Riboflavin (RF) and Immunity

Nutrition Expert- Saba Shaikh, Clinical Nutritionist, Mumbai.

  • Immunity

The immune system is constantly working to protect the body from infection, injury, and disease. It relies on an adequate supply of nutrients for its baseline functions as well as for ramping up its activity when necessary. It is well established that malnutrition (protein-energy malnutrition and obesity) and deficiencies in one or more micronutrients (vitamins and nutritionally essential minerals) diminish immune function. (1)

  • Riboflavin

Riboflavin (RF) is known as an essential vitamin B2, a water-soluble vitamin, is heat stable. Cooking does not lower levels of RF; however exposure to light could destroy it.

RF is poorly stored by vertebrates because of its limited absorption in humans. Therefore, orally supplied RF by a healthy diet is required to avoid ariboflavinosis which causes cheilitis, sore tongue, and a scaly rash on the scrotum or vulva. RF causes no known toxicity, since at higher intakes it is excreted in the urine and not stored. (2)

The two flavorprotein coenzymes derived from riboflavin, Flavin Mononucleotide (FMN) and Flavin Adenine Dinucleotide (FAD) are crucial rate limiting factors in most cellular enzymatic processes. The flavoproteins are also co-factors in the metabolism of essential fatty acids in brain lipids, the absorption and utilization of iron, and the regulation of thyroid hormones.

Riboflavin derivatives also have direct antioxidant properties and increase endogenous antioxidant status as essential cofactors in the glutathione redox cycle. (3)

  • Role of Vitamin b2

Vitamin B2 helps break down proteins, fats, and carbohydrates. It plays a vital role in maintaining the body’s energy supply.

Riboflavin helps convert carbohydrates into adenosine triphosphate (ATP). The human body produces ATP from food, and ATP produces energy as the body requires it. The compound ATP is vital for storing energy in muscles. (4)

  • Riboflavin and Immunity

RF activates phagocytic activity of neutrophils and macrophages, and stimulates the multiplication of neutrophils and monocytes. The reduction in RF concentration resulted in a decreased rate of cell proliferation. A combined supplementation consisting of RF, delta-tocotrienol and quercetin improved the inhibition of serum tumor necrosis factor alpha (TNF-α) and nitric oxide (NO) levels.

RF administration affects neutrophil migration, inhibiting the infiltration and accumulation of activated granulocytes into peripheral sites, which may lead to a decreased inflammatory influx and, thereby, a decrease in inflammatory symptoms. RF is a potential substance for use in virus inactivation, or as an adjuvant in chemo radiotherapy for cancer treatment because of its toxicological and photosensitizing attributes. RF suppressed T-cells infiltration and donor-reactive alloantibody formation during the early period after allotransplantation. (2)

  • Metabolism

The pro-inflammatory transcription nuclear factor kappa B (NF-κB) is normally activated by degradation of inhibitory kappa B (IκB). When this occurs, NF-κB translocates to the nucleus and binds to specific promoter regions of genes encoding pro-inflammatory proteins. Proteasomes are key regulators of lipopolysaccharide (LPS)-stimulated inflammatory signaling pathways. RF, as proteasome inhibitor, possibly down-regulates the NF-κB activation initiated by ROS, which are the potent activators of a plethora of general pro-inflammatory cytokines such as interleukin-6 (IL-6), TNF-α, etc. Therefore, ultimately, as proteasome inhibitor RF suppresses the production of TNF-α and NO, and exerts anti-inflammatory effects by inhibiting NF-κB, activation. As was recently reported, RF may protect against multitude of age-associated diseases by inhibition levels of secretion of TNF-α, NO production, activation of NF-κB, and degradation.(2)

  • Vitamin B2 Deficiency

Vitamin B2 deficiency is at significant risk when diet is poor, because the human body excretes the vitamin continuously, so it is not stored. A person who has a B2 deficiency normally lacks other vitamins too. (4)


Alcoholics are at increased risk of vitamin B2 (riboflavin) deficiency due to decreased intake, decreased absorption, and impaired utilization of riboflavin.

Additionally, anorexic individuals rarely consume adequate riboflavin, and lactose intolerant individuals may not consume milk or other dairy products which are good sources of riboflavin. (5)


Symptoms of vitamin B2 (riboflavin) deficiency include sore throat, redness and swelling of the lining of the mouth and throat, cracks or sores on the outsides of the lips and at the corners of the mouth, inflammation and redness of the tongue, and a moist, scaly skin inflammation. (5)

Ariboflavinosis is the medical name for clinical riboflavin deficiency. Riboflavin deficiency is rarely found in isolation; it occurs frequently in combination with deficiencies of other water-soluble vitamins. Other symptoms may involve the formation of blood vessels in the clear covering of the eye (vascularization of the cornea) and decreased red blood cell count in which the existing red blood cells contain normal levels of hemoglobin and are of normal size (normochromic normocytic anemia). Severe riboflavin deficiency may result in decreased conversion of vitamin B6 to its coenzyme form (PLP) and decreased conversion of tryptophan to niacin.(6)

Recommended Dietary Allowances (RDAs) for Riboflavin

Age groupRiboflavin (mg/d)
Infants (0-6 months)0.3
Infants(6-12 months)0.4
Children’s(1-3 years)0.6
Children’s(4-6 years)0.8
Children’s(7-9 years)1.0
Boys(10–12 years)1.3
Girls(10-12 years)1.2
Boys(13-15 years)1.6
Girls(13-17 years)1.4
Boys(16-17 years)1.8
Girls(16-17 years)1.2
Men (sedentary work)1.4
Men (Moderate work)1.6
Men (Heavy Work)2.1
Women (sedentary work)1.1
Women (Moderate work)1.3
Women (Heavy Work)1.7
Pregnant Women+0.3
Lactating Women(0-6 months)+0.4
Lactating Women(6-12 months)+0.3

Source: Nutrient Requirements and Recommended Dietary Allowances for Indians (ICMR 2010)

What Foods Provide Riboflavin:

Riboflavin is found naturally in some foods and is added to many fortified foods. You can get recommended amounts of riboflavin by eating a variety of foods, including the following:

  • Eggs, organ meats (such as kidneys and liver), lean meats, and low-fat milk
  • Green vegetables (such as asparagus, broccoli, and spinach)
  • Fortified cereals, bread, and grain products(7)


  1. https://lpi.oregonstate.edu/mic/health-disease/immunity-in-brief
  2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7037471/
  3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4772032/
  4. https://www.medicalnewstoday.com/articles/219561#Role
  5. https://www.nutri-facts.org/en_US/nutrients/vitamins/b2/deficiency.html
  6. https://lpi.oregonstate.edu/mic/vitamins/riboflavin
  7. https://ods.od.nih.gov/factsheets/Riboflavin-Consumer/

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