Obese Vegetarians and Omnivores Show Different Metabolic Changes: Analysis of 1340 Individuals

Abstract

Our study evaluated the association between the increase in body mass index (BMI) in men and women (menstruating and non-menstruating) (n = 1340) with different dietary groups (omnivores, semi-vegetarians, lacto-ovo-vegetarian, and vegans) and the measurement of the biochemical markers high-sensitive C-reactive protein (hs-CRP), ferritin, alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), glycated hemoglobin (HbA1C), and insulin resistance index (HOMA-IR). Increasing BMI values in all groups and dietary profiles were related to a significant increase in hs-CRP (p < 0.0001), ALT (p = 0.02), ferritin (p = 0.009), and HbA1C (p < 0.0001), with no difference between dietary groups (p < 0.05). The increase in BMI increases the levels of HOMA-IR (p < 0.0001) and GGT (p < 0.05), with higher values found in men when compared to women (p < 0.0001 for HOMA- IR and p = 0.0048 for GGT). The association between ALT and BMI was different between dietary groups, as it showed a decrease in vegan women who do not menstruate compared to other dietary groups (p = 0.0099). When including only obese individuals (BMI = 30 kg/m2, n = 153) in the analysis, we observed lower concentrations of GGT and ferritin in vegetarians than in omnivores, regardless of gender and menstrual blood loss (p = 0.0395). Our data showed that for both vegetarians and omnivores, the higher the BMI, the worse the metabolic parameters. However, regarding obesity, vegetarians showed better antioxidant status (lower GGT elevation) and lower inflammatory status (lower ferritin elevation), which may provide them with potential protection in the development of morbidities associated with overweight.

Plant-based and high protein diets are associated with a lower risk of obesity among Koreans at a high genetic risk of obesity.

“…This research revealed that modest differences in dietary choices could have a signi cant impact on fat accumulation in the Korean population. Other studies have shown that people who adhere to vegetarian diets are less obese than their omnivorous counterparts [42] and that vegetarians are healthier even at the same BMI [43]. However, the subjects in the present study with a plant-based diet were not necessarily vegetarians.…”

Healthy plant-based diets improve dyslipidemias, insulin resistance, and inflammation in metabolic syndrome. A narrative review

“…Slywitch et al. [ 65 ] analyzed the association between biochemical markers of inflammation, liver function, IR, and BMI values in vegetarian and omnivore individuals. Vegetarian obese individuals had lower concentrations of gamma-glutamyl transferase, a marker of hepatobiliary disease and oxidative stress, and ferritin than omnivores in this cross-sectional study [ 65 ].…”

“… [ 63 ] Cross-sectional 1340 adults (422 men] and 918 women) aged 18-60 y. (1) omnivores (2) semi-vegetarians (3) lacto-ovo- vegetarians and (4) vegans hs-CRP Ferritin No differences in CRP among diet groups A higher prevalence of obesity in omnivores when compared to lacto-ovo vegetarians semi-vegetarians and vegans Regardless of sex: vegetarian obese individuals had lower values of GGT and ferritin concentrations than omnivorous individuals [ 65 ] Cross-sectional 3690 Diabetes-free female participants in the Nurses’ Health Study. FFQ Red meat consumption divided into quartiles.…”

Association of Plant-Based and High-Protein Diets with a Lower Obesity Risk Defined by Fat Mass in Middle-Aged and Elderly Persons with a High Genetic Risk of Obesity

“…This research revealed that modest differences in dietary choices could have a significant impact on fat accumulation in the Korean population. Other studies have shown that people who adhere to vegetarian diets are less obese than their omnivorous counterparts [ 46 ] and that vegetarians are healthier even at the same BMI [ 47 ]. However, the subjects in the present study with a plant-based diet were not necessarily vegetarians.…”