Hypothyroidism is a syndrome of clinical symptoms caused by thyroxine deficiency. The disease is cited as the most important endocrine cause of obesity among children and adults. Very often, the first noticeable sign of hypothyroidism is weight gain, associated with excessive accumulation of adipose tissue and water in the connective tissue glycosaminoglycans, resulting in subcutaneous oedema.
What is there with Hashimoto’s?
Hashimoto’s disease with hypothyroidism presents not only with symptoms related to hormone deficiency, but also with complaints from the nervous system, i.e. chronic fatigue, impaired concentration, muscle weakness, poorer adaptation to temperature changes, increased predisposition to depression and anxiety.
The predominant problem is maintaining body weight due to reduced resting metabolism. In addition, obesity may accelerate the development of thyroiditis. Even simple lifestyle changes, characterised by increased physical activity and improved body composition even without accompanying BMI changes, lead to improved thyroid function.
Modifying body composition with a reduction in fat reduces inflammation, the secretion of pro-inflammatory cytokines and, consequently, improves thyroid function. In view of the above-mentioned factors, dietary changes are justified.
The main principles of nutrition in Hashimoto’s disease and hypothyroidism are to provide adequate amounts of wholesome protein (lean meat, fish, eggs), polyunsaturated fatty acids (vegetable oils, nuts, fish), carbohydrates with a low glycaemic index and to cover the need for: iodine, iron, selenium, zinc and vitamin D, vitamin B12 and antioxidant vitamins (vitamins A, E and C). A well-balanced diet supports the treatment. People suffering from hypothyroidism are recommended to take 3-5 meals a day. The last meal should be taken 2-3 hours before bedtime.
A regular supply of food prevents the metabolic rate from slowing down. The energy supply should be adapted individually to each patient, taking into account gender, age, physiological status, co-morbidities or physical activity. It is worth noting that excessive caloric restriction may cause an increase in TSH concentration and a decrease in metabolic rate. Restricting the energy value of meals plays a role in thyroid metabolism, probably as a result of increased cortisol production. Reducing calorie supply has an effect on hepatic deiodinase activity, leading to a reduction in serum triiodothyronine concentrations.
The protein supply in people with Hashimoto’s disease should be higher than in healthy people. Ideally, its source should be animal products containing complete protein. Protein is used for the production of thyroid hormones and also speeds up metabolism, which has a beneficial effect on the energy balance of hypothyroidism sufferers.
Not to forget fish, which, in addition to easily digestible protein, contains iodine and n-3 fatty acids (marine fish). Legume seeds are also a good source of protein, which, like meat, are rich in B vitamins and iron, and also contain complex carbohydrates.
Carbohydrates should be provided in the form of whole grain cereal products. This is because they have a lower glycaemic index and more minerals, vitamins and fibre than their refined counterparts. Low glycaemic index foods are important for patients with autoimmune thyroiditis and hypothyroidism, as these people often struggle with carbohydrate imbalances.
Dietary fibre can prevent constipation, which is a symptom of hypothyreosis. In addition to this, it binds toxic compounds in the gut, preventing their absorption, and increases the feeling of satiety, in addition to reducing serum glucose and cholesterol levels. People with Hashimoto’s disease have a higher risk of developing diabetes than the population without thyroid disease.
It is advisable to consume vegetable products containing fats ( olive oil, avocados, nuts, seeds and seeds) and fish, which are sources of unsaturated fatty acids. It is also worth mentioning that vegetable oils are rich in vitamin E. In people with Hashimoto’s disease, the supply of high-quality fat and the restriction of saturated fatty acids is extremely important to prevent cardiovascular disease. This is because it has been noted that patients with Hashimoto’s thyroiditis have higher levels of total blood cholesterol, triglycerides and the LDL cholesterol fraction than healthy people. They also have higher blood pressure, homocysteine and C-reactive protein levels.
A special role in thyroid disease is attributed to n-3 fatty acids, which exhibit anti-inflammatory properties and stimulate the conversion of triiodothyronine to thyroxine. Fatty acids of the n-3 family inhibit the excessive response of the immune system. They have also been noted to have an effect on the prevention of type 2 diabetes. As a result of too many n-6 fatty acids relative to n-3 fatty acids in the phospholipids of the cell membranes of muscle cells, their insulin sensitivity is reduced.
N-3 fatty acids also inhibit lipogenesis, which may be useful for people with hypothyroidism and coexisting obesity. In addition, they contribute to a reduction in serum triglyceride levels, as well as having anticoagulant and anti-atherosclerotic effects. However, it is important to note that supplementation with n-3 fatty acids may not provide the expected therapeutic benefit if the patient’s diet is characterised by a high intake of sugars. On the other hand, it is beneficial to combine supplements containing n-3 fatty acids with products containing protein.
Most of the dietary recommendations for people with hypothyroidism and Hashimoto’s disease overlap with those for the general population. In addition, sufferers will particularly benefit from improved body composition. People with hypothyroidism should pay particular attention to the dietary supply of selenium, zinc, iodine and vitamin D, and any deficiencies should be supplemented.
It is extremely important to control thyroid hormone levels, and those taking levothyroxine should look out for ingredients that cause reduced absorption of thyroid hormone replacement.
Due to the higher incidence of carbohydrate disorders, hypercholesterolaemia, depression, lactose intolerance or coeliac disease, people with hypothyroidism should focus on regular check-ups, medical consultations and an individually tailored diet for co-morbidities.
Author: Zuzanna Cybulska, MSc, clinical dietitian