Полезно ли сыроедение?

Zur Rohkost zählt im weiteren Sinn jedes frische, unerhitzte Lebensmittel pflanzlicher und tierischer Herkunft. Im engeren Sinn ist nur pflanzliche Rohkost gemeint, also eine vegane Variante, bei welcher – je nach Autor – die Schwerpunkte auf Obst, Gemüse, Wildkräuter, Getreide, Nüsse oder Sprossen gelegt werden. Gemeinsam ist allen als Dauerernährung konzipierten Rohkostformen das konsequente Ablehnen gekochter Nahrung oder zumindest eine starke Bevorzugung von Rohkost im Rahmen einer vollwertigen Ernährung. Die verschiedenen Formen der Rohkost-Ernährung unterscheiden sich in der empfohlenen Menge roher Nahrung (70–100 Gewichtsprozent) und im Anteil an tierischen Lebensmitteln. Rohe Nahrung wird als „lebendige Nahrung“ (living food) bezeichnet, während auf mehr als 42 °C erhitzte oder durch Kochen veränderte Nahrung als „tot“ oder „denaturiert“ gilt. Folglich zählen auch Honig, kaltgepresste Pflanzenöle, Trockenfrüchte, kaltgeräucherte Erzeugnisse (Fleisch/Fisch) sowie essig- und milchsaures Gemüse zur Rohkost.

Im 19. Jahrhundert machten im deutschsprachigen Raum viele Laien und Ärzte die Erfahrung, dass Rohkost-Diät zur Linderung und Heilung von Krankheiten führen kann. Diese Erkenntnis um die Bedeutung der Rohkost als Therapeutikum führte im Kontext der aufkeimenden Lebensreformbewegung und der sich anbahnenden grossen Krise der Schulmedizin zur Entstehung der ersten grossen Rohkostbewegung, der traditionellen Rohkostbewegung der 1920er- und 1930er-Jahre.

In Deutschland sind diesbezüglich an erster Stelle die beiden Brüder Adolf Just (1859–1936) und Rudolf Just (1877–1948) und deren 1896 gegründete Heilanstalt „Jungborn“ im Harz zu nennen. Dort wurden bis zum Zweiten Weltkrieg Tausende Patienten mit einer ausgereiften Methode des Heilfastens und anschliessender Rohkost-Diät behandelt. Der Jungborn war das weltweit erste grosse Zentrum für Heilfasten („Jungborn-Fasten“) sowie für Rohkosttherapie und Vollwert-Ernährung (Semler 2020). In Österreich war es der heute kaum mehr bekannte Arzt Reinhold Schwartz (1880–1967), der in seinem 1922 in Altheim in Oberösterreich eröffneten „Naturheilsanatorium Dr. Schwartz“ mehr als 7000 Patienten mit Heilfasten und Rohkost-Diät therapierte und in vielen Artikeln und Vorträgen davon berichtete (Semler 2019a).

Der Schweizer Arzt Max Bircher-Benner (1867–1939) teilte im Jahre 1900 erstmals seine spektakulären Erfolge mit Rohkostbehandlung mit. Diese veranlassten ihn dazu, die heilenden Wirkungen der Rohkost-Diät bei verschiedenen Krankheiten systematisch zu beobachten und zu erforschen. Seine Erfahrungen und Erkenntnisse in seiner Züricher Klinik „Lebendige Kraft“ an mehr als 10.000 Kranken sind in vielen Veröffentlichungen dokumentiert. Es ist besonders dem Engagement von Bircher-Benner zu verdanken, dass sich die medizinisch-wissenschaftliche Forschung in Deutschland Mitte der 1920er-Jahre intensiv mit den physiologischen und therapeutischen Wirkungen roher Nahrung beschäftigte.

Die vielen Ärzte der traditionellen Rohkostbewegung setzten strenge Rohkost nur als Therapie ein, passten die Höhe des Rohkostanteils immer dem jeweiligen individuellen Zustand sowie der Psyche des Patienten an und liessen vorab oftmals ein Heilfasten durchführen. Als Dauerernährung rieten sie in der Regel zu einer vollwertigen Ernährung mit einem Rohkostanteil von 50 %, wie er auch in der Vollwert-Ernährung empfohlen wird.

