Evaluation of a validated food frequency questionnaire for self-defined vegans in the United States

Development and validation of the MY-VEG-FFQ: A modular web-based food-frequency questionnaire for vegetarians and vegans

BACKGROUND AND OBJECTIVE

The adoption of plant-based diets in recent years has increased the need for accurate assessments of dietary intake among vegans, vegetarians, semi-vegetarians, and omnivores. This study aimed at developing and validating a modular web-based food-frequency questionnaire (FFQ), the MY-VEG-FFQ. This FFQ was based on the original FFQ (O-FFQ) designed for the Israeli population and incorporates a skip algorithm tailored for different dietary patterns.

METHODS

A convenience sample of 101 participants, recruited via social media, completed the MY-VEG FFQ, as well as a three-day food records, which served as the gold standard for this research. Relative validity of the new FFQ was evaluated by comparing nutrients with those in the three-day food records, using Pearson correlation coefficients, Bland-Altman plots, and cross-classification. The results were compared with 90 O-FFQs that previously had been completed by vegans.

RESULTS

The validation analysis showed that nutrient-intake estimates were generally higher for the MY-VEG-FFQ than those of the three-day food records. Pearson correlation coefficients ranged between 0.25-0.63, indicating an acceptable agreement between the two tools. The proportion of participants with exact or adjacent quartile agreement was between 73%-82%. The Bland-Altman analysis revealed overestimation of nutrient intake via the MY-VEG-FFQ. Compared to the O-FFQ, vegans who completed the MY-VEG-FFQ reported consumption of more food items. Additionally, the MY-VEG-FFQ showed a significantly higher intake of most macro- and micronutrients.

CONCLUSIONS

The My-VEG-FFQ demonstrated reasonable validity in assessing dietary intake among people who followed a plant-based diet. However, it tended to overestimate nutrient intake compared to the three-day food records. The development of a modular web-based FFQ with a skip algorithm tailored for specific dietary patterns, fills a crucial gap in accurately assessing the dietary intake of these populations. The MY-VEG-FFQ offers a practical and cost-effective tool for evaluating long-term dietary consumption among people who follow different dietary patterns.

The Association between Vegan Dietary Patterns and Physical Activity-A Cross-Sectional Online Survey

A balanced diet and sufficient physical activity (PA) are known to have positive health effects. The relationship between a vegan diet and PA levels is understudied. This cross-sectional online survey aimed to analyze whether different vegan dietary patterns differ in PA. In total, 516 vegan participants were included (June to August 2022). Different dietary patterns were compiled through principal component analysis, while group differences were calculated using independent tests, or chi-squared tests as well as logistic regression analyses. The population had an average age of 28.0 (SD: 7.7) years and had been living vegan for 2.6 (95% CI: 2.5-3.0) years. Two dietary patterns, the "convenience" and the "health-conscious" group, were identified. People with a convenience dietary pattern had significantly higher odds of sitting more (OR 1.10, 95% CI 1.04-1.18) and not achieving aerobic PA (OR 1.81, 95% CI 1.18-2.79) or strength training recommendations (OR 1.81, 95% CI 1.26-2.61) than people with a health-conscious dietary pattern. This study suggests the heterogeneity of vegan diets and that dietary patterns must be differentiated, as they also differ in the level of PA. Additional studies involving complete dietary assessment with a focus on ultraprocessed foods, blood metabolite analysis, and objective PA assessment are required.

Assessing Diet and Nutritional Intake of Rural Children in Zambia Using a Food Frequency Questionnaire

In this survey, to assess the energy and nutrient intake of rural children in Zambia, a semi-quantitative food frequency questionnaire (FFQ) was developed using the direct weighing method for 126 children, and then a dietary survey with 153 children was conducted using the FFQ. The dietary survey revealed that rural children in Zambia are deficient in energy intake compared to international standards. However, the protein intake met the recommended level; most of it came from vegetables. The carbohydrate intake rate was high, while the fat intake rate was relatively low because of a diet that was highly dependent on maize.

A Vegan Diet Is Associated with a Significant Reduction in Dietary Acid Load: Post Hoc Analysis of a Randomized Controlled Trial in Healthy Individuals

The composition of diet strongly affects acid–base homeostasis. Western diets abundant in acidogenic foods (meat and cheese) and deficient in alkalizing foods (fruits and vegetables) increase dietary acid load (DAL). A high DAL has been associated with numerous health repercussions, including cardiovascular disease and type-2-diabetes. Plant-based diets have been associated with a lower DAL; however, the number of trials exploring this association is limited. This randomized-controlled trial sought to examine whether an isocaloric vegan diet lowers DAL as compared to a meat-rich diet. Forty-five omnivorous individuals were randomly assigned to a vegan diet (n = 23) or a meat-rich diet (n = 22) for 4 weeks. DAL was determined using potential renal acid load (PRAL) and net endogenous acid production (NEAP) scores at baseline and after 3 and 4 weeks, respectively. After 3 weeks, median PRAL (−23.57 (23.87)) and mean NEAP_R (12.85 ± 19.71) scores were significantly lower in the vegan group than in the meat-rich group (PRAL: 18.78 (21.04) and NEAP_R: 60.93 ± 15.51, respectively). Effects were mediated by a lower phosphorus and protein intake in the vegan group. Our study suggests that a vegan diet is a potential means to reduce DAL, whereas a meat-rich diet substantially increases the DAL burden.

