Where it begins
Selenium is a naturally occurring trace element found in sedimentary rocks and volcanic soils. As these rocks break down, selenium enters soil, water, and eventually the food chain. However, its availability varies dramatically by region.
In much of sub-Saharan Africa, soil selenium levels are low, leading to low selenium levels in crops and, by extension, in local diets. This variation makes selenium status a geographic health issue more than a dietary one.
How it enters your plate
Selenium gets into your body through a range of foods, but its levels depend heavily on the selenium content of the soil where those foods are grown or raised.
In West African diets, selenium-rich foods may include:
- Organ meats like liver and kidney
- Seafood, including shellfish and small dried fish
- Grains, particularly maize and millet, when grown in selenium-rich soil
- Eggs, which reflect the selenium content of poultry feed
- Brazil nuts (a global source, though less common locally)
The selenium content in staple crops like maize or sorghum can vary more than tenfold depending on soil conditions.
What it does in your body
Selenium is a key component of selenoproteins, which play vital roles in:
- Protecting cells from oxidative damage through antioxidant enzymes like glutathione peroxidase
- Thyroid hormone metabolism, helping regulate growth and energy
- Immune system performance, particularly antiviral defense
- Reproductive health, supporting sperm motility and fertility
Selenium’s role in neutralizing harmful free radicals makes it important in the prevention of chronic inflammation and cellular aging.
Are you getting enough?
Because selenium content in food depends on geography, deficiency can occur even with a diverse diet, especially in areas where soils are selenium-poor.
At-risk groups include:
- People in selenium-deficient regions (parts of West Africa)
- Those with gastrointestinal disorders affecting absorption
- People with limited access to animal-source foods
Signs of deficiency can be subtle but may include:
- Fatigue and muscle weakness
- Poor immunity and frequent illness
- Thyroid imbalances
- In severe cases, Keshan disease, a heart condition linked to low selenium
Takeaway tips: Getting enough selenium
- Include small, dried fish or seafood in stews and soups where possible.
- Support soil health—selenium-enriched fertilizers are effective in increasing crop selenium.
- Diversify grains—rotate maize, millet, and sorghum to reduce regional crop limitations.
- When possible, include eggs or organ meats for reliable selenium intake.
