Thyroid Modifier Herbs

Summary

Thyroid Modifier Herbs

introduction:
Brassica (Cabbage and Mustard) family foods contain glucosilinates which form isothiocyanate compounds in humans. Isothiocyanates reduce iodine uptake by the thyroid and hence depress thyroxine levels which leads to feedback induced goiter (increase in thyroid size). They are also hepatoprotective and can induce Phase I detoxification enzymes. Mustards also contain high levels of tyrosine, a thyroid hormone precursor.

Iodine containing seaweeds have persistently been used by herbalists for treating hypothyroid conditions despite the fact that pharmaceutical iodide is considered an effective pharmaceutical treatment for hyperthyroid. Some herbalists suggest that at least a proportion of the effects of seaweed ingestion are due to correction of trace mineral deficiencies and consequent improvement in metabolic status rather than effects on thyroid activity as such.

It is known that some anti-goiter plants with activity on thyroid levels are acting via the pituitary/ TSH rather than at the thyroid gland itself, which lends credence to their possible "normalizer" role.
(Brinker F. 1998, 156; Duke JA. 1997, 227, 273; Newell C, et al, 1996 124-126.)


overview of interactions:
• herbal synergy: Thyroid Hormones

• herbal concern: Iodine toxicity potential.



Herbs

herbal synergy: Thyroid Hormones

• mechanism: Thyroid stimulating herbs are most effectively used as adjuncts to support lower doses of prescribed thyroid, unless the deficiency is very slight. This parallels the use of antidiabetic herbs as adjuncts to oral hypoglycemic drugs.

• herbal concerns: It is unusual for serious thyroid conditions, whether due to deficiency or excess, to be resolved entirely by herbal means.

herbal concern: Iodine toxicity potential

• mechanism: Long term ingestion of excessive levels of iodine-containing seaweeds may result in goiter in euthyroid individuals. Individuals with a history of thyroid disease should moderate intake of iodine-containing seaweeds.

• herbal concerns: Treatment of serious thyroid conditions should not be undertaken without consulting a physician.
(Hardman J, et al. 1996, 1492; Newell C, et al. 1996, 124-126.)

Thyroid hormone depressing herbs:
• Brassica spp. (glucosilinate-containing vegetables)
• Lithospermum officinale (Stoneseed)
• Lycopus spp. (Bugleweed)
• Melissa officinalis (Lemon Balm)
• Prunella vulgaris (Self Heal)
• Raphanus sativus (Radish)
• Verbena spp. (Verbena)

Thyroid hormone stimulating herbs:
• Centella asiatica (Gotu kola)
• Commiphora mukul (Guggul)
• Gentiana spp. (Gentian)
• Juglans spp. (Walnut)
• Sinapsis spp. (Mustard leaf)

Iodine-containing herbs:
• Chondrus crispus (Irish moss)
• Fucus spp. (Bladderwrack aka 'kelp')
• Laminaria spp. (Kelp, Kombu)
• Rhodemnnia palmetto (Dulse)

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Do not rely solely on the information in this article.

The information presented in Interactions is for informational and educational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, case reports, and/or traditional usage with sources as cited in each topic. The results reported may not necessarily occur in all individuals and different individuals with the same medical conditions with the same symptoms will often require differing treatments. For many of the conditions discussed, treatment with conventional medical therapies, including prescription drugs or over-the-counter medications, is also available. Consult your physician, an appropriately trained healthcare practitioner, and/or pharmacist for any health concern or medical problem before using any herbal products or nutritional supplements or before making any changes in prescribed medications and/or before attempting to independently treat a medical condition using supplements, herbs, remedies, or other forms of self-care.


References

Brinker F. Herb Contraindications and Drug Interactions. Second edition., Sandy, OR: Eclectic Institute Inc, 1998.

Duke JA. Green Pharmacy. Emmaus, PA: Rodale Press.1997.

Hardman J, et al. eds. Goodman & Gilman's Pharmacological Basis of Therapeutics. Ninth Edition. McGraw Hill, 1996.

Newall C, Anderson L, Phillipson JD. Herbal Medicines: A Guide for Health-care Professionals. London: The Pharmaceutical Press, 1996.