Integrated Health Nutritional Guidelines for the Surgical Weight Loss Patient: Micronutrients
Publication Date: January 1, 2017
Last Updated: March 14, 2022
1. Pre-WLS Nutrient Screening Recommendations
Thiamin
Routine pre-WLS screening* is recommended for all patients. (C, , 3)
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Vitamin B12 (cobalamin)
Routine pre-WLS screening of B12 is recommended for all patients. (B, , 2)
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Serum MMA is the recommended assay for B12 evaluation for symptomatic or asymptomatic patients and in those with history of B12 deficiency or preexisting neuropathy. (B, , 2)
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Folate (Folic Acid)
Routine pre-WLS screening is recommended for all patients. (B, , 2)
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Iron
Routine pre-WLS screening is recommended for all patients. (B, , 2)
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Screening patients for iron status, but not for the purpose of diagnosing iron deficiency, may include the use of ferritin levels. (B, , 2)
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A combination of tests (serum iron with serum transferrin saturation and total iron-binding capacity) is recommended for diagnosing iron deficiency. (B, , 2)
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Screening for iron deficiency should include assessment of clinical signs and symptoms common to this condition (e.g., feeling tired and weak, decreased work performance, decreased immune function, and glossitis). (B, , 2)
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Vitamin D and Calcium
Routine pre-WLS screening is recommended for all patients. (A, , 1)
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Routine pre-WLS screening of calcium status, vitamin D deficiency and insufficiency is particularly important for pre- and postmenopausal women. (D, , 4)
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Fat-soluble vitamins (A, E, K)
Routine pre-WLS screening is recommended for all patients. (C, , 3)
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Zinc
Routine pre-WLS screening of zinc status is recommended for patients before RYGB or BPD/ DS. (D, , 3)
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Zinc assays in pre-WLS patients should be interpreted in light of the fact that patients with obesity have lower serum zinc levels and lower concentrations of zinc in plasma and erythrocytes than leaner patients. Thus, repletion of zinc is indicated when signs and symptoms are evident and zinc assays are severely low. (C, , 3)
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Copper
Routine pre-WLS screening of copper using serum copper and ceruloplasmin is recommended for patients before RYGB or BPD/DS, but results must be interpreted with caution. (D, , 4)
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Erythrocyte superoxide dismutase is the preferred assay for determining copper status in patients who have undergone WLS. It is a more precise biomarker for screening of copper deficiency when it is available and affordable. (D, , 4)
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* “Routine pre-WLS screening” refers to acquiring a nutrient baseline before WLS.
2. Post-WLS Nutrient Screening Recommendations
Thiamin
Routine post-WLS screening* is recommended for high-risk WLS groups: (B, , 2)
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- Patients with risk factors for TD
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- Females
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- Blacks
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- Patients not attending a nutritional clinic after surgery
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- Patients with GI symptoms (intractable nausea and vomiting, jejunal dilation, mega-colon, or constipation)
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- Patients with concomitant medical conditions such as cardiac failure (especially those receiving furosemide)
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- Patients with SBBO.
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If signs and symptoms or risk factors are present in post-WLS patients, thiamin status should be assessed at least during the first 6 mo, then every 3–6 mo until symptoms resolve. (B, , 2)
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Vitamin B12
Routine post-WLS screening of vitamin B12 status is recommended for patients who have undergone RYGB, SG, or BPD/DS. (B, , 2)
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More frequent screening (e.g., every 3 mo) is recommended in the first post-WLS year, and then at least annually or as clinically indicated for patients who chronically use medications that exacerbate risk of B12 deficiency: nitrous oxide, neomycin, metformin, colchicine, proton pump inhibitors, and seizure medications. (B, , 2)
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Serum B12 may not be adequate to identify B12 deficiency. It is recommended to include serum MMA with or without homocysteine to identify metabolic deficiency of B12 in symptomatic and asymptomatic patients and in patients with history of B12 deficiency or preexisting neuropathy. (B, , 2)
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Folate
Routine post-WLS screening of folate status is recommended for all patients. (B, , 2)
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Particular attention should be given to female patients of childbearing age. (B, , 2)
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Iron
Routine post-WLS screening of iron status is recommended within 3 mo after surgery, then every 3–6 mo until 12 mo, and annually for all patients. (B, , 2)
