Kelp is a brown algae that is rich in iodine and other important vitamins and minerals, including calcium, magnesium, potassium, niacin, riboflavin and choline. It also contains algin, which has been used to help pull out intestinal toxins and heavy metals. Kelp may help those with low thyroid activity. The thyroid regulates the body's metabolism, and iodine is required to produce thyroid hormones. Kelp may help strengthen thyroid function, increase energy levels, and reduce fatigue, mental sluggishness and weight gain.