Effects of Greek Yogurt Versus Whey Protein Supplementation on Markers of Bone Turnover and Inflammation in University Athletes: A 24-Week Intervention Study.

No main effects or interactions were found for markers of bone formation across the intervention period.

• Bone formation markers analyzed included osteocalcin, amino-terminal propeptide of Type I collagen (P1NP), and insulin-like growth factor 1 (IGF-1).
• Neither Greek yogurt nor whey protein supplementation produced significant changes in these formation markers.
• The study included 32 university athletes (16 females) over a 24-week period including an 8-week control and 16-week intervention.

C-telopeptides of Type I collagen (CTX), a marker of bone resorption, showed a significant Time × Group interaction between Greek yogurt and whey protein groups.

• Time × Group interaction was statistically significant (p = .048).
• In the Greek yogurt group, CTX increased from pre- to postcontrol and returned to baseline concentrations postintervention.
• CTX remained stable throughout the study in the whey protein group.
• Greek yogurt provided 175 g per serving (17 g protein) twice daily; whey protein was isonitrogenous.

Receptor activator of nuclear factor kappa-B ligand (RANKL) increased from pre- to postcontrol across both groups and returned to baseline by midintervention.

• A significant time effect was observed for RANKL (p = .014).
• The increase occurred during the 8-week control period before any supplementation began.
• RANKL returned to baseline levels by midintervention (Week 16), with no significant group differences or Time × Group interaction reported.

Males had significantly higher sclerostin and interleukin 10 concentrations than females, with no sex-by-group interactions.

• Sex effect for sclerostin was significant (p = .021).
• Sex effect for interleukin 10 (IL-10) was significant (p = .004).
• No Time × Sex or Group × Sex interactions were reported for either marker.
• The sample included 16 male and 16 female university athletes.

Tumor necrosis factor-alpha (TNF-α) showed a trend toward increasing from pre- to postcontrol and then decreased to baseline levels postintervention.

• The time effect for TNF-α approached but did not reach conventional statistical significance (p = .053).
• TNF-α increased during the 8-week control period and decreased following the 16-week supplementation intervention.
• No significant Group × Time interaction was reported, suggesting the pattern was similar across both supplementation groups.

Interleukin 6 showed no main effects or interactions across time, group, or sex.

• IL-6 was measured as a pro-inflammatory marker at all four time points (Weeks 0, 8, 16, and 24).
• Neither Greek yogurt nor whey protein supplementation significantly altered IL-6 concentrations.
• No sex differences were observed for IL-6.

The study employed a controlled design with an 8-week habitual diet control period followed by random assignment to 16 weeks of Greek yogurt or whey protein supplementation.

• Participants were 32 university athletes (16 females) followed over a competitive season.
• Greek yogurt dose was two servings per day of 175 g (providing 17 g protein per serving).
• Whey protein was isonitrogenous to the Greek yogurt condition.
• Blood was collected at four time points: Week 0 (precontrol), Week 8 (postcontrol/preintervention), Week 16 (midintervention), and Week 24 (postintervention).
• Ten blood markers were analyzed: osteocalcin, P1NP, IGF-1, osteoprotegerin, CTX, sclerostin, RANKL, TNF-α, IL-6, and IL-10.