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Iron status in post-WLS patients should be monitored at regular intervals using an iron panel, complete blood count, total ironbinding capacity, ferritin, and soluble transferrin receptor (if available), along with clinical signs and symptoms. (C, , 3)
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Additional iron screening in post-WLS patients should be conducted as warranted by clinical signs or symptoms and/or laboratory findings, or in other instances in which a deficiency is suspected. (B, , 2)
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Vitamin D and Calcium
Routine post-WLS screening of vitamin D status is recommended for all patients. (B, , 2)
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More research is needed to establish a recommendation regarding the use of vitamin D binding protein assays as an additional tool for determining vitamin D status in post-WLS patients. (C, , 3)
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Vitamins A, E, K
Post-WLS patients should be screened for vitamin A deficiency within the first postoperative year, particularly those who have undergone BPD/DS, regardless of symptoms. (B, , 2)
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Vitamin A should be measured in patients who have undergone RYGB and BPD/DS, particularly in those with evidence of protein-calorie malnutrition. (B, , 2)
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While vitamin E and K deficiencies are uncommon after WLS, patients who are symptomatic should be screened. (B, , 2)
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Zinc
Post-RYGB and post-BPD/DS patients should be screened at least annually for zinc deficiency. (C, , 3)
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Serum and plasma zinc are the most appropriate biomarkers for zinc screening of post-WLS patients. (C, , 3)
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Zinc should be evaluated in all post-WLS patients when the patient is symptomatic for iron deficiency anemia but screening results for iron deficiency anemia is negative. (C, , 3)
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Post-WLS patients who have chronic diarrhea should be evaluated for zinc deficiency. (D, , 4)
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Copper
Routine post-WLS screening of copper status is recommended at least annually after BPD/DS and RYGB, even in the absence of clinical signs or symptoms of deficiency. (C, , 4)
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In post-WLS patients, serum copper and ceruloplasmin are the recommended biomarkers for determining copper status because they are closely correlated with physical symptoms of copper deficiency. (C, , 4)
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* “Routine post-WLS screening” refers to performing a nutrient assessment every 3–6 months in the first year and annually thereafter, unless otherwise specified.
3. Supplement Recommendations to Prevent Post-WLS Micronutrient Deficiency
Vitamin B1 (Thiamin)
Thiamin supplementation above the RDA is suggested to prevent thiamin deficiency
- All post-WLS patients should take at least 12 mg thiamin daily
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- and preferably a 50 mg dose of thiamin from a B-complex supplement or multivitamin once or twice daily
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to maintain blood levels of thiamin and prevent TD.
Vitamin B12 (Cobalamin)
All post-WLS patients should take vitamin B12 supplementation. (B2)
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Supplement dose for vitamin B12 in post-WLS patients varies based on route of administration:
- Orally by disintegrating tablet, sublingual, or liquid: 350–500 mg daily
- Nasal spray as directed by manufacturer
- Parenteral (IM or SQ): 1000 mg monthly.
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Folate (Folic Acid)
Post-WLS patients should take 400–800 mg oral folate daily from their multivitamin. (B2)
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Women of childbearing age should take 800–1000 mg oral folate daily.. (B2)
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Iron
Post-WLS patients at low risk (males and patients without history of anemia) for post-WLS iron deficiency should receive at least 18 mg of iron from their multivitamin. (C3)
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Menstruating females and patients who have undergone RYGB, SG, or BPD/DS should take at least 45–60 mg of elemental iron daily (cumulatively, including iron from all vitamin and mineral supplements). (C3)
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Oral supplementation should be taken in divided doses separately from calcium supplements, acid-reducing medications, and foods high in phytates or polyphenols. (D3)
Recommendation is downgraded to D, since majority of evidence is from non-WLS patients.
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Vitamin D and Calcium
All post-WLS patients should take calcium supplementation. (C3)
The appropriate dose of daily calcium from all sources varies by surgical procedure:
- BPD/DS: 1800–2400 mg/d
- LAGB, SG, RYGB: 1200–1500 mg/d
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The recommended preventative dose of vitamin D in post-WLS patients should be based on serum vitamin D levels: Recommended vitamin D3 dose is 3000 IU daily, until blood levels of 25(OH)D are greater than sufficient (30 ng/mL). (D4)
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A 70–90% lower vitamin D3 bolus dose is needed (compared to vitamin D2) to achieve the same effects as those produced in healthy non-bariatric surgical patients. (A1)
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To enhance calcium absorption in post-WLS patients:
- Calcium should be given in divided doses.
