Low-Cost Fast Shipping | $4.95 or Free on orders $99+

Nutritional Deficiencies after Weight Loss Surgery

Weight loss, Minerals, Vitamins | August 10, 2017 | Author: Naturopath

weight loss

Nutritional Deficiencies after Weight Loss Surgery

Nearly two-thirds (63%) of Australian adults are overweight or obese, as defined by a body mass index (BMI) ≥30 kg/m2. Obesity is associated with increased risk of type 2 diabetes, cancer, kidney, liver and heart disease. Since dietary and lifestyle interventions have proven ineffective for some, more individuals are now choosing a surgical treatment for weight loss.

What is weight loss surgery?

Weight loss surgery, also known as bariatric surgery, is a procedure that aims at inducing weight loss and improving health in obese patients by changing the normal digestive process and restricting the amount of food the stomach can hold. The most common weight loss procedure in Australia is laparoscopic sleeve gastrectomy.

Additional procedures include laparoscopic adjustable gastric banding, and gastric bypass.

Who is suitable for weight loss surgery?

According to Obesity Surgery Society of Australia & New Zealand, appropriate candidates usually include individuals in the following categories:

  • Weight greater than 45kg above the ideal body weight for sex, and height.
  • BMI > 40 by itself or >35 if there is an associated obesity illness, such as diabetes or sleep apnoea
  • Reasonable attempts at other weight loss techniques
  • Age 18-65
  • Obesity related health problems
  • No psychiatric or drug dependency problems
  • A capacity to understand the risks and commitment associated with the surgery

Safety of weight loss surgery

weight loss surgeryWeight loss surgery is considered the most effective intervention for severe obesity; however, as every surgical procedure, it is not without risks.

Complications may include problems with general anaesthesia, infections, leaks, haemorrhage, stenosis, bowel obstruction, ulcers, fistulas, hernia, gastroesophageal reflux, and slippage of the gastric band.

Nonetheless, most weight loss surgeries today are performed laparoscopically (keyhole surgery), which is a minimally invasive technique that reduces incidence of postoperative infections.

Weight loss surgery has the potential for long-term vitamin and mineral deficiencies

The most common deficiencies found in patients following weight loss surgery include vitamins B1 and B12; folate; iron; vitamins A, E, and K; calcium; vitamin D; copper; and zinc.

There are two reasons for nutritional deficiencies found in patients undergoing weight loss surgery:

  • Obese patients have pre-existing nutritional deficiencies before undergoing weight loss surgery, mainly due to eating high-energy foods with a poor nutritional value. Most of these deficiencies persist after weight loss surgery.
  • Weight loss surgery can cause malabsorption of nutrients not only because it reduces the amount of food eaten, but also, depending on the procedure, by bypassing absorption surface areas and changing the anatomy of the gastrointestinal tract. Additionally, vomiting and diarrhoea after surgery may contribute to deficiencies.

Can nutritional deficiencies after weight loss surgery be prevented?

Untreated nutritional deficiencies following weight loss surgery can lead to irreversible consequences. Deficiencies can be avoided by adherence to appropriate diet, nutritional supplementation and regular follow up.

Nutritional supplements

The American Society for Metabolic & Bariatric Surgery recommends undergoing an appropriate nutritional evaluation to assess pre-existing deficiencies before surgery.

nutritional supplementsAfter surgery, in order to identify and treat deficiencies early, regular blood work should be performed every three months in the first year, every six months in the second year, and every 6–12 months starting in the third year.

Supplements will be a lifelong requirement and it is important that you only take supplements as prescribed. Recommended supplements depend on the type of surgery, but usually include:


There are many brands and formulas of multivitamins, some more potent than others. The formula should include iron, folic acid and thiamine. Multivitamins are available in the form of tablets, capsules and liquid. Chewable form is recommended initially after surgery.

Vitamin D and calcium

Calcium is essential for bone building and maintaining bone, while vitamin D helps absorb calcium and plays a role in supporting growth and maintenance of the skeleton. Deficiency of both calcium and vitamin D can result in osteoporosis.

