What Lowers Selenium Levels? A Comprehensive Guide to Causes

January 2, 2026 •

2 min read

According to research, up to one billion individuals worldwide may suffer from inadequate selenium consumption. This essential trace mineral is critical for many bodily functions, and various factors—from diet to underlying health issues—can cause levels to fall below the optimal range.

Quick Summary

Several factors can cause reduced selenium levels in the body, including dietary habits, regional soil quality, certain medical conditions that cause malabsorption, and long-term use of specific medications.

Key Points

Dietary Intake: The most common cause of low selenium is inadequate consumption, often linked to the soil quality where food is grown.
Geographic Location: Residents of regions with naturally low-selenium soils, like parts of China and Europe, are at higher risk.
Malabsorption Issues: Conditions such as Crohn's disease, Celiac disease, and bariatric surgery can prevent proper selenium absorption.
Medical Treatments: Kidney dialysis and long-term Total Parenteral Nutrition (TPN) are known to lower selenium levels.
Medication Side Effects: Drugs like corticosteroids, PPIs, and chemotherapy agents can negatively impact selenium levels.
Increased Demand: Pregnancy, lactation, and severe illnesses can increase the body's need for selenium, depleting reserves.

Dietary Factors

Inadequate dietary intake is a primary cause of low selenium levels, as the body requires selenium from food sources. The amount of selenium in plant and animal products depends significantly on the selenium content of the soil they come from. Regions with low-selenium soils, such as parts of Europe, China, and New Zealand, can contribute to lower selenium intake for local populations. Intensive farming can further deplete soil minerals.

Vegan and vegetarian diets may pose a higher risk of selenium insufficiency, as animal products are typically richer and more consistent sources of this mineral than plant foods. Food processing and certain cooking methods can also diminish selenium content.

Medical and Physiological Conditions

Various health conditions can lower selenium levels by impairing absorption or increasing the body's need for the mineral.

Gastrointestinal Disorders

Conditions affecting the gut can reduce nutrient absorption:

Crohn's disease: Impairs nutrient uptake due to inflammation.
Celiac disease: Damages the intestinal lining, hindering absorption.
Chronic diarrhea: Increases nutrient loss.
Bariatric surgery: Alters the digestive tract, potentially causing malabsorption.

Other Conditions

Kidney Dialysis: Can remove trace minerals, including selenium, from the blood.
HIV/AIDS: Associated with malabsorption and increased selenium demand due to oxidative stress.
High Physiological Demand: Conditions like pregnancy, lactation, and severe illness increase the body's selenium requirements.

Medication and Substance Use

Certain medications and lifestyle factors can interfere with selenium.

Medication Interactions

Some drugs can impact selenium levels:

Corticosteroids: May increase selenium excretion.
Proton Pump Inhibitors (PPIs): Can affect absorption by changing the gut environment.
Chemotherapy agents: Can deplete mineral stores.
Gold salts: Can bind to selenium, reducing its availability.

Smoking and Alcohol Use

Smoking increases oxidative stress, potentially depleting selenium. Excessive alcohol intake may also lead to increased selenium loss.

Factors Affecting Selenium Levels: An Overview

This table summarizes key factors and their impact on selenium status.


Factor Category	Specific Causes	Mechanism
Dietary	Low selenium soil, Vegan/Vegetarian diets, Food processing	Inadequate intake
Geographic	Low-selenium regions	Reduced content in local food
Medical	Crohn's disease, Celiac disease, Bariatric surgery, HIV/AIDS	Impaired absorption
Physiological	Pregnancy, Lactation, Severe illness	Increased demand
Therapeutic	Kidney dialysis, TPN	Removal or lack of inclusion
Pharmacological	Corticosteroids, PPIs, Gold salts, Chemotherapy	Increased excretion or reduced absorption

Conclusion: Managing Your Selenium Status

Low selenium levels stem from various factors, including diet, geography, medical conditions, and medications. Inadequate intake from food grown in low-selenium soil is a significant factor, as are malabsorption issues and increased physiological demand. Certain drugs can also contribute to lower levels. If you suspect low selenium, consult a healthcare provider for testing. Addressing the root cause through dietary adjustments, supplementation, or medical management is key to maintaining healthy levels. Additional information is available from the NIH Office of Dietary Supplements.

Frequently Asked Questions

Medical conditions that lower selenium include gastrointestinal disorders like Crohn's and Celiac disease, chronic diarrhea, kidney dialysis, HIV/AIDS, and malabsorptive conditions following bariatric surgery.

Yes, dietary choices are a major factor. Inadequate intake of selenium-rich foods (e.g., seafood, meats, Brazil nuts) or relying on foods grown in selenium-poor soil can lead to low levels.

People on strict vegan or vegetarian diets may have lower selenium levels compared to omnivores, as plant-based sources are generally less consistent in their selenium content.

Soil selenium content varies significantly by geographic location. Living in regions with low-selenium soil, such as parts of Europe and China, can mean that locally grown foods contain less of the mineral.

Long-term use of certain medications, including corticosteroids, proton pump inhibitors (PPIs), some chemotherapy agents, and gold salts, can either increase selenium excretion or hinder its absorption.

Yes, research indicates that smokers tend to have lower selenium status. This is likely because smoking increases oxidative stress in the body, which consumes selenium's antioxidant defenses.

Yes, pregnancy and lactation increase the body's demand for selenium to support both the mother and child. Without sufficient intake, selenium reserves can become depleted.