Der Zweite Weltkrieg hat dieser Rohkostbewegung ein jähes Ende bereitet und viel wertvolles empirisches Wissen um die Rohkosttherapie geriet schnell in Vergessenheit.

In den 1980er- und 1990er-Jahren erschienen vermehrt Rohkost-Bücher, in welchen versucht wird, reine Rohkost-Ernährung als optimale Dauerernährung des Menschen darzustellen.

Auffallend in dieser modernen Rohkostbewegung ist, dass es sich bei den Autoren überwiegend um medizinische und naturwissenschaftliche Laien handelt und kaum um Ärzte oder Naturwissenschaftler.

Als die moderne Rohkostbewegung in den 2000er-Jahren in Deutschland deutlich nachliess, wurde sie durch den stark aufkommenden Trend zum Veganismus und verschiedene Impulse aus den USA („American way of raw“) neu belebt.

Diese jüngste Rohkostbewegung verwendet in Deutschland den Begriff „Rohvolution“.

Diese Szene ist von neuen Gesichtern sowie anderer Rhetorik und gemässigterer Zugangsweise geprägt, womit versucht wird, sich vom verstaubten, fanatischen Image der Rohkostbewegung der 1980er- und 1990er-Jahre zu befreien. Ein zentrales Anliegen ist es, zu zeigen, wie aus rohen Lebensmitteln durch kreative Zubereitungstechniken optisch ansprechende und geschmackvolle vegane Gerichte hergestellt werden können.

Das erstaunliche medizinische Desinteresse an der Rohkost als Therapie liegt heute zum einen an der in vielen Rohkost-Büchern praktizierten Propaganda, mit der Wissenschaftler und Ärzte nicht in Zusammenhang gebracht werden möchten. Zum anderen lässt sich mit Gemüse, Obst, Nüssen und Co. nicht das grosse Geld verdienen. Hinzu kommt, dass viele Mediziner die Vorstellung, allein mit „Grünzeug“ den Verlauf schwerer Erkrankungen günstig beeinflussen zu können, als zu banal und aufgrund der langsam eintretenden Wirkungen als zu wenig attraktiv bzw. spektakulär empfinden.

Buchkapitel

DOI: 10.1007/978-3-662-68881-6_13

Book: strong evidence

High consumption of vegetables and fruits is associated with reduced risk for cardiovascular disease. However, little information is available about diets based predominantly on consumption of fruits and their health consequences. We investigated the effects of an extremely high dietary intake of raw vegetables and fruits (70–100% raw food) on serum lipids and plasma vitamin B-12, folate, and total homocysteine (tHcy). In a cross-sectional study, the lipid, folate, vitamin B-12, and tHcy status of 201 adherents to a raw food diet (94 men and 107 women) were examined. The participants consumed ∼1500–1800 g raw food of plant origin/d mainly as vegetables or fruits. Of the participants, 14% had high serum LDL cholesterol concentrations, 46% had low serum HDL cholesterol, and none had high triglycerides. Of raw food consumers, 38% were vitamin B-12 deficient, whereas 12% had an increased mean corpuscular volume (MCV). Plasma tHcy concentrations were correlated with plasma vitamin B-12 concentrations (r = −0.450, P < 0.001), but not with plasma folate. Plasma tHcy and MCV concentrations were higher in those in the lowest quintile of consumption of food of animal origin (P_trend < 0.001). This study indicates that consumption of a strict raw food diet lowers plasma total cholesterol and triglyceride concentrations, but also lowers serum HDL cholesterol and increases tHcy concentrations due to vitamin B-12 deficiency.

Querschnittsstudie

DOI: 10.1093/jn/135.10.2372

Study: moderate evidence

Dietary carotenoids are associated with a reduced risk of chronic diseases. Raw food diets are predominantly plant-based diets that are practised with the intention of preventing chronic diseases by virtue of their high content of beneficial nutritive substances such as carotenoids. 

