The link between plant‐based diet indices with biochemical markers of bone turn over, inflammation, and insulin in Iranian older adults

BACKGROUND: The association of plant‐based diets and biomarkers of bone, insulin, and inflammation is still unclear. OBJECTIVES: We investigated the associations between biomarkers of bone, insulin, and inflammation and three plant‐based diet indices: an overall plant‐based diet index (PDI); a healthy plant‐based diet index (hPDI); and an unhealthy plant‐based diet index (uPDI). METHODS: We included 178 elderly subjects who referred to health centers in Tehran. Blood and urine samples were collected to measure osteocalcin. The Human C‐telopeptide of type Ⅰ collagen (u‐CTX‐I), highly sensitive C‐reactive protein (hs‐CRP), parathyroid hormone (PTH), 25(OH) D, and insulin resistance and sensitivity. We created an overall PDI, hPDI, and uPDI from semi‐quantitative food frequency questionnaire (FFQ) data. RESULTS: Dietary groups of Vegetables (r = .15, p = .03), nuts (r = .16, p = .03), dairy (r = .25, p = .001), eggs (r = .27, p < .001), red meat, and animal products (r = .25, p = .001) were directly correlated with osteocalcin. Refined grains were also had a positive association with serum insulin concentration (r = .14, p = .04). PTH levels are inversely associated with PDI score (β = −0.18, p = .01). Also, serum insulin concentration was negatively associated with PDI score (β = −0.10, p = .04). Urine CTX‐1 levels were significantly associated with hPDI score (β = −0.06, p = .04). u‐CTX‐1 levels are inversely associated with uPDI score. This significance did not change with the adjustment of the confounders (β = −0.28, p < .001). CONCLUSIONS: More adherence to PDI and hPDI and less in uPDI may have a beneficial effect on biomarkers of bone, inflammation, and insulin thus preserving chronic diseases.