Kelp is an iodine-rich sea plant that is used as both a food and medicinal supplement. Taking more than 2,000 mcg of kelp per day may lead to the development of overdose signs and symptoms. Overdosing on kelp significantly increases your blood levels of iodine -- a substance that can affect the ability of the thyroid gland to produce thyroid hormone. For this reason, the signs and symptoms of kelp overdose mimic hyperthyroidism, or high thyroid hormone, and hypothyroidism, or low thyroid hormone, symptoms. If you believe you've taken too much kelp, seek additional care from your medical provider.
Changes in Body Weight
Your thyroid gland is responsible for producing thyroid hormone, which regulates your metabolism. Taking too much kelp may cause your thyroid gland to produce too much or not enough of this hormone. High thyroid hormone levels may cause sudden weight loss, while low levels of thyroid hormone may result in unusual weight gain. These weight changes usually arise despite maintaining your normal diet and appetite.
Thyroid hormone is also responsible for regulating your core internal temperature. A kelp overdose may increase your sensitivity to cold due to low thyroid hormone levels, or increase your sensitivity to heat, due to high thyroid hormone levels. These temperature regulation problems may lead to unusual shivering or excessive sweating.
Consuming high doses of kelp may lead to skin problems such as acne, dryness or swelling. You may also notice that your skin appears unusually pale.
Regardless of whether your thyroid hormone levels are too high or too low due to a kelp overdose, you may develop flu-like symptoms. Common symptoms include fatigue, muscle aches, weakness, mood changes and difficulty sleeping. You may also develop either frequent or infrequent bowel movements. People with low thyroid hormone levels may also experience symptoms of depression, including lethargy, moodiness or lack of interest in usual activities. In addition, elevated thyroid hormone levels may result in nervousness, tremor or increased heart rate.
Menstrual Cycle Irregularities
Women who take too much kelp may experience menstrual cycle irregularities. Low thyroid hormone levels may cause heavier-than-usual menstrual periods, which may be accompanied by abdominal cramping or bloating. Alternatively, low thyroid hormone levels may cause spotting or unusually light or infrequent menstrual periods. Women who notice changes in their menstrual cycle should seek further evaluation from a medical professional.