Focus: Food in lieu of pills

Too much fat, too much sugar and not enough exercise: in developed countries, it would appear, eating makes you ill these days. Obesity, diabetes, cardiovascular diseases and cancer are on the increase and healthcare costs are running into billions. On the flipside, there is a dream: food that not only tastes nice and does you good, but can also help to prevent or cure illnesses. Food as medicine: if you believe what advertising and product declarations on yoghurts, margarines and co. tell you, this dream has already come true. Supermarket shelves are increasingly filled with food products to which health-enhancing substances have been added. Functional foods (see box on p. 34) also promise to become a multi-billion-dollar business.

Eating yourself healthy – the idea is nothing new. It was already introduced, if not exactly invented, in Switzerland over 100 years ago. In 1900 the Swiss doctor Maximilian Bircher-Benner concocted a meal that consisted of mostly uncooked oatmeal, grated apple and nuts: Bircher muesli. For many of the ailing luxury patients who flocked to his clinic on the Zürichberg, the dish initially came as quite a shock; for the new converts, however, Bircher muesli almost became a religion.

Oats as super-food

Laura Nyström, a professor at ETH Zurich’s Institute of Food, Nutrition and Health, is well aware that this raw-food diet is not everyone’s cup of tea. However, she was particularly taken with one ingredient of Bircher muesli: "We have been conducting extensive research into one of the components of oats," she explains.

The substance is called beta-glucan and is regarded as one of the plant fibres with the most promising positive effects on health. According to research, for instance, beta-glucan helps to reduce the cholesterol level, the cause of many heart diseases. Moreover, it delays the surge in the blood sugar level after a meal and enables it to decrease more slowly – good news for people at risk from diabetes and anyone who has to contend with voracious appetites and obesity. And last but not least, the plant fibres regulate digestion as roughage and could thus reduce the risk of developing bowel cancer. In short, Nyström is convinced that "Beta-glucan really is a super food component as far as boosting your health is concerned." And compared to other potential vegetable sources, oats contain an especially large amount of this super-substance – around five to eight times as much as rye, for instance.

In other words, your daily dose of Bircher muesli is not a bad idea, the researcher says. The catch is that in order for enough beta-glucan to be absorbed for you to benefit from its full range of effects, you would have to eat a lot of Bircher muesli. Moreover, much depends on how the beta-glucan is processed and prepared, and in which combinations it is absorbed. Preparatory processes such as grinding, baking and cooking have a major influence on its efficacy – "often a negative one," says Laura Nyström. "There is still a lot more detailed research to be done into how and when beta-glucan works."

Meanwhile, we know that beta-glucan needs to be soluble and to exhibit a certain molecular mass to be physiologically active. Combined with water, beta-glucan becomes viscous. Precisely this property ensures that it is unable to pass through the pores of the intestinal walls. The pores are more or less blocked as a result, meaning that less cholesterol can be absorbed via the intestine. However, beta-glucan loses its cholesterol-lowering properties and viscosity if treated with enzymes. As Laura Nyström and her colleagues discovered, oxidation processes occur during food processing, and it was feared until now that this had a primarily negative impact. Other research, however, suggests that certain forms of oxidation can also broaden the health-enhancing capabilities of beta-glucan. "This opens up a whole new research field," says the scientist.

In other words, it is worth taking a closer look at the seemingly so simple plant fibres. And that is precisely what Nyström and her team are doing. "Of course, we don’t cook up any porridge in the lab," she explains. Instead, measurements are taken in test tubes under controlled conditions. Using liquid chromatography and mass spectrometry, the scientists are trying to trace the tiniest of changes at molecular level that are responsible for particular effects – the proverbial search for the needle in a haystack. The beta-glucan molecule often consists of over 10,000 sugar units – a miniscule change here or there can make a huge difference. "And it is these very changes that we are trying to determine for sure," says Nyström. "Thanks to today’s highly sensitive methods, we can detect changes that have an impact."

Switzerland was not only a pioneer in things like Bircher muesli; the Swiss were also a driving force behind the recognition of beta-glucan as a health-enhancing additive by the European Food Safety Authority (EFSA) – here a major role was played by the Zug-based company Crea-Nutrition (which today belongs to DSM). Beta-glucan is today recognised by both EFSA and the Swiss Federal Office of Public Health (FOPH), and Swiss supermarkets have been selling corresponding products since 2012: breakfast cereals and various pastries enriched with beta-glucan. These are products that are not everyone’s cup of tea, Nyström says, but they are a great help to potential heart and/or diabetes patients or people who have already been diagnosed with such diseases. For her, eating healthily is par for the course and functional food could play a key role in this respect.

