Plant-based dietary patterns and risk of insomnia: a prospective study.

BACKGROUND: Accumulating evidence suggests that dietary factors may affect sleep, but the associations between dietary patterns and insomnia risk have been poorly explored. The aim of this study was to investigate if plant-based diets are associated with reduced insomnia risks in a cohort study design. METHODS: Tzu Chi Health Study participants (N = 5821) recruited from 2007 to 2009 without insomnia were followed until 2018. A traditional classification method (vegetarians vs. non-vegetarians) and a healthful plant-based index (hPDI) were used to define adherence to plant-based dietary patterns. Incident cases of insomnia were ascertained by linking with the National Health Insurance Research Database (NHIRD). Associations between plant-based diets and insomnia were estimated using Cox proportional hazard models. RESULTS: A total of 464 incident cases of insomnia were identified in the 55,562 person-years of follow up. Insomnia risk was lower in vegetarians when compared to non-vegetarians, hazard ratios (HR) 0.47 (95% CI: 0.27, 0.81) and 0.71 (95% CI: 0.55, 0.91) for males and females respectively. Male participants with the highest hPDI were associated with a significant lower risk of insomnia (HR 0.50 [95% CI: 0.30, 0.85]) when compared to those in the lowest quintile. No association between adherence to hPDI and insomnia in female participants was observed. CONCLUSIONS: Our study showed that vegetarians are associated with a lower risk of insomnia, but there may be sex-specific associations between adherence to hPDI and insomnia risk. These favorable associations are important when considering plant-based diets for their potential additional sleep benefits.

A Dietitian-Led Vegan Program May Improve GlycA, and Other Novel and Traditional Cardiometabolic Risk Factors in Patients With Dyslipidemia: A Pilot Study.

Background: Systematic inflammation and lipid profiles are two major therapeutic targets for cardiovascular diseases. The effect of a nutritionally balanced vegan diet on systematic inflammation and lipoprotein subclass awaits further examination. Objective: To investigate the change in novel and traditional cardiometabolic risk factors before and after a dietitian-led vegan program, and to test the bioavailability of vitamin B12 in Taiwanese purple laver as part of a vegan diet. Design: A one-arm pilot intervention study. Participants/Setting: Nine patients with dyslipidemia participated in this 12-week vegan program. Main Outcome Measures: Nuclear Magnetic Resonance (NMR) detected GlycA signals (systematic inflammation) and lipoprotein subclass (atherogenicity); trimethylamine N-oxide (TMAO); and other cardiometabolic risk factors. Statistical Analyses Performed: Wilcoxon signed-rank test. Results: In this 12-week vegan intervention emphasizing whole foods, systematic inflammation improved as indicated by a reduction in GlycA (median: -23 µmol/L, p = 0.01). LDL-c (low-density lipoprotein cholesterol) (median -24 mg/dl, p = 0.04) and LDL-p (low-density lipoprotein particles) (median -75 nmol/L, p = 0.02) both decreased significantly. VLDL (very-low-density lipoprotein) and chylomicron particles showed a decreasing trend (-23.6 nmol/L, p = 0.05). Without caloric restriction, body mass index (BMI) (-0.7 kg/m2, p = 0.03), waist circumferences (-2.0 cm, p < 0.001), HbA1c (-0.2%, p = 0.02), and (HOMA-IR) homeostatic model assessment for insulin resistance (-0.7, p = 0.04) have all improved. The change in the TMAO and vitamin B12 status as measured by holo-transcobalamin appeared to depend on baseline diets, TMAO, and vitamin B12 status. Conclusions: A dietitian-led vegan program may improve systematic inflammation and other novel and traditional cardiometabolic risk factors in high-risk individuals.

A Vegetarian Diet Is Associated with a Lower Risk of Cataract, Particularly Among Individuals with Overweight: A Prospective Study.

