Determination of Oxidative Stress Indexes of Follow-Up Formulas (> 12 Months) and Certain Flavored Milks

Background: Milk is known to contain some natural antioxidants, but limited literature is available on the antioxidant/oxidant content of flavored milks, which are commonly consumed in children > 12 months of age.

Purpose: This study was performed to investigate the total antioxidant status (TAS) and total oxidant status (TOS) and oxidative stress indices of children’s follow-up formulas (> 12 months) and flavored milks.

Materials and Methods: Milk samples (plain milk [n = 3], cocoa milk [n = 9], chocolate milk [n = 4], strawberry milk [n = 12], banana milk [n = 13], honey milk [n = 2], and children’s follow-up formula [> 12 months] [n = 8]) between January and March 2021 were included in the study. TAS and TOS levels were measured using commercially available kits (Relassay, Turkey) and Mindray BS300 Auto Biochemistry AnalyzerTM (China). All analyses were carried out in duplicate. The OSI value (arbitrary unit) was calculated.

Results: In this study, TOS values (μmol/L) of milk samples showed a significant difference between all groups (p < 0.05) and the lowest was in plain milk (14.90 ± 3.66 μmol/L). There was a difference in TOS values between plain milk and cocoa milk (p = 0.007) and between plain milk and chocolate milk (p = 0.035). There was a significant difference in TAS values between the groups (p < 0.001), and the highest TAS values were observed in chocolate milk (2.64 ± 0.02 mmol/L) and cocoa milk (2.35 ± 0.45 mmol/L), respectively. The differences in TAS values were found between banana–cocoa milks (p < 0.001), banana–chocolate milks (p = 0.007), and strawberry–cocoa milks (p = 0.033). There was a difference between the OSI values of the groups (p < 0.001), the lowest values were found in cocoa milk (2.57 ± 0.47) and chocolate milk (2.22 ± 0.46), respectively. The difference in OSI values was found between chocolate–banana milk (p = 0.006) and cocoa–banana milk (p = 0.001). A positive correlation (r = 0.945; p < 0.001) was found between TAS and energy content of follow-up formulas (> 12 months). Positive correlations were found between TAS and fat content (r = 0.679; p = 0.044) and saturated fat content (r = 0722; 0.028) of cocoa milk. There was no significant correlation between OSI and any macronutrient and energy in milk groups (p > 0.05).

Conclusion: Cocoa and chocolate milks have the highest antioxidant and oxidant capacity and the lowest oxidative stress index. However, plain milk had the lowest oxidant capacity. Furthermore, the linear relationship between the energy content of the follow-up formula and oxidant capacity indicates the importance of adequate-balanced and functional consumption of these milks.