Vitamins After WLS

Are Vitamins After WLS Necessary if a Patient Eats Healthy?

December 9, 2019

Those going through the pre-weight loss surgery workup may ask why they must have so many labs done?! If you’re anything like me, the thought makes you queasy. I promise there is a good reason, though, and even more reasons to make sure you have those labs checked regularly for life.

Recommended Vitamins After WLS

There are a number of things that the American Society for Metabolic and Bariatric Surgery (ASMBS) recommends screening for pre- and post-surgery, such as vitamin and mineral statuses. Routine checks are recommended for all surgery patients to make sure thiamin (vitamin B1), vitamin B12, folate, iron, vitamin D, calcium, vitamin A, vitamin E, and vitamin K levels are all normal. It is also recommended that zinc and copper levels be checked for those considering a malabsorptive procedure such as Roux-en-Y gastric bypass (RYGB) or biliopancreatic diversion with duodenal switch (BPD/DS).

We want to check these levels and make sure we’re not sending you into surgery undernourished. Weight is not a standalone marker for nutritional status. Deficiencies can increase bruising, inflammatory responses, and just generally complicate healing from surgery. And they are more common than you’d think. Check out how prevalent these can be:

Nutrient Patients Deficient Pre-Operatively
Thiamin/B1 29%
B12 2-30%1
Folate 54%
Iron 45%
Vitamin D 90%
Vitamin A 14%
Vitamin E 2.2%
Zinc 24-28%/74%2
Copper 70%3

(1) up to 30% in patients on PPIs
(2) in those pursuing BPD/DS
(3) in women prior to BPD/DS

These deficiencies could be due to a variety of things, including insufficient intake or medication interactions. For example, those on metformin or long-term use of proton pump inhibitors (medicines for reflux) may be at a higher risk for B12 deficiency. And look at how many people are vitamin D deficient!

Let’s take a quick glance at the typical daily needs of these nutrients for the average person with normal anatomy:

Supplement Amount* Translation to Food
Thiamin/B1 1.1-1.2 mg/day 1/2 cup rice=1.4 mg
B12 2.4 mcg/day 3 oz salmon=5.4 mcg
A 2300-3000 IU/day (700-900 mcg/day) 1/2 cup cantaloupe=117 mcg/390 IU
D 600-800 IU/day (15-20 mcg/day) 3 oz swordfish= 566 IU
E 15 mg/day 1 oz sunflower seeds=7.4 mg
K 90-120 mcg/day 1 cup spinach=145 mcg
Calcium 800-1000 mg/day 8 oz plain yogurt=415 mg
Iron 8-18 mg/day 1 cup white beans=8 mg
Folate 400 mcg/day 1/2 cup spinach cooked=131 mcg
Copper 0.9 mg/day 3 oz beef liver=12.4 mg
Zinc 8-11 mg/day 3 oz beef chuck roast=6.5 mg

*Pregnancy guidelines differ

No big deal, right? Our stomachs may be able to hold upwards of 32 ounces at a time, so theoretically we should be able to maintain our nutritional status through whole, balanced foods. But deficiencies are so common that it is important to know your levels well before surgery, so there is time to correct any problems to maximize the safety of the procedure.

Let’s talk about how things change after surgery. All procedures have a restrictive component to them-meaning you can eat less at a sitting. Directly after surgery, it may be only a couple of tablespoons at a time. Added to that is the strict diet progression. Many nutrient-dense items are avoided due to healing and tolerance. Generally, it is many weeks or months before anything remotely like sunflower seeds or roast are introduced back into the meal plan, and the volume is still quite small.

Malabsorptive procedures, like the bypass or duodenal switch, add another difficulty-not as many nutrients are able to be absorbed in the intestines. This combination of factors means that many nutrient intakes need to be increased for adequate absorption to maintain health. Take a look at the chart below for the daily supplement recommendations per ASMBS after each procedure:

Supplement Sleeve Gastric Band
Gastric Balloon
Bypass BPD/DS
Thiamin/B1 ≥12 mg/day ≥12 mg/day ≥12 mg/day ≥12 mg/day
B12 350-500 mcg/day 350-500 mcg/day 350-500 mcg/day 350-500 mcg/day
A 5,000-10,000 IU/day (1,500-3,000 mcg/day) 5,000-10,000 IU/day (1,500-3,000 mcg/day) 5,000-10,000 IU/day (1,500-3,000 mcg/day) 10,000 IU/day (3,000 mcg/day)
D 3,000 IU/day 3,000 IU/day 3,000 IU/day 3,000 IU/day
E 15 mg/day 15 mg/day 15 mg/day 15 mg/day
K 90-120 mcg/day 90-120 mcg/day 90-120 mcg/day 300 mcg/day
Calcium 1,200-1,500 mg/day 1,200-1,500 mg/day 1,200-1,500 mg/day 1,800-2,400 mg/day
Iron 18 mg/day 18 mg/day 45-60 mg/day 45-60 mg/day
Folate 400-800 mcg/day 400-800 mcg/day 400-800 mcg/day 350-500 mcg/day
Copper 1 mg/day 1 mg/day 2 mg/day 2 mg/day
Zinc 8-11 mg/day 8-11 mg/day 8-22 mg/day 16-22 mg/day

Do you think you can eat enough of those nutrient-rich foods to maintain these levels? Some of the daily needs are more than tripled than before surgery. It is almost physically impossible to eat these amounts after surgery, even as your stomach adjusts long-term.

A common misconception is that you are not at risk for the deficiency with a band, balloon, or sleeve. Supplements are a lifetime requirement as long as your surgical tool is in place.

A Bariatric Vitamin May Be All You Need

So, does this mean you have to take 10 vitamins and minerals after surgery? Luckily no! The good news is that a high-quality bariatric multivitamin meets a lot of these needs. Make sure to double-check the label and compare it to these recommendations.

Supplements are not well regulated, overall. Just because it says “bariatric” does not mean it meets the minimum recommendations.

You’ll likely still need some additional calcium with vitamin D, and potentially a separate iron. Beware of gummy multis-they do NOT contain thiamin (which is probably why they taste good).

Some frequent reasons for not taking supplements are taste or nausea/unsettled stomach. It’s important to find something that works for you for life. Here are some tips to help with tolerance:

  • Always take a multivitamin on a full stomach
  • Try different brands/flavors
  • Try capsule versus chewable
  • Try one without iron, and take a separate iron supplement to meet your needs

It is recommended that these nutrient levels be checked every 3-6 months for the first year after surgery, and then annually for life thereafter. We can store some vitamins and minerals in our bodies, but eventually, they will run out if we are not replacing them. We can store more of the fat-soluble vitamins (vitamins A, D, E, and K) in our liver and fat tissue, but think about how much of that you’re losing after surgery. Iron stores can last anywhere from 6 months to 3 years in some individuals. Not all nutrients are stored in significant amounts, though. Our bodies generally store minimal amounts of water-soluble vitamins and some other minerals (like all those B vitamins, and zinc), so this requires a constant influx of them. These stores can be used up within days.

Symptoms Of  Vitamin Deficiencies

You may not even realize your levels are low as symptoms can be vague or develop slowly. Symptoms of deficiencies can include muscle weakness, stomach upset, numbness/tingling, paleness, vision changes, memory problems, fast or irregular heartbeat, mouth ulcers or swollen tongue, hair loss, skin and taste changes. If not caught in time they can lead to permanent damage. A severe form of B1 deficiency, Wernicke-Korsakoff syndrome, can lead to permanent brain damage.

The best way to stay healthy for life after surgery is to follow up regularly with your bariatric team and take high-quality supplements that meet the ASMBS guidelines daily.

If you are not following up with your bariatric team, make sure a health care provider is monitoring all of these labs. Don’t be afraid to ask them to do so!

Vitamins After WLS


Emily L. Thevis, RDN, CSOWM, CDE is an Bariatric Coordinator for Memorial Hermann Memorial City Medical Center in Houston, TX. She is also the Metabolic and Bariatric Surgery Clinical Reviewer for Northwest Weight and Wellness in Everett, WA. Emily earned her BS in Nutritional Sciences from Louisiana State University. She is a Certified Specialist in Obesity & Weight Management and Certified Diabetes Educator. She is the 2019 Excellence in Emerging Practice Award winner for the Weight Management Dietetic Practice Group, and a member of the American Society for Metabolic and Bariatric Surgery, Obesity Action Coalition, and the Academy of Nutrition and Dietetics.

Read more articles from Emily!