Health and Nutritional Status of Vegetarian Candidates for Bariatric Surgery and Practical Recommendations

Data on vegetarianism and bariatric surgery (BS) are scarce. We herein describe the health and nutritional status of vegetarian patients who plan to undergo BS and propose combined recommendations for vegetarian patients who undergo BS, based on our clinical experience and current scientific literature in both nutrition fields. Cross-sectional analysis of a prospectively maintained database of all primary laparoscopic sleeve gastrectomies (LSG) performed at a bariatric center of excellence between January 2014 and November 2016 was carried out querying patients who declared a vegetarian or vegan lifestyle before surgery. Preoperative data collected included demographics, anthropometrics, dietary patterns, supplementation use, physical activity, smoking habits, co-morbidities, and blood tests. Each vegetarian was matched to five different omnivores based on age, gender, and BMI. During the study period, 1470 patients underwent primary LSG surgery (63.7% females). Twenty-one declared a vegetarian or vegan lifestyle (1.4%) pre-surgery. Most were classified as lacto-ovo (57.1%) and were driven from ethical reasons (85.7%). No differences were found between vegetarian and omnivore LSG candidates regarding co-morbidities and nutritional deficiencies, except for lower prevalence of impaired fasting glucose (14.3 vs. 47.1%;P = 0.007), lower ferritin levels (54.3 +/- 50.5 vs. 96.8 +/- 121.8 ng/ml; P = 0.052) and higher transferrin levels (313.9 +/- 42.7 vs. 278.4 +/- 40.4 mg/dl; P = 0.009) among the vegetarian cohort. Preoperative use of vitamin B12 and iron supplementation was higher among vegetarian LSG candidates than their omnivore counterparts (57.1 vs. 6.7%;P < 0.001 and 23.8 vs. 6.7%; P = 0.015, respectively). Vegetarians have comparable health status and nutritional deficiencies, lower iron stores, and higher supplementation use before surgery compared to omnivore LSG candidates.