- Calcium carbonate should be taken with meals.
- Calcium citrate may be taken with or without meals.
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Vitamins A, E, and K
Post-WLS patients should take vitamins A, E, and K, with dosage based on type of procedure:
- LAGB: Vitamin A 5000 IU/d and vitamin K 90–120 ug/d.
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- RYGB and SG: Vitamin A 5000–10,000 IU/d and vitamin K 90–120 ug/d.
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- LAGB, SG, RYGB, BPD/DS: Vitamin E 15 mg/d.
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- DS: Vitamin A (10,000 IU/d) and vitamin K (300 mg/d).
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Higher maintenance doses of fat-soluble vitamins may be required for post-WLS patients with a previous history of deficiency in vitamin A, E, or K. (D4)
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Water-miscible forms of fat soluble vitamins are also available to improve absorption. (D4)
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Special attention should be paid to post-WLS supplementation of vitamin A and K in pregnant women. (D3)
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Zinc
All post-WLS patients should take 4 RDA zinc, with dosage based on type of procedure:
- BPD/DS: Multivitamin with minerals containing 200% of the RDA (16–22 mg/d)
- RYGB: Multivitamin with minerals containing 100–200% of the RDA (8–22 mg/d)
- SG/LAGB: Multivitamin with minerals containing 100% of the RDA (8–11 mg/d).
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To minimize the risk of copper deficiency in post-WLS patients, it is recommended that the supplementation protocol contain a ratio of 8–15 mg of supplemental zinc per 1 mg of copper. (C3)
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Formulation and composition of zinc supplements should be considered in post-WLS patients to calculate accurate levels of elemental zinc provided by the supplement. (D4)
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Copper
All post-WLS patients should take 4 RDA copper as part of routine multivitamin and mineral supplementation, with dosage based on type of procedure:
- BPD/DS or RYGB: 200% of the RDA (2 mg/d)
- SG or LAGB: 100% of the RDA (1 mg/d).
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4. Repletion Recommendations for Post-WLS Micronutrient Deficiency
Thiamin
Practitioners should treat post-WLS patients with suspected thiamin deficiency before or in the absence of laboratory confirmation of deficiency AND monitor and evaluate resolution of signs and symptoms. (C3)
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Repletion dose for TD varies based on route of administration and severity of symptoms:
- Oral therapy: 100 mg 2–3 times daily until symptoms resolve.
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- IV therapy: 200 mg 3 times daily to 500 mg once or twice daily for 3–5 d, followed by 250 mg/d for 3–5 d or until symptoms resolve, then consider treatment with 100 mg/d orally, usually indefinitely or until risk factors have been resolved.
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- IM therapy: 250 mg once daily for 3–5 d or 100–250 mg monthly.
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- Simultaneous administration of magnesium, potassium, and phosphorus should be given to patients at risk for refeeding syndrome.
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Vitamin B12 (Cobalamin)
Post-WLS patients with B12 deficiency should take 1000 mg/d to achieve normal levels and then resume dosages recommended to maintain normal levels. (B2)
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Folate (Folic Acid)
All post-WLS patients with folate deficiency should take an oral dose of 1000 mg of folate daily to achieve normal levels and then resume recommended dosage to maintain normal levels. (B2)
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Folate supplementation above 1 mg/d is not recommended in post-WLS patients because of the potential masking of vitamin B12 deficiency. (B2)
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Iron
In post-WLS patients with post-WLS iron deficiency, oral supplementation should be increased to provide 150–200 mg of elemental iron daily to amounts as high as 300 mg 2–3 times daily. (C3)
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Oral supplementation should be taken in divided doses separately from calcium supplements, acid-reducing medications, and foods high in phytates or polyphenols. (D3)
Recommendation is downgraded to D, since majority of evidence is from non-WLS patients.
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Vitamin D and Calcium
Vitamin D levels must be repleted if deficient or insufficient to normalize calcium. (C3)
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All post-WLS patients with vitamin D deficiency or insufficiency should be repleted with the following doses:
- Vitamin D3 at least 3000 IU/d and as high as 6000 IU/d, or 50,000 IU vitamin D2 1–3 times weekly.
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- Vitamin D3 is recommended as a more potent treatment than vitamin D2 when comparing frequency and amount needed for repletion. However, both forms can be efficacious, depending on the dosing regimen.
