Your thyroid can make you cold, fat and tired

The thyroid gland in your neck controls your metabolism. And if it's sluggish, you could be one of the millions of Americans with hypothyroidism -- and not even know you have it.

About half of all people with this common disease are untreated, risking serious medical consequences. Thanks to updated guidelines, medical science is better able to interpret lab values and identify people with a mild form of the condition. But treatment remains tricky -- and controversial. "One size does not fit all," says endocrinologist Theodore C. Friedman, co-author of "The Everything Health Guide to Thyroid Disease." "You really have to individualize the treatment to the person."

Diagnosis and treatment depend on a mix of symptoms, risk factors and the amount of thyroid hormones in your blood. If you recognize early symptoms (including cold intolerance, constipation, depression, fatigue, brittle fingernails and weight gain), then ask your doctor to consider doing a blood test that will measure your T4 and TSH.

Treat your hypothyroidism and you also might avoid pregnancy complications and high cholesterol.

Check your neck

For a lesson on how to look for signs of an enlarged thyroid gland, visit the American Association of Clinical Endocrinologists website: powerofprevention