What Depletes Selenium? Understanding the Key Factors

October 5, 2025 •

4 min read

Millions of individuals worldwide experience selenium insufficiency, a deficiency linked to various health issues from weakened immune systems to impaired thyroid function. Understanding what depletes selenium is crucial for maintaining optimal health, particularly given the growing number of environmental and lifestyle factors impacting mineral availability.

Quick Summary

This article explores the primary reasons for selenium depletion, including insufficient dietary intake, malabsorption, kidney disease, chronic illnesses like HIV, alcoholism, and various medications. It explains how these factors interfere with selenium absorption and utilization, leading to potential health complications.

Key Points

Soil Content is Key: The amount of selenium in food is highly dependent on the mineral content of the soil it was grown in.
Malabsorption is a Major Culprit: Gastrointestinal disorders like Crohn's and celiac disease can prevent proper selenium absorption, even with a sufficient diet.
Chronic Illnesses Increase Risk: Conditions such as HIV/AIDS, kidney disease (especially dialysis), and liver disease can deplete selenium levels.
Alcohol Abuse Wreaks Havoc: Chronic, heavy alcohol consumption is strongly linked to lower plasma selenium levels due to its impact on oxidative stress and liver health.
Medications Can Interfere: Long-term use of certain drugs, including corticosteroids, some diuretics, and chemotherapy agents, can reduce selenium.
Dietary Restrictions Can Lead to Low Intake: Vegetarians and vegans are more prone to selenium insufficiency since plant-based foods are often lower in the mineral than animal-based products.
Supplementation May Be Necessary: For those with confirmed deficiency or significant risk factors, dietary changes may not be enough, and medical supervision for supplementation is advised.

The Importance of Selenium and How It Is Depleted

Selenium is a vital trace mineral that serves as a potent antioxidant, protecting cells from free radical damage and supporting numerous physiological processes. It is incorporated into selenoproteins, which play critical roles in immune function, thyroid hormone metabolism, and fertility. Because the body cannot produce it, selenium must be obtained through dietary sources. However, numerous factors can interfere with this process, leading to a deficiency that can have extensive health effects.

Environmental and Dietary Factors

Low-Selenium Soil Content: The selenium content of plant-based foods is directly influenced by the soil in which they are grown. In regions with low soil selenium levels, such as parts of China and Europe, the crops and animal products from those areas contain less of the mineral, putting residents at a higher risk of deficiency. Global food trade helps mitigate this issue, but local or regional food consumption can still be a risk factor.

Dietary Choices: Certain dietary patterns can increase the risk of low selenium intake. Individuals who follow a strict vegan or vegetarian diet may be more susceptible to insufficiency because plant-based foods generally contain lower selenium levels than animal-based products. The bioavailability of selenium from plant sources can also vary depending on the specific plant species and soil conditions.

Malabsorption Issues and Gastrointestinal Health

Chronic conditions affecting the gastrointestinal (GI) tract can significantly impair the body's ability to absorb and utilize nutrients, including selenium.

Crohn's Disease and Ulcerative Colitis: These inflammatory bowel diseases damage the lining of the GI tract, reducing the absorption of minerals like selenium. Selenium deficiency is a common finding in patients with inflammatory bowel disease, with severity correlating with the degree of disease.
Celiac Disease: This autoimmune disorder, triggered by gluten consumption, leads to damage of the small intestine lining, which can inhibit proper nutrient absorption. Even with adequate dietary intake, malabsorption can lead to deficiency.
Short Bowel Syndrome and Gastric Bypass Surgery: Surgical procedures that remove or bypass a significant portion of the intestine, such as gastric bypass or colon resection, can dramatically reduce the surface area available for nutrient absorption, resulting in selenium insufficiency.
Total Parenteral Nutrition (TPN): Patients who receive all their nutrients intravenously for extended periods without selenium supplementation are at a high risk of developing a severe deficiency.

Chronic Illnesses and Oxidative Stress

Several chronic health conditions can lead to selenium depletion, often due to increased oxidative stress or poor nutritional status.