Nutrient status and growth in vegan children

Vegan diets have risen in popularity over the past 9 years. However, few studies have examined nutrient status and the effect of a vegan diet on the growth of children. This study analysed the existing literature on the health impact and growth impact of selected nutrients in vegan children. We assessed the intake of calories and protein, as well as the nutrients iron, calcium, vitamin D, cobalamin and folate. With a small percentage of outliers, vegan children showed normal growth and were less often obese. We found limited evidence that children on a vegan diet can obtain all the examined nutrients. Furthermore, as proper planning and supplementation by caregivers is needed, it is currently unknown how often vegan children follow well-planned diets. Deficiencies in cobalamin, calcium, and vitamin D seem to be the biggest risks associated with a poorly planned vegan diet. For a more definitive assessment, data on the intake and nutrient status of omega-3 fatty acids, zinc, iodine, and selenium in vegan children are needed. Future research should account for demographic shifts in those following a vegan diet, and should discriminate between vegan sub-populations that are open or closed towards scientific approaches, towards health in general, and toward supplementation. Studies should assess the modes and dosages of supplementation and the use of fortified foods or drinks, as well as adherence to the diet itself. Plant ferritin as a source of iron and endogenous cobalamin synthesis warrants further scientific inquiry. In summary, the current literature suggests that a well-planned vegan diet using supplementation is likely to provide the recommended amounts of critical nutrients to provide for normal progression of height and weight in children, and can be beneficial in some aspects. However, data on 5 critical nutrients are still missing, hampering a more definitive conclusion.

Pattern analysis of vegan eating reveals healthy and unhealthy patterns within the vegan diet

OBJECTIVE

This study aimed to identify the types of foods that constitute a vegan diet and establish patterns within the diet. Dietary pattern analysis, a key instrument for exploring the correlation between health and disease, was used to identify patterns within the vegan diet.

DESIGN

A modified version of the EPIC-Norfolk FFQ was created and validated to include vegan foods and launched on social media.

SETTING

UK participants, recruited online.

PARTICIPANTS

A convenience sample of 129 vegans voluntarily completed the FFQ. Collected data were converted to reflect weekly consumption to enable factor and cluster analyses.

RESULTS

Factor analysis identified four distinct dietary patterns including: (1) convenience (22 %); (2) health conscious (12 %); (3) unhealthy (9 %) and (4) traditional vegan (7 %). Whilst two healthy patterns were defined, the convenience pattern was the most identifiable pattern with a prominence of vegan convenience meals and snacks, vegan sweets and desserts, sauces, condiments and fats. Cluster analysis identified three clusters, cluster 1 'convenience' (26·8 %), cluster 2 'traditional' (22 %) and cluster 3 'health conscious' (51·2 %). Clusters 1 and 2 consisted of an array of ultraprocessed vegan food items. Together, both clusters represent almost half of the participants and yielding similar results to the predominant dietary pattern, strengthens the factor analysis.

CONCLUSIONS

These novel results highlight the need for further dietary pattern studies with full nutrition and blood metabolite analysis in larger samples of vegans to enhance and ratify these results.

The impact of lacto-ovo-/lacto-vegetarian and vegan diets during pregnancy on the birth anthropometric parameters of the newborn

