Nutrition Diet: What are the symptoms of a lack of B2?

October 24, 2025 •

3 min read

According to the National Institutes of Health, while riboflavin (vitamin B2) deficiency is extremely rare in the United States, certain risk factors and conditions can lead to a deficiency, making it important to understand what are the symptoms of a lack of B2. Recognizing these signs early is crucial for proper treatment and prevention.

Quick Summary

A lack of vitamin B2, or riboflavin deficiency, manifests through various symptoms affecting the mouth, skin, and eyes, along with general fatigue and weakness. Causes range from poor diet to medical conditions, and treatment involves increasing riboflavin intake through food or supplements.

Key Points

Mouth Sores: A primary symptom of riboflavin deficiency includes angular cheilitis (cracks at the corners of the mouth) and glossitis (magenta-colored tongue).
Skin Rashes: Seborrheic dermatitis, causing greasy, scaly patches around the face and other areas, is a common sign of a lack of B2.
Eye Issues: Symptoms can affect the eyes, leading to light sensitivity (photophobia), itchy or bloodshot eyes, and blurred vision.
General Fatigue: As a key component in energy metabolism, a deficiency can manifest as general weakness and persistent fatigue.
Anemia Risk: Riboflavin deficiency can impair iron metabolism, contributing to a mild form of anemia, which exacerbates feelings of weakness.
Treatment is Effective: Most symptoms of a riboflavin deficiency are reversible with increased dietary intake or supplementation.

What is Vitamin B2 (Riboflavin)?

Vitamin B2, also known as riboflavin, is a water-soluble vitamin vital for various cellular functions, including energy production and metabolism. It is converted into coenzymes essential for processing carbohydrates, proteins, and fats into energy. Riboflavin also helps protect cells and is needed to metabolize other B vitamins. Since the body stores limited amounts, a consistent dietary intake is necessary.

Key Symptoms of Riboflavin Deficiency

Riboflavin deficiency, or ariboflavinosis, presents with various symptoms that often impact the mouth, skin, and eyes.

Oral and Throat Symptoms:

Angular Cheilitis and Cheilosis: Cracks or sores can develop at the corners of the mouth (angular cheilitis) and on the lips (cheilosis).
Glossitis (Magenta Tongue): The tongue may become inflamed, sore, and appear red or purplish.
Sore Throat: Swelling and soreness can affect the throat and other mucous membranes.

Skin Symptoms:

Seborrheic Dermatitis: A red, scaly rash can occur, often on the face and around the nose and mouth.
Dermatitis in Genital Areas: Scaly patches can also appear in the genital region.

Ocular (Eye) Symptoms:

Photophobia: Increased sensitivity to light is common.
Itchy and Bloodshot Eyes: Eyes may become red, itchy, or watery.
Vision Problems: Blurred vision and, in severe cases, cataracts can occur.

General and Systemic Symptoms:

Fatigue and Weakness: Reduced energy production can lead to tiredness and weakness.
Anemia: Riboflavin's role in iron metabolism means deficiency can contribute to a mild anemia.
Headaches and Migraines: A link between low riboflavin and headaches or migraines has been suggested.
Reproductive Issues: Severe deficiencies have been associated with reproductive problems.

Causes and Risk Factors for Riboflavin Deficiency

While not common in areas with diverse food availability, certain factors increase the risk of riboflavin deficiency:

Poor Diet: Not eating enough riboflavin-rich foods is a primary cause.
Chronic Alcohol Use: Alcohol can interfere with riboflavin absorption and use.
Malabsorption: Conditions affecting nutrient absorption, like celiac disease, can lead to deficiency.
Increased Requirements: Pregnancy, breastfeeding, and certain illnesses can increase the need for riboflavin.
Medical Treatments: Hemodialysis and certain long-term medications may increase risk.

Advanced and Systemic Effects

Untreated riboflavin deficiency can lead to more serious complications. Anemia can worsen fatigue. Neurological issues, particularly in children, have been reported in severe cases. Deficiency can also affect the metabolism of other B vitamins. Severe, long-term deficiency may cause irreversible changes, such as cataracts.

Comparison of Early vs. Advanced Riboflavin Deficiency Symptoms


Symptom Category	Early Symptoms (Reversible)	Advanced Symptoms (Potentially Irreversible)
Mouth/Throat	Angular cheilitis, cheilosis, magenta tongue, sore throat	Severe glossitis, infected mouth lesions
Skin	Red, scaly patches (seborrheic dermatitis) on face and scalp	Widespread dermatitis, hair loss
Eyes	Photophobia, itchy/bloodshot eyes, blurred vision	Cataracts, corneal neovascularization, potential vision loss
General	Fatigue, weakness, headaches	Anemia (normochromic-normocytic), neurological symptoms, impaired growth
Metabolic	Impaired energy metabolism	Impaired metabolism of other B vitamins, mitochondrial dysfunction

How to Treat and Prevent B2 Deficiency

Treatment involves increasing riboflavin intake. For mild cases, eating more riboflavin-rich foods is often enough. For more severe deficiencies, oral supplements may be recommended by a healthcare professional. Since other B vitamin deficiencies often occur with riboflavin deficiency, a multivitamin or B-complex supplement might be suggested.

To prevent deficiency, include good sources of riboflavin in your diet:

Dairy Products: Milk, cheese, and yogurt are good options.
Meat and Fish: Lean meats, liver, and eggs are rich in riboflavin.
Enriched Grains: Many cereals and breads are fortified.
Vegetables: Leafy greens like spinach and broccoli contain riboflavin.
Nuts and Legumes: Almonds and lentils are also good sources.

Conclusion

Knowing what the symptoms of a lack of B2 are is important for health. Riboflavin is vital for energy and cellular function. While deficiency is rare in well-nourished populations, certain factors increase risk. Symptoms like mouth sores, skin rashes, and eye problems are usually reversible with treatment through diet or supplements. Eating foods rich in riboflavin is key to prevention. Consult a healthcare provider for personalized advice.

Learn more about riboflavin from reliable sources like the Harvard T.H. Chan School of Public Health: https://nutritionsource.hsph.harvard.edu/riboflavin-vitamin-b2/.

Frequently Asked Questions

A lack of B2 can cause painful and cracked lips, a condition known as cheilosis, and fissures or sores at the corners of the mouth, called angular cheilitis.

Yes, riboflavin deficiency can cause fatigue and weakness. As a vital part of the energy production process, insufficient levels can hinder your body's ability to convert food into energy effectively.

Magenta tongue is a symptom of riboflavin deficiency characterized by a swollen, sore, and reddish-purple or magenta-colored tongue. The papillae on the tongue can become atrophied, making the surface look smooth.

Yes, riboflavin deficiency is linked to skin problems like seborrheic dermatitis. This condition causes red, greasy, and scaly patches to form on the skin, often around the face and mouth.

Risk factors for riboflavin deficiency include chronic alcoholism, malabsorption disorders like Crohn's disease, restrictive or poor dietary habits, and chronic illness.

Diagnosis of a B2 deficiency typically involves a physical examination to identify symptoms like oral sores or skin rashes, combined with blood or urine tests to measure riboflavin levels. Response to supplementation can also help confirm the diagnosis.

Foods rich in vitamin B2 include dairy products (milk, cheese), eggs, lean meats, liver, fortified cereals and breads, almonds, and leafy green vegetables.