Alternative Ernährungsformen: Allgemeine Aspekte und vegetarische Kostformen.

Alternative diets (AD) differ from the current common mixed diet; AD are recommended as a permanent diet. These diets are based on ethical, philosophical and health promoting principles and lead to very different recommendations for food selection. Even within a particular AD there is usually a broad spectrum of versions, so that a general evaluation is only possible to a limited extent. This is also true for single AD. Vegetarian diets and partly paleo-diets have been investigated to a reasonable extent. Plant based diets are appropriate as permanent diets and offer health benefits as compared with currently practiced diets (risk reduction of cancers by 10-18% and of heart diseases by 30%; favorable effect on blood pressure and lipid profile; no risk reduction on cancer and total mortality). Vegan diets have to be critically assessed: they are linked to an increased risk of deficits for single nutrients (vitamin B12, iodine and as the case may be. calcium and long chain omega-3 fatty acids), if suitable supplements or fortified foods are not consumed.

Vitamin D Status and Mortality: Meta-Analysis of Individual Participant Data Confirms Strong Association.

Scientists and physicians have suggested that poor vitamin D intake can result in increased cardio-vascular mortality. Also total mortality appears to be increased with poor vitamin D status. A research team of the German Cancer Research Center in Heidelberg (DKFZ) headed by Ben Schöttker was able to demonstrate this association in a meta-analysis of 8 European and US-based cohort studies. In addition, serum 25(OH)D concentration (calcidiol) was shown to constitute a prognostic parameter in patients with a history of cancer.

[Safety of folic acid]. / Sicherheit von Folsäure. Fakten und Fiktionen.

Improving dietary folate intake is a central public health goal. However, critical voices have become louder warning of too high intake of folic acid. Safety concerns of a high folic acid exposure are usually limited to synthetic folic acid contained in drugs and food supplements. Against this background, the present article focuses on two matters: (a) How do the absorption and metabolism of synthetic folic acid differ from that of other folates? (b) How has the longterm safety of folic acid to be judged, especially regarding the risk of colorectal cancer, autism, asthma, impaired immune defence, masking vitamin B12 deficiency and interactions with the methotrexate metabolism?

Folate and Prevention of Neural Tube Defects: New Insights from a Bayesian Model.

Maternal folate status before and during pregnancy influences a woman's risk of having a pregnancy affected by congenital malformations of the neural tube (neural tube defects, NTD). For NTD prevention, it is recommended that women use periconceptional supplementation of folic acid. However, the recommended dose varies considerably (400 - 800 µg folic acid/day). Insufficient data exists on the relation between folate status and the risk of NTD. A recent study published in the British Medical Journal provides evidence for a generalizable dose-response relation between folate status and risk of NTD. The lowest risk of having a child with NTD was related to red blood cell (RBC) folate concentrations of ≥ 1000 nmol/L.

[Food supplements--possibilities and limitations: Part 6, Safety and possible risks]. / Nährstoffsupplemente--Möglichkeiten und Grenzen. Teil 6: Sicherheit und mögliche Risiken.

Due to the precautionary principle in consumer protection, thresholds for long-term safety of nutrients have to be defined. Three toxical indicators are of interest: lowest observed adverse effect level (LOAEL); no observed adverse effect level (NOAEL) und tolerable level of upper intake (UL). An uptake of a nutrient within the range of UL is without side effects even on the basis of long-term consumption. The UL can be used to derive maximum levels for nutrients in food supplements. In general, vitamins can be regarded as safe nutrients except for vitamin A. Adverse effects only occur at excessive intake far beyond the recommended daily allowances. In contrast, the range of safe intake for minerals, especially trace elements, is much smaller. This can be seen clearly in the case of selenium. In order to prevent severe selenium deficiency a plasma concentration of > 0.25 micromol/l (> 20 microg/l) must be reached. To minimize cancer risk a plasma concentration of 1.5 micromol/l (120 microg/l) is needed. First signs of selenium intoxications occur at plasma levels over 250 microg/l. It is the dose that makes the preventive effect and the poison as well.

[Celiac disease--the chameleon among the food intolerances]. / Zöliakie. Das Chamäleon unter den Nahrungsmittelintoleranzen.

