The Essential Guide to Gastric Sleeve and Gastric Bypass Vitamins

Confused about which bariatric vitamin and mineral supplements are right for you? There are several things to keep in mind when making your selection.

Supplements after surgery

It’s been found that even prior to bariatric surgery, many people have one or more micronutrient (vitamin or mineral) deficiencies,1 and the risk of a nutrition deficiency increases with time after surgery. This happens for several reasons:2

  • Inadequate nutrient intake, often due to a lower intake of food
  • An altered or decreased ability to absorb vitamins and minerals
  • An increased need for certain vitamins and minerals

One thing that many healthcare practitioners agree on is that all patients after surgery should take vitamin and mineral supplements for life.

Because of this, there are several published bariatric guidelines that help healthcare practitioners guide you in selecting which supplements you need after surgery. 3,4

All vitamins and minerals play an important role in the body and are needed in adequate amounts for general health and wellbeing. Bariatric patients need larger doses of vitamins and minerals than the general public. Below, we review some key nutrients that are recommended in much higher amounts post-surgery.

Important micronutrients to take after bariatric surgery

Vitamin D

  • Vitamin D is the number one reported micronutrient deficiency before and after surgery.
  • Vitamin D is a fat-soluble vitamin found in very few foods; however, it is produced in the body when ultraviolet rays from the sun hit the skin.
  • It is responsible for hundreds of processes within the body including promotion of calcium absorption, maintaining calcium and phosphorus balance in the blood, playing a role in the immune system, and in cellular functioning. 
  • Clinical symptoms of vitamin D deficiency are rare but can include bone or muscle pain.


  • Calcium is the most abundant mineral in the body and is found primarily in dairy food sources, but also in dark green vegetables like broccoli and kale.
  • Like vitamin D, calcium is needed for several processes in the body including bone structure and function, contracting and dilating blood vessels, muscle function, nerve transmission, and hormonal secretion.
  • Very few obvious clinical signs occur with calcium deficiency as the body controls blood levels of calcium; the most obvious signs of calcium deficiency occur long-term as bone breakage.


  • Iron is a mineral that is naturally present in many foods.
  • It is necessary for hemoglobin and myoglobin (proteins that carry oxygen to tissues and muscles) structure, and supporting metabolism, growth, development, cellular functioning, and synthesis of several hormones and connective tissue.
  • Symptoms of iron deficiency include lack of energy, GI disturbances, poor concentration and difficulty with memory, decreased immune function, and poor body temperature regulation.

Vitamin B12

  • Vitamin B12 is a water-soluble vitamin found in animal products and added to fortified grains.
  • It is necessary for red blood cell formation, DNA synthesis, and brain function.
  • Symptoms of vitamin B12 deficiency include fatigue, weakness, loss of appetite, and constipation.

Thiamin (Vitamin B1)

  • Thiamin is a water-soluble vitamin found primarily in whole grains, meat, and fish. It is also added to fortified grains.
  • It is necessary for energy metabolism (especially to metabolize carbohydrates and alcohol, so people with a high intake of either have greater thiamin needs), and plays a role in the growth and function of cells.
  • Symptoms of deficiency include lack of appetite, weight loss, confusion, short-term memory loss, and muscle weakness.

Tips for Choosing a Bariatric Vitamin and Mineral Supplement

TIP 1: Know your appropriate nutrient dose

Specific doses of vitamins and minerals are recommended after surgery to prevent a micronutrient deficiency. Use the list below to ensure you are taking the right dose of the right nutrient. Doses vary depending on procedure type, gender, and other factors.Your healthcare practitioner can help guide you to determine the level you should take specific to your individual requirements.

The American Society for Metabolic and Bariatric Surgery (ASMBS), the largest nonprofit medical organization dedicated to metabolic and bariatric surgery and obesity-related diseases and conditions, recommends vitamin and mineral supplementation following bariatric surgery to prevent nutritional deficiencies.3,4 Recommended doses for oral vitamin and mineral intake are shown below.

