Petra Rust

B-vitamin status and concentrations of homocysteine in Austrian omnivores, vegetarians and vegans.

Background: A vegetarian diet is considered to promote health and longevity and reduce the risk of cardiovascular diseases and cancer. However, a vegetarian diet may be deficient in some nutrients. Exclusion of animal products in vegetarian diets may affect the status of certain B-vitamins, and further cause the rise of plasma homocysteine concentration. Objective: The nutritional status of various B-vitamins (B1, B2, B6, B12, folic acid) and the concentration of homocysteine in blood plasma of omnivores (n = 40), vegetarians (n = 36) and vegans (n = 42) in Austria was evaluated. Methods: The evaluation was done using the functional parameters erythrocyte transketolase (ETK), glutathione reductase (EGR) and glutamic oxaloacetic transaminase (EGOT) activation coefficients. Enzyme activity was measured photometrically. The quantity of vitamins B1, B2 and B6 in urine and the concentrations of vitamin B6 and homocysteine in plasma were determined by HPLC methods with fluorescence detection. Plasma concentration of vitamin B12 and folic acid were measured with radioimmunoassay. Results: Most of the subjects showed a satisfying vitamin B1 status. Vegans presented a significantly lower mean plasma vitamin B12 concentration than omnivores and vegetarians and deficiency in 2.4% of the volunteers but the highest mean value of plasma folate among the investigated groups. A deficient status of folate was found in 18% of omnivores and in approximately 10% of vegans and vegetarians. The status of riboflavin is considered to be deficient in about 10% of omnivores and vegetarians and in over 30% of vegans. According to the activation coefficient of GOT, approximately one third of all subjects showed vitamin B6 deficiency. Elevated homocysteine concentration in plasma was observed in 66% of the vegans and about 45–50% of the omnivores and vegetarians. Vegan subjects had significantly higher mean plasma homocysteine levels than omnivores. Conclusion: Thiamin and folate need not be a problem in a well-planned vegan diet. Vitamins B12 and B2 may need attention in the strict vegan diet, especially regarding elevated homocysteine levels in plasma. Pyridoxine status appeared to be independent of the diet.

The Thiamine Status of Adult Humans Depends on Carbohydrate Intake

Thiamine requirements for humans are generally expressed as absolute values per day (mg/d) or in relation to total caloric intake. Limited data are available on the relation between thiamine requirements and the intake of carbohydrates. This study was performed to investigate the influence of stepwise increases of carbohydrate intake on the status of thiamine in healthy volunteers under isocaloric conditions. During an adaptation phase of four days, the carbohydrate intake of twelve healthy volunteers (6 male, 6 female) was 55% of total energy intake. During the subsequent intervention periods, carbohydrate intake was increased to 65% of total energy for four days and to 75% for another four days. Thiamine intake, total energy intake, and physical activity were kept constant throughout the study. HPLC analysis was used to measure thiamine in plasma, urine and feces. Erythrocyte transketolase activity (ETK) was determined enzymatically. During the intervention periods thiamine decreased significantly (p < 0.05) in plasma (from 19.3 +/- 3.3 to 16.4 +/- 4.0 nmol/l) as well as in urine (from 72 +/- 56 to 58 +/- 21 mumol/mol creatinine). ETK and feces content of thiamine remained unchanged. An increase of dietary carbohydrate intake from 55% to 65% and 75%, respectively, of total caloric intake for four days per period at isocaloric conditions causes a decrease of plasma and urine levels of thiamine without affecting enzyme activities.

Fruit and vegetable intake in Austrian adults: intake frequency, serving sizes, reasons for and barriers to consumption, and potential for increasing consumption

