Autoimmune Thyroid Disorders: The Mediterranean Diet as a Protective Choice

Abstract

Autoimmune thyroid diseases are on the rise worldwide, and such a rapid increase is mainly driven by environmental factors related to changed lifestyles in "modern" societies. In this context, diet seems to play a crucial role. An unhealthy high-energy diet, rich in animal fat and proteins, salt and refined sugars (the so-called "Western diet") negatively influences the risk of autoimmunity by altering the immune balance and the gut microbiota composition, enhancing oxidative stress and promoting inflammation. In contrast, the Mediterranean diet represents a unique model of healthy eating, characterized by a high intake of food from vegetable sources, a low consumption of saturated fats in favor of unsaturated fats (mainly, olive oil), a moderate consumption of fish (typically, the small oily fishes) and dairy products, as well as a moderate consumption of wine at meals, and a low intake of meat. Thanks to its nutritional components, the Mediterranean Diet positively influences immune system function, gut microbiota composition, and redox homeostasis, exerting anti-oxidants, anti-inflammatory, and immunomodulatory effects. The present review was aimed at exploring the existing knowledge on the correlations between dietary habits and thyroid autoimmunity, to evaluate the role of the Mediterranean diet as a protective model.

Keywords: Hashimoto’s thyroiditis; Mediterranean diet; Western diet; autoimmune thyroid diseases; oxidative stress; vegetarianism.

Figure 1

Thanks to its nutritional components, the Mediterranean diet positively influences gut microbiota, redox homeostasis and immune system function, as opposite to the Western diet, and may be proposed for prevention and management of autoimmune thyroid disorders (a “precision nutrition” approach). PUFA: polyunsaturated fatty acids. ROS: reactive oxygen species.

Figure 2

Typical foods from Mediterranean diet and their possible role in the prevention of autoimmunity and inflammation. ↑ increased; ↓ decreased.

Figure 3

Possible sources of endocrine disruptor exposure through food consumption in the “From Farm to Food” process. PFAS: Per- and polyfluoroalkyl substances; BPA: Bisphenol A; PCB: Polychlorinated biphenyl.