Table 4.
Plant-derived proteins: effects on bone in relation to age, exercise, energy restriction and source.
| Reference | Study Design | Protein Composition | Measurements | Key Outcomes |
|---|---|---|---|---|
| Roughead et al., 2005 [87] | Randomised cross-over intervention study design Low meat soy supplemented vs. high meat n = 13 7 weeks, healthy postmenopausal females (F) (59.9 ± 5 years, mean ± standard deviation (SD)) |
Low meat soy supplemented—55 g/d meat, 25 g soy protein High meat—170 g/g meat All meals provided |
Calcium retention, urine composition, blood biomarkers of bone mineral status | No difference in calcium retention between groups No change in blood biomarkers of bone mineral status (i.e., 25-OH vitamin D, parathyroid hormone, insulin-like growth factor-I. |
| Kreijkamp-Kaspers et al., 2004 [119] | Randomised, double-blind, controlled parallel intervention design Soy protein supplement (n = 88) vs. milk protein supplement (n = 87) 12 months, healthy postmenopausal F (66 ± 5 years) |
Soy protein—25.6 g protein Milk protein—25.6 g protein Single daily ingestion |
Hip and lumbar spine bone mineral density (BMD), plasma lipid profiles | No difference in BMD from supplementation No change in plasma lipid profiles |
| Alekel et al., 2000 [116] | Randomised, double-blind, controlled parallel intervention design Isoflavone-rich soy protein (n = 24) vs. isoflavone-poor soy protein (n = 24) vs. whey protein control (n = 21) 24 weeks supplementation postmenopausal F (42–62 years, mean 50 years) |
All groups 40 g protein/d, 160 mg calcium/d Isoflavone-rich 80.4 mg aglycone Isoflavone-poor 4.4 g aglycone Single daily 500 kcal muffin (20 g protein) as a meal replacement |
Lumbar spine BMD and bone mineral content (BMC) | Both soy protein groups did not significantly decrease BMD, whereas the whey control group did BMC increase in the isoflavone-rich soy group and decreased in the whey protein control group. |
| Liu et al., 2010 [120] | Randomised, double-blind, controlled parallel intervention design Soy protein + isoflavone whey protein + isoflavone whey protein control 6 months postmenopausal F (56.1 ± 4.3 years, mean ± SD) |
Soy protein—15 g, 100 mg isoflavone Whey protein—15 g, 100 mg isoflavone Whey protein—15 g Daily supplementation |
Body composition | Soy protein with isoflavone supplementation demonstrated small but significant improvements in body weight, body mass index and body fat percentage |
Abbreviations: BMC, bone mineral content; BMD, bone mineral density; F, females; SD, standard deviation.