BACKGROUND: Cataracts are caused by oxidative stress in the lens of the eyes and plant-based dietary patterns can contain a wide variety of protective antioxidants. However, strict vegetarians with inadequate vitamin B-12 intakes can have elevated homocysteine levels, which could increase the risk of cortical cataracts. Whether the benefits of a vegetarian diet outweigh its risks in the development of cataracts warrants investigation. OBJECTIVE: Our aim was to study the prospective association between a Taiwanese vegetarian dietary pattern and cataract risk. DESIGN: This was a prospective cohort study. PARTICIPANTS/SETTING: The Tzu Chi Health Study recruited 6,002 participants from 2007 to 2009 at Dalin Tzu Chi Hospital. Diet was assessed through a validated food frequency questionnaire. Participants 40 years and older and without cataracts at recruitment (3,095 nonvegetarians and 1,341 vegetarians) were followed until the end of 2014, death, or occurrence of cataracts. MAIN OUTCOME MEASURES: Cataract incident cases ((International Classification of Diseases, 9th Revision, Clinical Modification code 366) were identified by linkage to the National Health Insurance Research Database in Taiwan. STATISTICAL ANALYSIS: Cox proportional hazard regression with age as the underlying scale was used to estimate the association between dietary patterns and cataract risk while adjusting for potential confounders. RESULTS: Compared with nonvegetarians, vegetarians had higher intakes of soy, vegetables, nuts, whole grains, dietary fiber, vitamin C, folate, and vitamin A equivalent. In the 25,103 person-years of follow-up, 476 incident cases of cataracts were identified. A vegetarian diet was associated with a 20% reduced risk of cataracts (hazard ratio 0.80, 95% CI 0.65 to 0.99; P = 0.04) after adjusting for sex, education, smoking, alcohol drinking habits, physical activities, Tzu Chi volunteer status, hypertension, diabetes, hyperlipidemia, corticosteroid prescription, and body mass index (calculated as kg/m2). This association was more pronounced among individuals with overweight (defined as body mass index ≥24 in Taiwan [hazard ratio 0.70, 95% CI 0.50 to 0.99; P = 0.04]). CONCLUSIONS: A vegetarian diet was associated with a lower risk of cataracts, particularly in study participants with overweight.

Characterization of TMAO productivity from carnitine challenge facilitates personalized nutrition and microbiome signatures discovery.

The capability of gut microbiota in degrading foods and drugs administered orally can result in diversified efficacies and toxicity interpersonally and cause significant impact on human health. Production of atherogenic trimethylamine N-oxide (TMAO) from carnitine is a gut microbiota-directed pathway and varies widely among individuals. Here, we demonstrated a personalized TMAO formation and carnitine bioavailability from carnitine supplements by differentiating individual TMAO productivities with a recently developed oral carnitine challenge test (OCCT). By exploring gut microbiome in subjects characterized by TMAO producer phenotypes, we identified 39 operational taxonomy units that were highly correlated to TMAO productivity, including Emergencia timonensis, which has been recently discovered to convert γ-butyrobetaine to TMA in vitro. A microbiome-based random forest classifier was therefore constructed to predict the TMAO producer phenotype (AUROC = 0.81) which was then validated with an external cohort (AUROC = 0.80). A novel bacterium called Ihubacter massiliensis was also discovered to be a key microbe for TMA/TMAO production by using an OCCT-based humanized gnotobiotic mice model. Simply combining the presence of E. timonensis and I. massiliensis could account for 43% of high TMAO producers with 97% specificity. Collectively, this human gut microbiota phenotype-directed approach offers potential for developing precision medicine and provides insights into translational research. Video Abstract.

Emission-related Heavy Metal Associated with Oxidative Stress in Children: Effect of Antioxidant Intake.