HIV/AIDS: Individuals with HIV/AIDS frequently experience selenium deficiency due to a combination of reduced dietary intake, chronic diarrhea leading to malabsorption, and increased oxidative stress. Low selenium levels are associated with a decline in CD4 counts and accelerated disease progression.
Kidney Disease: Patients with end-stage renal disease (ESRD) on dialysis are at a high risk of selenium deficiency. The dialysis process can remove some selenium from the blood, and dietary restrictions and poor appetite common in uremia can further limit intake. Low plasma selenium levels in these patients are associated with a higher risk of mortality.
Alcoholism: Chronic, heavy alcohol consumption is strongly associated with low plasma selenium levels. Alcohol intake impairs selenium metabolism and increases oxidative stress, placing a greater demand on the body's antioxidant defenses. This can contribute to liver damage and neurological symptoms often seen in alcoholics.

Medications and Drug Interactions

Some medications can interfere with selenium absorption, metabolism, or increase its excretion.

Corticosteroids: Drugs such as prednisone, dexamethasone, and fluticasone can deplete selenium. This interaction is one of several drug-micronutrient depletions associated with corticosteroids.
Antacids and Diuretics: Prolonged use of certain antacids and diuretics has been shown to potentially impact selenium levels.
Chemotherapy Drugs: Certain chemotherapy agents, like cisplatin, can cause selenium deficiency.
Estrogen-based Drugs: Hormone replacement therapy (HRT) or oral contraceptives containing estrogen can affect several micronutrient levels, including selenium.

Comparison of Selenium Depletion Mechanisms


Factor	Primary Mechanism	Affected Population	Potential Outcome (if not addressed)
Low Soil Levels	Reduced selenium content in food grown locally.	Residents of low-selenium regions (e.g., parts of Europe, China).	General selenium deficiency risk; endemic diseases like Keshan disease.
Malabsorption	Impaired intestinal absorption due to damaged gut lining or reduced surface area.	Individuals with Crohn's, celiac disease, or post-GI surgery.	Severe deficiency despite adequate intake; potentially cardiomyopathy or myopathy.
Chronic Illnesses	Increased oxidative stress, inflammation, and poor nutritional status.	HIV/AIDS patients, individuals with severe kidney disease, alcoholics.	Worsened disease progression, immune dysfunction, liver damage, higher mortality.
Medications	Interference with absorption, increased excretion, or altered metabolism.	Patients on corticosteroids, diuretics, chemotherapy, or HRT.	Variable, depending on duration and dosage; requires monitoring and potential supplementation.

Conclusion: Managing Selenium Levels

Selenium is a vital micronutrient vulnerable to depletion from a variety of sources. For those at risk, whether due to a restrictive diet, chronic illness, or long-term medication use, understanding these risk factors is the first step toward prevention. Addressing underlying malabsorption issues, adjusting dietary intake to include selenium-rich foods, and discussing medication-related deficiencies with a healthcare provider are key strategies. Regular monitoring of selenium status may be necessary for at-risk individuals, as appropriate supplementation, under medical guidance, can be effective in correcting deficiencies and supporting overall health.

For more information on the role of selenium in health, you can consult the National Institutes of Health (NIH) Office of Dietary Supplements website.

Frequently Asked Questions

Chronic conditions that cause malabsorption, such as Crohn's disease and celiac disease, are significant risk factors. Additionally, patients with end-stage renal disease, HIV/AIDS, and alcoholism are prone to low selenium levels.

While not guaranteed, a strict vegetarian or vegan diet can be a risk factor for selenium insufficiency because the mineral is generally found in lower concentrations in plant-based foods compared to animal products. Regular consumption of nuts, seeds, and fortified products from selenium-rich soil can help prevent this.

Certain medications, including long-term use of corticosteroids like prednisone, some diuretics, and chemotherapy agents like cisplatin, can interfere with selenium. Estrogen-based hormonal treatments may also have an impact.

Yes, the selenium content in soil varies geographically. People living in regions with low soil selenium, such as some areas of China and Eastern Europe, have a higher risk of deficiency from locally grown food.

Chronic, heavy alcohol consumption has been shown to lower plasma selenium levels by impairing metabolism and increasing oxidative stress. This can cause liver damage and further deplete the mineral.

Yes, if you have a malabsorption condition like Crohn's or celiac disease, your body may not be able to effectively absorb selenium from food, regardless of how much you consume.

Yes, patients undergoing long-term kidney dialysis are at increased risk. The dialysis process removes some selenium, while dietary restrictions and poor appetite common in kidney disease can limit intake.