Supporting a Healthy Immune System: The Power of Nutrition

Supporting a Healthy Immune System: The Power of Nutrition - Bariatric Fusion
Guest Blog by: Lillian Craggs-Dino, DHA, RDN, LDN

Your immune system is a remarkable defense network, tirelessly working to protect your body from environmental and biological hazards. Whether it’s the common cold, a dangerous pathogen, or a chronic illness, your immune system stands as the first line of defense. However, metabolic and bariatric surgery introduces unique challenges and opportunities when it comes to immune health.

In this blog, we delve into the fascinating world of the immune system, explore the ways metabolic and bariatric surgery can impact it, and offer practical strategies for supporting your immune function after surgery. 

Immune System Defenders

In the realm of our immune system, white blood cells play a crucial role in acquired immunity, generating antibodies and “killer cells” that target harmful pathogens, such as bacteria, viruses, and parasites.

Alongside white blood cells, cytokines such as interferons, interleukins, and tumor necrosis factor orchestrate a line of immune system functions. However, the presence of obesity can weaken this defense by reducing important immune components like macrophages, B-cells, T-cells, and natural killer cells. This compromise in immune strength leaves us more susceptible to infections. 

Research shows a connection between obesity and mortality in COVID-19 cases, as well as higher ICU admissions due to illnesses and infections.1 Obesity also impairs the effectiveness of vaccinations, further jeopardizing our protection.2

The good news is that metabolic and bariatric surgery has the potential to support the immune response. It achieves this through several mechanisms: 

  • Decreasing inflammation, which can negatively impact the function of immune cells
  • Shedding excess weight, particularly body fat, which can enable the immune system to respond more effectively to antibodies

Metabolic and bariatric surgery undeniably has a positive impact on immune health; however, there are also vitamins, minerals, and daily activities that can be incorporated to further support immune function.

Supporting Post-Surgery Immune Health

In the journey toward post-metabolic and bariatric surgery wellness, it's crucial to remember that our immune system is more than just a passive bystander.

There are steps we can take to ensure that the immune system operates at its full capacity after metabolic and bariatric surgery, including: 

  • Maintaining a balanced diet and healthy lifestyle: Healthy choices can allow your immune system to safeguard against pathogens, microorganisms, parasites, and allergens.
  • Following bariatric nutrition recommendations: Emphasize protein intake and the consumption of whole foods, such as fruits, veggies, and whole grains.
  • Maintaining an active lifestyle: Continue or initiate an exercise program within your comfort level.
  • Prioritizing vitamin and mineral supplements: Post-surgery, your body’s ability to absorb necessary nutrients from food alone can be compromised. Take recommended bariatric-specific supplements daily for nutritional and immune support.*
  • Supporting a healthy gut microbiome: Consider incorporating probiotics into your dietary regimen for gut support, considering 70-80% of immune cells reside there.3*

It’s important to acknowledge that due to the malabsorptive nature of metabolic and bariatric surgery, complete nutrition absorption from food alone is not guaranteed. Vitamins and minerals play an essential role in supporting your overall health.* 

For specific guidance on the recommended micronutrients for metabolic and bariatric patients, please refer to Chart 1 below.4

Chart 1. Recommended Micronutrients After Metabolic and Bariatric Surgery

Dietary Supplement


Adult multivitamin with iron

Adult dosage, preferably a bariatric multivitamin 



Vitamin D3

3,000IU (75mcg)

B complex with thiamin


Extra iron


Vitamin B12

500-1,000mcg, sublingual or quick dissolving

Targeted Nutrients for Immune Health*

Consuming nutrient-rich foods daily is always advised. However, given the circumstances post-surgery and decreased portion sizes, dietary supplements are necessary in addition to your daily meals. Therefore, consulting with your registered dietitian and healthcare team regarding vitamin and mineral supplements is essential in meeting nutrient needs. 