Heavy metals, the common pollutants emitted from industrial activities, are believed to cause harmful effects, partially through the mechanism of elevated oxidative stress, and antioxidant intake has been hypothesized to provide a potential protective effect against oxidative stress. This study aims to investigate the heavy metal exposure and the associated oxidative damage of young children living near a petrochemical complex and to assess the protective effect of antioxidant intake. There were 168 children recruited from the kindergartens near a huge petrochemical complex, with 87 as the high exposure group and 81 as the low exposure group. Urinary concentrations of eleven metals were detected by inductively coupled plasma mass spectrometry, and four biomarkers of oxidative stress were measured in urine by liquid chromatography-tandem mass spectrometry. The food frequency questionnaire was collected to assess participants' intake of antioxidants. Multiple linear regression was performed to determine the predictors of metals for oxidative stress and to measure the beneficial effect of antioxidants. Weighted quantile sum regression was performed to determine the contributors among metals to the oxidative stress. Results showed that high exposure group had significantly higher concentrations of chromium, manganese, nickel, arsenic, strontium, cadmium, and lead when compared to those in low exposure group. There was no obviously difference on the total antioxidant intake and dietary profile between two groups. The elevated levels of two oxidative stress markers were significantly associated with most of the urinary metal concentrations in all study subjects after adjusting confounders, while no significant association was found between oxidative stress and antioxidant intake. Among the metals, mercury and strontium showed the dominated contributions for elevated levels of oxidative stress. It concluded that higher metal exposure was associated with elevated oxidative stress but with no protective effect by antioxidant intake among the young children residents near a petrochemical industry.

The risk of urinary tract infection in vegetarians and non-vegetarians: a prospective study.

Urinary tract infection (UTI) is caused principally by ascending Escherichia coli infection via an intestine-stool-urethra route. Recent studies found that the strains of E. coli causing UTIs, called extra-intestinal pathogenic E. coli (ExPEC), were distinct from the intestinal pathogenic strains and normal commensal strains. Further analysis found the meat including poultry and pork is the major reservoir for ExPECs. Vegetarians avoid meat and should theoretically have less exposure to ExPEC. However, no study thus far has examined whether vegetarian diets reduce the risk of UTI. Our aim was to examine the association between vegetarian diet and UTI risk in a Taiwanese Buddhist population. We prospectively followed 9724 Buddhists free of UTI from 2005 to 2014. During the 10-year follow-up, 661 incident UTI cases were confirmed. Diet was assessed through a food frequency questionnaire. Cox regression was used to evaluate the prospective association between a vegetarian diet on risk of UTI while adjusting for age, sex, educational level, alcohol-drinking, smoking, hypertension, diabetes mellitus, hyperlipidemia, and disease conditions predisposing to UTIs. Overall, vegetarian diet was associated with 16% lower hazards (hazard ratio [HR]: 0.84, 95% confidence interval [CI]: 0.71-0.99). In subgroup analysis, the protective association between vegetarian diet and UTI is observed mainly in the female (HR: 0.82, 95% CI: 0.69-0.99), never smokers (HR: 0.80, 95% CI: 0.67-0.95), and for uncomplicated UTI (HR: 0.81, 95% CI: 0.68-0.98).

Vegetarian diet and incidence of total, ischemic, and hemorrhagic stroke in 2 cohorts in Taiwan.

OBJECTIVE: To determine how a vegetarian diet affects stroke incidence in 2 prospective cohorts and to explore whether the association is modified by dietary vitamin B12 intake. METHODS: Participants without stroke in the Tzu Chi Health Study (cohort 1, n = 5,050, recruited in 2007-2009) and the Tzu Chi Vegetarian Study (cohort 2, n = 8,302, recruited in 2005) were followed until the end of 2014. Diet was assessed through food frequency questionnaires in both cohorts at baseline. Stroke events and baseline comorbidities were identified through the National Health Insurance Research Database. A subgroup of 1,528 participants in cohort 1 were assessed for serum homocysteine, vitamin B12, and folate. Associations between vegetarian diet and stroke incidences were estimated by Cox regression with age as time scale, adjusted for sex, education, smoking, alcohol, physical activities, body mass index (only in cohort 1), hypertension, diabetes, dyslipidemia, and ischemic heart diseases. RESULTS: Vegetarians had lower serum vitamin B12 and higher folate and homocysteine than nonvegetarians. In cohort 1, 54 events occurred in 30,797 person-years follow-up. Vegetarians (vs nonvegetarians) experienced lower risk of ischemic stroke (hazard ratio [HR], 0.26; 95% confidence interval [CI], 0.08-0.88). In cohort 2, 121 events occurred in 76,797 person-years follow-up. Vegetarians (vs nonvegetarians) experienced lower risk of overall stroke (HR, 0.52; 95% CI, 0.33-0.82), ischemic stroke (HR, 0.41; 95% CI, 0.19-0.88), and hemorrhagic stroke (HR, 034; 95% CI, 0.12-1.00). Our explorative analysis showed that vitamin B12 intake may modify the association between vegetarian diet and overall stroke (p interaction = 0.046). CONCLUSION: Taiwanese vegetarian diet is associated with a lower risk of ischemic and hemorrhagic strokes.