Celiac disease is an autoimmune disorder resulting from gluten intolerance and is based on a genetically predisposition. Symptoms occur upon exposure to prolamin from wheat, rye, barley and related grain. The pathogenesis of celiac disease has not yet been sufficiently elucidated but is being considered as an autoimmune process. At its core are the deamidation of prolamin fragments, the building of specific antibodies and the activation of cytotoxic T-cells. The immunological inflammatory process is accompanied by structural damages of the enterocytes (villous atrophy, colonization and crypt hyperplasia). The symptoms and their extent depend on the type of the celiac disease; classic and non-classic forms are being distinguished (atypical, oligosymptomatic, latent and silent celiac disease). Characteristics of the classic presentation are malabsorption syndrome and intestinal symptoms such as mushy diarrhea and abdominal distension. The diagnosis of celiac disease is based on four pillars: Anamnesis and clinical presentation, serological evidence of coeliac specific antibodies (IgA-t-TG; IgA-EmA), small intestine biopsy and improvement of symptoms after institution of a gluten-free diet. The basis of the therapy is a lifelong gluten-free diet, i. e. wheat, rye, barley, spelt, green-core, faro-wheat, kamuth and conventional oats as well as food items obtained therefrom. Small amounts of up to 50 mg gluten per day are usually tolerated by most patients; amounts of > or = 100 mg/day lead mostly to symptoms. Gluten-free foods contain < or = 20 ppm or 20 mg/kg (Sign: symbol of the 'crossed ear' or label 'gluten-free'). At the beginning of the therapy the fat and lactose intake may need to be reduced; also the supplementation of single micronutrients (fat-soluble vitamins, folic acid, B12, iron, and calcium) may be required. Alternative therapies are being developed but have not yet been clinically tested.

[The updated recommendations of the US Institute of Medicine (IOM) on the intake of vitamin D. A critical appraisal]. / Die aktuellen Empfehlungen des US-amerikanischen Institute of Medicine (IOM) für die Vitamin-D-Zufuhr. Eine kritische Würdigung.

In the context of optimization long-term health, the research activities on the secosteroid vitamin D have become an important field of discourse. The discussion has focused on whether and, if so, to what extent, vitamin D might contribute to the prevention of various disorders, e.g. infections, autoimmune diseases, several types of cancer and diabetes mellitus type 2. Accordingly, in the recent past many voices were raised asking for a significant elevation of the recommended vitamin D intake. In November 2010 the decisive US Food and Nutrition Board (FNB) of the Institute of Medicine (IOM) revised the dietary reference intake for vitamin D. The updated recommendations were awaited eagerly and have now been published. This article discusses the new recommendation and comments on aspects which have to be considered critically.

Nutrition in oncology: the case of micronutrients (review).

In the course of cancer disease, many oncological patients develop tumor-associated malnutrition characterized by an insufficient supply of macro- and micronutrients. The inadequate nutritional status and the cancer anorexia-cachexia syndrome related to it are clinically relevant, as the response to antineoplastic measures, such as radiation and chemotherapy, is diminished, their side effects aggravated and the patient's quality of life and prognosis negatively affected. Therefore, the supportive nutrition care of oncological patients is of central importance. In this context, vitamins, minerals and long-chain omega -3 fatty acids are becoming more and more relevant in oncology although the benefit of such supplements is discussed controversially. Starting from a description of the etiopathogenesis and the pathophysiological consequences of cancer-associated malnutrition, the present study provides an overview of the importance of micronutrients for oncological patients. In the case of reduced food intake and/or inappropriate food choice the use of a multi-vitamin-multimineral supplement administered in physiological doses, i.e. nutrient quantities approximately corresponding to the recommended daily allowances, can be generally recommended. However, to enhance postoperative wound healing, it seems that cancer patients require higher amounts of micronutrients than healthy individuals. Because vitamin D deficiency is highly prevalent in oncological patients, improvement of vitamin D status is of special interest.

[Nutrition and colorectal cancer]. / Ernahrung und Tumorerkrankungen des Kolons und Rektums. Was ist wissenschaftlich gesichert?

Diet plays an important role in the pathogenesis of colorectal cancer. Current prospective cohort studies and metaanalysis enable a reevaluation of how food or nutrients such as fiber and fat influence cancer risk. Based on the evidence criteria of the WHO/FAD, risk reduction by a high intake of fruit is assessed as possible, while a lowered risk by a high vegetable intake is probable. Especially raw vegetables and fruits seem to exert anticancer properties. The evidence of a risk reducing effect of whole grain relating to colorectal cancer is assessed as probable whereas the evidence of an increased risk by high consumption of refined white flour products and sweets is (still) insufficient despite some evidences. There is a probable risk reducing effect of milk and dairy products. e available data on eggs and red meat indicate a possible risk increasing influence. Stronger clues for a risk increasing effect have been shown for meat products leading to an evidence assessed as probable. Owing to varied interpretations of the data on fiber, the evidence of a risk reducing effect relating to colorectal cancer is assessed as possible or insufficient. The available data on alcohol consumption indicate a possible risk increasing effect. In contrast to former evaluations, diets rich in fat seem to increase colorectal cancer risk only indirectly as part of a hypercaloric diet by advancing the obesity risk. Thus, the evidence of obesity, especially visceral obesity, as a risk of colorectal cancer is judged as convincing today. Prospective cohort studies suggest that people who get higher than average amounts of folic acid from multivitamin supplements have lower risks of colorectal cancer. The evidence for a risk reducing effect of calcium, selenium, vitamin D and vitamin E on colorectal cancer is insufficient. As primary prevention, a diet rich in vegetables, fruits, whole grain products, and legumes added by low-fat dairy products, fish, and poultry can be recommended. In contrast the consumption of sweets, refined white flour products and meat products should be reduced.

