Vegans without stomachs

Updated 23 June 2018

In cases of severe obesity some people have their stomachs or a big part of their stomachs removed surgically. This in theory leads to eating less (a smaller volume of) food.

A small study from Israel included five vegans who underwent this operation. The study includes some nutrient recommendations for vegans who have had their stomachs (partly) cut out.

“Among the 21 patients who declared on vegetarian diet presurgery, 57.2% (n = 12) declared on lacto-ovo pattern, 19.0% (n = 4) declared on pesco-vegetarian pattern, and 23.8% (n = 5) declared on vegan pattern.”

Table 3 [...]
Nutrient Recommendations for [..] vegan bariatric surgery patients
Protein intake requirement following BS [bariatric surgery] is 60–90 gr/day or 1.1–1.5 g/kg ideal weight (i.e., BMI = 25 kg/m2)
• Foods high in protein should be prioritized over foods high in carbohydrates or fats
• Consume a variety of plant-based proteins such as unprocessed soy products, legumes and seitan, [...]
• Patients who fail to consume adequate protein in their diet may need to increase protein intake through protein supplements to preserve muscle mass
• Vegan protein powder are currently available
• Consume plant-based (e.g. unprocessed soy products, legumes, and nuts) [...] high-iron foods [...] and adhere to iron supplementation recommendation
• Life-long supplementation with 45–60 mg/day iron by multivitamin and additional supplement as needed is required for deficiency prevention [Avoid this at all cost if you don’t have iron deficiency.]
• Vitamin C should be consumed by food or supplement with iron supplements in order to ameliorate iron absorption
• Consume high plant-based zinc foods (e.g., unprocessed soy products, legumes, grains, [.] and nut[s]) and adhere to the recommended supplementation
• Organic acids, such as citric acid, should be consumed by food in order to improve zinc absorption
• The routine daily multivitamin should contain 8–22 mg of zinc/day
• Consume [...] plant-based high calcium foods (e.g., unprocessed soy products, chick peas, kale, turnip greens, and Chinese cabbage), [...] and adhere to the recommended supplementation
• 1200–2400 mg/day of calcium by food and supplement should be consume by BS patients
• To date, gaps are present in the literature regarding the association between BS and trace element status
• Consume [a] multivitamin supplement which contains a wide variety of minerals including iodine
• Vitamin B12 absorption decreases following BS because of changes in hydrochloric acid production and decrease of intrinsic factor
• Routine B12 supplementation is required following Roux-en-Y gastric bypass (RYGB) and biliopancreatic diversion (BPD) in order to prevent deficiencies; however, for LSG [laparoscopic sleeve gastrectomy] patients there is currently no such uniform guidance
• All vegetarians [including vegans] should take at least 500 μg/day of a B12 supplementation
• Adhere at least to the routine vitamin B12 supplementation recommendations for vegetarian or vegan patients
• The routine recommended dose of vitamin D post-surgery is 3000 IU, but it depends on the serum concentration (adequate serum levels are >30 ng/ml)
• Supplements of Vitamin D3 which is made from animal sources (lanolin) and vitamin D2 which is made from plant [fungal] sources (UV irradiation of ergosterol from yeast) are available; however, currently vitamin D3 from plant source [lichen] are also available
• At doses lower than 1000 IU, vitamins D2 and D3 appear equally effective; however, at doses higher than 1000 IU/day, vitamin D3 appears to be significantly more effective at raising serum D concentrations
• Adhere to vitamin D supplementation in order to preserve adequate serum levels
• Include ALA sources in the diet such as flaxseed, chia, walnuts, canola oil, and soy [...]
• In cases of supplementation use, supplements of omega-3 fatty acids based on ALA (e.g., flaxseed or clary sage [clary sage seed, Salvia sclarea, see]) or DHA-rich microalgae supplement are available“