Vegetarian diet and risk of gout in two separate prospective cohort studies.

BACKGROUNDS & AIMS: Plant-based diets may target multiple pathways in gout pathogenesis (uric acid reduction and anti-inflammation) while improving gout associated cardiometabolic comorbidities. We aim to prospectively examine the relationship between a vegetarian diet and gout, and to explore if this relationship is independent of hyperuricemia. METHODS: We followed 4903 participants in the Tzu Chi Health Study (Cohort1, recruited in 2007-2009) and 9032 participants in the Tzu Chi Vegetarian Study (Cohort2, recruited in 2005) until end of 2014. Baseline serum uric acid was measured in Cohort1. Vegetarian status was assessed through a diet questionnaire that includes dietary habits and a food frequency questionnaire. Incidence of gout was ascertained by linkage to the National Health Insurance Database. Hazard Ratio of gout in vegetarians versus nonvegetarians was assessed by Cox regression, adjusted for age, sex, lifestyle and metabolic risk factors. Hyperuricemia was additionally adjusted in Cohort1. RESULTS: In Cohort1, lacto-ovo vegetarians had the lowest uric acid concentration, followed by vegans, then nonvegetarians (men: 6.05, 6.19, 6.32 mg/dL, respectively; women: 4.92, 4.96, 5.11 mg/dL, respectively); 65 gout cases occurred in the 29,673 person-years of follow-up; vegetarians experienced a lower risk of gout (without adjustment for hyperuricemia: HR: 0.33; 95% CI: 0.14, 0.79; with adjustment for hyperuricemia: HR: 0.40; 95% CI: 0.17, 0.97). In Cohort2, 161 gout cases occurred in the 83,019 person-years follow-up, and vegetarians also experienced a lower risk of gout (HR: 0.61; 95% CI: 0.41, 0.88). CONCLUSION: Taiwanese vegetarian diet is associated with lower risk of gout. This protective association may be independent of baseline hyperuricemia. STUDY REGISTERED: URL: https://www.clinicaltrials.gov. Unique Identifier: NCT03470584.

Vegetarian Diets and Medical Expenditure in Taiwan-A Matched Cohort Study.

Vegetarian diets and lifestyle have been shown to reduce the risk of many chronic non-communicable diseases, which now accounts for the major global burden of diseases. We aimed to determine the contribution of vegetarian diets and lifestyle to the actual direct medical cost in a population-based study. Through linkage to the National Health Insurance Research Database of Taiwan, we compared the health care utilization and medical expenditure of 2166 vegetarians and 4332 age-sex-matched omnivores recruited from the Buddhist Tzu Chi Foundation. Diet and lifestyle questionnaires were self-administered and prospectively collected. We used the general linear model to estimate the 5-year average medical expenditure in vegetarians versus omnivores while adjusting for age, sex, education, exercise habits, smoking, and alcohol drinking. Medical expenses related to non-diet associated lifestyle factors (smoking, alcohol drinking, active community volunteering, and religious emotional support) were estimated through a comparison with the published population medical cost data standardized to match the age and sex characteristics of the cohort. Tzu Chi vegetarians had significantly lower outpatient visits. This translated into 13% lower outpatient (p = 0.007) and 15% lower total medical expenditures (p = 0.008) when compared with the Tzu Chi omnivores, who had an additional 10% lower medical expenditure when compared with the general population. No difference in dental visits and expenses were found between diet groups. Vegetarian diets are associated with significantly lower medical care expenditure and could be an effective strategy to alleviate the medical-economic burden in selected populations.