Vitamin A5,000 IU–10,000 IU (1,500 mcg–3,000 mcg) per day
Vitamin DAt least 3,000 IU (75 mcg) per day
Vitamin E15 mg (16.7-22.4 IU depending on form of vitamin E)
Vitamin K90-300 mcg per day
Thiamin12-100 mg per day
Riboflavin100-200% DV per day
Niacin100-200% DV per day
Vitamin B6100-200% DV per day
Vitamin B12350-500 mcg per day
Folic Acid400-800 mcg per day
Calcium1,200-2,400 mg per day
Iron18-60 mg per day
Copper1-2 mg per day
Zinc8-22 mg per day

Additional vitamins and minerals that do not have a specific bariatric guideline, but are essential for health and wellbeing:

  • Vitamin C
  • Biotin
  • Pantothenic acid
  • Iodine
  • Copper
  • Manganese
  • Chromium
  • Molybdenum
  • Choline
  • Phosphorus
  • Potassium
  • Sodium
  • Sulfur
  • Chloride
  • Fluoride
  • Selenium
  • Magnesium

It is difficult to determine and maintain a regimen that includes the proper nutrients at the recommended levels for a bariatric patient. Bariatric specialty supplements accomplish this. The appropriate nutrients and ratios have been developed into bariatric-specific formulations to provide convenience and peace of mind for patients.

TIP 2: Choose a trusted brand that guarantees what is on the label is actually what is inside the bottle

Vitamin and mineral supplements are regulated by the FDA. However, not all companies choose to closely follow the regulations and current Good Manufacturing Practices (cGMP) requirements.

Check with the manufacturer regarding their quality processes. Here are some standards to look for:

Scientific formulations: Are the products created specifically for bariatric patients? What are the qualifications of the company’s research and development team? Check for references that indicate an evidence-based approach to product development—one that incorporates the latest published research and ASMBS guidelines.

Comprehensive testing: What kind of testing is performed on the raw ingredients and finished goods? Ingredient suppliers may provide incorrect information to manufacturers that can end up on the product label. What is the manufacturer doing to ensure quality and efficacy of the ingredients in their products? High-quality supplements should include tests on raw materials as well as final formulations. Supplement ingredients lose efficacy over time. Ask whether products are tested at expiration date, and not just at time of manufacture. 

Label accuracy and transparency: Ask whether the sources have been chosen with a bariatric patient’s physiology in mind. Some mineral sources can cause GI distress or be less bioavailable. Read the supplement facts label. Are the vitamin sources listed? As an example, vitamin D3 is preferred over vitamin D2 because it is more effective at maintaining blood levels of vitamin D.5

Quality factors should also be considered. While chelated mineral sources are considered superior, proof of chelation is difficult to obtain. Companies that do not conduct their own raw materials testing are just taking the word of their suppliers. High-quality companies test raw materials and strive to use the most bioavailable forms for bariatric surgery patients.

GMP-Certified:  Check that the manufacturer follows current Good Manufacturing Practices (cGMP) to ensure quality standards. 

TIP 3: Choose a product that you like and are willing to take every day

While we know that there are bariatric-specific, identified doses of vitamins and minerals that your body needs daily to avoid a nutrient deficiency, we also know that you must take your supplements in order for them to work.

If at first you don’t succeed, try and try again! Healthcare practitioners know that patients are much more likely to stick to their regimens lifelong when they enjoy taking their supplements. If you don’t like a chewable, try another flavor or switch to a capsule, because finding a supplement that you like taking and that tastes good is critical to your success. 

Remember, to avoid nutrient deficiencies after surgery, it is critical that you do the following lifelong:

  • Take vitamin and mineral supplements (at specific doses) every day
  • Follow-up with your healthcare practitioner annually

The Bariatric Advantage team of PhDs and clinicians review literature and guidelines to ensure our products align with requirements. Our product development process includes testing on raw materials, formulations after blending, finished products, and products at expiration date to ensure efficacy. Explore Bariatric Advantage multivitamins, calcium, and protein offerings today.


  1. Shankar P et al. Micronutrient deficiencies after bariatric surgery. Nutrition. 2010 Nov-Dec;26(11-12):1031—7.
  2. Patel JJ et al. Micronutrient Deficiencies After Bariatric Surgery: An Emphasis on Vitamins and Trace Minerals. Nutr Clin Pract. 2017 Aug;32(4):471—480.
  3. Parrott J et al. American Society for Metabolic and Bariatric Surgery Integrated Health Nutritional Guidelines for the Surgical Weight Loss Patient 2016 Update: Micronutrients. Surg Obes Relat Dis, Volume 13 , Issue 5, 727—741.
  4. Aills L et al. ASMBS Allied Health Nutritional Guidelines for the Surgical Weight Loss Patient. Surg Obes Relat Dis. 2008 Sep-Oct;4(5 Suppl):S73—108.
  5. Tripkovic L et al. Comparison of vitamin D2 and vitamin D3 supplementation in raising serum 25-hydroxyvitamin D status: a systematic review and meta-analysis. Am J Clin Nutr. 2012 Jun;95(6):1357—64