Nutrition Corner with Dr D 

Thyroid-Food Connection: Optimizing Thyroid Health

Understanding Your ThyroidYour thyroid, a butterfly-shaped gland located at the base of your neck, plays a significant role in regulating your body's metabolism. It produces two main hormones, thyroxine (T4) and triiodothyronine (T3), which help maintain optimal energy levels, body temperature, and even support healthy brain function.d.

Vitamin D: The Sunshine NutrientVitamin D is crucial for regulating calcium and phosphate, aiding healthy bone, teeth, and muscle development. Low levels of vitamin D have been associated with thyroid disorders. However, this relationship is not clearly defined and may be coincidental. During autumn and winter, sunlight in the UK is not strong, and vitamin D deficiency is common. The NHS suggests adults and children over the age of five take a 10mcg vitamin D supplement daily. Those with darker skin or who don't get enough sunlight should consider taking a 10mcg supplement throughout the year. Calcium: Building Blocks for Bone HealthCalcium-rich foods and supplements can interfere with the absorption of levothyroxine, a common medication for underactive thyroid. Leave a four-hour gap between levothyroxine and calcium intake to maintain thyroxine levels. Weight watchers opting for lower-fat milk still receive a high calcium content, beneficial for bone health.

Iodine: The Thyroid EssentialIodine is essential for thyroxine production and is especially important for pregnant women for the baby's brain development. However, if you are taking levothyroxine for hypothyroidism or goitre, there's no need for iodine supplements. And in case of hyperthyroidism, iodine supplements can counteract the benefits of anti-thyroid drugs. Navigating the Soya ConundrumSoya, also known as soy, is a nutrient-dense plant-based protein that is a staple in many diets worldwide. Despite its health benefits, soya poses a particular challenge for individuals with thyroid conditions, specifically those on thyroxine medication. Thyroxine is a hormone replacement medication used to treat hypothyroidism, a condition in which the thyroid gland doesn't produce enough thyroid hormones. However, research has indicated that soya can interfere with the absorption of thyroxine, leading to decreased effectiveness of the medication. A 2011 study in the Journal of Clinical Endocrinology and Metabolism found that infants with congenital hypothyroidism needed significantly higher doses of thyroxine when their diets were supplemented with soya formula. This suggests that soya products can interfere with the absorption of thyroxine in the gut. If you're taking thyroxine, it's advisable to minimize your soya intake. If soya consumption is unavoidable, it's crucial to ensure a long interval between consuming soya and taking thyroxine. Most healthcare professionals recommend waiting at least four hours after consuming soya to take your thyroxine dose. It's also worth noting that some brands of soya milk have been withdrawn from the market in countries like Ireland, Australia, New Zealand, and Japan. These brands were found to contain excessive amounts of iodine or were highly enriched with seaweed products that naturally contain iodine. Consuming high amounts of iodine can disrupt normal thyroid function, especially in individuals already suffering from thyroid disorders.

Kelp: A Hidden RiskKelp is a type of seaweed that's packed with nutrients, particularly iodine. This high iodine content has led some to tout kelp as a 'thyroid booster', asserting its ability to support optimal thyroid function. However, current research suggests a more complex picture. Iodine is indeed an essential nutrient for thyroid health as the thyroid gland uses it to produce the hormones that control metabolism. But as with many things, balance is key. Too little iodine can lead to hypothyroidism (an underactive thyroid), but paradoxically, too much iodine can also disrupt normal thyroid function. Scientific studies have shown that excessive iodine intake can lead to either hyperthyroidism (an overactive thyroid) or hypothyroidism, depending on the individual's circumstances. This is particularly concerning given the high iodine content of kelp and the potential for individuals to consume too much iodine if they're using kelp supplements.

A 2019 study published in the Journal of Endocrinological Investigation found a case where a woman developed hyperthyroidism after consuming kelp-containing supplements. Another 2014 study in Thyroid noted that a 45-year-old woman developed severe hypothyroidism and myxedema due to a kelp-containing diet. Furthermore, the iodine content in kelp is variable and can be significantly higher than what's listed on the supplement labels, increasing the risk of consuming excessive amounts. A 2007 research published in the Journal of the American Dietetic Association found that the actual iodine content in eight out of nine commercial kelp supplements significantly exceeded the amount listed on the label, with some supplements providing almost 2000 micrograms of iodine per recommended daily serving. Moreover, kelp supplements have been found to be contaminated with heavy metals, such as arsenic, further exacerbating the potential health risks. This was highlighted in a 2017 study in Food and Chemical Toxicology. Given these potential risks, it's wise to avoid kelp in all its forms if you have thyroid disease or are taking thyroid medication.

Iron Supplements: A Delicate BalanceIron tablets can interfere with thyroxine absorption. If you're taking iron supplements, ensure a four-hour gap before taking your thyroxine medication. Note that some multivitamins also contain iron. Brassicas: A Grey AreaBrassicas, a family of vegetables also known as cruciferous vegetables, include cabbage, cauliflower, kale, broccoli, and Brussels sprouts. While these vegetables are nutritional powerhouses, rich in vitamins, fiber, and disease-fighting phytochemicals, there's been a long-standing concern about their potential impact on thyroid health due to their goitrogenic substances. Goitrogens are naturally occurring compounds that can interfere with the thyroid's ability to utilize iodine, which is crucial for the production of thyroid hormones. In theory, consuming high amounts of foods containing goitrogens could contribute to the development of a goiter—an enlargement of the thyroid gland—especially in individuals who have an iodine deficiency.

However, evidence suggests that brassicas need to be consumed in very high amounts to pose a significant risk. Most dietary patterns, even those high in vegetables, are unlikely to provide a harmful amount of goitrogens. In fact, a 2016 review in Nutrients concluded that the health benefits of consuming cruciferous vegetables far outweigh the potential adverse effects on thyroid function, especially for individuals with adequate iodine intake. Selenium and Zinc: Micro Minerals with Macro BenefitsSelenium and zinc are trace minerals that play critical roles in maintaining thyroid health. Selenium is integral to the proper functioning of the thyroid gland because it helps regulate hormone synthesis. It's also a potent antioxidant that protects the thyroid gland from oxidative damage. Selenium deficiency can exacerbate conditions like Hashimoto's thyroiditis and Graves' disease. A 2013 review in the Journal of Clinical Endocrinology and Metabolism highlighted selenium's essential role in thyroid hormone metabolism and immunity. Zinc is another trace mineral essential for thyroid function. It's involved in hormone synthesis, regulation, and binding to receptors. Zinc deficiency has been associated with hypothyroidism and reduced levels of thyroid hormones. A 2015 study published in Biological Trace Element Research found that zinc supplementation improved thyroid function in hypothyroid patients. Both selenium and zinc can be found in a range of foods. Selenium is rich in Brazil nuts, tuna, sardines, eggs, and legumes (beans, chickpeas, lentils). Zinc is found in shellfish, beef, chicken, and legumes. However, when considering supplementing these minerals, it's crucial to remember that more is not always better. Excessive intake of selenium or zinc can lead to toxicity and health issues. The Final Word: Maintaining Thyroid HealthYour thyroid health depends significantly on your diet and lifestyle choices. Although tempting, avoid exceeding the recommended intake of vitamins or supplements. Instead, aim for a balanced diet and healthy lifestyle. Consult your doctor or pharmacist before introducing any new supplement into your diet. Always maintain at least a four-hour gap from your thyroid medication unless otherwise indicated. By staying mindful of these guidelines, you can make the right choices for your thyroid health.

Home Page