Plant-based protein supplements as emerging sources of metal exposure: A risk assessment study

The growing demand for plant-based diets has prompted the food industry to develop nutritional supplements, particularly plant-based protein supplements (PS), designed to meet the needs of vegans and vegetarians. While these supplements offer essential nutrients, they may also contain potentially toxic elements (PTEs) that pose health risks. This study assessed the metal content of 56 plant-based PS samples from European sources using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). Dietary exposure to these elements was evaluated across three consumption scenarios, considering established reference intake values (AI/TDI/TWI/UL) and the Margin of Exposure (MOE) for lead (Pb). The analysis identified plant-based PS as significant sources of essential elements, including sodium (9101.66 mg/kg), potassium (5784.91 mg/kg), calcium (2201.45 mg/kg), molybdenum (1.63 mg/kg), manganese (25.14 mg/kg), copper (11.59 mg/kg), iron (132.58 mg/kg), zinc (62.56 mg/kg), chromium (0.45 mg/kg), and cobalt (0.11 mg/kg). However, these products also contained PTEs such as lead (0.07 mg/kg), cadmium (0.09 mg/kg), aluminum (18.39 mg/kg), nickel (1.19 mg/kg), strontium (5.67 mg/kg), barium (1.86 mg/kg), boron (4.59 mg/kg), and vanadium (0.05 mg/kg). At the recommended consumption level of 30 g/day, exposure to both essential and PTEs did not exceed reference intake limits. However, this dose accounted for 75 % of the Adequate Intake (AI) for molybdenum. Excessive consumption (100 g/day) raised concerns about exceeding the AI for copper (105.40 %) and magnesium (105.90 %) in women, as well as molybdenum (250.16 %) and iron (120.53 %) for men and postmenopausal women. These findings underscore the dual role of plant-based PS as valuable sources of essential nutrients and potential vectors for PTEs.