Low iron levels are one of the most common reasons for chronic coldness. Here’s why: Iron is a key mineral that helps your red blood cells carry oxygen throughout your body, bringing heat and other nutrients to every cell in your system, explains Dr. Phillips. Without enough iron, red blood cells can’t effectively do their job, and you shiver.

Iron is also crucial because a deficiency can make your thyroid lethargic, leading to hypothyroidism, which further leaves you freezing, says Moon. Iron supplements can help, but the best way to boost your iron intake is through healthy food: meat, eggs, leafy greens like spinach, and seafood are the best options, says Moon.

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