Vitamin B2: Benefits and sources

Vitamin B2: Benefits and sources

Vitamin B2, or riboflavin, is one of eight B vitamins essential to human health. It can be found in dairy products, grains and plants. It is important to break down components of the food, consume other nutrients, and sustain tissues.

Vitamin B2 is a water-soluble vitamin and is thus dissolved in water. Both vitamins are soluble in water, or soluble in fat. Water-soluble supplements are processed into the bloodstream, and anything unwanted passes out of the body into urine.

People need to eat vitamin B2 every day, since the body can only store small quantities of vitamin B2 and supplies are going down quickly.

For certain foods riboflavin occurs naturally, added to others, and can be used as supplements. It is mainly absorbed in the small intestine.


Cruciferous vegetables are a source of vitamin B2, but steam them rather than boiling them.
Cruciferous vegetables are a source of vitamin B2, but steam them rather than boiling them.

Vitamin B2 helps break down proteins, carbohydrates and fats. This plays a crucial role in maintaining supply of energy to the body.

Riboflavin helps to convert carbohydrates to triphosphate Adenosine (ATP). The human body creates ATP from food, and ATP generates energy, as the body needs it. The ATP compound is important for storing muscle strength.

Vitamin B is important, along with vitamin A, to:

  • Maintaining the mucous membranes in the digestive system
  • Maintaining a healthy liver
  • Converting tryptophan into niacin, an amino acid
  • Keeping the eyes, nerves, muscles and skin healthy
  • Absorbing and activating iron, folic acid, and vitamins B1, B3 and B6
  • Hormone production by the adrenal glands
  • Preventing the development of cataracts
  • Fetal development, especially in areas where vitamin deficiency is common

Some research suggests that vitamin B2 may help prevent cataracts and migraine headache, but to confirm this, further studies are needed.

Other studies have shown that vitamin B2, B6, and magnesium supplements tend to reduce levels of excessive organic acids in the urine in children with autism.


Vitamin B2 comes from food.

Sources of B2 include:

Meat, fish, and dairy products provide vitamin B2.
Meat, fish, and dairy products provide vitamin B2.
  • Fish, meat, and poultry, such as turkey, chicken, beef, kidneys, and liver
  • Eggs
  • Dairy products
  • Asparagus
  • Artichokes
  • Avocados
  • Cayenne
  • Currants
  • Fortified cereals
  • Kelp
  • Lima beans, navy beans, and peas
  • Molasses
  • Mushrooms
  • Nuts
  • Parsley
  • Pumpkins
  • Rosehips
  • Sage
  • Sweet potatoes
  • Cruciferous vegetables, such as broccoli, Brussels sprouts, spinach, dandelion greens, and watercress
  • Whole-grain breads, enriched breads, and wheat bran
  • Yeast extract

Vitamin B2 is water-soluble, so it can be lost to cooking foods. By boiling, about twice as much B2 is lost as it is by steaming or microwave.

How much do we need?

According to Oregon State University, for men aged 19 years and over, the recommended daily allowance (RDA) for vitamin B2 is 1.3 milligrams per day, and for women is 1.1 milligrams per day. Females will have 1.4 mg / day during pregnancy, and 1.6 mg / day during breastfeeding.


Deficiency of vitamin B2 is a major risk when diet is poor, because the human body constantly excretes the vitamin, so it is not retained. A individual suffering from a B2 deficiency usually often lacks other vitamins.

There are two types of riboflavin deficiency:

  • Primary riboflavin deficiency happens when the person’s diet is poor in vitamin B2
  • Secondary riboflavin deficiency happens for another reason, maybe because the intestines cannot absorb the vitamin properly, or the body cannot use it, or because it is being excreted too rapidly

Riboflavin deficiency is also known as ariboflavinosis.

Signs and symptoms of deficiency include:

Mouth ulcers
A lack of vitamin B2 can lead to mouth ulcers and other complaints.
  • Angular cheilitis, or cracks at the corners of the mouth
  • Cracked lips
  • Dry skin
  • Inflammation of the lining of the mouth
  • Inflammation of the tongue
  • Mouth ulcers
  • Red lips
  • Sore throat
  • Scrotal dermatitis
  • Fluid in mucous membranes
  • Iron-deficiency anemia
  • Eyes may be sensitive to bright light, and they may be itchy, watery, or bloodshot

People who consume large quantities of alcohol run a greater risk of deficiency in vitamin B.


The vitamin B2 is normally considered healthy. An overdose is unlikely because up to 27 milligrams of riboflavin can be consumed by the body and it expels any excess quantities in urine.

However, before taking any supplements, it is important to speak to a doctor, particularly because these can interfere with other medications.

Supplements may interfere with other medications, and B2 supplements may affect the efficacy of other medications, such as anticholinergic drugs and tetracycline.

For example, if a patient takes a drug that may interfere with the absorption of riboflavin, a doctor can often prescribe supplementation.

Drugs which can interfere with levels of riboflavin in the body include:

  • Tricyclic antidepressants, such as imipramine, or Tofranil
  • Some antipsychotic drugs, such as chlorpromazine, or Thorazine
  • Methotrexate, used for cancer and autoimmune diseases, such as rheumatoid arthritis
  • Phenytoin, or Dilantin, used to control seizures
  • Probenecid, for gout
  • Thiazide diuretics, or water pills

Doxorubicin, a medication used in cancer therapy, can deplete riboflavin levels, and riboflavin can affect the way doxorubicin works.

The Medical Center of the University of Maryland (UMM) states that extremely high levels of vitamin B2 can result in itching, numbness, burning or prickling, yellow or orange urine and light sensitivity. If supplementation is required, they recommend using a B-complex vitamin to avoid an excess of B vitamins.


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