As of 2015, there is no evidence to support that any foods increase thyroid function in people with hypothyroidism, as confirmed by Mayo Clinic. However, leafy greens, nuts and iodized salt contain nutrients that are important for overall thyroid function, as stated by WebMD.
People in the United States normally get plenty of iodine in their diet due to the abundance of iodized salt, but they should still remember to check labels when purchasing salt to ensure they consume sufficient iodine to support healthy thyroid functioning, according to WebMD. Leafy greens such as lettuce and spinach contain magnesium, another essential mineral for normal thyroid function. Symptoms such as heartbeat changes, muscle cramps and fatigue may signal that an individual is not getting enough. Magnesium is also available in cashew nuts, pumpkin seeds and almonds. Brazil nuts contain magnesium along with thyroid-supporting selenium.
No matter what they choose to consume, patients with hypothyroidism should take their hormone replacement medications according to their doctor's instructions, as urged by Mayo Clinic. They should also avoid fiber-rich foods and certain other foods for several hours before and after taking their hormone replacements as they may inhibit absorption. These foods include walnuts, cottonseed meal and soybean flour. Iron supplements, calcium supplements and certain antacids may also interfere with the medication.