Therefore, we investigated vitamin A and carotenoid status and related food sources in raw food diet adherents in Germany. Dietary vitamin A, carotenoid intake, plasma retinol and plasma carotenoids were determined in 198 (ninety-two male and 106 female) strict raw food diet adherents in a cross-sectional study. Raw food diet adherents consumed on average 95 weight% of their total food intake as raw food (approximately 1800 g/d), mainly fruits. Raw food diet adherents had an intake of 1301 retinol activity equivalents/d and 16·7 mg/d carotenoids. Plasma vitamin A status was normal in 82 % of the subjects ( ≥ 1·05 μmol/l) and 63 % had β-carotene concentrations associated with chronic disease prevention ( ≥ 0·88 μmol/l). In 77 % of subjects the lycopene status was below the reference values for average healthy populations ( < 0·45 μmol/l). Fat contained in fruits, vegetables and nuts and oil consumption was a significant dietary determinant of plasma carotenoid concentrations (β-carotene r 0·284; P < 0·05; lycopene r 0·168; P = 0·024). Long-term raw food diet adherents showed normal vitamin A status and achieve favourable plasma β-carotene concentrations as recommended for chronic disease prevention, but showed low plasma lycopene levels. Plasma carotenoids in raw food adherents are predicted mainly by fat intake.

Querschnittstudie

DOI: 10.1017/S0007114507868486

Study: moderate evidence

The urinary mercapturic acids N-acetyl-S-(2-carbamoylethyl)-L-cysteine (AAMA) and N-acetyl-S-(2-carbamoyl-2-hydroxyethyl)-L-cysteine (GAMA) are short-term biomarkers of exposure from acrylamide and its metabolite glycidamide, respectively. The medium-term exposure to acrylamide and glycidamide is monitored by the adducts N-(2-carbamoylethyl)-Val (AA-Val) and N-(2-carbamoyl-2-hydroxyethyl)-Val (GA-Val) in hemoglobin (Hb), respectively.

two diet studies including 36 omnivores, 36 vegans and 16 strict raw food eaters (abstaining from any warmed or heated food for at least four months)

Median urinary AAMA excretion per day in non-smoking omnivores, vegans and raw food eaters were 62.4, 85.4 and 15.4 µg/day, respectively; the corresponding median AA-Val levels were 27.7, 39.7 and 13.3 pmol/g Hb, respectively. Median levels in strict raw food eaters were about 25% (AAMA excretion) and 48% (AA-Val) of those in omnivores. In comparison to 2017, AAMA and GAMA excretion levels were hardly altered in 2021, however, levels of AA-Val and GA-Val in 2021 slightly increased. There was a weak correlation between AAMA excretion levels determined four years apart (r_S = 0.30), and a moderate correlation between levels of AA-Val (r_S = 0.55) in this timeframe. Our data in strict raw food eaters confirm a significant endogenous formation to acrylamide in a size range, which is—based on the levels of AA-Val—distinctly higher than reported previously based on levels of urinary AAMA excretion. The relatively lower AAMA excretion in raw food eaters likely represents a lower extent of glutathione conjugation due to missing hepatic first-pass metabolism in case of endogenous formation of acrylamide, which leads to a higher systemic exposure.

Querschnittstudie

DOI: 10.1007/s00204-024-03798-z

Study: moderate evidence

Endurance sport requires a healthy and balanced diet. In this case report we present the findings of an ultra-triathlete (three times Ironman, means 11.4 km swim, 540 km bike, 125 km run in 41:18 h as a whole) living on a raw vegan diet and having finished the competitions under these nutritional conditions. To this end, the vegan ultra triathlete and a control group of 10 Ironman triathletes of similar age living on a mixed diet were investigated, using echocardiography and spiroergometry. In addition, blood samples were taken from the vegan athlete both in the sporting season and in the off-season. The vegan athlete showed no signs of dietary deficiencies or impaired health. In comparison with the control group, the vegan athlete showed a higher oxygen intake at the respiratory compensation point. This case demonstrates that even top-class sporting performance, like that of a three-time Ironman, is possible on a vegan diet. Whether a vegan diet offers advantages or disadvantages for the performance of endurance athletes remains an open question.