Healthy thanks to bacteria

For much longer – for over fifteen years, to be precise – consumers have been buying another form of functional food in their supermarkets: so-called probiotic food. The most well-known are yoghurts and yoghurt drinks which have been enhanced with specific bacterial cultures that can have a positive impact on one’s health. A digestive ef­fect and a boost to the immune system are just some of the promises they make. However, what is actually so different about these products compared to normal yoghurt, which is also created solely from bacterial cultures? "The products are probiotic if the bacterial cells not only survive yoghurt production and storage, but also gastric juices and digestive processes in the gut, where they take effect," explains Pro­fessor Christophe Lacroix, a specialist in functional micro­organisms. His food biotechnology group studies bacteria and fungi from food ecosystems to research their role in foodstuffs and their possible effects in the human and ani­mal gut.

Lacroix does not primarily see his specialisation in the production of functional food. "Part of our work is also to find and characterise functional microorganisms that im­prove the quality, safety and healthiness of high-quality food." Many of his microorganisms primarily help to make food safer and keep for longer.

For instance, lactobacilli and propionibacteria cultures are used to reduce the development of mould in fruit yo­ghurts or the spread of other microorganisms in cheese or sausage that affect both their quality and our health – and not just to the delight of shop-owners and consumers here in this country, either. Lacroix and his team are also study­ing the microbial composition of traditional fermented Af­rican foodstuffs to make them safer and keep for longer. After all, the road from the field to the kitchen has grown longer in Africa, too.

Complex universe of the bowel

Lacroix is convinced that probiotic bacterial cultures can also make a direct contribution towards health, but only if they are used extremely selectively. And that is easier said than done. After all, the bowel is a universe with billions of microorganisms that are in close contact with the intestinal epithelium cells and have to work together in perfect harmony in a healthy person. "Adding new elements to this universe can have unfathomable consequences."

For instance, Lacroix teamed up with Michael Zimmermann’s Human Nutrition research group at ETH Zurich to look for ways to make the source of iron safer for women and children in Africa, who often suffer from iron deficiency. For studies have revealed that the risk of suffering from diarrhoea for people in areas where diarrhoeal pathogens are more common actually increased if they were given iron supplements. Lacroix and the Human Nutrition group were the first to examine more closely the impact of iron on the microorganisms in the bowels of children in regions of Africa with different hygiene standards. In further tests, they simulated the processes in the gut systematically in the test tube, so-called in-vitro intestinal fermentation models, which they combined with cell models. Studies on rats were then conducted to investigate in more detail the effect of iron on the composition and metabolic activity of the intestinal flora, and to find out how the gut reacts to it. The researchers compared the results with the data from clinical trials conducted in the Ivory Coast, Kenya and South Africa in collaboration with the Human Nutrition group. Consequently, they were able to demonstrate that iron is also a key factor in the production of butyrate in the intestinal flora, an important nutrient for intestinal cells with many cell-regulating functions.

Together with industry, the researchers are now working on a concept as to how babies in Africa can be supplied with iron without giving pathogens a helping hand, too. A combined strategy should guarantee the necessary source of iron while boosting "good" microorganisms that keep the pathogens in check and are able to stabilise the intestinal flora, such as bifidus bacteria. "A special form of functional food, if you like," says Lacroix, "but specifically developed for a highly specified group with precisely defined effects." And it is not intended as food or part of artificial baby milk but rather a supplement to boost intestinal health during treatment with iron preparations.

"Selected probiotic bacterial strains could also be useful to prevent or treat other illnesses," says Lacroix. For instance, his team has been researching a strain of bacteria that has the potential to prevent or alleviate Clostridium difficile infections, a diarrhoeal pathogen that is especially dangerous for the elderly. And they are devising a method to prevent salmonella infections in animals by feeding them special bacteria instead of antibiotics.

The researcher sees potential in such applications. In the event of illness, he would not think twice about supporting selective therapy with specific probiotic bacteria strains if the modes of action are studied scientifically. However, he is horrified by the notion of only seeing food as a mixture of pieced-together functionalities. "Food is also a source of great pleasure!" Special food for people with particular deficiencies is necessary, such as for people with bowel diseases. However, like most healthy normal citizens with a healthy lifestyle, he personally does not really need functional food. "We have got every opportunity to eat healthy, fresh and enjoyable food and I hope that this will also con¬tinue to be the case in the future."