Dietary Intake of High-Protein Foods and Other Major Foods in Meat-Eaters, Poultry-Eaters, Fish-Eaters, Vegetarians, and Vegans in UK Biobank

Vegetarian Epidemiology: Review and Discussion of Findings from Geographically Diverse Cohorts

Epidemiologic cohort studies enrolling a large percentage of vegetarians have been highly informative regarding the nutritional adequacy and possible health effects of vegetarian diets. The 2 largest such cohorts are the European Prospective Investigation into Cancer and Nutrition-Oxford (EPIC-Oxford) and the Adventist Health Study-2 (AHS-2). These cohorts are described and their findings discussed, including a discussion of where findings appear to diverge. Although such studies from North America and the United Kingdom have been important, the large majority of the world's vegetarians live in other regions, particularly in Asia. Findings from recent cohort studies of vegetarians in East and South Asia are reviewed, particularly the Tzu Chi Health Study and Indian Migration Study. Important considerations for the study of the health of vegetarians in Asia are discussed. Vegetarian diets vary substantially, as may associated health outcomes. Cohort studies remain an important tool to better characterize the health of vegetarian populations around the globe.

Associations between active travel and diet: cross-sectional evidence on healthy, low-carbon behaviours from UK Biobank

OBJECTIVES

To examine whether there are associations between active travel and markers of a healthy, low-carbon (HLC) diet (increased consumption of fruit and vegetables (FV), reduced consumption of red and processed meat (RPM)).

DESIGN

Cross-sectional analysis of a cohort study.

SETTINGS

Population cohort of over 500 000 people recruited from 22 centres across the UK. Participants aged between 40 and 69 years were recruited between 2006 and 2010.

PARTICIPANTS

412 299 adults with complete data on travel mode use, consumption of FV and RPM, and sociodemographic covariates were included in the analysis.

EXPOSURE MEASURES

Mutually exclusive mode or mode combinations of travel (car, public transport, walking, cycling) for non-work and commuting journeys.

OUTCOME MEASURES

Consumption of FV measured as portions per day and RPM measured as frequency per week.

RESULTS

Engaging in all types of active travel was positively associated with higher FV consumption and negatively associated with more frequent RPM consumption. Cycling exclusively or in combination with walking was most strongly associated with increased dietary consumption of FV and reduced consumption of RPM for both non-work and commuting journeys. Overall, the strongest associations were between non-work cycling and FV consumption (males: adjusted OR=2.18, 95% CI 2.06 to 2.30; females: adjusted OR=2.50, 95% CI 2.31 to 2.71) and non-work cycling and RPM consumption (males: adjusted OR=0.57, 95% CI 0.54 to 0.60; females: adjusted OR=0.54, 95% CI 0.50 to 0.59). Associations were generally similar for both commuting and non-work travel, and were robust to adjustment with sociodemographic and behavioural factors.

CONCLUSIONS

There are strong associations between engaging in active travel, particularly cycling, and HLC dietary consumption, suggesting that these HLC behaviours are related. Further research is needed to better understand the drivers and dynamics between these behaviours within individuals, and whether they share common underlying causes.

Hematological parameters and prevalence of anemia in white and British Indian vegetarians and nonvegetarians in the UK Biobank

BACKGROUND

There may be differences in hematological parameters between meat-eaters and vegetarians.

OBJECTIVE

The aim of this study was to perform cross-sectional analyses of hematological parameters by diet group in a large cohort in the United Kingdom.

METHODS

A complete blood count was carried out in all UK Biobank participants at recruitment (2006-2010). We examined hemoglobin, red and white blood cell counts, and platelet counts and volume in regular meat eaters (>3 times/wk of red/processed meat consumption, n = 212,831), low meat eaters (n = 213,092), poultry eaters (n = 4815), fish eaters (n = 10,042), vegetarians (n = 6548), and vegans (n = 398) of white ethnicity and meat eaters (n = 3875) and vegetarians (n = 1362) of British Indian ethnicity.

RESULTS

In both white and British Indian populations, compared with regular meat eaters (or meat eaters in Indians), the other diet groups had up to 3.7% lower age-adjusted hemoglobin concentrations (difference not significant in white vegan women) and were generally more likely to have anemia (e.g., 8.7% of regular meat eaters compared with 12.8% of vegetarians in white premenopausal women; P < 0.05 after Bonferroni correction). In the white population, compared with regular meat eaters, all other diet groups had lower age- and sex-adjusted total white cells, neutrophils, lymphocytes, monocytes, and eosinophils (P-heterogeneity < 0.001 for all), but basophil counts were similar across diet groups; in British Indians, there was no significant difference in any of the white blood cell counts by diet group. Compared with white regular meat eaters, the low meat eaters, poultry eaters, fish eaters, and vegans had significantly lower platelet counts and higher platelet volume, whereas vegetarians had higher counts and lower volume. Compared with British Indian meat eaters, vegetarians had higher platelet count and lower volume.

CONCLUSIONS

In the UK Biobank, people with low or no red meat intake generally had lower hemoglobin concentrations and were slightly more likely to be anemic. The lower white blood cell counts observed in low and non-meat eaters, and differences in mean platelet counts and volume between diet groups, warrant further investigation. This observational study was registered at http://www.isrctn.com/ as ISRCTN10125697.

