When you think of potatoes, you might not think of them as a superfood. But that's if you're thinking of chips (one of the foods most closely linked to weight gain), fries, or loaded mashed potatoes. But in their purest form, they are an excellent source of nutrients. "Potatoes are an excellent source of vitamin C, which is linked to immunity, synthesis of collagen for skin and tissue strength and elasticity, protection from cell-damaging free radicals and iron absorption," says Beth Stark, RDN, LDN, a registered dietitian…