Your thyroid is your body's silent workhorse—most of the time, it functions so smoothly that we forget it's there. But this little, butterfly-shaped gland that sits at the base of your neck helps regulate your metabolism, temperature, heartbeat, and more, and if it starts to go haywire, you'll notice. An underactive thyroid—when the gland fails to produce enough thyroid hormone (TH)—can bring on weight gain, sluggishness, depression, and increased sensitivity to cold. An overactive thyroid, on the other hand, happens when your body produces too much TH, and can cause sudden weight loss, irregular heartbeat, sweating, nervousness, and irritability.
Genetics, an autoimmune condition, stress, and environmental toxins can all mess with your thyroid—and so can your diet, one factor you can completely control. Here are the foods that may help keep your thyroid humming along, as well as some that won't.