Nutritional Composition and Estimated Iron and Zinc Bioavailability of Meat Substitutes Available on the Swedish Market

Abstract

Transition towards plant-based diets is advocated to reduce the climate footprint. Health implications of a diet composed of meat substitutes are currently unknown, and there are knowledge gaps in their nutritional composition and quality. Samples of available meat substitutes were bought in two convenience stores in the city of Gothenburg, Sweden, and were included in the study. Meat substitutes (n = 44) were analyzed for their contents of dietary fiber, fat, iron, zinc, phytate, salt, total phenolics and protein, as well as for their amino acid and fatty acid composition. Bioavailability of iron and zinc was estimated based on the phytate:mineral molar ratio. We found large variations in the nutritional composition of the analyzed meat substitutes. Amino acid profiles seemed to be affected by processing methods. Mycoprotein products were rich in zinc, with a median content of 6.7 mg/100 g, and had very low content of phytate, which suggests mycoprotein as a good source of zinc. Degradability of fungal cell walls might, however, pose as a potential aggravating factor. None of the products could be regarded as a good source of iron due to very high content of phytate (9 to 1151 mg/100 g) and/or low content of iron (0.4 to 4.7 mg/100 g). Phytate:iron molar ratios in products with iron contents >2.1 mg/100 g ranged from 2.5 to 45. Tempeh stood out as a protein source with large potential due to low phytate content (24 mg/100 g) and an iron content (2 mg/100 g) close to the level of a nutrition claim. Producers of the products analyzed in this study appear to use nutritional claims regarding iron that appear not in line with European regulations, since the iron is in a form not available by the body. Meat substitutes analyzed in this study do not contribute to absorbed iron in a relevant manner. Individuals following mainly plant-based diets have to meet their iron needs through other sources. Salt and saturated fat were high in certain products, while other products were more in line with nutritional recommendations. Further investigation of the nutritional and health effects of protein extraction and extrusion is needed. We conclude that nutritional knowledge needs to be implemented in product development of meat substitutes.