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University of Basel

When fever shuts down the appetite.

Text: Michelle Isler

The negative impact of malnutrition on the course of an illness has been well known in hospitals for a long time. Yet surprisingly few scientific studies have examined the effects of nutritional medicine to date. A recent survey of 2,000 patients is among the first of its kind.

Tray with meal in a hospital. (Image: Cantonal Hospital Aarau)
Up to a third of hospitalized patients suffering from chronic illnesses are at risk of malnutrition. (Image: Cantonal Hospital Aarau)

T uberculosis used to be known as consumption, while the unintended
weight loss often associated with Aids is referred to as “wasting”. Both terms allude to the loss of appetite caused by chronic illnesses of this kind. Even the fever that comes with a severe case of flu can have the effect of suppressing
appetite. For fundamentally healthy people, this is not a cause for
concern, but in patients suffering from chronic illnesses the resulting weight
loss can be life-threatening.

Defensive reaction

“Up to a third of our hospitalized patients suffering from chronic illnesses are at risk of malnutrition,” reports Professor Philipp Schuetz, an SNSF professor at the University of Basel and Head of Internal Medicine and Emergency Medicine at Kantonsspital Aarau. He is also well aware that malnutrition is closely linked to the risk of mortality among those affected. “This has actually
been known for an extremely long time – as far back as Hippocrates!”

This loss of appetite can be explained in biological terms: The body initiates an inflammatory response to fight the disease, breaking down proteins in the body that no longer function properly. Furthermore, to expedite the process of cell detoxification, the body shies away from food intake: Patients lose their appetite. Although this is not a new finding, Schuetz is among the first researchers to examine the role of nutritional medicine in a large-scale study.

“Like a faith war”

Physicians have yet to agree on whether – and how – to deal with appetite loss in hospitalized patients, Schuetz explains. While there have been some indications that tailored nutrition strategies can improve patients’ condition, evidence-based studies are lacking, he says. The result is that debate on the issue has turned into something of a faith war. According to Schuetz, some experts believe that the best approach is to concentrate on treating the underlying illnesses, upon which the patient’s appetite would return of its accord, while others argue that nutrition plays a crucial role in the healing process, and should therefore be the primary focus. On the other hand, in the last few years in particular physicians have come to realize that an excess of additional calories can cause a substantial deterioration, particularly among acutely ill patients in intensive care. “It is a contradictory situation overall,” Schuetz concludes. “Fundamentally, people need more calories when they are ill, as the body needs more energy to recover. At the same time, however, it shuns food, which seems paradoxical.”

A complex – and not very profitable – issue

Does this complexity explain the scarcity of large-scale studies? “Nutrition is a complex and highly specific area,” Schuetz replies. However, he believes other factors are at play too – not least among them funding. “Research is invariably expensive, and the pharmaceutical industry is obviously not going to be very interested in studies about food that don’t lead to patents and  expensive products. Nutrition is often regarded as a complement to therapy, not a form of therapy in its own right.”

The results of Schuetz’s study could now mark the beginning of a shift in mindset. By examining data from around 2,000 subjects, he succeeded in showing that tailored nutrition has a beneficial impact on chronically ill patients in hospital. “The study was very well received in expert circles,” he reports. In concrete terms, it showed that malnutrition is a modifiable factor in the course of an illness. In other words, “the study taught us that tailored nutrition strategies are an effective tool to combat dangerous weight loss and some of the associated complications and mortality.”

Inflammation as a key factor

Since the study, Schuetz has gone a step further with his research: “We asked ourselves whether there might be subgroups within the study that responded particularly well to nutrition therapy,” he explains. His conclusion was that not all patients benefit equally from tailored nutrition. “For those with very high levels of inflammation, this form of treatment didn’t help much. Meanwhile, we observed significant positive effects among patients in which inflammation was less severe, or had already subsided.”

These results might also explain why earlier studies yielded partially contradictory results, as they failed to take this distinction into account. In any case, Schuetz is quite certain that inflammation is one of the primary factors influencing the effectiveness of nutrition therapy. He hopes that his results will ultimately lead to increased acceptance for therapy based on tailored nutrition, and help it to become more widely established. “Of course, it is also a question of resources,” the physician points out, “which makes it all the more important to know whom this kind of therapy can benefit.”

Empowering patients

The therapeutic approach studied by Schuetz has a key advantage: It does not involve medication. He explains that his patients often ask what steps they can take to support their recovery. Their options are not limited to popping pills: “Nutrition is something that patients can take charge of themselves,” he explains, adding that it is also a way for relatives to become involved in the healing process.

Schuetz predicts that “the problem of malnutrition is likely to become more serious as society ages.” Considering that we have known about it for thousands of years, and the fact that food is a relatively simple matter, we know remarkably little about it, he observes. Accordingly, he believes that nutrition therapy has a great deal of untapped potential for dealing with deficiency symptoms. “Once we have a better understanding of how this therapy works, we can even apply it preventively – before weight loss sets in. After all: An ounce of prevention is worth a pound of cure.”

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