It is no longer a myth that a balanced diet is fundamental for general health. Common dietary components including vitamins A and D, omega-3 and probiotics are now widely accepted to be essential to protect against many diseases with an inflammatory nature. On the other hand, high fat diets are documented to exert multiple deleterious effects, including fatty liver diseases. Here we discuss the effect of dietary components on regulatory T cell (Tregs) homeostasis, a central element of the immune system to prevent chronic tissue inflammation. Accordingly, evidence bearing on the impact of dietary components on diseases in which Tregs play a seminal role will be discussed. Among chronic diseases where dietary factors could have a direct influence via modulation of Tregs homeostasis and functions, we will review chronic tissue-specific autoimmune and inflammatory conditions such as IBD, T1D, MS, RA and allergies.