Hypothyroidism occurs when the thyroid gland fails to produce enough hormones for the body to function properly. Symptoms of hypothyroidism include chronic tiredness, lethargy, weight gain, depression, forgetfulness and increased sensitivity to cold. As the macrobiotic diet contains two foods -- seaweed and soy -- that could potentially affect the thyroid gland, there is some debate about whether the macrobiotic diet is advisable for this condition.
Iodine from Seaweed
Seaweed, a macrobiotic staple, is rich in iodine, which is used to produce thyroid hormones. However, extra iodine from seaweed won't improve thyroid function if you aren't already deficient in it. According to the New York University Langone Medical Center website, genuine iodine deficiency is rare in America. Furthermore, too much iodine can have the opposite effect by causing hypothyroidism in some people. This is a classic case of "more is not better." Both too little iodine and too much iodine can disrupt thyroid function.
Soy Foods and Hypothyroidism
Research published in the "Journal of Animal Physiology and Animal Nutrition" shows that phytic acid found in soy decreases thryoid hormone levels in rats. A 1998 article in the "Journal of Nutritional Science and Vitaminology" states that fermentation processes often used to produce traditional soy foods degrade phytic acid. Fermentation, however, does not diminish phytoestrogen levels. When phytoestrogens are consumed, subclinical hypothyroidism, a condition in which levels of thyroid stimulating hormone are high while thyroid hormones themselves remain normal, can become overt hypothyroidism, in which thyroid hormone levels are low, according to a 2011 article in the "Journal of Clinical Endocrinology and Metabolism."
Soy and Autism
A 2001 article published in the "Journal of Neurological Science" suggested the possibility that prenatal exposure to flavanoids could be a risk factor for autism. Flavanoids are antioxidant compounds found in soy, fruits and vegetables. The flavanoids genistein and daidzein inhibit an enzyme that plays a crucial role in the synthesis of thyroid hormones. Animal research has shown that even temporary prenatal hypothyroidism causes changes in the brain structures of rats that are similar to those found in autistic people.
Weight Loss
Weight gain is a frequent side effect of hypothyroidism. If you or someone you know is concerned about this issue, a macrobiotic diet that has been modified to exclude soy products may be useful. People adopting this diet often lose weight rapidly because the diet is low in simple sugars and fats and high in fiber and vegetables. If you want to follow a macrobiotic diet, consult your doctor and an experienced macrobiotic counselor who can help you design a diet that is right for your particular condition.
References
- "Journal of Clinical Endocrinology and Metabolism"; The Effect of Soy Phytoestrogen Supplementation on Thyroid Status and Cardiovascular Risk Markers in Patients With Subclinical Hypothyroidism: A Randomized, Double-blind, Crossover Study; T.Sathyapalan, et al.; May 2011
- "Journal of Neurological Science"; Autism: Transient in Utero Hypothyroxinemia Related to Maternal Flavonoid Ingestion During Pregnancy and to Other Environmental Antithyroid Agents; G.C. Roman; November 2001
- "Journal of Animal Physiology and Animal Nutrition"; Phytic Acid-Induced Metabolic Changes in the Rat; T. Szkudelski ; December 2005
- "Journal of Nutritional Science and Vitaminology"; Fermentation of Soybean Flour With Aspergillus Usamii Improves Availabilities of Zinc and Iron in Rats; M. Hirabayashi, et al.; December 1998
- "Journal of Clinical Endocrinology and Metabolism"; Iodine Status and Thyroid Function of Boston-Area Vegetarians and Vegans; A.M. Leung, et al.; May 25, 2011
- New York University Langone Medical Center: Hypothyroidism
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