Information Articles Thyroid and diet factsheet Information about diet and thyroid disorders is also available in Polish. 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. The NHS Eatwell Guide (https://www.nhs.uk/live-well/eat-well/) recommends you should try to: eat at least 5 portions of a variety of fruit and vegetables every day base meals on higher fibre starchy foods like potatoes, bread, rice or pasta have some dairy or dairy alternatives (such as soya drinks) eat some beans, pulses, fish, eggs, meat and other protein choose unsaturated oils and spreads, and eat them in small amounts drink plenty of fluids (at least 6 to 8 glasses a day) It isn't always easy to maintain a varied and healthy diet, and for this reason some people may wish to take additional vitamins and supplements. If you decide to take vitamins and supplements you should avoid taking them in excessive amounts. This is because some can interfere with your thyroid function or your thyroid blood test results. We recommend you take appropriate advice from your doctor or pharmacist before you start taking any supplements or vitamins. Vitamin D Vitamin D helps regulate calcium and phosphate production and is needed for healthy bones, teeth and muscles. Some studies have shown that the people with low levels of vitamin D may also have thyroid disorders but the link is not clearly defined and may be coincidental. Since most people may be deficient in vitamin D (particularly in the autumn and winter months when the sunlight in the UK is not strong) the NHS advises that all adults and children over the age of five take a supplement of 10mcg each day. This applies during the autumn and winter for most people but throughout the year if you are concerned you may not get enough sunlight even at other times of the year, e.g. you aren’t often outdoors or you tend to cover yourself up with clothes when you are outside. If you have dark skin you are also at risk of not getting enough vitamin D from sunlight and should consider taking 10mcg supplements throughout the year. Calcium 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 use lower fat milk (i.e. semi-skimmed or skimmed), this remains high in calcium despite being lower in fat. Iodine For people with a properly functioning thyroid iodine is essential as it is required for the production of thyroxine. It is particularly important in women who are pregnant as it is needed to ensure the development of a baby's brain during pregnancy and early life. If you are taking levothyroxine for hypothyroidism (underactive thyroid) or for a goitre (thyroid swelling) there is no need to take iodine supplements. If you are being treated for hyperthyroidism (overactive thyroid) taking an iodine supplement is unnecessary and can worsen the condition. The extra iodine can counteract the benefits of the anti-thyroid drugs. For more information about iodine see: Iodine and diet FAQs British Dietetic Association iodine fact sheet Soya 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. Kelp Avoid products such as kelp, as they may interfere with thyroid function and 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. Iron Tablets 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 of your doctor or pharmacist. Be aware that some multivitamin tablets contain iron. Brassicas Brassicas (cabbage, cauliflower, kale etc) may contribute to the formation of a goitre (swelling or enlargement of the thyroid gland) in some cases, but consumption would need 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.