The most common forms of calcium in supplements are calcium carbonate and calcium citrate. However, calcium citrate is recommended as it can be taken without food, and is thought to be better absorbed. Supplements may take the form of oral (swallowed) tablets, chewable tablets, effervescent tablets or soluble powder.

Vitamin D supplements are available as tablets, capsules, drops or liquid. Most supplements come as vitamin D3. It is also possible to take a calcium/vitamin D combination.


Iron deficiency is the most common cause of anaemia and is very common after weight loss surgery. Deficiency can be corrected with oral iron in the form of capsules, tablets or liquid. Although your multivitamin should contain iron, additional supplement is usually necessary. Your doctor might suggest iron administration by infusion or injection if you have difficulty in absorbing iron, and sometimes vitamin C is recommended to enhance absorption.

Vitamin B12

Long-term deficiency of B12 can lead to irreversible neurologic damage, and supplement is required to maintain levels. Supplements usually come in three forms: Cyanocobalamin, usually found in tablet forms, Hydroxocobalamin, usually in injection form, and Methylcobalamincan in a sublingual form and also as injectable.


dietAfter surgery

Follow a meal program given to you by your surgeon and dietitian. Typically, meal plans progress from clear liquid to full liquid, pureed food, ground or soft, and, ultimately, regular diets with certain restrictions.

Eat regular meals and avoid skipping meals

Consume smaller amounts cut into small pieces

Eat slowly and chew well and drink fluids separately

Avoid distraction when eating. Practise mindful eating

Adhere to principles of healthy eating. Include at least 5 daily servings of fresh fruits and vegetables.

Protein intake. The body needs additional protein during the period of rapid weight loss to maintain your muscle mass. Most patients get 60-80 grams daily, but some may require more. The body cannot absorb more than approximately 30 grams at once so consume protein across multiple meals or healthy snacks.

Avoid excessive carbohydrate intake. Such as starchy foods (breads, pastas, crackers, refined cereals) and sweetened foods (cookies, cakes, candy, or other sweets).

Maintain adequate hydration. Carry a bottle of water with you all day, even when you are away from home; remind yourself to drink even if you don’t feel thirsty.

www.superpharmacy.com.au  Australia’s best online discount chemist


Aills, L. et al., 2008. ASMBS Allied Health Nutritional Guidelines for the Surgical Weight Loss Patient. Available at: https://asmbs.org/

American Society for Metabolic and Bariatric Surgery, Life After Bariatric Surgery. Available at: http://asmbs.org/patients/life-after-bariatric-surgery

Australian Institute of Health and Welfare 2017. Weight loss surgery in Australia 2014–15: Australian hospital statistics. Available at: http://www.aihw.gov.au/  

Hernández, J. & Boza, C., 2016. Novel treatments for complications after bariatric surgery. Annals of surgical innovation and research, 10, p.3. Available at: http://www.ncbi.nlm.nih.gov/pubmed/26981148

Kehagias, I., 2016. Sleeve gastrectomy: have we finally found the holy grail of bariatric surgery? A review of the literature. European Review for Medical and Pharmacological Sciences, 20: 4930-4942.  Available at: http://www.europeanreview.org

Mechanick, J.I. et al., 2013. Clinical practice guidelines for the perioperative nutritional, metabolic, and nonsurgical support of the bariatric surgery patient-2013 update: cosponsored by American association of clinical endocrinologists, the obesity society, and American society for metabolic & bariatric surgery. endocrine practice, 19(2). Available at: https://www.aace.com/files/publish-ahead-of-print-final-version.pdf

Obesity Surgery Society of Australia & New Zealand. Available at: http://www.ossanz.com.au/

Osteoporosis Australia. Available at: https://www.osteoporosis.org.au/resources

RACGP - The bariatric surgery patient – nutrition considerations. Available at: http://www.racgp.org.au/afp/2013/august/the-bariatric-surgery-patient/

Sawaya, R.A. et al., 2012. Vitamin, mineral, and drug absorption following bariatric surgery. Current drug metabolism, 13(9), pp.1345–55. Available at: http://www.ncbi.nlm.nih.gov/pubmed/22746302

backBack to Blog Home