Humboldtians in Focus

You Are What You Eat

By Stefanie Schramm

Eating and sex are controlled by the same regions of the brain, the neurobiologist and brand new Humboldt Professor Tamas Horvath has discovered. His research could help to combat diseases like Parkinson’s.

Foto: Bill Cramer

Green salad with lean duck breast and mineral water. That is all Tamas Horvath has ordered. “The brain works better if you eat less,” says the professor of neurobiology. “We’ve tried it out on mice.” Horvath himself does not look as though he has taken this to heart. Yes, of course, he assures me, during the day he sticks to his own recommendations. But when the working day comes to an end, he leaves science behind: “When I get home in the evening, I really tuck in.”p>

Horvath researches into the ways our eating behaviour affects the workings of the brain and vice versa at the elite US university Yale. “If you want to understand our thinking, there’s no point beginning with the cerebrum. You have to look at the really old parts of the brain,” he says. And they deal with precisely two things: eating and sex. Back in the early 1990s, Horvath was one of the first to suggest that our desire for steak and chocolate is controlled by hormones and, indeed, hormones that reside in the same part of the brain that regulates ovulation. A daring thesis. And a correct one as it turned out.

“His idea that the same part of the brain controls reproduction and food intake was revolutionary,” comments Jens Brüning, coordinator of the Cluster of Excellence on ageing research at the University of Cologne. “Tamas Horvath is a world-leader in research in this field.” And now he is coming to Germany. The head of section at Yale has been awarded an Alexander von Humboldt Professorship.

New therapies for overweight townies

Horvath will soon start work in Cologne. The resident gerontology researchers hope that the neurobiologist will drive forward their investigations into metabolic disorders like diabetes and obesity which increase with age. His work could lead to new therapies for one of the biggest health issues in industrialised countries: excess pounds.

In addition, the award winner is supposed to help combat geriatric diseases like Parkinson’s. “He has discovered completely new mechanisms underlying the emergence of neurodegenerative diseases,” Brüning comments. Horvath had been the first to demonstrate that a particular protein, which was actually responsible for energy conversion, also played a key role in keeping brain cells alive – metabolism and a sound brain are related. This could be a starting point for new medicines.

“If you simply switch off interest in food, first you get thin, then stupid, then dead.”

The Cologne-Bonn region is in the process of becoming a major centre for ageing research. “Academically, Cologne is a much better location for me than Yale,” Horvath notes. Born in Hungary, he and his Italian wife, who researches in the same field, had often thought of moving back to Europe. Then came the Humboldt Professorship and now Horvath is on his way. “It’s an outstanding offer. The Excellence Initiative has already shown that Germany wants to do things differently than most of the other European countries,” he believes. By establishing the Clusters of Excellence the universities had tried to create an attractive environment for researchers from all over the world. And Horvath is in a position to judge: he did, after all, advise the Cologne Cluster on the selection of researchers.

The 42 year-old moved to New Haven 19 years ago and stayed. “Apparently I’m not the type to keep moving,” Horvath says. When he left Hungary for the United States he had one main ambition: to flee his job as a vet. His father and grandfather had been vets so he had initially studied veterinary medicine, too. “But, actually, I wasn’t really that interested in animals, apart from eating them, of course,” he comments and laughs out loud.

Foto: Humboldt Foundation

When a friend of his veterinary professor at Yale University was looking for staff , Horvath grabbed the opportunity. He ended up in a working group investigating the part of the brain that regulates ovulation. So it was coincidence that brought him together with the people with whom he was soon to formulate his daring thesis on the connection between eating and sex. But everyone made that connection at some stage, the researcher comments: “When you fall in love, you lose weight. When the relationship cools down, you put it back on again."

Finally, molecular biologist Jeffrey Friedman confirmed the hypothesis. He discovered the hormone leptin which docks onto the same area of the brain, the hypothalamus, and curbs the appetite. A breakthrough, not least for Horvath. He changed from reproduction to nutrition research.

