Spicing up nutrition: investigation of trace elements in some spices locally sold in two markets in Kisumu-Kenya

Spices are integral to Kenyan cuisine, adding depth of flavour and aroma to dishes. Information on the levels of macro- and micronutrients in these spices is scarce, as they are sold locally in Kisumu City, Kenya; however, these species have medicinal value. The study reports the trace elements composition of eight selected spices (black pepper, cloves, ginger, cardamom, turmeric, cumin, red chillies, and garlic) sold in two open-air markets in Kisumu City. The trace elemental compositions for Zn, Ca, Fe, S, K, Na, P, Mg, Mn, B, Co, Li, Cu, Pb, and Cd were analysed using inductively coupled plasma-optical emission spectrometry (ICP-OES). Ginger had the highest mean concentrations of most essential elements, K (5767.86 ± 43.44 mg/kg), Mg (4615.36 ± 76.27 mg/kg), B (132.08 ± 0.66 mg/kg), Li (33.52 ± 0.84 mg/kg), Mn (365.29 ± 2.22 mg/kg), and Zn (70.44 ± 0.85 mg/kg), followed by Ca (5290.44 ± 147.34 mg/kg), Na (1361.88 ± 41.01 mg/kg), P (3954.25 ± 122.68 mg/kg), and S (4031.88 ± 106.95 mg/kg), while turmeric had the lowest. The concentrations of macro-elements in spices from the Kibuye market were slightly higher than those from the Jubilee market; however, these differences were not statistically significant (p < 0.05). Concentrations of Pb and Cd heavy metals were detected and reported for all spices in the two markets, although the levels were below the WHO standard; hence, the spices are safe for use as supplements for essential trace elements in addition to their medicinal uses.