There are no specific foods or dietary supplements that are helpful in treating thyroid disorders.
To ensure that you remain as healthy as possible it is important to eat the right variety of foods in the correct proportions. For example, choose low fat, low calorie spread rather than butter or ordinary margarines, avoid high salt intake and cut down on hidden fats & sugars (cakes, biscuits, chocolate). More information is available from NHS guidance.
We recommend a varied and healthy diet, with calcium rich foods and / or supplements, and normal vitamin D levels. If choosing to take any supplements, do so with care and not in excessive amounts, after appropriate advice from your doctor or pharmacist.
Some calcium rich foods and supplements interfere with levothyroxine absorption. A gap of 4 hours between the two would be adequate to ensure there is no significant impact on blood thyroxine levels. If you are trying to lose weight and using lower fat milk (i.e. semi-skimmed or skimmed) note that these remain high in calcium despite being lower in fat.
Soya interferes with thyroxine absorption, therefore if you are taking thyroxine you should try to avoid soya. If you wish to take soya, there should be as long a time interval as possible between eating the soya and taking the thyroxine.
There is evidence of certain brands of soya milk being withdrawn from sale by authorities in countries such as Ireland, Australia, New Zealand and Japan because they contained excessive amounts of iodine or being highly enriched with seaweed products that naturally contain iodine.
Avoid products such as kelp, as they may interfere with thyroid function & wellbeing. Kelp is derived from seaweed and is naturally high in iodine. Because of this it is sometimes marketed as a "thyroid booster" and can be purchased in dry preparations and tablets. As with iodine itself, it is of no health benefit to those with thyroid disease.
People with hypothyroidism should avoid preparations high in iodine as it can make the condition paradoxically worse. Additionally, in certain people it could provoke hyperthyroidism.
The British Thyroid Association has issued the following statement on the use of iodine supplements and we have advised our members accordingly
- The thyroid gland requires iodine for normal function. Adults need 150mcg of iodine per day.
- Typically we obtain the iodine we need from a normal healthy, balanced diet. Table & cooking salt in the UK contains little or no iodine. Too little iodine can result in thyroid swelling (a goitre). Goitre in the UK is not due to iodine deficiency Too much iodine can be dangerous and cause either under activity of the thyroid (hypothyroidism) or, in some cases over activity (hyperthyroidism).
- If you are taking thyroid hormone (eg. levothyroxine) for hypothyroidism or for a goitre (an enlarged thyroid gland) there is no need to supplement with iodine. It will do no good.
- Also, it can be harmful and dangerous to take iodine if you have an overactive thyroid, even if you are on standard anti thyroid drugs, as the extra iodine counteracts their effects.
- Should you take iodine supplements at any time? Only if it is recommended by your GP or hospital consultant.
Some medications such as iron tablets (ferrous sulphate) can interfere with the absorption of thyroxine. Some doctors recommend a two-hour interval between taking thyroxine and the iron. Follow the advice or your doctor or pharmacist. Be aware that some multi vitamin tablets contain iron.
Brassicas (cabbage, cauliflower, kale etc) may contribute to formation of a goitre (enlargement of the thyroid gland) in some cases, but consumption needs to be very high before this is a real concern. In the UK, under normal dietary conditions, this is not normally a problem and the risk is very low.