Blueberries and Thyroid Cancer: Are They Safe and Helpful?

Blueberries are generally safe to eat for people with thyroid cancer and can be part of a healthy, balanced diet rich in fruits and vegetables. Guidance for thyroid cancer care encourages maintaining a diet with a variety of fruits and vegetables to support overall health during and after treatment. ^{[1] [2]} Eating fruits and vegetables is commonly recommended as part of lifestyle measures that promote well‑being in thyroid conditions. ^[3]

Key Takeaways

• Safety: Blueberries are safe for most individuals with thyroid cancer. ^{[1] [2]}
• Benefits: They provide antioxidants, fiber, and vitamins that support general health. Emphasizing fruits and vegetables aligns with dietary advice for thyroid care. ^{[1] [2] [4]}
• Medication timing: If you take levothyroxine (thyroid hormone), do not eat blueberries or any food at the same time as your dose; take the medication on an empty stomach and wait before eating. Certain foods and fibers can interfere with absorption, so spacing is important. ^{[5] [6]}

Why Blueberries Fit a Thyroid‑Friendly Diet

Blueberries are high in antioxidants and part of the broader fruit-and-vegetable category that is encouraged for people during and after thyroid cancer treatment to help maintain health and recovery. ^{[1] [2]} Increasing fruits and vegetables provides antioxidants and other nutrients associated with general cancer-preventive dietary patterns. ^[4] While supplements of single antioxidants often do not show cancer-preventive effects, whole foods like berries contribute synergistic nutrients within a balanced diet. ^{[7] [4]}

Considerations with Thyroid Medication (Levothyroxine)

• Take on an empty stomach: Levothyroxine should typically be taken on an empty stomach to ensure consistent absorption. ^[6]
• Wait before eating: Foods especially those high in fiber can reduce levothyroxine absorption; many clinicians recommend waiting about 30–60 minutes before eating after your dose. ^[6] High dietary fiber can reduce levothyroxine bioavailability, and certain foods (soy, walnuts, cottonseed meal) are specifically known to bind the medication. ^[5]
• Grapefruit caution: Grapefruit juice may delay levothyroxine absorption and reduce bioavailability, so it should be avoided close to dosing; blueberries do not have this specific interaction. ^[5]

Iodine and Goitrogen Myths

Blueberries are not a significant source of iodine, nor are they known to adversely affect iodine status or thyroid function in typical amounts as part of a balanced diet. The best approach to meeting micronutrient needs, including iodine, is a varied diet rather than relying on single foods. ^[8] Some cruciferous vegetables (like cabbage or broccoli) contain compounds that can affect the thyroid in certain contexts, but they also have antioxidant benefits; overall, varied vegetable intake is still encouraged. ^[9]

Practical Tips for Eating Blueberries

• Include regularly: Enjoy blueberries fresh or frozen as part of your daily fruit intake for fiber and antioxidants. ^[4]
• Space from medication: Take levothyroxine first thing in the morning with water, then wait before eating blueberries or any breakfast. This helps avoid absorption issues. ^{[6] [5]}
• Balance matters: Combine blueberries with other fruits, vegetables, whole grains, and lean proteins to support recovery, energy, and overall health. ^{[1] [2]}

Bottom Line

Blueberries are safe for people with thyroid cancer and can be a healthy addition to your diet. Just remember to time them away from levothyroxine to keep your medication working properly. ^{[5] [6]} Following a diet rich in varied fruits and vegetables aligns with supportive care during and after thyroid cancer treatment. ^{[1] [2]}