How Does Lack of Vitamin B Make You Feel? Unpacking the Symptoms of Deficiency

October 24, 2025 •

2 min read

According to the National Institutes of Health, vitamin B deficiencies can cause a range of physical, neurological, and psychological problems, which may develop slowly over time. Understanding precisely how does lack of vitamin B make you feel? is essential for identifying potential issues and seeking timely treatment.

Quick Summary

A deficiency in one or more B vitamins can lead to a variety of symptoms, including profound fatigue, nerve issues like tingling and numbness, mood changes, and anemia. The specific effects depend on which B vitamin is lacking, with conditions ranging from megaloblastic anemia to neurological damage if left untreated.

Key Points

Diverse Symptoms: Lack of vitamin B can make you feel fatigued, weak, irritable, or even confused, with specific symptoms depending on which B vitamin is deficient.
Neurological Impact: A B12 deficiency can cause serious nerve damage, leading to numbness, tingling, difficulty walking, and cognitive problems.
Anemia Risk: Deficiencies in vitamin B12 or folate (B9) are primary causes of megaloblastic anemia, a blood condition that results in tiredness and weakness.
High-Risk Groups: Vegetarians, vegans, older adults, and people with certain medical conditions like Crohn's disease are at a higher risk of developing deficiencies.
Reversible Conditions: Many symptoms of vitamin B deficiency, such as fatigue and anemia, are treatable with supplements or dietary changes, but neurological damage from severe B12 deficiency may be irreversible if left untreated.
Preventative Measures: A varied diet including meat, fish, eggs, dairy, and fortified foods is the best way to prevent deficiencies, though some individuals may require supplements.

The B-complex family consists of eight distinct vitamins, each playing a crucial role in your body's energy production, cell function, and overall health. As they are mostly water-soluble, except for vitamin B12, they are not stored in the body for long, highlighting the need for regular dietary intake. Insufficient intake or poor absorption can disrupt bodily functions, leading to a range of physical and mental symptoms.

The Role of B Vitamins in Your Body

B vitamins are vital for converting food into energy, cellular metabolism, red blood cell formation, and nervous system maintenance. A deficiency can cause systemic problems. For more details on the symptoms, causes, and treatment of B vitamin deficiencies, refer to {Link: MSD Manuals https://www.msdmanuals.com/home/disorders-of-nutrition/vitamins/vitamin-b12-deficiency}.

Causes and Risk Factors for Deficiency

Factors like diet, malabsorption conditions, age, certain medications, and alcohol abuse can contribute to B vitamin deficiencies.

Treatment and Prevention

Consult a healthcare provider for diagnosis if you suspect a deficiency. Treatment options include oral supplements or injections, and dietary adjustments are key for long-term prevention.

Comparison of B12 and B9 Deficiencies


Feature	Vitamin B12 Deficiency	Folate (Vitamin B9) Deficiency
Associated Anemia	Megaloblastic anemia	Megaloblastic anemia
Neurological Damage	Can cause irreversible nerve damage, including numbness, tingling, and balance problems	Neurological symptoms are less common and not as severe as with B12 deficiency
Primary Cause	Often linked to poor absorption (e.g., pernicious anemia) or lack of animal products in the diet	Primarily caused by inadequate dietary intake, malabsorption, or increased bodily needs (e.g., pregnancy)
Cognitive Impact	Can lead to serious cognitive issues like confusion, dementia, and memory loss	Can cause irritability and trouble concentrating, but typically not severe cognitive decline
Treatment Considerations	Diagnosis requires careful consideration, as folate supplementation can mask the anemia of B12 deficiency while neurological damage progresses	Treatment with folic acid tablets is generally effective for dietary deficiencies

How to Increase Your Vitamin B Intake

A varied diet with sources like animal products, legumes, leafy greens, and fortified foods is important.

Conclusion

Symptoms of vitamin B deficiency are varied and depend on the specific vitamin lacking. Prompt medical attention and treatment are important. A balanced diet is the best preventive measure. More information is available from the {Link: NIH Office of Dietary Supplements https://ods.od.nih.gov/factsheets/VitaminB-HealthProfessional/}.

Frequently Asked Questions

One of the most common and earliest signs of a vitamin B deficiency is a persistent feeling of fatigue and general weakness. This is often because B vitamins are essential for converting food into energy.

Yes, deficiencies in certain B vitamins, particularly B12 and B6, can have a significant impact on your mental well-being, leading to mood changes like depression, irritability, and anxiety.

Severe and long-term vitamin B12 deficiency can lead to nerve damage, or peripheral neuropathy, which causes numbness, tingling, and a loss of sensation, particularly in the hands and feet. Neurological symptoms can sometimes be irreversible.

Vegans are at a higher risk for vitamin B12 deficiency because this vitamin is found almost exclusively in animal products like meat, eggs, and dairy. Supplementation or consuming fortified foods is highly recommended for those on a vegan diet.

A doctor can diagnose a vitamin B deficiency through a physical examination and a blood test that measures the levels of B vitamins in your body. It's important to get tested if you suspect a deficiency.

A wide variety of foods contain B vitamins, including meat, fish, dairy products, eggs, leafy green vegetables, legumes, and fortified cereals and plant-based milks.

Folate is the naturally occurring form of vitamin B9 found in foods, while folic acid is the synthetic form used in fortified foods and supplements. Both are important, but folic acid is often prescribed for those needing higher amounts, like pregnant women.

Yes, excessive alcohol consumption can lead to B vitamin deficiencies because it impairs absorption and increases the rate at which the body flushes B vitamins from the system.