Biodiversity is a reservoir of potential sources of novel food and feed ingredients with suitable compositions for the improvement of the diet and well-being of humans and farmed animals. The halophyte Atriplex portulacoides occurs in habitats that are exposed to seawater inundations, and shows biochemical adaptations to saline and oxidative stresses. Its composition includes long chain lipids, sterols, phenolic compounds, glutathione and carotenoids. These organic compounds and micronutrients, such as Fe, Zn, Co and Cu, make this plant suitable as an optimal functional food that is potentially able to reduce oxidative stress and inflammatory processes in humans and animals. Indeed, many of these compounds have a protective activity in humans against cardiovascular pathologies, cancer, and degenerative processes related to aging. The analysis of its history as food and forage, which dates back thousands of years, attests that it can be safely consumed. Here, the limits of its chemical and microbiological contamination are suggested in order to comply with the European regulations. The productivity of A. portulacoides in natural environments, and its adaptability to non-saline soils, make it a potential crop of high economic interest.