Introduction: The data in the literature on the appropriateness of vegetarian diets during pregnancy and the impact on the birth anthropometric parameters of the newborn are divergent and conflicting. The aim of the present study is to compare the birth anthropometric parameters of three groups of children distinguished according to the dietary pattern followed by their mothers during pregnancy. Moreover, the second aim is to study the cultural inference of vegetarianism.Materials and methods: Between September 2017 and May 2018, from the Pediatric Service of the Campus Bio-Medico University Hospital of Rome and vegetarian-oriented societies, detailed information have been provided to all mothers who showed interest in participating in the study. More than 100 mothers gave their consent, but in consideration of the criteria of inclusion and exclusion only 55 with the respective children (for a total of 63 kids) have been enlisted in the study. Based on the dietary pattern followed by women during pregnancy, the participants have been divided into three groups: vegan group, lacto-ovo-/lacto-vegetarian group, and omnivorous group. The data necessary for the study have been collected through a questionnaire previously created and sent electronically to 55 enrolled mothers.Results: From our statistical analysis, it has emerged that birth weight, both when expressed in grams and when expressed in growth percentiles, of the vegan mothers' children is lower than that of the omnivorous mothers' children. No significant difference has emerged from the comparison for the length, cranial circumference and BMI at birth between the three groups.Conclusion: Although from our study statistically significant differences in birth weight between the vegan group and the omnivorous one has emerged, the values of this anthropometric parameter were all included within the physiological range decided by the experts in the field. From this, it emerges that the planning of any type of diet with experts in the field is indispensable to ensure a physiological development of the fetus, but given the limited number of participants we cannot draw unequivocal and certain conclusions on this subject.

Physiological and Dietary Determinants of Iron Status in Spanish Vegetarians

Vegetarian diets may compromise iron status, as they provide non-haem iron which has low bioavailability. Spanish lacto-ovo vegetarians (n = 49) and vegans (n = 55) were recruited and haematological and biochemical iron parameters were analysed. Food and supplements consumption, body composition, physical activity, menstrual blood losses and hormonal contraceptive use were assessed. Four groups were studied: Iron deficiency anaemia (IDA), iron depletion (ferritin <15 ng/mL), iron deficiency (ferritin ≥15 to ≤30 ng/mL), and iron sufficiency (ferritin >30 ng/mL). IDA was uncommon (n = 5, 4.8%), 27.9% of participants were iron-depleted, and 30.8% were iron-deficient. Serum ferritin was lower in women than men (p < 0.001) and IDA and iron depleted individuals were all women. There were no differences attributed to diet type, time being vegetarian or physical activity. The menstrual period length was negatively associated with transferrin saturation (ρ = −0.364, p = 0.001) and hormonal contraceptive use (ρ = −0.276, p = 0.014). Iron supplements were consumed most frequently by IDA and iron-deficient subjects (p = 0.031). Conclusions: Iron status did not vary between lacto-ovo vegetarians and vegans and there was not an influence of the time following a vegetarian diet. Although men were iron-sufficient, iron deficiency was frequent in women, who should apply strategies to increase iron bioavailability, especially if they experience intense menstrual blood losses.

HIV Status Does Not Affect Rectal Microbiome Composition, Diversity, or Stability over Time: A Chicago Women's Interagency HIV Study

It remains unclear whether differences in gut microbiota noted between HIV-infected and uninfected individuals are driven by HIV or sexual behavior. We evaluated rectal swab microbiota of HIV-infected and uninfected women with similar demographic, neighborhood, and diet characteristics enrolled in the Chicago Women's Interagency HIV Study (WIHS). DNA was amplified for sequencing of fragments of bacterial small subunit (SSU or 16S) ribosomal RNA (rRNA) genes. HIV-infected and uninfected women did not differ by Shannon diversity index (p = .14), non-metric multidimensional scaling (NMDS) plot of Bray-Curtis indices (p = .488, r = 0.0027), or copy number of individual taxa. Both groups demonstrated marked microbiome stability over time (p = .889).

Vitamin B12 and folate status in Spanish lacto-ovo vegetarians and vegans

Studies on the nutritional status of vegetarians in Spain are lacking. Prevention of vitamin B₁₂ deficiency is the main concern, as dietary sources are of animal origin. The present study aimed to evaluate vitamin B₁₂ and folate status of Spanish vegetarians using classical markers and functional markers. Participants were adult and healthy lacto-ovo vegetarians (forty-nine subjects) and vegans (fifty-four subjects) who underwent blood analyses and completed a FFQ. Serum vitamin B₁₂, homocysteine (Hcy), methylmalonic acid (MMA), erythrocyte folate and haematological parameters were determined. The effects of the type of plant-based diet, and the intake of supplements and foods were studied by a FFQ. Mean erythrocyte folate was 1704 (sd 609) nmol/l. Clinical or subclinical vitamin B₁₂ deficiency was detected in 11 % of the subjects (MMA>271 nmol/l) and 33 % of the participants showed hyperhomocysteinaemia (Hcy>15 µmol/l). Regarding plant-based diet type, significantly higher Hcy was observed in lacto-ovo vegetarians compared with vegans (P = 0·019). Moreover, use of vitamin B₁₂ supplements involved an improvement of vitamin B₁₂ status but further increase in erythrocyte folate (P = 0·024). Consumption of yoghurts was weakly associated with serum vitamin B₁₂ adequacy (P = 0·049) and that of eggs with lower Hcy (P = 0·030). In conclusion, Spanish vegetarians present high folate status but vitamin B₁₂ subclinical deficiency was demonstrated using functional markers. The lack of influence of dietary sources on functional markers and the strong effect of vitamin B₁₂ supplement intake emphasise the need of cobalamin supplementation in both lacto-ovo vegetarians and vegans.

