Nutrition, geoepidemiology, and autoimmunity

As well represented by the impaired immune function of malnourished individuals encountered in developing countries and the incidence of specific diseases following local nutrient deficiencies, nutrition and immunity have been linked to each other for centuries while the specific connection between dietary factors and autoimmunity onset or modulation is a more recent acquisition. Autoimmune diseases manifest limited prevalence rates in developing countries while numerous immunity-related claims have been proposed in the field of functional foods. Nevertheless, over the past years multiple lines of evidence have supported a major role for specific dietary factors (including vitamin D, vitamin A, selenium, zinc, omega-3 fatty acids, probiotics, and flavanols) in determining the immune responses involved in infections, allergies, and autoimmune diseases. Interestingly, the link between nutrition and autoimmunity may well contribute to the geoepidemiology observed for numerous conditions. In general terms, most data that will be discussed herein were obtained in experimental or animal models while human data from real-life clinical settings or randomized clinical trials remain largely unsatisfactory. Our current knowledge on the beneficial impact of nutrition on autoimmunity prompts us to encourage the search for evidence-based nutrition to support the everyday diet choices of patients.