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You are here: MEDICA Portal. Magazine & More. MEDICA Magazine. Topic of the Month. Volume archives. Our Topics in 2010. August 2010: Of the Stomach and Gut. Physicians.

“Our Body is Not Prepared for the Diet of Today“

“Our Body is Not Prepared for the Diet of Today“

Photo: Professor Hauner asked Professor Hans Hauner, director of the Chair for Nutritional Medicine at the Science Center Weihenstephan and the Else Kröner-Fresenius-Center at the Technical University Munich, how our digestive system reacts to these chemical substances. Professor Hauner, the gastrointestinal tract controls thousands of chemical substances and differentiates between toxins and nutrients. It works very hard for many years, because many unhealthy splurges like for instance schnitzels or French fries need to be digested. How do both of these organs withstand these burdens?

Hans Hauner: Today we are living in a time of chronic excess nutrition. Our organism is not really prepared for this kind of diet. Our metabolism and our digestive system have formed over thousands of years and have adjusted to what was usable or edible. These were primarily plant- or animal foods, which provided energy. Human beings thus are designed to eat vegetables and lean meat. Today many products are very rich. If they are consumed in large amounts, it stresses organs and also the gastrointestinal tract. But there is a large reserve capacity here, which means: The bowels can process larger meals, because it has always been crucial for survival.

A second point is: Today increasingly new chemical substances are produced and end up in the food chain in different ways. Most notably plastic materials present a real problem, albeit less for the intestinal tract, but more for the body’s hormonal system – they are called “endocrine disrupters“ and can impair the hormonal system of the body. Unfortunately we know far too little on what this means in individual cases for a person’s health. Of course food production should preferably always stay away from foreign substances. Many substances, especially the fat-soluble ones, accumulate in the body and sometimes are stored a long time in the fat tissue or also in other organs with uncertain consequences for your health. Are the stomach and bowels designed for country-specific eating habits?

Hauner: The human intestinal tract, irrespective of its ethnical affiliation and eating conditions, produces every digestion movement which is determined in the human genome– thus these are the same for everybody. The function of alimetary organs certainly also adapts to what is needed. This is probably somewhat different for each person, depending on genetic variability. Modern food chemistry uses many tricks to make foods look more appetizing, colorful and versatile. This often happens by using dyes. How does this agree with the stomach and the gut?

Hauner: Knowledge about this issue is also limited. Not everything that reaches the intestinal tract is ingested. The metabolic degradation of many dyes is also little known. Currently about 40 of these food colors are approved in the European Union and must be stated at their application. The possible risks for human beings are sparsely researched, but there is some evidence that some trigger allergies. Azoic dyes in foods have been linked to hyperactivity and attention deficits in children. That is why this is important: As a general principle use dyes as sparingly as possible. Aside from dyes there is an endless number of additives, preservatives, flavoring agents and thickening agents in several foods, especially in convenience products. What can these do to a delicate digestive system?

Hauner: We often discover that many people have food sensitivities – frequently concerning convenience foods. It is difficult though to establish a clear connection, because our foods are very complex. There are always hundreds of possibilities, to which discomfort can be attributed to. To identify reasons, you would need to do an elimination diet, where you consequently eliminate foods and then gradually reintroduce individual foods. In fact, food sensitivities have increased during the past few years, but it is questionable whether this alone is a result of modern food production, since at the same time certainly also the sensitivity for such issues has increased with consumers and consumer protection. What should you pay attention to in case you are food intolerant?

Hauner: Just like with classical food allergies that are for instance often seen in children and pertain to eggs or nuts, you should systematically omit these foods. In the case of non-specific food sensitivities, which are not exactly diagnostically classifiable, it is advisable to eat a natural diet. Whenever possible, food should be self prepared and convenience products with many additives should be avoided as much as possible.

Photo: Fruit market 
Vegetable and low-fat food not
only treat the gastrointestinal tract
with care©Thomas Weiss/ Is there a connection between the increasing use of chemical additives in foods and the rising frequency of reflux diseases, which already over 20 percent of the Western population is afflicted with?

