Soy Consumption Associated With Congenital Hypothyroidism
According to a case report published in Pediatrics, soy products are linked to congenital hypothyroidism, an endocrinologic disorder. Congenital hypothyroidism is a rare disease that affects 1 in 4000 infants. There are multiple causes that can lead hypothyroidism, the most common being iodine deficiency, but sometimes defects in the formation of thyroid hormones can have the same consequence. Another cause is lack of thyroid (thyroid aplasia or hypoplasia). Without hormone replacement therapy, hypothyroidism cause delays in development, not only physical but also mental development (mental retardation or cretinism). There are several signs and symptoms of congenital hypothyroidism such as exaggerated jaundice, excessive sleeping, constipation, low body temperature. Other signs of hypothyroidism are macroglossia (enlarged tongue), enlarged anterior fontanelle and others.
The observation was made in two female patients by doctors at University of California San Diego in La Jolla. They found that thyroid function in patients, diagnosed with congenital hypothyroidism and treated with hormone replacement, did not improve. It was noticed that the two patients were also receiving a soy formula. Instead, after stopping soy formula, thyroid function improved.
Hypothyroidism is an endocrine disorder in which the thyroid does not produce enough thyroid hormone. This disorder can be congenital or acquired.
There are many causes that determine such impairment because there are several glands and nervous structures that control thyroid hormone levels. Hypothyroidism can be induced by thyroid gland, pituitary gland or hypothalamus. When the thyroid is involved, it is called primary hypothyroidism, if pituitary gland (which produces TSH, tyroid stimulating hormone)is implied, there the hypothyroidism is secondary, and if it is involved the hypothalamus (that produces tyrotropin releasing hormone) the disorder is called tertiary hypothyroidism. But most often hypothyroidism is related to iodine deficiency.
Hypothyroidism is characterized by increased TSH levels while levels of free T4 (thyroxine) are low. Signs and symptoms of hypothyroidism include bradycardia (low heart rate), intolerance to cold, fatigue, weight gain, dry skin due to water retention and edema (myxedema), depression, gastrointestinal disorders (constipation), infertility.
Hypothyroidism can be kept under control if diagnosed early and treated appropriately. As far as congenital hypothyroidism is concerned, there is a newborn screening showing what children suffer from hypothyroidism and who do not. Hormone replacement therapy (levothyroxine) begins in the first weeks of life. Doses of hormones increases as the child grows. It is important to note that hormone replacement therapy lead to normal development of the child, even in those with athyreosis (lack of development of the thyroid gland).