Bariatric Surgery and Vitamin B12, what do I need to know?


Vitamin B12 deficiency can be a complication after bariatric surgery.

Malabsorptive surgeries such as the gastric bypass and the duodenal switch (rarely performed in the UK) are at higher risk of deficiency.

Vitamin B12 is often prescribed after bariatric surgery to prevent deficiency.

Vitamin B12 is absorbed in the small intestine. The lining of the mouth is also capable of absorbing vitamin B12 from food, but it is a small insignificant amount.

The stomach produces a glycoprotein called intrinsic factor which is essential for the absorption of vitamin B12 in the small intestine.

Why is vitamin B12 needed?

Vitamin B12 helps keep the body’s nervous system and blood cells healthy. Vitamin B12 also helps prevent megaloblastic anaemia.

Deficiency of vitamin B12 occur after bariatric surgery

Bariatric surgeries either reduce the size of the stomach or lessen the absorption of nutrients or both.

In Gastric Sleeve surgery the reduced size of the stomach results in a decrease in ghrelin (the hunger hormone) and reduced food intake.

There is also reduced production of an intrinsic factor which is needed for vitamin B12 absorption.

In Gastric Bypass surgery, the part of the stomach where the intrinsic factor is produced is avoided and never exposed to food.

When does deficiency of vitamin B12 occur?

The liver can store up to 3 years requirement of vitamin B12, so deficiency does not usually happen early after bariatric surgery.

Studies show that a significant number of patients become symptomatic within 1-2 years of gastric bypass surgery if not supplemented with Vitamin B12. Vitamin B12 injections are usually prescribed every 3 months for life following Bariatric Surgery. There are other forms of vitamin B12 available (sub lingual and nasal spray.) You should discuss this with your bariatric surgeon or bariatric dietitian.


Signs and Symptoms of vitamin B12 deficiency:


  • Feeling Weak
  • Fatigue
  • Dizziness
  • Loss of appetite
  • Diarrhoea
  • Painful swollen tongue
  • Pins and Needle sensations in the hands and feet
  • Nerve damage
  • Abnormal heart function
  • Poor Memory


Vitamin B12 supplementation is important after bariatric surgery, especially those patients who have had Gastric bypass surgery.

Preventing common problems after surgery.

Tips to prevent common problems:

Eat slowly, chew foods thoroughly and stop eating as soon as you feel satisfied to avoid discomfort, nausea and vomiting and ultimately stretching your stomach pouch.

To prevent nutritional deficiencies always take your vitamin and mineral supplements as directed by your bariatric team alongside a healthy balanced diet. Symptoms of deficiencies can be: fatigue, achy muscles, tingling feet, calves or hands.

Some hair loss can be experienced around months 4-8 post surgery, this is caused by rapid weight loss and/or lack of protein or vitamins/minerals in the diet. To prevent this, patients should consume the amount of protein recommended by their bariatric dietitian (usually 60mg daily) and take vitamins/minerals as directed. Gateway Health patients are usually recommended to take 2 x complete multi vitamin and mineral supplements per day or 1 x prescribed Forceval vitamin and mineral supplement a day. Be reassured that we do find that hair does grow back after 12 months and often thicker than it was before surgery.

Dehydration is caused by drinking too little fluid or by persistent vomiting. Signs and symptoms include dark and strong-smelling urine, dry mouth, headache, and fatigue.  Drinking with meals is to be avoided after bariatric surgery, so it is important to sip liquids frequently throughout the day to avoid dehydration.

Dumping syndrome is caused by food emptying too quickly from the new stomach after gastric bypass surgery. Signs and symptoms include diarrhoea, nausea, cold sweats, and light-headedness. Avoid eating or drinking refined sugars and high-fat foods or drinks and wait for 30 minutes after finishing your meals before drinking.