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The recommendations for repletion of calcium deficiency varies by surgical procedure:
- BPD/DS: 1800–2400 mg/d calcium
- LAGB, SG, RYGB: 1200–1500 mg/d calcium.
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Vitamin A
In post-WLS patients with vitamin A deficiency without corneal changes: a dose of vitamin A 10,000–25,000 IU/d should be administered orally until clinical improvement is evident (1–2 wk). (D4)
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In post-WLS patients with vitamin A deficiency with corneal changes: a dose of vitamin A 50,000–100,000 IU should be administered IM for 3 d, followed by 50,000 IU/d IM for 2 wk. (D4)
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Post-WLS patients with vitamin A deficiency should also be evaluated for concurrent iron and/or copper deficiencies because these can impair resolution of vitamin A deficiency. (D4)
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Vitamin E
The optimal therapeutic dose of vitamin E in post-WLS patients has not been clearly defined. There is potential for antioxidant benefits of vitamin E to be achieved with supplements of 100–400 IU/d. This is higher than the amount typically found in a multivitamin, thus additional vitamin E supplementation may be required for repletion. (D4)
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Vitamin K
For post-WLS patients with acute malabsorption, a parenteral dose of 10 mg vitamin K is recommended. (D4)
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For post-WLS patients with chronic malabsorption, the recommended dosage of vitamin K is either 1–2 mg/d orally or 1–2 mg/wk parenterally. (D4)
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Zinc
There is insufficient evidence to make a dose-related recommendation for repletion. The previous recommendation of 60 mg elemental zinc orally twice a day needs to be reevaluated in light of emerging research that this dose may be inappropriate. ()
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Repletion doses of zinc in post-WLS patients should be chosen carefully to avoid inducing a copper deficiency. (D3)
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Zinc status should be routinely monitored using consistent parameters throughout the course of treatment. (C3)
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Copper
In post-WLS patients with copper deficiency, the recommended regimen for repletion of copper will vary with the severity of the deficiency. (C3)
- Mild to moderate deficiency (including low hematologic indices): Treat with 3–8 mg/d oral copper gluconate or sulfate until indices return to normal
- Severe deficiency: 2–4 mg/d intravenous copper can be initiated for 6 d or until serum levels return to normal and neurologic symptoms resolve.
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Once copper levels are normal: monitor copper levels every 3 mo. (C3)
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WLS, weight loss surgery; BEL, best evidence level; GI, gastrointestinal; SBBO, small bowel bacterial overgrowth; TD, thiamin deficiency; RYGB, Roux-en-Y gastric bypass; SG, sleeve gastrectomy; BPS/DS, biliopancreatic diversion/duodenal switch; MMA, methyl malonic acid; PTH, parathyroid hormone; AGB, adjustable gastric band.
Recommendation Grading
Overview
Title
Integrated Health Nutritional Guidelines for the Surgical Weight Loss Patient: Micronutrients
Authoring Organization
American Society for Metabolic and Bariatric Surgery
Publication Month/Year
January 1, 2017
Last Updated Month/Year
August 2, 2023
Document Type
Guideline
External Publication Status
Published
Country of Publication
US
Document Objectives
The focus of this paper is to update the 2008 American Society for Metabolic and Bariatric Surgery Nutrition in Bariatric Surgery Guidelines with key micronutrient research in laparoscopic adjustable gastric banding, Roux-en-Y gastric bypass, laparoscopic sleeve gastrectomy, biliopancreatic diversion, and biliopancreatic diversion/duodenal switch.
Target Patient Population
Patients with severe obesity
Inclusion Criteria
Female, Male, Adolescent, Adult, Older adult
Health Care Settings
Ambulatory, Hospital, Operating and recovery room, Outpatient
Intended Users
Nurse, nurse practitioner, physician, physician assistant
Scope
Treatment
Diseases/Conditions (MeSH)
D009765 - Obesity, D050110 - Bariatric Surgery, D018977 - Micronutrients
Keywords
obesity, nutrition, bariatric surgery, micronutrient
Source Citation
J. Parrott et al. / Surgery for Obesity and Related Diseases ] (2017) 00–00
Supplemental Methodology Resources
Methodology
Number of Source Documents
18
Literature Search Start Date
January 1, 2007
Literature Search End Date
April 1, 2016