Healthy Vegan Lifestyle Habits among Argentinian Vegetarians and Non-Vegetarians

Although current research has contributed to the promotion of whole-food plant-based diets, few studies have examined healthy vegan dietary and lifestyle factors, especially in South America. Therefore, we aimed at investigating the adherence to healthy vegan lifestyle habits among Argentinian vegetarians and omnivorous, using a recently developed vegetarian lifestyle index adapted to the vegan dietary pattern. Also, accessibility of vegetarian foods, and the proportion of household income spent on food were assessed in a cross-sectional approach with 1454 participants. The population was comprised of females (84.9%), singles (55.0%), young-adults (mean age 32.1, standard deviation (SD) = 13.6), employed (50.8%), with high educational levels (50.4%), and low prevalence of both tobacco smoking (7.0%) and frequent alcohol consumption (7.6%). The mean score of adherence to healthy vegan lifestyle habits was 6.64 (SD = 1.72), with higher scores indicating better adherence. Non-vegetarians (5.75; 95% confidence interval (CI), 5.61–5.89) had a significantly lower adjusted mean score compared to semi-(6.32; 95% CI, 6.17–6.47), pesco-(6.99; 95% CI, 6.59–7.39), lacto-ovo-vegetarians (7.10; 95% CI, 6.96–7.24), as well as vegans (8.59; 95% CI, 8.35–8.83). The mean proportion of household income spent on food was significantly lower among vegans compared with other dietary patterns. The whole population that was studied showed a low consumption of whole grains, legumes, vegetables, nuts, and seeds. Although vegans showed a better diet and lifestyle pattern there is a need to improve eating and lifestyle habits to address risk factors for non-communicable diseases in Argentina.

A Comparison of Eating Attitudes Between Vegans/Vegetarians and Nonvegans/Nonvegetarians in Terms of Orthorexia Nervosa

This descriptive study was performed to compare signs of orthorexia nervosa and eating habits and attitudes of vegans/vegetarians and nonvegans/nonvegetarians. The study sample included 62 people, of whom 31 were vegan/vegetarian and 31 were nonvegan/nonvegetarian. Data were gathered with a personal characteristics form, Orthorexia Nervosa Evaluation Scale-11, Eating Attitudes Test-40 and Maudsley Obsessive Compulsive Inventory. There were not any significant differences between scores for Orthorexia Nervosa Evaluation Scale-11, Eating Attitudes Test-40 and Maudsley Obsessive Compulsive Inventory (p>0,05). As scores for Orthorexia Nervosa Evaluation Scale-11 decreased, predisposition to orthorexia nervosa increased. Therefore, although correlation coefficients were negative, they were considered positive. There was a significant, negative relation between Eating Habits Test-40 scores and Orthorexia Nervosa Evaluation Scale-11 scores (r=-0.290, p=0.002) and between Maudsley Obsessive Compulsive Inventory scores and Orthorexia Nervosa Evaluation Scale-11 scores (r=-0.319, p=0.012). As poor eating habits and obsessive symptoms increased, so did orthorectic symptoms. In light of obtained results, it seems that people become vegan/vegetarian mainly for ethical reasons and that veganism/vegetarianism is not associated with obsession of healthy eating.

Reproducibility and validity of a semi-quantitative FFQ for trace elements

The aim of this study was to test the reproducibility and validity of a self-administered FFQ for the Trace Element Study of Korean Adults in the Yeungnam area (SELEN). Study subjects were recruited from the SELEN cohort selected from rural and urban areas in Yeungnam, Korea. A semi-quantitative FFQ with 146 items was developed considering the dietary characteristics of cohorts in the study area. In a validation study, seventeen men and forty-eight women aged 38-62 years completed 3-d dietary records (DR) and two FFQ over a 3-month period. The validity was examined with the FFQ and DR, and the reproducibility was estimated using partial correlation coefficients, the Bland-Altman method and cross-classification. There were no significant differences between the mean intakes of selected nutrients as estimated from FFQ1, FFQ2 and DR. The median correlation coefficients for all nutrients were 0·47 and 0·56 in the reproducibility and validity tests, respectively. Bland-Altman's index and cross-classification showed acceptable agreement between FFQ1 and FFQ2 and between FFQ2 and DR. Ultimately, 78 % of the subjects were classified into the same and adjacent quartiles for most nutrients. In addition, the weighted κ value indicated that the two methods agreed fairly. In conclusion, this newly developed FFQ was a suitable dietary assessment method for the SELEN cohort study.