Vitamin and Mineral Supplements

Must-Have Vitamin and Mineral Supplements after Bariatric Surgery

October 5, 2022

When you have weight loss surgery, vitamin and mineral supplementation is one of those items that will remain on your daily to-do list. The right vitamin and mineral supplements are part of your new lifelong strategy for success.

You might be thinking “Wow, no one told me about all of these supplements.” Nutritional deficiencies occur frequently after weight loss surgery and the type of surgery performed makes a difference. For example, vitamin and mineral deficiencies are more common after procedures like Roux-en-Y gastric bypass or biliopancreatic diversion as compared to (LSG) sleeve gastrectomy and adjustable gastric banding (LAGB). Additionally, recommendations for supplementation can vary between surgical centers and even professional groups so don’t be surprised if your supplement suggestions are different from someone else you know who’s had surgery.

Three tips to get started on your supplements for success:

  1. Vitamin & mineral supplementation usually begins when you go home from the hospital, typically 2–4 days after surgery.
  2. Your body has likely changed in its ability to absorb vitamins and minerals. The extent of change depends on the surgical procedure. In the first 3-6 months you may find that liquids or chewable / suckable pills work better for you. Then down the track, you can change to  capsules or tablets if you prefer.
  3. Regular vitamin and mineral screenings/lab tests should be part of your healthcare. These tests will vary with your procedure and your surgical center.

So much has changed in the vitamin/mineral supplement space. In the not-too-distant past, bariatric-specific supplements weren’t available so we combined various over-the-counter supplements to try and achieve what was needed. Many companies now provide a wide variety of bariatric supplements. It’s easy to feel overwhelmed or unclear about which ones to choose as there are so many products. You’ll need to do some label sleuthing.

Which supplements do you really need? Let’s dive into the general suggestions for bariatric surgery knowing that your health care team may tweak these.

Must-Have Vitamin and Mineral Supplements

*A bariatric specific “complete”multivitamin plus mineral supplement. Complete means it contains the typical A-Z formulation of vitamins and minerals similar to what you find in an adult supplement but in amounts recommended for bariatric surgery.

Make sure it includes both vitamins and minerals and specifically check for vitamins A, D, E, K, folic acid and thiamine along with the minerals iron, zinc, selenium and copper. If it’s a good quality bariatric supplement it will contain all of these and more.

The number of capsules, chewables or tablets you take every day will vary based on the brand and formulation. Typically, the dose will be one or two per day but again this can vary with the procedure you had done. Some supplements are now developed to be procedure specific. How do you know what’s what when it comes to the products you are reviewing?

Become a Label Sleuth

Let’s take a look at the supplement you are considering. Read the front and back for general information. Now take a look at the Supplement Facts label which you’ll find on the back of most products. This Supplement Facts label is what you’ll find in the US so if you live in another country, you’ll likely have a different label. At the top of the label you’ll see the serving size such as 1 chewable tablet. Then you’ll see listed each vitamin and mineral along with the amount per serving and the percent Daily Value. Percent daily value or DV is the percentage that one chew provides toward your daily needs for each of the vitamins and minerals listed.  You’ll want to see 100-200% Daily Value for most every vitamin and mineral but there will likely be a few that are higher such as thiamine, vitamin B12 or iron.


Multivitamin/mineral supplements are available both with and without iron. The iron in your multivitamin mineral supplement may be sufficient and you won’t need to purchase a separate one. You can find doses of iron in multis ranging from 18 mg up to 36, 45, 60mg or even more but these are typical amounts. Your dose will depend on your lab work, if you’re female and still have your period, hope to get pregnant or if you’re anemic whether male or female. Discuss your specific iron need with your bariatric dietitian.

Boost iron absorption with vitamin C

Take vitamin C or consume a vitamin C rich food at the same time as you take your iron to increase iron absorption. If both C and iron are in your multi, you’re good to go. If you’re eating an iron rich food such as black beans for example, also eating food containing vitamin C such as a tangerine will boost the iron absorption.

Vitamin B-12 (cobalamin)

The typical bariatric specific dose is 250-500 micrograms a day with most suggestions in the 350-500 microgram range or 1000 micrograms every other day. Your multivitamin/mineral supplement may have enough B-12 in it so check the label before you buy additional. Also, be sure and discuss your lab screenings with your health care team before you decide to take any extra B-12. The dose depends on your surgery, your lab results and the route of administration…meaning under the tongue, you swallow it, etc. Your health care team may even order an intramuscular injection of B12 or a nasal spray.

The good news…you can take B12 at any time or with any other supplements.

Science 101 on Vitamin B-12. The absorption of B-12 can be affected by bariatric surgery due to changes in acid production and reduced availability of what’s called the intrinsic factor. This intrinsic factor helps the B-12 to be absorbed and used by the body. When it’s not there or insufficient, B-12 doesn’t get absorbed and used as it should. You could experience neurological symptoms which include numbness and tingling of your arms, legs and skin plus feel like your coordination is off. This is a prime reason why routine screenings are so important and typically done every six months or so. These screenings help your health care provider pick up on a possible deficiency hopefully before it becomes a problem.


Calcium citrate is better absorbed than other types of calcium such as calcium carbonate. A recommended daily dose will be somewhere from 600 milligrams per day up to 1,200-1,500 milligrams per day.

TIP: Be sure and take your calcium at a different time from your iron supplement or your multi vitamin/mineral supplement that contains iron. Aim for about 2 hours before or 2 hours after or the calcium will not be absorbed well by your body.

The other important strategy for calcium is to take it in divided doses of 500-600 mg at a time. That’s the maximum amount your body can absorb at one time and you don’t want to waste it.

Vitamin D

Calcium is often sold in combination with vitamin D which helps increase the absorption of calcium from the intestine. You can take vitamin D with your calcium or get your vitamin D in your multi. The general recommendation is to take 3,000 International Units (IU) of vitamin D3 per day. Your dose may be higher depending on your blood test. Be sure and look at the Supplement Facts label on the multi vitamin/mineral supplement or the calcium/vitamin D product to determine if the vitamin D is in the form of D3, how much of it is in the supplement and the percent Daily Value.

Thiamin (vitamin B 1)

 Put those label sleuth skills to work one more time and see how much thiamin is in your daily multi. At least 12 mg should be included to prevent a deficiency so again check the label before you purchase.

A thiamin deficiency can occur with rapid weight loss, persistent vomiting, or not getting enough through diet and you may be treated more quickly with higher doses than found in a supplement. It’s very important to have your screening for thiamine deficiency as it can make you quite sick.

Remember to circle back with your health care team for clarity if you’re unsure about which supplements they recommend for your procedure. Take your supplements on schedule. It makes a huge difference in your success.

Registered dietitian nutritionist Dr. Susan Mitchell is host of the podcast Bariatric Surgery Success.

Vitamin and Mineral Supplements
Susan Mitchell


Bariatric dietitian Dr. Susan Mitchell is host of the podcast Bariatric Surgery Success. Selected as one of the Best 35 Dietitian Podcasts, Bariatric Surgery Success was chosen from thousands of podcasts on the web ranked by traffic, social media followers, domain authority & freshness. Dr. Susan helps you conquer cravings, emotional eating and weight regain after bariatric surgery with a focus on your nutrition and health, journey and success. Read more articles by Susan!