A 48-year-old male finished Triple-Ironman distance in 41 hours and 18 minutes (11.4 km swimming, 540 km cycling, and 126 km running). At the time of the examinations, he had been practising his current diet of raw vegan diet for 6 years. Prior to this, the vegan athlete had been living as a vegan for 3 years and as a vegetarian for the previous 13 years.

All last competitions were performed only based on a raw diet. 

Fallbericht

DOI: 10.1155/2014/317246

Study: weak evidence

English-speaking attendees at Hippocrates Health Institute (Florida, US), a raw vegan institute, were recruited on arrival and typically stayed 1–3 weeks.

Of 107 attendees eligible for the questionnaire study and 82 for the blood marker substudy, 51 and 38 participants, respectively, provided complete follow-up data. Overall QOL improved 11.5% (p = 0.001), driven mostly by the mental component. Anxiety decreased 18.6% (p = 0.009) and perceived stress decreased 16.4% (p < 0.001). Participants’ ratings of the food's taste were unchanged, but their ratings of how well they were taking care of themselves improved. CRP, lymphocytes, T cells, and B cells did not change significantly, but CD4, CD8, and NK cells decreased slightly.

A stay at a raw vegan institute was associated with improved mental and emotional QOL. Studies are needed to determine the feasibility of conducting a clinical trial of the raw vegan diet among healthy people, and subsequently among patients with specific diseases.

Prospektive Beobachtungsstudie (longitudinal)

DOI: 10.1016/j.ctim.2008.02.004

Study: moderate evidence

The purpose of this study was to evaluate adherence and identify predictors of adherence to a raw vegan diet (i.e., uncooked plant foods) following a stay at a raw vegan institute. In this cohort study of guests at a raw vegan institute, subjects completed written questionnaires upon arrival and 12 weeks later. Of 107 eligible guests, 84 participated. Mean age was 54 years, 23 were male, and 73 white. Fifty-one completed the 12-week follow-up. Eight (16%) reported their diet to be ⩾80% raw vegan at baseline and 14 (28%) at follow-up. Based on a raw vegan dietary adherence score (range 0–42) created for this study, mean adherence (SD) increased from 15.1 (5.4) to 17.0 (5.8) over 12 weeks (). Baseline predictors of adherence included: education (), severity of disease , and self-efficacy to adhere . Future interventions that evaluate this diet should address self-efficacy, an important, potentially remediable predictor of adherence.

Kohortenstudie

DOI: 10.1016/j.ctcp.2006.12.005

Study: moderate evidence

To examine the relationship between the strictness of long-term raw food diets and body weight loss, underweight and amenorrhea.

In a cross-sectional study 216 men and 297 women consuming long-term raw food diets (3.7 years; SE 0.25) of different intensities completed a specially developed questionnaire. Participants were divided into 5 groups according to the amount of raw food in their diet (70–79, 80–89, 90–94, 95–99 and 100%). A multiple linear regression model (n = 513) was used to evaluate the relationship between body weight and the amount of raw food consumed. Odds of underweight were determined by a multinomial logit model. 

From the beginning of the dietary regimen an average weight loss of 9.9 kg (SE 0.4) for men and 12 kg (SE 0.6) for women was observed. Body mass index (BMI) was below the normal weight range (< 18.5 kg/m²) in 14.7% of male and 25.0% of female subjects and was negatively related to the amount of raw food consumed and the duration of the raw food diet. About 30% of the women under 45 years of age had partial to complete amenorrhea; subjects eating high amounts of raw food (> 90%) were affected more frequently than moderate raw food dieters. Conclusions: The consumption of a raw food diet is associated with a high loss of body weight. Since many raw food dieters exhibited underweight and amenorrhea, a very strict raw food diet cannot be recommended on a long-term basis.

