ARI Publication 40 – 2013 Version
Rationale: About 5-10% of the general population has a thyroid disorder requiring
supplementation, and that percentage may be higher in autism. Poor thyroid function due to lack
of iodine is the major cause of mental retardation in the world, resulting in over 80 million cases of
mental retardation, and decreased energy level. Poor thyroid function can be caused by other
factors as well.
Iodine is required for normal thyroid functioning, and a major national study (NHANES) found that
levels of iodine fell more than 50% from the early 1970’s to the early 1990’s, presumably due to
decreased use of table salt (which is one of the major sources of iodinized salt). Non-iodinized salt
is used in most processed foods (potato chips, crackers, etc). Therefore, iodine deficiency is an
increasing concern today.
Hollowelt JG et al, ‘Iodine nutrition in the UnitedStates. Trends andpublic health implications: iodine
excretion data from National Health and Nutrition Examination Surveys I andIII (1971-1974 and 1988-
1994); _J Clin Endocrinol Metab 83(10): 3401-8 (1998).
If individuals do not use iodinized salt or take a vitamin/mineral supplement containing iodine, then
they are at high risk of iodine deficiency.
The most accurate testing is a blood measurement of thyroid hormones and iodine level.
Thyroid hormone is measured as part of the newborn screening to rule out congenital
hypothyroidism and to start treatment early in life if necessary, in order to prevent mental
retardation. If a child has not had a newborn screening test or has symptoms of hypothyroidism in
infancy, it is important to check thyroid hormones immediately.
A simple initial assessment can be done by measuring body temperature before waking. A low
body temperature is a possible indicator of too low a level of thyroid function. Overall low
energy/activity, low muscle tone, constipation, brittle hair, dry hair and developmental delays can
also be a possible indicator of a thyroid problem, but could be caused by other factors also.
If iodine levels are low, then one can begin with iodine supplementation. If that does not normalize
thyroid levels, then one can consider thyroid supplements. We recommend natural thyroid
supplements derived from animals, as they will provide a complete thyroid source (both T3 and T4
hormones). Synthetic thyroid supplements contain only T4.
It is important to treat low thyroid conditions as early as possible, to prevent the risk of mental
Some individuals have thyroid dysfunction due to thyroid autoantibodies or congenital abnormalities
in thyroid development, so an evaluation by an endocrinologist is important if abnormalities in
thyroid function are suspected.