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.

Using gas chromatography and mass spectrometry to determine 25-hydroxyvitamin D levels for clinical assessment of vitamin D deficiency.

Vitamin D is responsible for multiple metabolic functions in humans. Rickets are the most common disease caused by vitamin D deficiency. It is caused by poor calcium intake resulting in poor serum-ionized calcium. The purpose of this study is to develop a rapid, sensitive, and feasible method to determine the 25-hydroxy-vitamin D3 (25(OH)D3) levels in blood samples for clinical assessment. In this study, gas chromatography coupled mass spectrometry with trimethylsilyl derivatization (TMS-GC-MS) is the most suitable protocol for quantitative analyses of 25(OH)D3. Performance of method was evaluated and compared with liquid chromatography and immunoassay. Method validation has been carried out with plasma specimens. The limit of quantitation of TMS-GC-MS method is 1.5 ppb with good linear correlation. Furthermore, the dietary intake and nutritional status of vegetarian and non-vegetarians in Taiwan were assessed by our validated method. As a result, this vitamin D nutrition survey demonstrates that most Taiwanese people have insufficient vitamin D. Due to dietary habits; the male vegans may have the highest risk of vitamin D deficiency.

Plant-Based Diet, Cholesterol, and Risk of Gallstone Disease: A Prospective Study.

Vegetarian diets may lower symptomatic gallstone disease via cholesterol lowering. This study aimed to examine the risk of symptomatic gallstone disease (GSD) in Taiwanese vegetarians vs. nonvegetarians in a prospective cohort and to explore if this association is related to cholesterol concentration. We prospectively followed 4839 participants, and in the 29,295 person-years of follow-up, 104 new incident GSD cases were confirmed. Diet was assessed through a validated food frequency questionnaire. Symptomatic GSD was ascertained through linkage to the Taiwan National Health Insurance Research Database. Blood cholesterol profiles were measured at recruitment. Cox regression was applied to assess the effect of diet on symptomatic GSD, adjusting for age, education, smoking, alcohol, physical activities, diabetes, kidney diseases, body mass index, lipid-lowering medication, and hypercholesterolemia. Vegetarian diet was associated with a decreased risk of symptomatic GSD compared with nonvegetarian diet in women (hazard ratio [HR], 0.52; 95% confidence interval [CI], 0.28⁻0.96) but not in men. In women, nonvegetarians with hypercholesterolemia had 3.8 times the risk of GSD compared with vegetarians with normal cholesterol (HR, 3.81, 95% CI, 1.61⁻9.01). A vegetarian diet may therefore protect against GSD independent of baseline hypercholesterolemia. A nonvegetarian diet and hypercholesterolemia may have an additive effect in increasing GSD risk in women.

Identification of TMAO-producer phenotype and host-diet-gut dysbiosis by carnitine challenge test in human and germ-free mice.