Refer to Chart 2 below for comprehensive details on these micronutrients, including their immune support functions, recommended dosages, and examples of nutrient-rich foods.* 

Chart 2. Nutrients for Immune System Support**


Immune System Support*

Recommended Dosage After Metabolic and Bariatric Surgery2

Nutrient-Rich Foods

Vitamin A

  • Antioxidant support*
  • Promotes mucosal barrier development*
  • Influences the function of natural killer cells, T-cells, and B-cells*

LAGB: 5,000IU/d

RYGB: 5,000-10,000IU/d 

Preformed retinoids (liver, kidney, eggs, dairy) and provitamin carotenoids (brightly colored fruits and vegetables (beta-carotene))

Vitamin D

  • Supports immune response*
  • Manages inflammatory cytokines*

3,000IU/d (75mcg)

Fish, eggs, fortified foods, cod liver oil

Vitamin E

  • Antioxidant support*
  • Promotes function of natural killer cells and lymphocytes*
  • Maintains cell communication*


Oils, green leafy vegetables, wheat germ, liver, egg yolks, nuts, seeds, and whole grains

Vitamin B12

  • Supports immune response*
  • Promotes development and function of T-cells and natural killer cells*
  • Orally by disintegrating tablet, sublingual, melts, or liquid: 350-500mg daily
  • Nasal spray as directed by manufacturer (once a week)
  • Injection: 1,000mg monthly

All animal proteins such as dairy, eggs, poultry, seafood, shellfish, and red meat

Vitamin C

  • Antioxidant support*
  • Promotes function of natural killer cells and lymphocytes*
  • Strengthens chemotaxis*

No specific recommendation after MBS, so follow the DRIs:

  • Ages 19+ males: 90mg
  • Ages 19+ females: 75mg

Citrus fruit, tomato, potatoes, brussels sprouts, cauliflower, broccoli, peppers, strawberries, cabbage and spinach

Folic acid

  • Proliferation of antibodies*
  • 400-800mcg/d 
  • Women of childbearing age: 800-1,000mcg/d

Green leafy vegetables, whole grains, oranges, orange juice, and fortified cereals


  • Supports function of macrophages and neutrophils*
  • Promotes growth of lymphocytes*

Menstruating females and patients who have undergone gastric bypass, sleeve gastrectomy, or duodenal switch should take at least 45-60mg

Heme sources (dairy, eggs, poultry, seafood, shellfish, and red meat)

Non-heme from plant sources (spinach, pulses, and legumes)


  • Supports the development of neutrophils, natural killer cells, T-cells, B-cells, and macrophages*
  • Protects the epithelial cells to provide a natural mucosa barrier*
  • BPD/DS: 16-22mg/d
  • RYGB: 8-22mg/d
  • SG/LAGB: 8-11mg/d
  • To minimize the risk of copper deficiency, add 1mg of copper for every 8-15mg of zinc

Seeds (pumpkin, sesame, and sunflower), garlic, wheat germ, and dark chocolate


  • Antioxidant support*
  • Supports function of neutrophils, T-cells, B-cells, antibodies, and macrophages*

No specific recommendation; follow the DRIs: 

  • Ages 19+ males and females: 55mcg

Brazilian nuts, tuna, oysters, mussels, and eggs


Undoubtedly, metabolic and bariatric surgery serves a purpose beyond weight loss. It contributes significantly to overall health. 

A robust immune system is instrumental in safeguarding our well-being, protecting us from potential immune threats, and preserving our quality of life.


1. Ho JSY et al. Ann Acad Med Singap. 2020;49(12):996-1008.
2. Painter SD et al. Vaccine. 2015;33(36):4422-4429.
3. Wiertsema SP et al. Nutrients. 2021;13(3):886.
4. Parrott J et al. Surg Obes Relat Dis. 2017;13(5):727-741.

*These statements have not been evaluated by the Food & Drug Administration (FDA). These products are not intended to diagnose, treat, cure, or prevent any disease.

**Discuss with your registered dietitian and bariatric healthcare team, as they can provide tailored recommendations aligned with your specific lab work and needs.

This blog is for information and education purposes only. This information is not intended to substitute professional medical advice, diagnosis, or treatment. Please consult with your bariatric surgeon or another qualified healthcare provider with any questions in regard to a medical condition. A qualified healthcare professional can best assist you in deciding whether a dietary supplement is suitable based on your individual needs.

Dr. Lillian Craggs-Dino is a retained consultant for Bariatric Fusion.

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