Comparison of Major Protein-Source Foods and Other Food Groups in Meat-Eaters and Non-Meat-Eaters in the EPIC-Oxford Cohort

Differences in health outcomes between meat-eaters and non-meat-eaters might relate to differences in dietary intakes between these diet groups. We assessed intakes of major protein-source foods and other food groups in six groups of meat-eaters and non-meat-eaters participating in the European Prospective Investigation into Cancer and Nutrition (EPIC)-Oxford study. The data were from 30,239 participants who answered questions regarding their consumption of meat, fish, dairy or eggs and completed a food frequency questionnaire (FFQ) in 2010. Participants were categorized as regular meat-eaters, low meat-eaters, poultry-eaters, fish-eaters, vegetarians and vegans. FFQ foods were categorized into 45 food groups and analysis of variance was used to test for differences between age-adjusted mean intakes of each food group by diet group. Regular meat-eaters, vegetarians and vegans, respectively, consumed about a third, quarter and a fifth of their total energy intake from high protein-source foods. Compared with regular meat-eaters, low and non-meat-eaters consumed higher amounts of high-protein meat alternatives (soy, legumes, pulses, nuts, seeds) and other plant-based foods (whole grains, vegetables, fruits) and lower amounts of refined grains, fried foods, alcohol and sugar-sweetened beverages. These findings provide insight into potential nutritional explanations for differences in health outcomes between diet groups.

Vegetarian diets and risk of hospitalisation or death with diabetes in British adults: results from the EPIC-Oxford study

BACKGROUND

The global prevalence of diabetes is high and rapidly increasing. Some previous studies have found that vegetarians might have a lower risk of diabetes than non-vegetarians.

OBJECTIVE

We examined the association between vegetarianism and risk of hospitalisation or death with diabetes in a large, prospective cohort study of British adults.

METHODS

The analysed cohort included participants from the European Prospective Investigation into Cancer and Nutrition (EPIC)-Oxford study who were diabetes free at recruitment (1993-2001), with available dietary intake data at baseline, and linked hospital admissions and death data for diabetes over follow-up (n = 45,314). Participants were categorised as regular meat eaters (≥50 g per day: n = 15,181); low meat eaters (<50 g of meat per day: n = 7615); fish eaters (ate no meat but consumed fish: n = 7092); and vegetarians (ate no meat or fish, including vegans: n = 15,426). We used multivariable Cox proportional hazards models to assess associations between diet group and risk of diabetes.

RESULTS

Over a mean of 17.6 years of follow-up, 1224 incident cases of diabetes were recorded. Compared with regular meat eaters, the low meat eaters, fish eaters, and vegetarians were less likely to develop diabetes (hazard ratio (HR) = 0.63, 95% confidence interval (CI) 0.54-0.75; HR = 0.47, 95% CI 0.38-0.59; and HR = 0.63, 95% CI 0.54-0.74, respectively). These associations were substantially attenuated after adjusting for body mass index (BMI) (low meat eaters: HR = 0.78, 95% CI 0.66-0.92; fish eaters: HR = 0.64, 95% CI 0.51-0.80; and vegetarians: HR = 0.89, 95% CI 0.76-1.05).

CONCLUSIONS

Low meat and non-meat eaters had a lower risk of diabetes, in part because of a lower BMI.

Within- and Between-Subject Variation in Dietary Intake of Fermentable Oligo-, Di-, Monosaccharides, and Polyols Among Patients with Irritable Bowel Syndrome

BACKGROUND

A diet low in fermentable carbohydrates, fermentable oligo-, di-, monosaccharides, and polyols (FODMAPs) is a promising treatment option for patients with irritable bowel syndrome (IBS). In order to correctly estimate and study the intake of FODMAPs, information about within- and between-subject variations in intakes is needed, but is currently lacking.

OBJECTIVES

The aim was to characterize the variation in FODMAP intake among patients with IBS and to calculate how many days of observations are required to capture absolute intakes as well as to rank individuals.

METHODS

Food intake was recorded during 4 consecutive days, and intakes of energy and FODMAPs were calculated. The coefficient of variation within subjects (CVw), coefficient of variation between subjects (CVb), number of days required to estimate an individual's intake, and number of observations required to correctly rank individuals into quartiles of consumption were calculated.

RESULTS

Diet records were provided from 151 women and 46 men with IBS. The reported mean energy intake was 2039 ± 502 kcal among women and 2385 ± 573 kcal among men, and the median FODMAP intakes were 18.7 g (range 3.7-73.4) and 22.8 g (range 3.6-165.7), respectively. The ratio of CVw/CVb for total FODMAP intake was 0.83 for women and 0.67 for men, and below 1 for all FODMAPs. To capture intake of FODMAPs at the individual level, 19 d of observations are required. Ranking individuals within a group would require 2-6 d of observations.

CONCLUSION

There is more variation between subjects than within subjects regarding FODMAP intake. To correctly estimate an individual's absolute intake of FODMAPs, the number of days of diet records required exceeds what is reasonable for a participant to accomplish. However, ranking individuals into quartiles of FODMAP consumption can be achieved using a 4-d food record. This trial was registered at www.clinicaltrials.gov as NCT02107625 and NCT01252550.