2.5.1. Non-Carcinogenic Risk

Hazard quotient (HQ) looks at the non-carcinogenic risk to human health from exposure to toxic and potentially toxic elements [22]. HQ assesses the relationship between the estimated daily intake (EDI) of potentially harmful elements with respect to the established oral reference dose (RfD). The RfD of a substance is an estimate of the acceptable level of exposure where the risk of negatively impacting human health is negligible. Hence, hazard quotient was used to characterise potential health risks associated with the consumption of the thirty-six protein powder samples under investigation.

A summary of the available RfD values can be found in Table 5. There are no established RfD values for Pt, Bi, Mg, Ti or total Cr. Therefore, these analytes were omitted from the risk assessment.

Reference oral dose (RfD) and carcinogenic slope factor (CSF) values for toxic and potentially toxic elements.

If HQ < 1, the risk of exposure is not expected to pose any adverse health effects, while HQ > 1 indicates that ingestion of the product carries an increased health risk for consumers. To estimate HQ, the following formulae (2) and (3) were used [14]:

where Cfinal = calculated concentration of analyte in the original sample (µg·kg⁻¹); IR = intake rate of protein powder per respective manufacturer serving sizes (kg·day⁻¹, 1–3 servings); BW = bodyweight (70 kg); RfD = reference oral dose (µg·kg⁻¹ BW·day⁻¹).

Where a product contains more than one toxic/potentially toxic element, exposure to the product may incur interactive effects, which can enhance the overall risk to the consumer. The hazard index (HI) estimates this increased risk through the addition of the calculated HQs of each element [23], as per the following Equation (4):

As with individual HQs, if HI < 1, the product is not expected to cause harm to the consumer. However, if HI > 1, the product is potentially unsafe for consumption.