Selenium | SEP15 (rs5845)

What this means

The AA genotype at rs5845 is associated with decreased selenium transport into cells. Even with adequate dietary selenium, people with this genotype may process and make selenium available to SEP15 and possibly other selenoproteins less efficiently. This could subtly affect antioxidant capacity, immune support, and thyroid-related processes.

Diet recommendations

• Prioritize selenium-rich foods daily: 1 to 2 Brazil nuts (do not exceed 2 per day to avoid excess), seafood (tuna, sardines, shrimp), organ meats, beef, poultry, eggs, and dairy.
• Combine selenium foods with balanced meals containing healthy fats and protein to support absorption and overall nutritional status.
• Eat a varied diet including fruits, vegetables, whole grains, and legumes to support antioxidant networks that work alongside selenium.

Supplement guidance

• Supplements may help if dietary intake is low, but use caution. Selenium has a narrow safe range and excess can cause adverse effects.
• If considering a supplement, typical supplemental doses range from 50 to 200 micrograms daily, but individual needs vary. Consult your healthcare provider before starting.

Lifestyle and general wellness

• Support antioxidant status with a diet high in colorful produce and regular physical activity tailored to your fitness level.
• Manage chronic stress and get regular sleep; both support immune and thyroid function.

Blood tests and monitoring

• Discuss measuring plasma or serum selenium and thyroid function tests (TSH, free T4, free T3) with your clinician if you have symptoms or risk factors.
• Consider periodic monitoring if taking selenium supplements to avoid exceeding the upper intake level.

What this means

The AG genotype is associated with likely decreased selenium transport into cells. This heterozygous state may have a milder effect than AA but could still influence how efficiently selenium is used to make SEP15 and other selenoproteins.

Diet recommendations

• Include selenium-rich foods regularly: 1 Brazil nut a day can contribute substantially, plus seafood, lean meats, eggs, and dairy across the week.
• Maintain a nutrient-dense, balanced diet to support antioxidant systems and thyroid health.

Supplement guidance

• Supplements can be considered if intake is inconsistent or if labs show low selenium. Start under medical supervision.
• Avoid long-term high-dose supplementation without monitoring.

Lifestyle and general wellness

• Regular moderate exercise, stress reduction techniques, and adequate sleep support immune and metabolic health.
• Avoid smoking and limit excessive alcohol, which can impair antioxidant defenses.

Blood tests and monitoring

• Talk with your provider about checking selenium status and thyroid panels when clinically appropriate.
• If supplementing, periodic lab checks help ensure levels remain in a safe range.

What this means

The GG genotype is associated with typical cellular handling of selenium. SEP15 function and construction of selenoproteins are expected to proceed normally when dietary selenium is adequate.

Diet recommendations

• Maintain a balanced diet with selenium-rich foods: Brazil nuts in moderation, seafood, meats, eggs, and dairy.
• The recommended dietary allowance for most adults is about 55 micrograms per day, which is typically achievable through varied food choices.

Supplement guidance

• Supplements are usually unnecessary for people with adequate diets. Consider supplements only if advised by your healthcare provider based on lab results or special conditions.
• Be mindful of total intake from diet plus supplements to avoid exceeding the tolerable upper intake level.

Lifestyle and general wellness

• Continue healthy lifestyle habits that support antioxidant and thyroid health: balanced diet, regular activity, sleep, and stress management.

Blood tests and monitoring

• Routine selenium testing is not commonly required unless there are symptoms or conditions that affect status. Discuss testing with your clinician if concerns arise.