Self-experiments for the sake of science

The neurobiologist considers the last salad leaf on his plate. “I keep trying to lose weight but apparently I still eat too much,” he says. When he cooks himself he chooses hearty Hungarian dishes: “With lots of meat, very unhealthy.” How much easier it would all be if you could reduce your desire for burgers, chips and pizza! The professor has tried it out – on mice. He deactivated one of the genes that is important for reproducing mitochondria – the building blocks that deliver energy to the cells, i.e. also to the brain cells responsible for appetite. It was supposed to take the kick out of eating. And it worked. “But it took the kick out of everything else, too. They just sat around dully and died earlier,” Horvath explains. It is risky to meddle with appetite regulators in the brain: “If you simply switch off interest in food, first you get thin, then stupid, then dead.”

Even so, Horvath is still taken with the idea of optimising the metabolism because it does not only influence our waist measurements but life expectancy, too. The professor experiments on mice, rats and apes in the laboratory – and at home on himself. “I’ve tried all the dietary supplement pills. I simply wanted to know how you achieve the best cell metabolism."

“Horvath has discovered completely new mechanisms underlying the emergence of neurodegenerative diseases.”

The supermarket is a good location for explaining Horvath’s research which he likes to demonstrate at his usual discounter. He marches straight past all the cleaning agents to the shelves with pill bottles and takes down the largest box: “Fish oil with omega-3 fatty acids. That protects the cells from metabolic waste products. We’ve done scientific investigations on this effect as well.” When energy is converted in the mitochondria, free radicals are produced which harm the cells and allow the body to age or encourage cancer. “The fatty acids help the mitochondria to multiply. They then produce fewer free radicals overall because the individual power station doesn’t have to keep working flat out."

Horvath continues shuffling though the shelves of pills looking for the perfect metabolic mixture. “Here you are, coenzyme Q10, that’s a super combination, you can go really hyper on those,” he says and holds the box next to the jar with the fish oil capsules. If he were looking into a television camera you would think you were watching an American infomercial. “They help the mitochondria to convert the food into energy and remove free radicals."

As neurodegenerative diseases like Parkinson’s only occur in old age they must have something to do with deterioration caused by metabolic waste. If we were able to dispose of the waste without causing harm this might be a way of addressing geriatric diseases. But it is not as easy as all that. Free radicals play an important role in energy conversion in the body, we cannot do without them altogether. The professor himself certainly did not benefit from the supermarket pill treatment, on the contrary: “I got side-effects, my heart started beating faster, so I stopped taking them."

At the Cologne Cluster of Excellence Horvath wants to continue investigating what it is that harms cells, particularly those in the brain. But he accepts that he will not find a panacea for ageing any more than he has for obesity, and not just since his self-experiments. “There aren’t going to be any pills against it. So far, the only thing that helps is moderation,” he preaches, and grins.

The hypothalamus controls elementary life functions such as nutritional intake and sleep needs.
The hypothalamus controls
elementary life functions
such as nutritional intake
and sleep needs.
Foto: Humboldt Foundation

And that would not be easy in Cologne, Horvath realised during his first visits. Together with his wife he has not only looked at the research institute, potential residential areas and the English School for his children but the local watering holes, too. “You get one beer put in front of you after the other. You don’t have any choice,” he explains after his test visit to the brewery. “I also tried this enormous piece of pork, ‘Hämmchen’ or whatever it’s called."

Once he has arrived in Cologne, however, the professor has another problem to solve: He needs a dog. “I promised my son one when we moved,” he explains and looks rather distressed. Of all things, the former vet has a dog allergy. Soon Horvath will be moving to Germany with his family. Then he will have to get a dog. Maybe it will finally help him to lose a few pounds.

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Stefanie Schramm Stefanie Schramm

Stefanie Schramm is a freelance science and technology journalist. She focuses on the fields of energy, climate and the environment and writes for newspapers such as Die Zeit, Zeit Wissen, Frankfurter Allgemeine Zeitung and Frankfurter Allgemeine Sonntagszeitung.

This piece is a slightly modified version of an article by Stefanie Schramm that appeared in “Zeit Wissen” (02/2009).

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