Dietary iron intake and iron status of German female vegans: Results of the German Vegan Study

Background: As shown in previous studies vegetarians and especially vegans are at risk for iron deficiency. Our study evaluated the iron status of German female vegans. Methods: In this cross-sectional study, the dietary intakes of 75 vegan women were assessed by two 9-day food frequency questionnaires. The iron status was analyzed on the basis of blood parameters. Results: Mean daily iron intake was higher than recommended by the German Nutrition Society. Still 42% of the female vegans <50 years (young women, YW) had a daily iron intake of <18 mg/day, which is the recommended allowance by the US Food and Nutrition Board. The main dietary sources of iron were vegetables, fruits, cereals and cereal products. Median serum ferritin concentrations were 14 ng/ml for YW and 28 ng/ml for women ≥50 years (old women, OW). In all, 40% (tri-index model (TIM) 20%) of the YW and 12% (TIM 12%) of the OW were considered iron-deficient based on either serum ferritin levels of <12 ng/ml or a TIM. Only 3 women had blood parameters which are defined as iron deficiency anemia. Correlations between serum ferritin levels and dietary factors were not found. Conclusion: Although the mean iron intake was above the recommended level, 40% (TIM 20%) of the YW were considered iron-deficient. It is suggested that especially YM on a vegan diet should have their iron status monitored and should consider taking iron supplements in case of a marginal status. Copyright © 2004 S. Karger AG, Basel

Homocysteine and cobalamin status in German vegans

Objective: The study aimed to evaluate the homocysteine and cobalamin status of German vegans and determine whether the intake of very small amounts of foods of animal origin can improve this status. Design and setting: Cross-sectional study, Germany. Subjects: The dietary and nutritional intakes of 131 vegans (73 women, 58 men; age range: 20.2-82.1 years) were evaluated using a general questionnaire and two food-frequency questionnaires. Results: The prevalence of inadequate cobalamin status in volunteers of the German Vegan Study was 28.2%, and that of hyperhomocysteinaemia, 38.1%. Moderate vegans were affected to a lesser extent than were strict vegans. Duration of veganism and cobalamin concentration were inversely correlated (Spearman's r= - 0.175, P = 0.047). Folate concentration and erythrocyte aspartic acid aminotransferase activity were not correlated with plasma homocysteine concentration, but duration of veganism correlated positively with homocysteine concentration (Spearman's r= 0.319, P < 0.001). Cobalamin and homocysteine concentrations were inversely correlated (when controlling for duration of veganism; r= -0.602, P < 0.001). Conclusion: Cobalamin status needs to be improved in order to minimise the risk of hyperhomocysteinaemia

Diet-dependent net endogenous acid load of vegan diets in relation to food groups and bone health-related nutrients: Results from the German Vegan Study

Background/Aims:Dietary composition has been shown to affect acid-base homeostasis and bone health in humans. We investigated the potential renal acid load (PRAL) and the estimated diet-dependent net acid load (net endogenous acid production, NEAP) in adult vegans and evaluated the relationships between NEAP, food groups and intake of bone health-related nutrients. Methods: The German Vegan Study (GVS) is a cross-sectional study. Data from healthy men (n = 67) and women (n = 87), aged 21–75 years, who fulfilled the study criteria (vegan diet for ≧1 year prior to study start; age ≧18 years, and no pregnancy/childbirth during the last 12 months) were included in the analysis. NEAP values were calculated from diet composition using two models: one based on the protein/potassium quotient and another taking into account an anthropometry-based loss of urinary organic anions. Results:Mean daily intakes of phosphorus, potassium, sodium, magnesium and vitamin C were above, and vitamin D and calcium below Dietary Reference Intake (DRI). Regardless of the model used, the diet in the GVS was characterized by a nearly neutral NEAP. A strong correlation was observed between the NEAP values of the two models (rs = 0.873, p < 0.001). Only the consumption of fruits decreased constantly across the increasing quartiles of NEAP. Conclusions: It can be hypothesized that vegan diets do not affect acid-base homeostasis. With respect to bone health, the significance of this finding needs further investigation

Overall glycemic index and glycemic load of vegan diets in relation to plasma lipoproteins and triacylglycerols

Background: To investigate the overall glycemic index (GI), glycemic load (GL), and intake of dietary fiber, and to examine the associations between these factors and plasma lipoproteins and triacylglycerols in adult vegans in the German Vegan Study (GVS). Methods: Cross-sectional study, Germany. Healthy men (n = 67) and women (n = 87), who fulfilled the study criteria (vegan diet for ≧1 year prior to study start; minimum age of 18 years; no pregnancy/childbirth during the last 12 months) and who participated in all study segments. Results: The average dietary GL of the GVS population was 144, and the average GI was 51.4. The adjusted geometric mean total, HDL, and LDL cholesterol concentrations decreased across the increasing quartiles of GL, carbohydrate and dietary fiber intake. The associations between total cholesterol, HDL cholesterol, LDL cholesterol and GL density and GI were inconsistent. Also, associations between GI, GL, the intake of carbohydrates, and triacylglycerol concentration were not observed. Conclusions: Fiber-rich vegan diets are characterized by a low GI and a low to moderate GL. The data do not support the hypothesis that a carbohydrate-rich diet per se is associated with unfavorable effects on triaclyglycerols that would be predicted to increase the risk of coronary heart disease