After weight loss surgery you eat less food and fibre. To prevent constipation drink plenty of water, exercise daily, include fibre in your diet and we find taking a fibre supplement such as Benefiber or Fibresure is helpful. (found in large supermarkets near the vitamin aisle)

If you find it difficult to follow advice, whether that is due to poor motivation, poor understanding of nutrition/what is required, poor planning, lack of knowledge as to how to prepare meals/meet your dietary needs or emotional eating …. It is important to seek professional expert advice to avoid a poor result and future weight regain.

Weight loss surgery is just a tool, if long term dietary, exercise and mind set are not changed, weight regain is a real possibility. Find a bariatric provider who can expertly meet all of your individual needs.

What do you value most?


Values are the things in life that we most care about and consider important.

There might be values you think are important, and others that don’t matter so much to you.

Below is a little activity that I think is very interesting and can be quite insightful, to see what is most important to you and whether you are doing enough to meet your own personal values?


Below are some common values, read through them and consider what is important to you.


1.Write a few notes next to each value on the list below


  1. Give each value a score as to how important it is to you:

(0 = not important, 10 = very important).


  1. Give each area a rating according to how successfully you have lived your life in accordance with this value in the past month

(0 = not at all well, 10 = very well).


  1. Look at the rated scores for Number 2 compared to the rated scores for Number 3, are your values in sync?


When the scores for Number 2 and Number 3 match you are being true to yourself, to your personal values.

When your scores do not match up, how can you make changes in your life to even the scores out?




What kind of family relationships do you want? What sort of brother / sister / mother / father / aunt / uncle / niece / nephew do you want to be? How do you want to be in those relationships?



What kind of partner do you want to be? What kind of relationship do you want to be a part of? What sort of partnership do you want to build? What kind of person do you want to be in a relationship?



What sort of parent do you want to be? What qualities do you want your children to see in you? What kind of relationships do you want to build with them?



What sort of friend do you want to be? What friendships are important to cultivate? How would you like to act towards your friends? What kind of social life matters to you?



What kind of work is valuable to you? What qualities do you want to bring as an employee? What kind of work relationships would you like to build? What kind of work matters to you?



How would you like to grow as a person? What kind of skills would you like to develop? What matters to you about education and learning? What would you like to know more about?



How would you like to enjoy yourself? What relaxes you? When are you most playful?



What kind of relationship do you want with God / nature / the Earth?



What kind of environment do you want to be a part of? How do you want to contribute to your community? What kind of citizen would you like to be?



What kind of values do you have regarding your physical wellbeing? How important to you is your health? How do you want to look after yourself?






Marriage / Couple / Intimacy




Friendships / Social life


Career / Employment


Education / Personal growth & development


Recreation / Fun / Leisure




Citizenship / Environment / Community


Health / Physical wellbeing

Aftercare makes all the difference…


Surgical weight loss specialists all know for sure that bariatric surgery is a tool to help you lose weight. It is without any doubt the most effective proven weight loss method, but it still is not a miracle cure. Weight regain can and does happen.

Permanent dietary and activity changes need to be made and often for this to happen we need to get rid of old habits and change our mindset.

A good aftercare programme needs to support you medically, nutritionally and emotionally through the early days, weeks, months and possibly years following surgery….


Things to consider in the early weeks

What is normal, what are the physical warning signs? Who do I contact?

What should I be eating and drinking? What amount should I be eating? What texture of food should I be eating?

When can I go back to work? What activities can I do? Are my wounds ok?


And months later…………………………

My relationships are changing, some people are helpful, others not so much! How best to deal with this?

After a lifetime of an unhealthy relationship with food, how do I turn it into a new healthy relationship?

How do I deal with cravings? What’s triggering my cravings? How do I eat the ‘right’ things when I’m craving the ‘wrong’ foods?

How do I change a lifetime of habits? How do I make my new habits stick?

I used to use food to feel calmer after a stressful day at work, it used to lift my mood, ease my anxiety, what should I do now?

How do I recognise the signs of stress, depression, anxiety? What help can I get for this?

How can I change my negative thoughts?

I’m losing my motivation now a few months have passed how can I get it back?

Will I get loose skin? What can I do to help myself with this as I’m losing weight?


Check with your provider who will guide and support you along your journey……