OBJECTIVE To assess the intake frequency of fruit and vegetables, serving sizes, reasons for and barriers to consumption, and the potential for increasing fruit and vegetable intake. DESIGN A nationwide postal questionnaire survey was conducted in 2006 over all four seasons. The participants were stratified according to occupation and sex. The response rate for 5130 questionnaires sent out was 52.7 %. SETTING Austria. SUBJECTS Austrian adults, aged 19-64 years. RESULTS Daily fruit consumption was reported by 57.1 % of the participants and daily vegetable consumption by 36.2 %. On average, 2.1 (SD 1.9) servings (250 (SD 225) g) of fruit and 1.7 (SD 1.3) servings (198 (SD 159) g) of vegetables were consumed daily. Women ate fruit and vegetables both more frequently and in greater quantities than men. Both intake frequency and the number of fruit and vegetable servings were largely independent of seasonal fluctuations. The primary reason for the consumption of both fruit and vegetables was taste. The greatest barrier to higher intake was the perception that current individual consumption was already sufficient. Price did not constitute a relevant barrier in Austria. At present, the potential for increasing fruit and vegetable intake can be estimated at two servings. CONCLUSIONS Austrian adults still consume less fruit and vegetables than recommended. Strategies to increase intake should pay more attention to the taste instead of the various health aspects.

Epigenetic regulation of human buccal mucosa mitochondrial superoxide dismutase gene expression by diet

The impact of nutrition on the epigenetic machinery has increasingly attracted interest. The aim of the present study was to demonstrate the effects of various diets on methylation and gene expression. The antioxidative enzyme mitochondrial superoxide dismutase (MnSOD) was chosen as the model system because epigenetic regulation has been previously shown in cell lines for this gene. Promoter methylation and gene expression of MnSOD in buccal swabs from three sample groups were analysed. The three groups included: (1) forty vegetarians (aged 20-30 years); (2) age-matched omnivores; (3) elderly omnivores (aged>85 years). A 3-fold increase in the expression of the MnSOD gene was associated with decreased CpG methylation of the analysed promoter region in the vegetarian group compared with the age-matched omnivores group. Expression and promoter methylation of the MnSOD gene in elderly omnivores showed no significant differences compared with younger omnivores. In accordance with previous findings in various tissues, DNA global methylation was found to be significantly higher (30 %) in buccal swabs of younger subjects (independent of the diet), than in those of elderly omnivores. In the control experiment which was designed to verify the findings of the human buccal swab studies, the Caco-2 cell line was treated with zebularine. Results of the control study showed a 6-fold increase of MnSOD expression, an approximately 40 % decreased methylation of specified CpG in the MnSOD promoter and a 50 % reduction of global DNA methylation. These results indicate that diet affects the epigenetic regulation of human MnSOD.

Long-Term Oral β-Carotene Supplementation in Patients with Cystic Fibrosis – Effects on Antioxidative Status and Pulmonary Function

To investigate the efficacy of long-term oral β-carotene supplementation for optimizing the antioxidant status and pulmonary function in patients with cystic fibrosis (CF), 24 patients (aged 12.8 ± 6.3 years) were randomized to a CF supplementation or to a CF placebo group. As controls 14 healthy age-matched subjects (aged 14.7 ± 6.2 years) were studied. Patients of the CF supplementation group received 1 mg β-carotene/kg body weight (BW)/day (maximally 50 mg β-carotene/day) for the first 12 weeks; during the following 12 weeks, dosage was reduced to 10 mg β-carotene/day. At study entry, plasma β-carotene concentrations were significantly lower in CF patients than in controls (p < 0.001). In the CF supplementation group, plasma β-carotene concentrations were significantly increased (baseline: 0.08 ± 0.04 μmol/l) at the end of high-dose treatment (12th week; 0.6 ± 0.4 μmol/l; p < 0.001), but decreased again during supplementation with 10 mg β-carotene/day to 0.3 ± 0.2 μmol/l at the end of the study (p < 0.001). β-Carotene supplementation did not affect plasma concentrations of other carotenoids and retinol, but an increase in plasma α- and γ-tocopherol concentrations was noticed. During high-dose treatment, a significant decrease in TBA-MDA complexes and a correction of total antioxidative capacity was observed. During the treatment, pulmonary exacerbation could be corrected significantly (p < 0.05). We conclude that CF patients can be efficiently supplemented with 1 mg β-carotene/kg BW/day (maximally 50 mg β-carotene/day) to achieve plasma concentrations of healthy control subjects and to minimize oxidative stress, improving the quality of life of CF patients.

