Subclinical hypothyroidism is defined as a normal serum free thyroxine level combined with an elevated thyroid stimulating hormone level. The causes of subclinical hypothyroidism are the same as those of overt hypothyroidism. There is good evidence that subclinical hypothyroidism is associated with progression to overt disease. The management of subclinical hypothyroidism is remains controversial. Patients with a serum thyroid stimulating hormone level greater than 10 mU/L have a higher incidence of elevated serum low-density lipoprotein cholesterol concentrations; however, evidence is lacking for other associations. There is insufficient evidence that hormone treatment of subclinical hypothyroidism is beneficial. The use of thyroid stimulating hormone level lone as a diagnostic and assessment tool for hypothyroidism is inadequate because this test cannot identify numerous conditions this sentence is unclear in its meaning. Using an expanded list of clinical signs and symptoms associated with dysfunction of the Hypothalamus-Pituitary-Thyroid axis, it is possible to hypothesize that subclinical hypothyroidism may be more common in a population of patients with early signs of age-related diseases than most practitioners realize. To improve thyroid function in subclinical hypothyroidism patients, practitioners should become familiar with foods and nutrients that can hinder or support thyroid function.