OBJECTIVE: The gut microbiota-derived metabolite, trimethylamine N-oxide (TMAO) plays an important role in cardiovascular disease (CVD). The fasting plasma TMAO was shown as a prognostic indicator of CVD incident in patients and raised the interest of intervention targeting gut microbiota. Here we develop a clinically applicable method called oral carnitine challenge test (OCCT) for TMAO-related therapeutic drug efforts assessment and personalising dietary guidance. DESIGN: A pharmacokinetic study was performed to verify the design of OCCT protocol. The OCCT was conducted in 23 vegetarians and 34 omnivores to validate gut microbiota TMAO production capacity. The OCCT survey was integrated with gut microbiome, host genotypes, dietary records and serum biochemistry. A humanised gnotobiotic mice study was performed for translational validation. RESULTS: The OCCT showed better efficacy than fasting plasma TMAO to identify TMAO producer phenotype. The omnivores exhibited a 10-fold higher OR to be high TMAO producer than vegetarians. The TMAO-associated taxa found by OCCT in this study were consistent with previous animal studies. The TMAO producer phenotypes were also reproduced in humanised gnotobiotic mice model. Besides, we found the faecal CntA gene was not associated with TMAO production; therefore, other key relevant microbial genes might be involved. Finally, we demonstrated the urine TMAO exhibited a strong positive correlation with plasma TMAO (r=0.92, p<0.0001) and improved the feasibility of OCCT. CONCLUSION: The OCCT can be used to identify TMAO-producer phenotype of gut microbiota and may serve as a personal guidance in CVD prevention and treatment. TRIAL REGISTRATION NUMBER: NCT02838732; Results.

Vegetarian diet, change in dietary patterns, and diabetes risk: a prospective study.

BACKGROUND/OBJECTIVES: Vegetarian diets are inversely associated with diabetes in Westerners but their impact on Asians-whose pathophysiology differ from Westerners-is unknown. We aim to investigate the association between a vegetarian diet, change in dietary patterns and diabetes risk in a Taiwanese Buddhist population. METHODS: We prospectively followed 2918 non-smoking, non-alcohol drinking Buddhists free of diabetes, cancer, and cardiovascular diseases at baseline, for a median of 5 years, with 183 incident diabetes cases confirmed. Diet was assessed through a validated food frequency questionnaire at baseline and a simple questionnaire during follow-ups. Incident cases of diabetes were ascertained through follow-up questionnaires, fasting glucose and HbA1C. Stratified Cox Proportional Hazards Regression was used to assess the effect of diets on risk of diabetes. RESULTS: Consistent vegetarian diet was associated with 35% lower hazards (HR: 0.65, 95% CI: 0.46, 0.92), while converting from a nonvegetarian to a vegetarian pattern was associated with 53% lower hazards (HR: 0.47, 95% CI: 0.30, 0.71) for diabetes, comparing with nonvegetarians while adjusting for age, gender, education, physical activity, family history of diabetes, follow-up methods, use of lipid-lowering medications, and baseline BMI. CONCLUSION: Vegetarian diet and converting to vegetarian diet may protect against diabetes independent of BMI among Taiwanese.

Vascular burden and brain aging in a senior volunteer cohort: A pilot study.

OBJECTIVE: To test the feasibility of establishing a senior volunteer cohort and describe vascular risks, cognitive function, and brain aging indices in a pilot study. MATERIALS AND METHODS: We enrolled 40 senior volunteers from the Tzu Chi Foundation and other organizations in Hualien in 2014-2015. We conducted in-person interviews to collect information on demographic features, physical fitness, dietary habits, comorbidities, and narratives of aging. Vascular risks including blood pressure, body mass index (BMI), serum glucose level, and lipid profile were examined. Each participant underwent a comprehensive battery of neuropsychological tests and structural brain magnetic resonance imaging (MRI). Descriptive statistics and tabulation were applied to characterize this pilot cohort. RESULTS: There were more volunteers from the Tzu Chi Foundation (n = 25) than other organizations. The mean age was 66.7 years (standard deviation = 5.1) and there was a female predominance (M:F = 13:27). The mean number of comorbid chronic diseases was 2.1 and the mean BMI was 24.5. Most participants (77.5%) engaged in outdoor walking activities every week. Nutrient intake in vegetarians (n = 18) did not differ from nonvegetarians except for lower Vitamin B12 levels (mean = 0.9 µg). All participants but one scored 26 or above in the Mini-Mental State Examination (mean = 28.4). Among the other cognitive tests, only one task related to inhibition and switching abilities was at the low average level. The mean values of vascular risk markers were within the normal ranges. The most common genotype of apolipoprotein E was ɛ3/ɛ3 (n = 32). The quality of MRI was sufficient for volumetric analysis. CONCLUSION: It is feasible to establish a volunteer-based cohort to study brain aging in Taiwan. The senior volunteers were physically active and cognitively healthy. Vascular risks were well distributed among these participants. Future longitudinal study will allow us to observe changes in these markers over time and provide dynamic evidence about vascular health and cognitive aging.

