Evidence supporting the use of: Knotted kelp
For the health condition: Goiter
Synopsis
Source of validity: Scientific
Rating (out of 5): 3
Knotted kelp (Ascophyllum nodosum) is a type of seaweed that is naturally high in iodine, an essential micronutrient required for the synthesis of thyroid hormones. Iodine deficiency is a well-established cause of goiter, an enlargement of the thyroid gland. Historically, seaweeds have been used in traditional medicine systems, particularly in coastal regions, to prevent and treat goiter. However, the scientific basis for this use is centered on the iodine content rather than any unique property of knotted kelp itself.
Numerous clinical and epidemiological studies have demonstrated that increasing iodine intake in iodine-deficient populations reduces the prevalence of goiter. The use of kelp and other seaweeds as a dietary iodine supplement is recognized in modern medicine, especially in areas where iodized salt is not widely available. The U.S. National Institutes of Health and the World Health Organization both identify dietary iodine supplementation as an effective means of goiter prevention.
However, excessive intake of kelp can lead to iodine toxicity, which may result in thyroid dysfunction. Therefore, while there is scientific validation for using iodine-rich seaweeds like knotted kelp to treat or prevent goiter due to iodine deficiency, dosage and monitoring are important. The evidence is rated 3/5 because while the link between iodine and goiter is strong, direct studies on knotted kelp itself are limited, and effectiveness depends on context and individual iodine status.