Querschnittstudie

DOI: 10.1159/000012770

Study: moderate evidence

In this cross-sectional study, we compared 16 non-smoking strict raw food eaters (5 women and 11 men, age 44.6 ± 12.3 years, duration of following the diet 11.6 ± 10.8 years) with the non-smoking participants (32 vegans, 27 omnivores) of the “Risk and Benefits of a Vegan Diet” (RBVD) study. We investigated body composition, dietary intake from 3-day weighed food records, and relevant fasting blood and serum parameters. Food choice and dietary behavior were very heterogenic in raw food eaters. They had lower mean values of BMI and percentage of body fat than the respective RBVD participants. The same holds true for energy supply and intakes of protein, carbohydrate, calcium and iodine. Serum levels revealed lower levels of HDL cholesterol, triglycerides, zinc, and vitamin D3. The raw food eaters with (n = 9) and without (n = 7) supplementation of vitamin B12 had median vitamin B12 levels of 399 and 152 ng/L, respectively. Accordingly, eight raw food eaters (50%) had homocysteine levels above 12 µmol/L. The study allows a close look at strict raw food eaters with respect to possible dietary deficiencies, but also provides insights into motivations and daily life.

The 16 strict raw food eaters were compared to non-smoking vegans (n = 32) and omnivores (n = 27) not avoiding the heating of food. These “control” subjects were participants of the “Risk and Benefits of a vegan diet” (RBVD) study also performed at the BfR (in 2017), and had to follow their diet for at least one year. In the RBVD study, an omni-vorous diet was defined as at least three servings of meat or two servings of meat and two servings of sausages a week. Detailed information about the RBVD study was published elsewhere.

Querschnittstudie

DOI: 10.3390/nu14091725

Study: moderate evidence

The aim of the current study was to conduct a systematic literature review of the available evidence to assess and investigate the effects of a raw vegetarian diet with a review of clinical trial studies. The literature search to find related studies were performed through three scientific databases, including PubMed, SCOPUS, and Google Scholar with related keywords. Based on our findings from the literature, a raw vegan diet with more than 90% raw food cannot be recommended for a long time due to micronutrient deficiencies as well as related complications. In order to investigate possible advantages and disadvantages, it seems well-designed clinical trials are necessary to clarify these effects.

It seems that raw vegan diet has disadvantages such as the inactivation of toxins and pesticides and contamination with microorganisms due to insufficient heating and insufficient intake of some nutrients such as protein, vitamin B12, iron, calcium, selenium, zinc, omega-3 fats, and vitamin D. The increase in tHcys is related to low B12 intake in these patients. Urine MMA assay has been shown to be much more effective than serum cobalamin in identifying raw vegans at risk for vitamin B12 deficiency and monitoring the improvement of cobalamin status. Early detection and supplementation are the best way to prevent permanent neurological damage and disorders. The occurrence of amenorrhea in women on a raw vegan diet is also a sign of functional problems in the long-term following of such a diet.

Narratives Review

DOI: 10.1016/j.nutos.2023.04.001

Study: weak evidence

We performed a cross-sectional study on 18 volunteers (mean ± SD age, 54.2 ± 11.5 years; male/female ratio, 11:7) on a RF vegetarian diet for a mean of 3.6 years and a comparison age- and sex-matched group eating typical American diets. We measured body composition, bone mineral content and density, bone turnover markers (C-telopeptide of type I collagen and bone-specific alkaline phosphatase), C-reactive protein, 25-hydroxyvitamin D, insulin-like growth factor 1, and leptin in serum.

The RF vegetarians had a mean ± SD body mass index (calculated as weight in kilograms divided by the square of height in meters) of 20.5 ± 2.3, compared with 25.4 ± 3.3 in the control subjects. The mean bone mineral content and density of the lumbar spine (P= .003 and P<.001, respectively) and hip (P = .01 and P<.001, respectively) were lower in the RF group than in the control group. Serum C-telopeptide of type I collagen and bone-specific alkaline phosphatase levels were similar between the groups, while the mean 25-hydroxyvitamin D concentration was higher in the RF group than in the control group (P<.001). The mean serum C-reactive protein (P = .03), insulinlike growth factor 1 (P = .002), and leptin (P = .005) were lower in the RF group.

