the Institute working on?
We have a lot of interesting topics, but let me pick out two examples. One is the question of the extent to which diet promotes or inhibits inflammation in the body. This is important to know because many diseases and the ageing process itself are associated with inflammation. In collaboration with the German Institute of Human Nutrition in Potsdam-Rehbrücke, employees are currently developing an inflammatory index that can be used to determine the inflammatory potential of food. Another working group is looking at smart home solutions for older people to help them live longer at home. 

Finally, a myth-or-fact question: can we all live to be 150 years old or older, as is often claimed recently?
No, I don’t think so. The maximum lifespan of every species is genetically determined. In humans, it is around the age reached by the French woman Jeanne Calment, who died in 1997 at the age of 122. 122 years for women, 118 years for men – we won’t be able to break these records in the future either. But what good are such records if you are ill? I think ageing in good health is something worth striving for.

Liane G. Benning, biogeochemist, on earthshaking interfaces, microbes in the Arctic ice and her El Dorado of research. 

Professor Benning, at the next meeting of the GDNÄ you will be giving a public evening lecture entitled “The big melt: small cells, big consequences”. Why should people make a note of this date?
I will be presenting new, previously little-known findings that are important for future climate forecasts. For example, it will be about snow and ice algae and their major influence on the melting of the Greenland ice sheet, which contributes significantly to global sea level rise. So anyone who is interested in current climate research and wants to know what we as scientists in Potsdam and Berlin are contributing to this is cordially invited to my lecture.

You head the Interface Geochemistry research group at the GFZ Helmholtz Centre Potsdam. What do interfaces have to do with the climate?
I need to expand a little on that. My research group is concerned with interfacial reactions. This refers to chemical, physical and biological reactions on and in the surfaces of a wide variety of materials that characterise their shape, structure and function. Our planet owes its appearance, both large and small, to such processes, which control the cycle of carbon, nutrients and trace elements. Climate change is also a consequence of interfacial reactions. One example is the reactions between carbon dioxide and the atmosphere. Another, more indirect example is the chain reactions in the Arctic ice.

© Katie Sipes

Field research that’s fun: GFZ doctoral student Rey Mourot collects snow and ice samples in southern Greenland. The helicopter in the background is standing by for safety reasons. The weather can change quickly, in which case the work has to be cancelled immediately. The photo was taken in May 2022.

How do you record the processes in interfaces?
We combine experimental approaches and measurements in nature, for example in Greenland, with satellite images, microbial sequencing and high-resolution electron microscopy and spectroscopy imaging techniques that we are constantly developing. In this way, we can observe interactions in interfaces down to the atomic level. The realisation that algae, viruses and bacteria play a key role in climate processes is thanks to this large repertoire of methods. 

Please explain in more detail how all this is connected.
Let’s take Greenland as an example. I’m there time and again with my team to take measurements on site and take ice samples, which we analyse when we return to Potsdam. The Greenland ice is still kilometres thick, but on average one metre melts away every year and goes into the oceans. This trend has been accelerating for years. This has to do not only with increasing global warming, but also with dark areas on the ice. They reduce the so-called albedo, i.e. the reflectivity of the surface, and heat it up. For a long time, it was thought that soot or dust particles blown onto the ice were blackening it. However, we now know that naturally occurring snow and ice algae, in combination with other microorganisms, play a significant role in the darkening – and are multiplying rapidly in Greenland. In the south-western part of the island, up to 26 per cent of the albedo reduction is due to ice algae. And as part of the major EU project “Deep Purple”, we are also investigating whether special viruses may control the algal bloom and how the bloom is slowed down by tiny fungi. 

Can such findings be used to slow down climate change?
What we are doing is purely basic research. We are not involved in measures to mitigate the effects of climate change. I also believe that bioengineering or geoengineering on the basis of previous research findings is premature because we still know far too little about the overall system. Individual interventions can cause great damage, so we have to be very careful. 

Is the new knowledge about algae and co. already being incorporated into climate forecasts?
In the last Intergovernmental Panel on Climate Change report from 2023, the contribution of algae was already mentioned, but bio-albedo is not yet included in the predictions. I am confident that the next assessment report will go into more detail about the effect.

© Katie Sipes

Liane G Benning and her doctoral student Rey Mourot in front of a snowfield in southern Greenland. You can clearly see how green, yellowish and red snow algae proliferate here.

You have been working in this specialised field for a long time. How did this come about?
I’ve actually always been fascinated by processes in the environment. I first studied mineralogy in Kiel and continued my studies at the ETH in Zurich, where I made geochemical reactions the subject of my doctorate. This was followed by academic posts in the USA and the UK, and over time I realised that I couldn’t make any scientific progress without biology. So I familiarised myself with the subject, especially genetics, and eventually I became a biogeochemist. 

You spent 17 years at the University of Leeds before moving to Potsdam and Berlin. How did you experience the change?
Coming back to Germany was a bit of a culture shock. In everyday life, I first had to get used to the rustic manners in Berlin and Brandenburg – things are a bit more polite in England. And then there’s the excessive bureaucracy with which the Germans torment themselves and others. The British – especially at universities – often work much more efficiently, so we can learn a lot from them. 

You’ve now been in the region for ten years and hopefully you’ve discovered some positive things.
A lot of positive things, in fact. Scientifically, I have fantastic opportunities here. If I need a modern, expensive measuring device for my research, I can almost always find it in the region –  be it at another Helmholtz Institute, at facilities of the Max Planck Society or at the Federal Institute for Materials Testing. And, just as importantly, my colleagues are highly competent, helpful and open to co-operation. For example, the collaboration with Thomas Leya from the Fraunhofer Institute for Cell Therapy and Immunology in Potsdam is brilliant. His biobank contains a wonderful snow algae culture that is ideal for comparisons with our ice algae. We were able to benefit greatly from the expertise of our Fraunhofer colleagues when setting up our culture. All in all, I couldn’t wish for a better environment for my research. 

Berlin-Brandenburg, an El Dorado for geoscientists?
I can agree with that. 

Then you probably have few problems attracting good young people to your team?
When we advertise a position, we receive applications from all over the world. That was the case again just now for a junior scientist position. But we didn’t find what we were looking for, the applications simply weren’t good enough. For some it was the incomplete documents, for others it was the narrow qualifications that were not sufficient for our interdisciplinary tasks. Some applicants just want to test their chances and are not serious. So it’s not that easy for us. 

How do you solve the problem?
In this specific case, we are now re-advertising the position with more precise criteria. I’m also sending the advert to colleagues I know around the world. Personal recommendations are very valuable. I also try to attract good young people from my degree programme at the FU Berlin to the GFZ: for an internship or for their final thesis. If it goes well, it can turn into a job. I also say this to the student interns from Potsdam who have been with us in recent years. My team has been great at dealing with their questions and requests and we are always happy to take on new interns from the region.