Journal Title (Medline/Pubmed accepted abbreviation): Nutr Metab (Lond)
Page Numbers: 71 (open access)
doi (if applicable):10.1186/1743-7075-8-71
Background:Osteoporosis primarily affects older postmenopausal women, decreasing quality of life and increasing societal cost. The decline in bone health in older postmenopausal women parallels estrogen depletion and increased inflammatory activity. Previous studies suggest that polyunsaturated fatty acids (PUFA) supplementation and exercise may suppress inflammation and bone resorption.
Hypothesis/Purpose: Exercise combined with PUFA supplementation may inhibit inflammation and bone resorption, thereby preserving bone mineral density (BMD).
Subjects: Seventy-nine women ≥ 8 years past menopause with a body mass index ranging from 25.1 to 28.5 kg/m2 and 58 to 78 years of age were enrolled. All women were in good health and were not taking any medications. Analysis was based on 70 women who completed the study.
Experimental design: Randomized, independent groups. Details regarding placebo and blinding procedures were not provided.
Treatments and protocol:
Women were randomized to 1 of 4 study arms: exercise + supplement (E+S), exercise (E), supplement (S), or control (C). The E+S and S groups received a total of 1,000 mg/day N-3 PUFA. In the first 12 weeks, subjects in E+S and E groups exercised 25 to 30 minutes/day, 3 to 4 days/week, at 45% to 55% of previously determined maximal heart rate (HRmax). In the second 12-week period, exercise was increased to 40 to 45 minutes/day, 4 to 6 days/week, at an intensity of 55% to 65% of HRmax. Blood samples for serum tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), prostaglandin E2 (PGE2), estrogen, osteocalcin, 1,25-vitamin D, carboxy-terminal collagen crosslinks (CTX), parathyroid hormone (PTH), calcitonin (CT), calcium, phosphorus, and fatty acid composition of neutrophil extracts were collected at baseline and at 12 and 24 hours after the last exercise. BMD was assessed at the lumbar spine (LS; L2-L4) and femoral neck (FN) at baseline and at 12 and 24 weeks.
In sedentary postmenopausal women, exercise and PUFA supplementation may help maintain skeletal health. Although the individual interventions of exercise and PUFA supplementation appear to have beneficial effects, a synergistic benefit is derived when both are combined. The significant gains in BMD at LS and FN as a result of E+S intervention are consistent with the observed effects of these interventions on estrogen, calciotropic hormones, and inflammatory cytokines. PUFA supplementation appears to augment the benefit of exercise by increasing estrogen levels and decreasing calcium resorption from bone.