A 12-week intervention with nonivamide, a TRPV1 agonist, prevents a dietary-induced body fat gain and increases peripheral serotonin in moderately overweight subjects.

Scope: A bolus administration of 0.15 mg nonivamide has previously been demonstrated to reduce energy intake in moderately overweight men. This 12‐week intervention investigated whether a daily consumption of nonivamide in a protein‐based product formulation promotes a reduction in body weight in healthy overweight subjects and affects outcome measures associated with mechanisms regulating food intake, e.g. plasma concentrations of (an)orexigenic hormones, energy substrates as well as changes in fecal microbiota. Methods and results: Nineteen overweight subjects were randomly assigned to either a control (C) or a nonivamide (NV) group. Changes in the body composition and plasma concentrations of satiating hormones were determined at fasting and 15, 30, 60, 90, and 120 min after a glucose load. Participants were instructed to consume 0.15 mg nonivamide per day in 450 mL of a milk shake additionally to their habitual diet. After treatment, a group difference in body fat mass change (–0.61 ± 0.36% in NV and +1.36 ± 0.38% in C) and an increase in postprandial plasma serotonin were demonstrated. Plasma metabolome and fecal microbiome read outs were not affected. Conclusions: A daily intake of 0.15 mg nonivamide helps to support to maintain a healthy body composition.

Effects of beta-carotene supplementation on free radical mechanism in healthy adult subjects.

AIM The objective of this study was to examine whether increasing doses of beta-carotene supplements have effects on biological markers of lipid peroxidation in healthy volunteers. SUBJECTS AND METHODS Forty-two healthy subjects were supplemented with 5 mg, 10 mg, 20 mg or 40 mg beta-carotene/day, respectively for five weeks. Plasma beta-carotene and tocopherol levels, malondialdehyde-thiobarbituric reactive substances (MDA-TBARS), and conjugated dienes were determined using high-performance liquid chromatography (HPLC). Concentrations of ascorbic acid, uric acid, and the total antioxidative capacity (TAC) in plasma were measured photometrically. RESULTS Plasma beta-carotene levels increased significantly according to the intervention dose (p < 0.001), and concentrations of tocopherol equivalents and ascorbic acid were within the physiological range except in the 5 mg intervention group where a significant decrease of vitamin C was assessed (p < 0.05). Uric acid in plasma decreased significantly in all groups (p < 0.05) up to the end of investigation, but was within the normal range. Trolox equivalent antioxidative capacity (TEAC) decreased significantly (p < 0.001) in all groups during supplementation. MDA-TBARS remained unchanged after five weeks except for the 40 mg beta-carotene substitution group, where a significant decrease was observed (p < 0.05). CONCLUSION Beta-carotene supplementation of healthy subjects significantly increased plasma beta-carotene status without inducing adverse biological effects. Beta-carotene did not especially protect against oxidative stress, except for the 40 mg group. These data suggest that additional effects of beta-carotene supplementation on well-nourished, healthy subjects are limited.

Gestational Diabetes Mellitus and Diet: A Systematic Review and Meta-analysis of Randomized Controlled Trials Examining the Impact of Modified Dietary Interventions on Maternal Glucose Control and Neonatal Birth Weight

OBJECTIVE Medical nutrition therapy is a mainstay of gestational diabetes mellitus (GDM) treatment. However, data are limited regarding the optimal diet for achieving euglycemia and improved perinatal outcomes. This study aims to investigate whether modified dietary interventions are associated with improved glycemia and/or improved birth weight outcomes in women with GDM when compared with control dietary interventions. RESEARCH DESIGN AND METHODS Data from published randomized controlled trials that reported on dietary components, maternal glycemia, and birth weight were gathered from 12 databases. Data were extracted in duplicate using prespecified forms. RESULTS From 2,269 records screened, 18 randomized controlled trials involving 1,151 women were included. Pooled analysis demonstrated that for modified dietary interventions when compared with control subjects, there was a larger decrease in fasting and postprandial glucose (−4.07 mg/dL [95% CI −7.58, −0.57]; P = 0.02 and −7.78 mg/dL [95% CI −12.27, −3.29]; P = 0.0007, respectively) and a lower need for medication treatment (relative risk 0.65 [95% CI 0.47, 0.88]; P = 0.006). For neonatal outcomes, analysis of 16 randomized controlled trials including 841 participants showed that modified dietary interventions were associated with lower infant birth weight (−170.62 g [95% CI −333.64, −7.60]; P = 0.04) and less macrosomia (relative risk 0.49 [95% CI 0.27, 0.88]; P = 0.02). The quality of evidence for these outcomes was low to very low. Baseline differences between groups in postprandial glucose may have influenced glucose-related outcomes. As well, relatively small numbers of study participants limit between-diet comparison. CONCLUSIONS Modified dietary interventions favorably influenced outcomes related to maternal glycemia and birth weight. This indicates that there is room for improvement in usual dietary advice for women with GDM.