Querschnittstudie

DOI: 10.1001/archinte.165.6.684

Study: moderate evidence

The aim of the study was to investigate the frequency and severity of dental erosions and its association with nutritional and oral hygiene factors in subjects living on a raw food diet. As part of a larger dietary study 130 subjects whose ingestion of raw food was more than 95% of the total food intake were examined. The median duration of the diet was 39 (minimum 17, maximum 418) months. Before the clinical examination, the participants answered questionnaires and recorded their food intake during a 7–day period. Dental erosions were registered using study models. As a control 76 sex– and age–matched patients from our clinic were randomly selected. The raw food diet records showed the median daily frequency of ingesting citrus fruit to be 4.8 (minimum 0.5, maximum 16.1). The median intake of fruit was 62% (minimum 25%, maximum 96%) of the total, corresponding to an average consumption of 9.5 kg of fruit (minimum 1.5, maximum 23.7) per week. Compared to the control group subjects living on a raw food diet had significantly (p≤0.001) more dental erosions. Only 2.3% of the raw food group (13.2% of the controls) had no erosive defects, whereas 37.2% had at least one tooth with a moderate erosion (55.2% of the controls) and 60.5% had at least one tooth with a severe erosion (31.6% of the controls). Within the raw food group no significant correlation was found between nutrition or oral health data and the prevalence of erosions. Nevertheless, the results showed that a raw food diet bears an increased risk of dental erosion compared to conventional nutrition.

Querschnittstudie

DOI: 10.1159/000016498

Study: moderate evidence

Macronutrients and micronutrients present in different types of diet could influence different aspects of both inflammatory and immune responses; thereby, diets could influence oral health and the periodontal condition. The raw vegan diet is a subset of vegetarianism in which only uncooked plant-derived foods are consumed. The present study's aim was to evaluate the effect of the raw vegan diet on periodontal and dental health parameters.

A total of 118 participants (59 raw vegans and 59 controls) were interviewed about their level of education and oral health habits. Samples of unstimulated whole saliva were collected for pH analysis, and dental and periodontal parameters were examined. Then, statistical analysis was performed.

Raw vegans had better oral hygiene (P = 0.001). The decayed-missing-filling indices were relatively equal in both groups. The probing depth, bleeding on probing (BOP), and simplified oral hygiene index were significantly lower in raw vegans (P = 0.047, P = 0.017, and P = 0.001, respectively). Multiple regression analyses disclosed that probing depth and BOP were significantly related to debris index.

Based on this study's results, it can be presumed that the better periodontal condition in raw vegans is a result of their better oral care and lifestyle.

Querschnittstudie

DOI: 10.4103/tcmj.tcmj_161_19

Study: moderate evidence

Book: strong evidence

Thermal treatment affects both the cell wall and carotenoid content of plants, in turn altering their bioavailability. Aschoff et al. [27] demonstrated that the bioavailability of β-cryptoxanthin, zeinoxanthin and lutein in pasteurized orange juice is higher than in fresh orange juice. In contrast, Vimala et al. [28] evaluated carotenoid content in sweet potato undergoing different treatments (cooking, frying, oven-drying, and sun-drying). Oven-drying (50–60 °C) maintained 90% of β-carotene in sweet potato compared to the fresh product, whereas all other treatments decreased carotenoid content between 15% and 30%. Odriozola-Serrano et al. [29] examined the effect of pasteurization and electrical pulses on the carotenoid content of tomato juice. They found that tomato juice treated with electrical pulses had a higher carotenoid content. Thus, pulse treatment is the most efficient method of preserving carotenoid content and increasing their bioavailability compared to the traditional treatment. In all previously cited examples, there is a decrease in total carotenoid content; nevertheless, the bioavailability of carotenoids improves by reducing dietary fiber, releasing cellular content, softening plant material, and reducing the interactions between carotenoids and other food components. Thus, promoting both the release of carotenoids and formation of micelles helps increase their absorption.