An example for a daily meal plan for vegan bariatric surgery patients
   Soy yogurt, 1 teaspoon of flaxseeds and ½ banana
Morning snack
   Whole wheat bread with spoon of hummus salad
   Cup of chick peas, white rice and cooked vegetable
Afternoon snack
   Small apple
   100 g of tofu steak and small vegetable salad with spoon of whole sesame tahini
Night snack
   Soy protein powder with glass of soy milk“

[I have some but very limited knowledge on bariatric surgery. If you somehow can avoid it, and lose weight by eating a healthy, fibre-rich, plant-based diet, I would recommend avoiding this operation. If you regularly overeat consider counseling by a specialized psychologist.
As you can see from the sample menu – this is not a lot of food, and not a lot of fruit and vegetables, so not a lot of antioxidants and other phytonutrients that might be able to aid in the prevention of disease.
If you are a vegan who is considering bariatric surgery or has had bariatric surgery I would love to hear from you.]

Sherf-Dagan S, Hod K, Buch A, Mardy-Tilbor L, Regev Z, Ben-Porat T, Sakran N, Goitein D, Raziel A: Health and Nutritional Status of Vegetarian Candidates for Bariatric Surgery and Practical Recommendations. Obes Surg. 2017 Jul 11. doi: 10.1007/s11695-017-2810-7. [Epub ahead of print]

Here you can see my "standard" nutrient recommendations for vegans with intact stomachs and an intact digestive system. 


"HoloTC and MMA were superior to B12 to detect early changes in B12 status following bariatric surgery. Our data challenge the current concept that liver B12 stores secure long-term maintenance of B12 status. They indicate that B12 treatment in pharmacological doses may be warranted immediately after surgery." (Kornerup et al. 2018)

"Oral VB12 [vitamin B12] supplementation is effective and safe in patients who underwent total gastrectomy and should be considered the preferential form of supplementation." (Moleiro et al. 2018)

"Folic acid supplementation should be advised only after a vitamin B12 deficiency has been excluded or treated, because of the interaction of vitamin B12 and folate. When serum vitamin B12 is <200 pmol/L in BS [bariatric surgery] patients, this should be treated or MMA/homocysteine should be measured at least in order to exclude a deficiency. In addition, customized high-dose MVSs [multivitamin supplements] are recommended, regardless of the type of surgery." (Smelt et al. 2018)

"The efficacy of oral vitamin B-12 supplementation [1000 µg of methylcobalamin per day] was similar to that of hydroxocobalamin injections [2000 µg as the first dose and from then on 1000 µg twice per month] in the present study [with people after Roux-en-Y gastric bypass (RYGB)]. Oral supplementation can be used as an alternative to hydroxocobalamin injections to treat RYGB patients with low values of serum vitamin B-12." (Schijns et al. 2018)

Kornerup LS, HvasCL, Abild CB, Richelsen B, Nexo E: Early changes in vitamin B12 uptake and biomarker status following Roux-en-Y gastric bypass and sleeve gastrectomy. Clin Nutr 2018 Feb 15. pii: S0261-5614(18)30070-0. doi: 10.1016/j.clnu.2018.02.007 . [Epub ahead of print]

Moleiro J, Mao de Ferro S, Ferreira S, Serrano M, Silveira M, Dias Pereira A: Efficacy of Long-Term Oral Vitamin B12 Supplementation after Total Gastrectomy: Results from a Prospective Study. GE Port J Gastroenterol 2018 Apr;25(3):117-122. doi: 10.1159/000481860 Epub 2017 Nov 8.

Schijns W, Homan J, van der Meer L, Janssen IM, van Laarhoven CJ, Berends FJ, Aarts EO: Efficacy of oral compared with intramuscular vitamin B-12 supplementation after Roux-en-Y gastric bypass: a randomized controlled trial. Am J Clin Nutr 2018 Jun 21. doi: 10.1093/ajcn/nqy072 . [Epub ahead of print] 

Smelt HJM, Pouwels S, Said M, Smulders JF: Neuropathy by folic acid supplementation in a patient with anaemia and an untreated cobalamin deficiency: a case report. Clin Obes 2018 May 31. doi: 10.1111/cob.12254 . [Epub ahead of print]