Reproducibility of MRI Dixon-based attenuation correction in combined PET/MR with applications for lean body mass estimation

The aim of this study was to assess the reproducibility of standard, Dixon-based attenuation correction (MR-AC) in PET/MR imaging. A further aim was to estimate a patient-specific lean body mass (LBM) from these MR-AC data. Methods: Ten subjects were positioned in a fully integrated PET/MR system, and 3 consecutive multibed acquisitions of the standard MR-AC image data were acquired. For each subject and MR-AC map, the following compartmental volumes were calculated: total body, soft tissue (ST), fat, lung, and intermediate tissue (IT). Intrasubject differences in the total body and subcompartmental volumes (ST, fat, lung, and IT) were assessed by means of coefficients of variation (CVs) calculated across the 3 consecutive measurements and, again, across these measurements but excluding those affected by major artifacts. All subjects underwent a body composition measurement using air displacement plethysmography (ADP) that was used to calculate a reference LBMADP. A second LBM estimate was derived from available MR-AC data using a formula incorporating the respective tissue volumes and densities as well as the subject-specific body weights. A third LBM estimate was obtained from a sex-specific formula (LBMFormula). Pearson correlation was calculated for LBMADP, LBMMR-AC, and LBMFormula. Further, linear regression analysis was performed on LBMMR-AC and LBMADP. Results: The mean CV for all 30 scans was 2.1 ± 1.9% (TB). When missing tissue artifacts were excluded, the CV was reduced to 0.3 ± 0.2%. The mean CVs for the subcompartments before and after exclusion of artifacts were 0.9 ± 1.1% and 0.7 ± 0.7% for the ST, 2.9 ± 4.1% and 1.3 ± 1.0% for fat, and 3.6 ± 3.9% and 1.3 ± 0.7% for the IT, respectively. Correlation was highest for LBMMR-AC and LBMADP (r = 0.99). Linear regression of data excluding artifacts resulted in a scaling factor of 1.06 for LBMMR-AC. Conclusion: LBMMR-AC is shown to correlate well with standard LBM measurements and thus offers routine LBM-based SUV quantification in PET/MR. However, MR-AC images must be controlled for systematic artifacts, including missing tissue and tissue swaps. Efforts to minimize these artifacts could help improve the reproducibility of MR-AC.

Main Sources, Socio-Demographic and Anthropometric Correlates of Salt Intake in Austria

Excessive salt intake is known to increase blood pressure and cardiovascular risk. Nevertheless, salt intake exceeds the recommendations in most countries. To face this problem, it is important to identify high consumers as well as the main contributors of salt intake. Overall, data of 2018 adults between 18 and 64 years were analysed to determine the main sources, socio-demographic and anthropometric correlates of salt intake. Dietary intake was assessed from 24-h-recalls, information on socio-demographic characteristics was obtained using a questionnaire and anthropometric data were measured. Salt intake was significantly higher in males than in females. There was a significant positive association between salt intake and body mass index. No significant differences in salt intake were observed for other variables including affluence, educational level, smoking status and physical activity. The main contributor to salt intake were condiments including table salt (32.6%), followed by cereals and cereal products (27.0%), meat and meat products (16.1%) and dairy products (14.0%). These results highlight that specific population groups need to be targeted by public health initiatives and that a reduction in salt intake can only be achieved in tandem with the food producers by the reduction of salt in processed foods.