Blood test only measure T4/T3 (TSH- Thyroid Stimulating Hormone) hormone blood level, while temperature readings measures how much energy is actually being generated in the cells.

Allergy causing foods left over from incomplete digestion turn into acidic waste. Carried by blood, this waste lodges in the capillaries near the thyroid, blocking the flow of oxygen and glucose, materials the thyroids needs to generate energy. Toxic wastes from food allergies can have effect on the liver, further reducing energy production, since the liver stores sugar (glycogen) as well as converting thyroxin (T4) to active T3 when more energy is needed.

Thyroid function is also inhibited by the heavy metal residues in processed foods and food which come from the metal used in their manufacturing. Two examples are the aluminum used to hydrogenate oils, and sulfuric acid and chromium in the production of food additives.
Vitamin E, Vitamin A, Mineral complex in liquid form ( as it converts tyrosine, an amino acid to thyroxin) . Vitamin B, Vitamin C to eliminate side effects of thyroid drug and 2 table spoons daily of coconut oil to counteracts the toxic effects of unsaturated oils on the thyroid gland.