Can You Have Bariatric Multivitamins with Calcium?

With so many different multivitamins available, it is hard to know which product is best for you as a bariatric surgery patient and what your body can actually absorb. Unfortunately, not all companies (including many over-the-counter brands and some bariatric vitamin brands) follow the rules of how the body absorbs various nutrients. Some multivitamins include nutrients that cannot be absorbed when taken together, or nutrients that need to be provided in a certain ratio for optimal health and to prevent deficiencies.

One question I get asked a lot is: "Should my multivitamin contain calcium?" The answer is not a simple "yes" or "no" – a few questions must be asked first.

Does the multivitamin contain iron?

The first question is: "Does the multivitamin also contain iron?" If a multivitamin contains both iron and calcium, the body does not absorb the iron as well. While this might be acceptable for the general population (who are not at risk of iron deficiency), it is not ideal for a bariatric surgery patient. For optimal absorption, iron should be taken separately from calcium – in fact, iron and calcium should be separated by at least 2–4 hours.

This is critical for bariatric surgery patients, as their risk of iron deficiency increases over time. Most, if not all, bariatric surgery patients will eventually develop an iron deficiency if they do not properly supplement with iron long term.* About 20–52% of patients develop an iron deficiency within 3 years of bariatric surgery, some as soon as six months post-op (1–6). Menstruating women, the super obese and long-limb Roux-en-Y gastric bypass patients have an increased risk of iron deficiency compared with other patients.

How much calcium is included?

If the answer is "No, my multivitamin does not contain iron", then it is feasible for your multivitamin to contain calcium. However, the amount of calcium should also be considered. The human body can only absorb about 500 milligrams (mg) of calcium per dose period (500 mg over a 2–4 hour period). I have seen products on the market containing as much as 1,000–1,200 mg of calcium designed to be taken as one dose. The sad truth is that the body will still only absorb 500 mg of the 1,000–1,200 mg, so you are just wasting your money and doing a disservice to your bone health. If your multivitamin does NOT contain iron, it may contain up to 500 mg of calcium per dose period.

What is the form of calcium?

It is also important to consider the form of calcium in your multivitamin (or calcium supplement). Calcium citrate is the recommended form for bariatric surgery patients (7,8). Many multivitamins for bariatric surgery patients contain other forms, such as calcium carbonate, which is more difficult to absorb in a low-acid environment (often caused by bariatric surgery). This means you may not be absorbing the amount of calcium you think you are getting. While this will not show up in your blood work immediately, it can have detrimental long-term effects on your bone health and may lead to osteoporosis and/or an increased risk of bone fractures. Calcium citrate is the preferred form for bariatric patients for the following reasons:

• Stomach acid: calcium carbonate needs an acidic environment to be absorbed. This is fine for the general population, but it is one of the main reasons calcium carbonate is not preferred for bariatric patients. After bariatric surgery, the stomach is smaller (regardless of the procedure) and produces less stomach acid. Calcium citrate can be absorbed regardless of the amount of stomach acid. Many patients also take proton pump inhibitors or acid reducers (such as Prevacid, Nexium, Protonix or Prilosec) after surgery, which further increases the need for calcium citrate.
• Timing: calcium carbonate must be taken with meals; calcium citrate can be taken at any time (with or without meals). This helps bariatric patients, because sometimes taking their vitamins alone is enough to fill them up, with no room for a meal plus vitamins.
• Kidney stones: calcium citrate reduces the risk of developing kidney stones compared with calcium carbonate. While this is not the only reason kidney stones may develop, reducing the risk is certainly beneficial.

Getting down to the mechanics

Biochemically, calcium is a large molecule, especially in the recommended form, calcium citrate. It takes up a lot of space, which is why most multivitamins do not contain calcium – and if they do, they usually contain calcium carbonate (since it is smaller). Think about one of our chewable multivitamins and one of our chewable Calcium PLUS 500s: put those two together and you would have one HUGE chewable that most bariatric patients would not take.

* Proper supplementation should be viewed as an individualised regimen based on each patient's medical history, laboratory studies and current medication use. Patients should follow the instructions of their bariatric surgery team, follow up at the recommended intervals and stay up to date with requested lab work.

This article is for general information only and does not replace personal medical advice. Always discuss your situation, blood test results and supplementation with your bariatric team or healthcare provider.