Vitamins and Lab Tests After a Gastric Sleeve

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Vitamins and Lab Tests After a Gastric Sleeve

After a gastric sleeve you need vitamin and mineral supplements for life, and regular blood tests to check they are working. The American Society for Metabolic and Bariatric Surgery (ASMBS) says these typically include a multivitamin, vitamin B12, calcium, vitamin D and iron. Published schedules test nutrients every 3 to 6 months in the first year and yearly after that.

Why a sleeve changes your vitamin needs

A sleeve gastrectomy removes a large part of the stomach. You eat much less, so less of every nutrient comes in. The smaller stomach also makes less acid and less intrinsic factor, a protein the body needs to absorb vitamin B12. The intestine is not rerouted, so a sleeve causes less malabsorption than a gastric bypass, but shortfalls still occur.

A 2020 review in Annals of Translational Medicine (Osland and colleagues) gives reported deficiency rates after a sleeve: vitamin D 30% to 70%, iron 15% to 45%, vitamin B12 10% to 20%, folate 10% to 20%, vitamin A 10% to 20% and zinc 7% to 15%. Rates vary because studies measure and report these differently, and the same review notes that the course of nutrient levels after surgery is poorly described in the literature.

Supplements listed for sleeve patients

The amounts below are the daily amounts for adults after a sleeve in the Osland review, which draws on the ASMBS 2016 micronutrient update (Parrott and colleagues) and the 2013 clinical practice guidelines. They are published figures, not a personal prescription. Your own plan depends on your lab results, so ask your surgical team what to take and when to start.

Nutrient	Daily amount listed after a sleeve
Adult multivitamin with minerals	2 tablets
Thiamin (vitamin B1)	At least 12 mg
Vitamin B12	350 to 500 mcg by mouth or under the tongue, or 1,000 mcg a month by injection
Folic acid	400 to 800 mcg; 800 to 1,000 mcg for women of childbearing age
Iron	45 to 60 mg, counting the multivitamin
Calcium	1,200 to 1,500 mg from food and calcium citrate together, in divided doses
Vitamin D	3,000 IU, adjusted upward if needed to reach a blood level above 30 ng/mL
Vitamins A, E and K	Vitamin A 5,000 to 10,000 IU, vitamin E 15 mg and vitamin K 90 to 120 mcg
Zinc and copper	Zinc 8 to 11 mg and copper 1 mg, supplied by the multivitamin

A 2024 Obesity Medicine Association statement (Benson-Davies and colleagues) gives a similar minimum list, with some differences, such as 2 mg of copper and 16 to 22 mg of zinc. Published lists do not all agree, which is one more reason to follow a plan written for you.

A few practical points come from the same two papers. Take calcium apart from a multivitamin that contains iron, with at least 2 hours between them, because calcium blocks iron absorption. Acid-reducing medicines and foods high in phytates or polyphenols also impair iron absorption. Calcium citrate may be absorbed better than calcium carbonate. Check the label of any product against your plan, because amounts vary between brands.

Protein counts too

Protein is not a vitamin, but it is watched in the same way. The Obesity Medicine Association statement gives a general recommendation of at least 60 grams of high-quality protein a day, or up to 1.5 grams per kilogram of ideal body weight. Our page on nutrition after bariatric surgery covers food choices, and hair shedding is covered in hair loss after a gastric sleeve.

Blood tests and how often

The Obesity Medicine Association statement sets out this schedule of tests for sleeve patients:

Iron, thiamin and vitamin D. At 1 to 3 months, then every 3 to 6 months in the first year, then yearly. Iron is checked with ferritin and a full iron panel.
Vitamin B12. At 1 to 3 months if indicated, then every 3 to 6 months in the first year, then yearly. Metformin and proton pump inhibitors (acid reducers) can lower B12, so tell your doctor if you take them.
Folate and calcium. Every 3 to 6 months in the first year, then yearly.
Zinc. Yearly.

The Osland review notes there is little direct evidence behind these exact time frames, and schedules differ. Practices differ too, so ask which tests your surgeon wants, how often, and whether you need a bone density scan. The usual visit pattern is on our follow-up schedule page. If your sleeve was done somewhere else and you have had no labs for a year or more, say so when you call.

When to call

Go to an emergency room or call 911 if

You have been vomiting for days and now have confusion, double vision, trouble walking or new numbness in your legs. These can be signs of thiamin deficiency, which can cause a serious brain condition called Wernicke-Korsakoff encephalopathy, and they need treatment the same day.
You cannot keep liquids down.
You have chest pain, shortness of breath, fainting or black stools.

Call the office if

You feel unusually tired, short of breath on stairs, or look pale
You notice tingling or numbness in your hands or feet
You have stopped your supplements, or cannot tolerate them
You are planning a pregnancy; see pregnancy after a gastric sleeve

Frequently asked questions

Do I have to take vitamins forever after a gastric sleeve?

Yes. ASMBS says patients need vitamin and mineral supplements for life after any weight loss surgery, and yearly visits with a bariatric specialist for life. Your intake stays lower than before surgery, and deficiencies are reported long after the first months. Yearly blood tests are how you and your surgeon learn whether your doses are still right or need to change.

Can I use gummy or patch vitamins after a sleeve?

The Obesity Medicine Association statement says skin patches are not recommended after bariatric surgery. It notes that gummies and soft chews usually hold fewer nutrients than tablets and may add sugar. Tablets, chewables, capsules and liquids each have tradeoffs. Compare each amount on the label with your plan, and ask your surgical team before switching products.

Why should iron and calcium be taken at different times?

Calcium blocks iron absorption when the two are taken together. The Obesity Medicine Association statement advises taking 500 to 600 mg of calcium apart from a multivitamin with iron, leaving at least 2 hours between them. A simple routine is the multivitamin or iron at one time of day and calcium at two or more others, with tea and coffee kept away from your iron.

What if my vitamin D or B12 is low even though I take supplements?

That happens, and it is the reason for testing. For low vitamin D, the Obesity Medicine Association statement lists repletion options of 3,000 to 6,000 IU a day or a high dose of 50,000 IU one to three times a week. For low B12, it lists a higher daily dose. Your surgeon or doctor adjusts the dose and repeats the test.

Talk with Dr. Davtyan in Rancho Cucamonga

Dr. David G. Davtyan, MD, FACS, FICS, FASMBS, is a bariatric surgeon with Davtyan Medical Weight Loss & Wellness at 8330 Red Oak Street, Suite 201, Rancho Cucamonga, CA 91730. Call 909-355-2525 or toll free 877-9-BE-SLIM (877-923-7546), or use our contact page. The first consultation is complimentary, and Hablamos Español. More topics are in our Rancho Cucamonga gastric sleeve guide.

Vitamins and Lab Tests After a Gastric Sleeve

Vitamins and Lab Tests After a Gastric Sleeve

Why a sleeve changes your vitamin needs

Supplements listed for sleeve patients

Protein counts too

Blood tests and how often

When to call

Go to an emergency room or call 911 if

Call the office if

Frequently asked questions

Do I have to take vitamins forever after a gastric sleeve?

Can I use gummy or patch vitamins after a sleeve?

Why should iron and calcium be taken at different times?

What if my vitamin D or B12 is low even though I take supplements?

Talk with Dr. Davtyan in Rancho Cucamonga

Sources

More in the Gastric Sleeve in Rancho Cucamonga guide

Understanding the sleeve

Weighing your options

Getting care in Rancho Cucamonga

Adult BMI Calculator

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Glendale

Rancho Cucamonga

South Coast Lap-Band

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