Hauner: I would negate that. The connection in this instance is somewhere else: In reflux diseases excess weight plays an important role, because excess fat tissue is pushing the diaphragm strongly upwards. This changes the anatomy and triggers a compression effect. Reflux disease in general is for instance more common in overweight people than in a slim person, who eats a more balanced diet. Probiotics, especially the much advertised probiotic yoghurts, are another phenomenon of a supposedly healthy diet. They say that these help to remove pathogenic bacteria from the gut. Other studies in fact point out a long-term destruction of the intestinal flora. Which one is correct?

Hauner: The question is whether you can really significantly influence the microflora of a healthy person by taking in probiotics. At the moment little speaks in favor of this. With probiotics, specific germs like lactobacilli for example are usually administered in yoghurts. The hope is that they have beneficial effects on the composition of the intestinal microflora. These are usually only short-term effects, since every person has his/her own intestinal microflora, which is defined maternally. You could compare it to a finger print, which makes every person identifiable. This individual microflora cannot be changed just like that. This is also known from studies with antibiotics, which in part massively disrupt and destroy the microflora in the gut. However, over and over again the intestine rebuilds the same pattern, except in the case of serious diseases and diseases that have a direct influence on the microflora. The argument from manufacturers of probiotic yoghurts, that intestinal health can be improved by using these products, is therefore barely supportable. Thus far food companies have not been successful in proving convincingly that their probiotic products have a beneficial effect on one’s health. What is that precisely based on?

Hauner: They took inflammation indicators and other parameters of the immune system, which were measured in the blood. However it is unclear, what these state about the function of the microflora. There is no consensus on whether for instance you can read from blood tests what really has improved in the intestinal flora. It simply is not possible.

All positive changes that have been detected thus far after consuming probiotics, could almost solely be noticed in patients with certain gastric diseases – such as chronic inflammatory gastric diseases, but also just certain forms of it. Other studies show that in the case of diarrhea diseases, especially those incurred during travel or those triggered by antibiotic intake, symptoms are somewhat alleviated by consuming probiotic foods. In this instance, using probiotics actually makes sense. Guidelines of gastroenterological associations name a few indications where probiotics can be used – admittedly usually in the shape of highly dosed capsules. According to dietary experts you should consume servings of fruit or vegetables five times a day. This is a recommendation or a campaign that has been around for over ten years. Would you support this recommendation to ensure a healthy digestion?

Hauner: I would still very much support this. In their previous history, humans have predominantly fed off vegetables. We had always consumed significantly more dietary fiber than we do today. Just 100 years ago, daily fiber intake was about 50-70 grams, today that’s only about 20 grams. Dietary fiber for instance is important for the large intestine and so to speak the fodder for the microflora. It assists in eliminating certain toxic substances better and helps the digestive process. In addition, fiber also has an important impact on protecting against cardiovascular diseases and metabolic disorders. That is why it makes sense to also continue to recommend that the modern person consume dietary fiber. We can also take in many vitamins, minerals and micronutrients through fruit and vegetables. Fruit and vegetables counteract weight gain. Unfortunately, we are still far away from implementing these recommendations. EFSA, the European Food Safety Agency , also provides food guidelines. What do these nutritional recommendations involve? Can you treat your stomach and bowels with care through them?

Hauner: The EFSA indeed has published diet recommendations lately, but such recommendations are also available from many other associations like for example the German Association for Nutrition, which has engaged in this subject for many years and provided very well documented and current guideline values. Essentially, it always aims in the same direction: A plant-based, low fat diet, which above all contains little saturated fat. You can read in the guidelines, how you can eat healthy as a normal person and consumer. This makes sense and should continue to be promoted. A topical question: Midsummer temperatures do not just put a strain on the cardiovascular system, but also on the gastrointestinal tract. What good things in regards to digestion can I do for these two “top athletes”?

Hauner: Above all you should eat light and low-fat foods and you should stay away from consuming large meals. Fruits, vegetables and salads are perfect. It is also important to drink enough liquids. Especially when we perspire, we lose many minerals through our skin. In hot temperatures you should drink significantly more than what is usually recommended.

The interview was conducted by Diana Posth and translated by Elena O'Meara


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