[Vegetarian nutrition: Preventive potential and possible risks. Part 1: Plant foods]. / Vegetarische Ernährung: Präventives Potenzial und mögliche Risiken. Teil 1: Lebensmittel pflanzlicher Herkunft.

Today vegetarian nutrition is more accepted and widespread in Europe than in former years. For a long time scientific research on vegetarian diets has focused mostly on malnutrition, whereas nowadays research centers increasingly on the preventive potential of plant-based diets. We followed a nutritive and a metabolic-epidemiological approach to obtain dietary recommendations. A MEDLINE research was performed for all plant food groups relevant for a vegetarian diet (key words: all relevant food groups, "vegetarian diet", "chronic disease", "cancer", "cardiovascular disease", "diabetes mellitus", "osteoporosis"). All relevant food groups were characterized regarding their nutrient content and rated with respect to the available metabolic-epidemiological evidence. Based on the evidence criteria of the WHO/FAO, cancer risk reduction by a high intake of vegetables and fruits is assessed as probable or possible, while a lowered risk of cardiovascular disease is convincing and a lowered risk of osteoporosis is probable. The evidence of a risk reducing effect of whole grain relating to colorectal cancer is assessed as possible, whereas it is probable relating to cardiovascular disease and diabetes mellitus type 2. There is an insufficient risk-reducing effect of legumes like soja relating to epithelial tumours and cardiovascular disease. The evidence of a risk-reducing effect of nuts to cardiovascular disease is assessed as probable, and in relation to cholelithiasis and diabetes mellitus type 2 as possible and insufficient, respectively. In conclusion, high consumption of fruits, vegetables, whole grains and nuts can lower the risk for several chronic diseases.

[Vegetarian nutrition: preventive potential and possible risks. Part 2: animal foods and recommendations]. / Vegetarische Ernährung: Präventives Potenzial und mögliche Risiken : Teil 2: Lebensmittel tierischer Herkunft und Empfehlungen.

INTRODUCTION: As shown in the first part of this article, consuming high amounts of fruits, vegetables, whole grains and nuts can lower the risk for several chronic diseases. However, the relevance of animal foods consumed within a vegetarian diet is less well-known. MATERIALS AND METHODS: We followed a nutritive and a metabolic-epidemiological approach to obtain dietary recommendations. A MEDLINE-research was performed for all animal food groups relevant with a vegetarian diet (key words: "eggs", "milk", "dietary pattern" "vegetarian diet", "cancer", "cardiovascular disease", "diabetes mellitus", "osteoporosis", "vitamin D", "vitamin B(12)", "iron", "iodine"). All relevant food groups were characterized regarding their nutrient content and rated with respect to the available metabolic-epidemiological evidence. RESULTS: Based on the evidence criteria of the WHO/FAO, colorectal cancer risk reduction by a high intake of milk and milk products is assessed as probable, while a higher risk of prostate and ovarial carcinomas is also probable. The evidence of a risk-increasing effect of eggs relating to cardiovascular disease, colorectal cancer and breast cancer is assessed as probable. As the data of prospective cohort studies suggest, a prudent diet pattern characterized high in fruits, vegetables, whole grains and nuts is associated with a lower risk of coronary heart disease and diabetes mellitus type 2. In contrast, there is no overall association between prudent diet pattern and risk of breast cancer or colorectal cancer. The critical key nutrients for vegetarians are vitamin D and B12, iodine and iron. CONCLUSION: For the first time evidence based dietary recommendations were provided for persons on a vegetarian diet in the D-A-CH-region.

Folic acid and colorectal cancer prevention: molecular mechanisms and epidemiological evidence (Review).

Epidemiological studies suggest that a diet rich in fruits and vegetables protects against colorectal cancer. This effect may result from their high levels of folic acid (pteroylglutamic acid). Folic acid holds a key position in DNA synthesis and mitosis as well as DNA methylation and regulation of gene expression. Folic acid deficiency has been associated with site- and gene specific DNA hypo- and hypermethylation. Furthermore thymidylate synthesis is restricted by folic acid deficiency which causes misincorporation of nucleotides and DNA strand breaks. Much epidemiological evidence supports the hypothesis that insufficient folic acid supply favors the development of colorectal tumors, particularly prospective studies have supported this connection. However, the data from case-control studies are less consistent. Functional polymorphisms in folate-metabolizing genes, especially the methylenetetrahydrofolate reductase (MTHFR) are capable of modifying the risk of colorectal cancer. Observational studies show that individuals with the homozygote genotype for the MTHFR (677C-->T) polymorphism are at higher risk when folic acid supply is low. Currently there are only few human intervention trials which show that folic acid can modify and inhibit the development of colorectal tumors. Additional studies are required in order to determine whether folic acid will be a useful agent in colorectal cancer prevention.