The Best Time to Take Selenium for Thyroid Health and Antioxidant Protection

Selenium is a trace mineral that can impact thyroid health and antioxidant defense. While there isn’t definitive evidence for a single best time to take selenium, research suggests consistent long-term intake may help achieve and sustain healthy selenium levels for these and other benefits.

Take Selenium at Mealtime for Potential Thyroid and Antioxidant Benefits

Research doesn’t support a single best time for selenium for thyroid health and antioxidant protection.

However, research on selenium indicates that taking selenium with food at mealtime may be optimal:

• Lab studies found that food improves the digestive environment by increasing enzyme activity and nutrient breakdown, thereby potentially enhancing mineral absorption.
• Gut microbiota and food composition may influence the bioavailability of minerals, including selenium, supporting the concept that the food matrix (the physical and chemical structure of food) can affect how your body absorbs selenium.
• Eating food triggers the secretion of digestive secretions, including gastric acid, digestive enzymes, and bile, which support nutrient breakdown and absorption. This process may also help reduce adverse gastrointestinal effects when a supplement is taken with a meal.
• Research suggests that the impact of selenium isn’t immediate, with changes occurring after three to six months of daily supplementation, regardless of timing.
• This may indicate that consistency, rather than precise timing, affects the way selenium delivers health benefits.

How Selenium May Support Thyroid Health and Antioxidant Protection

Research indicates that selenium is essential to thyroid health and antioxidant protection in the following ways:

• Thyroid hormone production: Your thyroid gland contains the highest concentration of selenium per gram of tissue in your body. Selenium is incorporated into selenoproteins, which help convert the inactive thyroid hormone thyroxine (T4) into the active thyroid hormone triiodothyronine (T3).
• Antioxidant defense: Selenium enables the production of antioxidant enzymes that protect thyroid cells against oxidative damage from free radicals during thyroid hormone production.
• Management of Hashimoto’s thyroiditis: Selenium supplementation may help reduce autoantibody levels, a common cause of hypothyroidism. Research has linked selenium supplementation with lower serum TSH levels, significantly lower thyroid peroxidase antibodies (TPOAb), and lower malondialdehyde (MDA), a marker of oxidative stress in the thyroid gland.
• Potential protection against thyroid disease development and progression: Maintaining healthy selenium levels may help prevent and slow the progression of thyroid disease, especially autoimmune conditions such as Graves’ disease, Graves’ eye disease, and Hashimoto’s thyroiditis. Selenium supplementation is also linked with improved quality of life in some thyroid disorders.

Safe Selenium Dosage Guidelines

• Selenium is a trace element that you only need in small amounts. The Recommended Dietary Allowance (RDA) for selenium is 55 to 70 micrograms (mcg) per day for adults and 15 to 70 mcg per day for children, based on age and life stage.
• You can risk selenium toxicity if you consume more than the established daily Tolerable Upper Intake Level (UL) for selenium, which is 400 mcg for adults and 45 mcg to 400 mcg for children, depending on age.
• Taking more than the daily UL of selenium can lead to selenosis, a condition caused by long-term excess selenium consumption that results in hair loss, brittle/lost nails, garlic-like breath, metallic taste, fatigue, and gastrointestinal problems.
• While selenium deficiency is rare in the United States, low selenium levels can occur because of long-term IV feeding, kidney dialysis, and gastrointestinal disorders such as Crohn’s disease.
• Since selenium can interact with certain medications and fluctuate due to some medical conditions and treatments, you should consult your healthcare provider before taking selenium supplements if you have a chronic condition or take prescribed medication.