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Vitamins and Minerals After Bariatric Surgery

Understanding what you need after surgery

Posted on Thursday October 12, 2023

Vitamins and Minerals After Bariatric Surgery

What are vitamins and minerals?

They are nutrients, also known as micronutrients, which are needed in small amounts for the body to work well and stay healthy.  Each micronutrient plays a specific role in the body. The body cannot make them but usually most people get all the nutrients they need from their diet.  In some situations, like after bariatric surgery, it can be difficult to meet needs just through diet and so vitamin and mineral supplements are required.

What is a nutritional deficiency?

A deficiency can result in a range of health problems, many are treatable but some can be severe and irreversible.  A deficiency happens when the body does not get the required amount of nutrient or when the ability for the body to absorb it is reduced.  They can develop over time.

What happens if I take a different type of supplement to the ones advised? 

It may increase your risk for deficiency because the nutritional content may not be as good as those that we recommend.  It may also increase your risk of having excess nutrients which can also cause health issues.

What happens if I choose not to take any supplements? 

You will be at increased risk of developing nutrient deficiencies, including those that are serious and irreversible.

Can I have too many vitamin and mineral supplements?

Yes. It is important to follow our advice and take the recommended vitamin and mineral supplements, have regular nutritional blood tests and attend follow up appointments for support and guidance.

Can I still get a nutritional deficiency if I take the recommended supplements?

Yes, however your risk is much lower.

Can I take all of my supplements together?

We’d recommend splitting the doses of your supplements over the course of the day to help aid absorption. It’s also best to take your iron and combined calcium and vitamin D supplements at least 2 hours apart.>

I really like the gummy vitamins I took immediately after surgery, can I stay on them?

Most gummy vitamins do not contain the full range of vitamins and minerals you need to stay healthy post-op. They are good at filling the gap while you are on the liquid diet phase but then you will need to convert to a more complete A-Z vitamin and mineral supplement after the first 6 weeks.

I’m in the liquid diet phase and struggling to fit it all in- what can I do?

If you are really struggling in the early stages post-op then you can stop the liquid iron and calcium and vitamin D sachets while you build up your textures. You will need to remember to start these again as soon as you feel able to or you will be at risk of developing deficiencies. Try and continue with your multivitamin and mineral gummies if you can.

I’m struggling to tolerate one or more of my supplements, what should I do?

Discuss with your Dietitian or GP. There are often alternative preparations which may be better tolerated.

My diet is really healthy, do I still need to take supplements?

As you progress out of surgery you are likely to be tolerating a much more balanced range of foods.  However, even if you are able to manage a nutrient rich diet you will still need to take your supplements as your body will not be able to absorb as much nutrition from your food than it did prior to surgery.

My hair is falling out, can I take a hair supplement?

We don’t recommend adding in a hair supplement as these often contain high doses of just a few vitamins or minerals which can lead to difficulties in your body absorbing all the other nutrients and potentially lead to deficiencies. Instead have a chat to your dietitian if you notice hair loss post-surgery.>

Why do I need a B12 injection instead and not an oral supplement?

After a sleeve gastrectomy and gastric bypass the body is unable to absorb B12 via the gastrointestinal tract as well and so injections are recommended to maintain normal levels.  A vitamin B12 deficiency can cause irreversible, lifelong problems so we want our patients to reduce this risk.

If I’m taking all my supplements, do I still need blood tests?

Yes. You will still need to monitor your bloods even if you are taking all the supplements advised. This is because there is individual variation, you may need more or less vitamins and minerals than the ‘average’ person, and requirements change with age.

Will the supplements and blood test advice change?

We review our advice regularly and as new scientific evidence emerges it can result in changes. We will post updates to any change in recommendations.

Are there any medications that interact with vitamin and mineral supplements?

Yes, there are a few. During your assessment, the team will ask you about your current medication and advise you of any potential interactions and what the best timings for taking them are to avoid interactions. Interactions can include affecting the absorption of either the medication or the vitamins and minerals.  If you start a new medication please speak to your dietitian or pharmacist for advice.

Can I talk to someone about my blood results? 

Yes. We offer annual nutritional reviews with our specialist dietitians which includes reviewing your blood test results and providing advice about what you need. This is a great way of discussing how things are going, including eating habits.

If you would like to arrange an appointment with one of our specialist dietitians click on the 'book now' button at the top of the page or email

Let us know how we can support you

0117 235 5354

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