Narratives Review

DOI: 10.3390/plants12020313

Study: weak evidence

The results of the present study show that long-term consumption of a low-calorie lowprotein vegan diet or regular endurance exercise training is associated with a decrease in multiple risk factors for CHD. Moreover, eating a low-calorie low-protein vegan diet, which is low in sodium and high in fiber and potassium, might have greater beneficial effects on blood pressure than endurance exercise, independent of adiposity.

Querschnittsstudie mit Kontrollgruppe

DOI: 10.1089/rej.2006.0529

Study: moderate evidence

Methodik

Zur Erfassung des Ernährungs- und Gesundheitsverhaltens von Rohköstlern wurde im Rahmen der Giessener Rohkost-Studie ein umfangreicher Fragebogen entwickelt. Neben soziodemografischen Daten wurden u. a. Informationen zu folgenden Themen erfragt: Gesundheitszustand vor und während der Rohkost-Ernährung, gesundheitsbezogenes Verhalten, Ernährungsverhalten, Begründung und Einstellung zur Ernährungsweise [8]. Dieser Fragebogen wurde im Jahre 2003 modifiziert und an die 201 Teilnehmer des Endkollektivs der Giessener Rohkost-Studie (1993/94) versandt, von denen 116 antworteten (Rücklaufquote: 57,7 %). In 27 Fällen (13,4 %) kam die Postsendung ungeöffnet zurück: die aktuelle Adresse konnte aber nicht ermittelt werden. Von 48 Personen (23,9 %) wurde der Fragebogen nicht ausgefüllt, 10 Personen (5 %) waren bereits verstorben. Von den 116 befragten Personen gaben 43 an, keine Rohkost-Ernährung mehr zu praktizieren (d. h. Rohkostanteil < 70 %). Für die deskriptive Auswertung der verbliebenen 73 Fragebögen wurde das Statistikprogramm SPSS 12.0 für Windows verwendet.

Narratives Review

Study: weak evidence

Unser derzeitiges Verständnis der menschlichen Verdauungsspezialisierung im Vergleich zu anderen Primaten beschränkt sich jedoch weitgehend auf anatomische und weniger auf physiologische Merkmale, wie die Verkleinerung von Mund, Zähnen, Magen und Dickdarm. Obwohl diese Veränderungen stark auf eine Anpassung an leicht zu kauende und schnell verdauliche Nahrung hindeuten, treffen diese Beschreibung auch auf einige Rohkostprodukte zu, beispielsweise Früchte, Knochenmark, Hirn, Leber, Honig und bestimmte Lebensmittel wie Samen, die von einer nicht-thermischen Verarbeitung deutlich profitieren. 

Gene, die bei Mäusen, die mit rohem bzw. gekochtem Fleisch gefüttert wurden, unterschiedlich exprimiert waren, zeigten fast ausschliesslich bei der Rohfleischdiät eine Hochregulation. Diese Gene waren stark mit Genen angereichert, die mit dem Immunsystem in Zusammenhang stehen. Dies stützt die weit verbreitete, aber wenig belegte Annahme, dass das Kochen von Fleisch eine kostspielige Immunantwort verhindert ( Ragir 2000 ; Carmody und Wrangham 2009 ). Die spezifischen Auslöser der Immun-Hochregulation bei der Rohfleischdiät sind jedoch weiterhin unklar. 

Bei Knollen stellten wir fest, dass Gene, die am Kohlenhydratstoffwechsel beteiligt sind, bei gekochten Knollen im Vergleich zu rohen Knollen weniger stark exprimiert wurden. Dies deckt sich mit etablierten Forschungsergebnissen, die zeigen, dass Kochen die Kohlenhydratverdauung durch Verkleisterung der Stärke verbessert. 

Experimentell-genomische und evolutionsbiolgische Studie

DOI: 10.1093/gbe/evw059

Study: weak evidence