What can cause your vitamin B to be low? Exploring the Root Causes

October 9, 2025 •

2 min read

Research indicates that up to 20% of older adults in some developed Western countries may experience marginal vitamin B12 deficiency. Understanding the various factors involved is crucial for anyone asking, what can cause your vitamin B to be low? Deficiency can stem from a variety of sources, including dietary habits, medical conditions, and lifestyle choices.

Quick Summary

Low vitamin B levels can result from insufficient dietary intake, poor nutrient absorption due to gastrointestinal issues, certain medications, excessive alcohol consumption, and age-related changes. Underlying medical conditions can also be a factor.

Key Points

Dietary Deficiencies: Inadequate consumption of B-vitamin-rich foods, particularly B12 in vegan/vegetarian diets, is a common cause.
Malabsorption Disorders: Conditions like pernicious anemia, Crohn's disease, and celiac disease can prevent the body from properly absorbing B vitamins.
Impact of Medications: Certain drugs, such as metformin and proton pump inhibitors (PPIs), can interfere with B-vitamin absorption.
The Effect of Aging: Age-related decreases in stomach acid can impair B12 absorption from food in older adults.
Alcohol's Role: Excessive and chronic alcohol consumption can deplete B-vitamin stores and hinder absorption.
Importance of Medical Diagnosis: Self-diagnosis is risky; a healthcare professional is needed to determine the specific cause and recommend the right treatment, which may include injections for malabsorption issues.

The B-vitamin complex, a group of eight water-soluble vitamins, is vital for numerous bodily functions, including energy production and nervous system health. Since most B vitamins (except B12) are not significantly stored in the body, a consistent supply through diet or supplements is essential. A deficiency can lead to various health problems.

Dietary Reasons for Low Vitamin B

Insufficient intake of foods rich in B vitamins is a key factor, although the impact varies for each vitamin. These include following vegan or vegetarian diets without adequate supplementation for B12, excessive alcohol consumption which hinders absorption, and poor cooking methods that can deplete B vitamins due to their sensitivity to heat.

Gastrointestinal and Malabsorption Disorders

Even with adequate intake, issues with absorbing B vitamins can lead to deficiency. Conditions like pernicious anemia (affecting B12 absorption), atrophic gastritis (reducing stomach acid), digestive diseases such as Crohn's or Celiac, bariatric surgery, and bacterial overgrowth can all impair the body's ability to absorb these essential nutrients.

Medications that Lower B-Vitamin Levels

Certain medications can interfere with the body's handling of B vitamins. Examples include Metformin (reducing B12 absorption), Proton Pump Inhibitors (PPIs) and Antacids (decreasing stomach acid needed for B12 release), some anticonvulsants (affecting B6 and folate), and long-term antibiotics (altering gut bacteria).

Other Risk Factors

Other elements can also contribute to low B-vitamin levels. Aging is a risk factor due to decreased stomach acid, as are genetic factors that affect B vitamin metabolism (like the MTHFR gene), and increased metabolic needs during pregnancy or chronic diseases.

Comparison: Dietary vs. Malabsorption-Related Causes

A table comparing dietary insufficiency and malabsorption issues regarding root cause, primary example, supplement absorption, time to develop, and common treatment can be found on {Link: MSD Manuals https://www.msdmanuals.com/home/disorders-of-nutrition/vitamins/vitamin-b12-deficiency}.

Next Steps to Address Low Vitamin B

If you experience symptoms suggestive of low vitamin B, such as fatigue or tingling, consulting a healthcare professional is essential. They can perform tests to confirm a deficiency and identify the cause. Treatment depends on the cause; dietary changes and supplements may be sufficient for intake issues, while injections might be needed for malabsorption problems. Addressing the underlying factor is key to managing the deficiency.

Conclusion

Low vitamin B levels result from a mix of factors beyond just poor diet. Malabsorption disorders, medications, and age all play a role. To determine what can cause your vitamin B to be low, a medical evaluation is crucial. Understanding these potential causes helps in taking steps for better nutritional health. {Link: The National Institutes of Health https://ods.od.nih.gov/factsheets/list-Vitamins-Consumer/} provides further information on the health impacts of low vitamin B status.

Frequently Asked Questions

The most common cause of vitamin B12 deficiency is malabsorption, particularly in older adults due to reduced stomach acid and the subsequent inability to release B12 from food proteins.

Yes, several medications can interfere with B-vitamin absorption, including diabetes medication (metformin), acid reflux drugs (PPIs and antacids), and some anticonvulsants.

Yes, because vitamin B12 is found almost exclusively in animal products, strict vegans and vegetarians are at a high risk of deficiency if they don't consume fortified foods or take supplements.

Excessive alcohol consumption hinders the body's ability to absorb B vitamins from the digestive tract and increases their excretion by the kidneys, depleting the body's stores.

As people age, their bodies often produce less stomach acid, which is necessary to separate B12 from food proteins for absorption. This can lead to low B12 levels even with sufficient dietary intake.

Yes, surgeries like gastric bypass that remove or alter parts of the stomach or small intestine can significantly reduce the body's capacity to absorb B vitamins.

Pernicious anemia is an autoimmune condition where the body attacks and destroys the stomach cells that produce intrinsic factor, a protein required for vitamin B12 absorption.

Yes. If an underlying malabsorption issue is the cause, such as a lack of intrinsic factor, oral supplements may not be absorbed effectively, and injections may be necessary.