Vegetarian diet reduces the risk of hypertension independent of abdominal obesity and inflammation: a prospective study.

OBJECTIVES: A vegetarian diet may prevent elevation of blood pressures and lower the risk for hypertension through lower degrees of obesity, inflammation, and insulin resistance. This study investigated the association between a vegetarian diet and hypertension incidence in a cohort of Taiwanese adult nonsmokers and examined whether this association was mediated through inflammation, abdominal obesity, or insulin resistance (using fasting glucose as a proxy). METHODS: This matched cohort study was from the 1994-2008 MJ Health Screening Database. Each vegetarian was matched with five nonvegetarians by age, sex, and study site. The analysis included 4109 nonsmokers (3423 nonvegetarians and 686 vegetarians), followed for a median of 1.61 years. The outcome includes hypertension incidence, as well as SBP and DBP levels. Regression analysis was performed to assess the association between vegetarian diet and hypertension incidence or future blood pressure levels in the presence/absence of potential mediators. RESULTS: Vegetarians had a 34% lower risk for hypertension, adjusting for age and sex (odds ratio: 0.66, 95% confidence interval: 0.50-0.87; SBP: -3.3 mmHg, P < 0.001; DBP: -1.5 mmHg, P < 0.001). The results stay statistically significant after further adjustment for C-reactive protein, waist circumference, and fasting glucose (odds ratio: 0.72, 95% confidence interval: 0.55-0.86; SBP: -2.4 mmHg, P < 0.05; DBP: -1.1 mmHg, P < 0.05). The protective association between vegetarian diet and hypertension appeared to be consistent across age groups. CONCLUSION: Taiwanese vegetarians had lower incidence of hypertension than nonvegetarians. Vegetarian diets may protect against hypertension beyond lower abdominal obesity, inflammation, and insulin resistance.

Cross-sectional and longitudinal comparisons of metabolic profiles between vegetarian and non-vegetarian subjects: a matched cohort study.

Several previous cross-sectional studies have shown that vegetarians have a better metabolic profile than non-vegetarians, suggesting that a vegetarian dietary pattern may help prevent chronic degenerative diseases. However, longitudinal studies on the impact of vegetarian diets on metabolic traits are scarce. We studied how several sub-types of vegetarian diets affect metabolic traits, including waist circumference, BMI, systolic blood pressure (SBP), diastolic blood pressure, fasting blood glucose, total cholesterol (TC), HDL, LDL, TAG and TC:HDL ratio, through both cross-sectional and longitudinal study designs. The study used the MJ Health Screening database, with data collected from 1994 to 2008 in Taiwan, which included 4415 lacto-ovo-vegetarians, 1855 lacto-vegetarians and 1913 vegans; each vegetarian was matched with five non-vegetarians based on age, sex and study site. In the longitudinal follow-up, each additional year of vegan diet lowered the risk of obesity by 7 % (95 % CI 0·88, 0·99), whereas each additional year of lacto-vegetarian diet lowered the risk of elevated SBP by 8 % (95 % CI 0·85, 0·99) and elevated glucose by 7 % (95 % CI 0·87, 0·99), and each additional year of ovo-lacto-vegetarian diet increased abnormal HDL by 7 % (95 % CI 1·03, 1·12), compared with non-vegetarians. In the cross-sectional comparisons, all sub-types of vegetarians had lower likelihoods of abnormalities compared with non-vegetarians on all metabolic traits (P<0·001 for all comparisons), except for HDL and TAG. The better metabolic profile in vegetarians is partially attributable to lower BMI. With proper management of TAG and HDL, along with caution about the intake of refined carbohydrates and fructose, a plant-based diet may benefit all aspects of the metabolic profile.

