Dr. Michael Ruscio, DC is a clinician, Naturopathic Practitioner, clinical researcher, author, and adjunct professor at the University of Bridgeport. His work has been published in peer-reviewed medical journals and he speaks at conferences around the globe.
What effect does diet have on thyroid autoimmunity? We look at a study that observes the beneficial effects of a lower-carbohydrate diet in overweight patients with Hashimoto’s thyroiditis.
If you need help with thyroid autoimmunity, click here
The Benefits of a Lower Carbohydrate Diet for Those with Hashimoto’s
The thyroid is one of the metabolism-regulating glands. Its function is to determine the number of calories the body has to burn to maintain normal weight.
Thyroid autoimmunity is when your immune system attacks your thyroid gland. Over time, as the damage worsens, it can lead to hypothyroidism.
Today, Hashimoto’s disease is the leading cause of hypothyroidism in most countries throughout the world. It is more common in women, and its incidence increases with age. Hashimoto’s thyroiditis, an acute immune condition (aggression of the thyroid gland by the body’s own immune system), generally tends to evolve toward hypothyroidism.
In the vast majority of cases, Hashimoto’s thyroiditis has an insidious onset, and thyroid hormone levels usually remain within the normal range at first, with the first symptoms appearing only after the disease has progressed toward overt hypothyroidism.
In patients with Hashimoto’s thyroiditis, anti-thyroid peroxidase antibodies (TPO Abs) are usually detectable, while a minor percentage of patients also have anti-thyroglobulin antibodies.
A recent study evaluated the effects of diet on thyroid autoimmunity. Specifically, researchers looked at a group of overweight subjects with thyroid autoimmunity and the effect of following a lower-carbohydrate diet. This was not an ultra low-carb diet, but more of a moderately low-carb diet.
The study enrolled a total of 180 patients: 84 males and 96 females, aged 30 to 45 years. Hashimoto’s disease was detected in all of the subjects. Additionally, each patient showed other autoimmune symptoms typical in Hashimoto’s disease. All the patients were monitored weekly.
The experimental group, which consisted of a total of 108 patients (44 males and 64 females), started a diet program based on the following proportions: 12% to 15% carbohydrates, 50% to 60% proteins, and 25% to 30% lipids.
These patients were instructed to eat large leafy and other types of vegetables and only lean parts of red and white meat, avoiding goitrogenic food. The following items were also excluded from the diet: eggs, legumes, dairy products, bread, pasta, fruits, and rices.
This protein-rich diet plan was implemented for 3 weeks. At the end of the 3 weeks, bioimpedance tests, body weight measurements, and blood tests were performed.
The remaining 72 patients (40 males and 32 females), who made up the control group, followed a simple, low-calorie diet without restrictions regarding the type of food to consume, but adhered to the recommended dietetic allowances, as suggested by the National Research Institute on Food and Nutrition. After 3 weeks, the same tests were performed in this group of patients as those performed in the treatment group.
Patients on the low-carb diet saw significant reductions of anti-thyroid, anti-microsomal, and anti-peroxidase markers. Most notably, the decrease in TPO antibodies was 44%. TPO is the most important marker for thyroid autoimmunity. Additionally, a reduction in body weight of 5% and a reduction in BMI of 4% were observed over the 3-week period. The untreated patients in the control group saw an increase of these thyroid markers.
A dietary plan based on the reduction of carbohydrate content and free of goitrogenic foods leads not only to a decrease in body weight, but also determines a decrease in fat mass and a significant drop of autoantibodies in those with Hashimoto’s thyroiditis.
Goitrogenic foods contain substances that may interfere with iodine metabolism. These substances (known as goitrogens) are found especially in products of the cruciferous family (rapeseed or canola, cabbage, turnip, watercress, arugula, radish, horseradish) and in milk produced by cattle nourished with these vegetables. Other goitrogens include soy, spinach, millet, tapioca, and lettuce. These foods can prevent iodine uptake by the thyroid gland and induce iodine deficiency, which can cause hypothyroidism.
Why is a lower-carbohydrate diet helpful?
One reason could be that when you cut out carbs, you typically cut out most gluten-containing food. We know that gluten can be a trigger for several autoimmune conditions, including thyroid autoimmunity.
Another reason could be that patients experience improved metabolic health when they reduce carbohydrate intake.
The concern of low-carb diets damaging the thyroid is invalidated as observed in this study. When people change the way they eat, they may see a shift in some thyroid levels, but that is just the body getting adjusted. There’s no thyroid damage being done. It’s simply an adjusting of hormones, and if anything, a lower-carbohydrate diet may be healthier for your thyroid gland.
By simply restricting common sources of dense carbohydrates, like breads, cereals, rices, and fruits, you can have a positive impact on your thyroid autoimmunity.
To discover more about low-carb diets and thyroid autoimmunity, click here for a short video.
If you need help with thyroid autoimmunity, click here
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