Long‐chain Polyunsaturated Fatty Acid Status Associates with Bone Mass in Overweight and Obese Children

Abstract

Children who are obese are at increased risk of fractures. However, linkages to possible nutritional imbalances are unclear. Experimental studies suggest long‐chain polyunsaturated fatty acids (LCPUFA) such as arachidonic acid (AA C20:4 n6) modulate bone mass in a biphasic manner, yet it is uncertain whether this is observed in humans. This study examined the relationship between LCPUFA status and bone mass in overweight and obese (OvOb) children. Participants (n=119, 9.28 ± 1.89 y, BMI‐z 3.03 ± 1.02) were assessed for bone mass with DXA (Hologic Discovery). Fatty acid profile was measured in red blood cells (RBC) using gas chromatography. A generalized linear model was used to determine relationships between LCPUFA in RBC and bone outcomes with adjustments for Tanner stages and BMI. Saturated fatty acids palmitate (C16:0) and stearate (C18:0) inversely related to lumbar spine bone mineral density (r=‐0.18 and ‐0.22 respectively, p<0.05); while the omega‐3 fatty acid α‐linoleneate (ALA, C18:3 n3) positively related to whole body, total hip, ultra‐distal and mid forearm bone area, mineral content (BMC) and density (r=0.21 to 0.31, p<0.05). When children were divided into three groups by AA tertiles (cutoffs by 33rd and 67th percentile of % total FA) and compared with MIXED model ANOVA, those in the second tertile had greater forearm bone area and BMC than those in the first or third tertiles (Table 1), indicating higher AA levels may not confer additional benefits in bone growth and mineral accrual. These data suggest LCPUFA may play important roles in modulating bone mass during growth in OvOb children. 1st tertile (n=39) [4.67‐7.51%] 2nd tertile (n=35)[7.52‐ 8.42%] 3rd tertile (n=45)[8.44‐14.06%] Ultra‐dista Area (cm2) 4.09 ± 0.64a 4.67 ± 0.67b 4.29 ± 0.63a BMC (g) 1.32 ± 0.05 1.51 ± 0.09 1.38 ± 0.07 Mid Area (cm2) 7.50 ± 0.47ab 9.21 ± 0.55a 7.75 ± 0.32b BMC (g) 3.05 ± 0.22a 4.02 ± 0.34b 3.31 ± 0.19a 1/3 distal Area (cm2) 4.33 ± 0.10a 4.74 ± 0.10b 4.38 ± 0.06a BMC (g) 2.11 ± 0.09 2.43 ± 0.13 2.28 ± 0.09