Taiwanese vegetarians and omnivores: dietary composition, prevalence of diabetes and IFG.

INTRODUCTION: Vegetarian diets have been shown to improve glucose metabolism and reduce risk for diabetes in Westerners but whether Chinese vegetarian diets have the same benefits is unknown. METHODS: We evaluated the association between diet and diabetes/impaired fasting glucose (IFG) among 4384 Taiwanese Buddhist volunteers and identified diabetes/IFG cases from a comprehensive review of medical history and fasting plasma glucose. RESULTS: Vegetarians had higher intakes of carbohydrates, fiber, calcium, magnesium, total and non-heme iron, folate, vitamin A, and lower intakes of saturated fat, cholesterol, and vitamin B12. Besides avoiding meat and fish, vegetarians had higher intakes of soy products, vegetables, whole grains, but similar intakes of dairy and fruits, compared with omnivores. The crude prevalence of diabetes in vegetarians versus omnivores is 0.6% versus 2.3% in pre-menopausal women, 2.8% versus 10% in menopausal women, and 4.3% versus 8.1% in men. Polytomous logistic regression adjusting for age, body mass index, family history of diabetes, education, leisure time physical activity, smoking and alcohol, showed that this vegetarian diet was negatively associated with diabetes and IFG in men (OR for diabetes: 0.49, 95% CI: 0.28-0.89; OR for IFG: 0.66, 95% CI: 0.46-0.95); in pre-menopausal women (OR for diabetes: 0.26, 95% CI: 0.06-1.21; OR for IFG: 0.60, 95% CI: 0.35-1.04); and in menopausal women (OR for diabetes: 0.25, 95% CI: 0.15-0.42; OR for IFG: 0.73, 95% CI: 0.56-0.95). CONCLUSION: We found a strong protective association between Taiwanese vegetarian diet and diabetes/IFG, after controlling for various potential confounders and risk factors.

Relative validity and reproducibility of a quantitative FFQ for assessing nutrient intakes of vegetarians in Taiwan.

OBJECTIVE: To assess the relative validity and reproducibility of the quantitative FFQ used in the Tzu Chi Health Study (TCHS). DESIGN: The reproducibility was evaluated by comparing the baseline FFQ with the 2-year follow-up FFQ. The validity was evaluated by comparing the baseline FFQ with 3 d dietary records and biomarkers (serum folate and vitamin B12). Median comparison, cross-classification and Spearman correlation with and without energy adjustment and deattenuation for day-to-day variation were assessed. SETTING: TCHS is a prospective cohort containing a high proportion of true vegetarians and part-time vegetarians (regularly consuming a vegetarian diet without completely avoiding meat). SUBJECT: Subsets of 103, seventy-eight and 1528 TCHS participants were included in the reproducibility, dietary record-validity and biomarker-validity studies, respectively. RESULTS: Correlations assessing the reproducibility for repeat administrations of the FFQ were in the range of 0·46-0·65 for macronutrients and 0·35-0·67 for micronutrients; the average same quartile agreement was 40%. The correlation between FFQ and biomarkers was 0·41 for both vitamin B12 and folate. Moderate to good correlations between the baseline FFQ and dietary records were found for energy, protein, carbohydrate, saturated and monounsaturated fat, fibre, vitamin C, vitamin A, K, Ca, Mg, P, Fe and Zn (average crude correlation: 0·47 (range: 0·37-0·66); average energy-adjusted correlation: 0·43 (range: 0·38-0·55); average energy-adjusted deattenuated correlation: 0·50 (range: 0·44-0·66)) with same quartile agreement rate of 39% (range: 35-45%), while misclassification to the extreme quartile was rare (average: 4% (range: 0-6%)). CONCLUSIONS: The FFQ is a reliable and valid tool to rank relative intake of major nutrients for TCHS participants.