One year soy protein supplementation has positive effects on bone formation markers but not bone density in postmenopausal women.
BACKGROUND
Although soy protein and its isoflavones have been reported to reduce the risk of osteoporosis in peri- and post-menopausal women, most of these studies are of short duration (i.e. six months). The objective of this study was to examine if one year consumption of soy-containing foods (providing 25 g protein and 60 mg isoflavones) exerts beneficial effects on bone in postmenopausal women.


METHODS
Eighty-seven eligible postmenopausal women were randomly assigned to consume soy or control foods daily for one year. Bone mineral density (BMD) and bone mineral content (BMC) of the whole body, lumbar (L1-L4), and total hip were measured using dual energy x-ray absorptiometry at baseline and after one year. Blood and urine markers of bone metabolism were also assessed.


CONCLUSIONS
Sixty-two subjects completed the one-year long study. Whole body and lumbar BMD and BMC were significantly decreased in both the soy and control groups. However, there were no significant changes in total hip BMD and BMC irrespective of treatment. Both treatments positively affected markers of bone formation as indicated by increased serum bone-specific alkaline phosphatase (BSAP) activity, insulin-like growth factor-I (IGF-I), and osteocalcin (BSAP: 27.8 and 25.8%, IGF-I: 12.8 and 26.3%, osteocalcin: 95.2 and 103.4% for control and soy groups, respectively). Neither of the protein supplements had any effect on urinary deoxypyridinoline excretion, a marker of bone resorption.


CONCLUSIONS
Our findings suggest that although one year supplementation of 25 g protein per se positively modulated markers of bone formation, this amount of protein was unable to prevent lumbar and whole body bone loss in postmenopausal women.
Arjmandi
Bahram H
BH
Department of Nutritional Sciences, Oklahoma State University, Stillwater, Oklahoma 74078, USA. arjmand@okstate.edu
Lucas
Edralin A
EA
Khalil
Dania A
DA
Devareddy
Latha
L
Smith
Brenda J
BJ
McDonald
Jennifer
J
Arquitt
Andrea B
AB
Payton
Mark E
ME
Mason
Claudia
C
D015502:Absorptiometry, Photon; D000469:Alkaline Phosphatase / Q000097:blood; D000596:Amino Acids / Q000652:urine; D015415:Biomarkers / Q000032:analysis*; D015992:Body Mass Index; D015519:Bone Density / Q000187:drug effects*; D002118:Calcium / Q000378:metabolism; D004032:Diet; D015930:Diet Records; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D004044:Dietary Proteins / Q000008:administration & dosage; D004311:Double-Blind Method; D002149:Energy Intake; D005260:Female; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D008159:Lumbar Vertebrae; D008875:Middle Aged; D009747:Nutritional Physiological Phenomena; D015675:Osteocalcin / Q000097:blood; D010012:Osteogenesis / Q000187:drug effects*; D010384:Pelvic Bones; D017698:Postmenopause; D030262:Soybean Proteins / Q000008:administration & dosage*; D011795:Surveys and Questionnaires
D000596:Amino Acids; D015415:Biomarkers; D004040:Dietary Carbohydrates; D004044:Dietary Proteins; D030262:Soybean Proteins; D015675:Osteocalcin; D007334:Insulin-Like Growth Factor I; C036020:deoxypyridinoline; D000469:Alkaline Phosphatase; D002118:Calcium
Med J Aust. 2002 Feb 18;176(4):182-3
11913921
J Bone Miner Res. 1994 Oct;9(10):1643-9
7817812
J Nutr Sci Vitaminol (Tokyo). 1998 Apr;44(2):257-68
9675706
Menopause. 2001 Jul-Aug;8(4):259-65
11449083
Fed Regist. 1999 Oct 26;64(206):57700-33
11010706
Am J Clin Nutr. 1999 Oct;70(4):574-5
10500030
Endocrinol Metab Clin North Am. 2003 Mar;32(1):233-52, viii
12699301
Menopause. 2004 May-Jun;11(3):246-54
15167303
J Clin Endocrinol Metab. 1993 Oct;77(4):1046-53
8104954
J Bone Miner Res. 2000 Dec;15(12):2504-12
11127216
Osteoporos Int. 1998;8(3):274-81
9797913
Eur J Obstet Gynecol Reprod Biol. 1999 Jul;85(1):47-51
10428321
Osteoporos Int. 1999;9(3):242-53
10450414
J Nutr Biochem. 2002 Mar;13(3):130-137
11893477
Am J Clin Nutr. 2004 Feb;79(2):326-33
14749241
J Nutr. 2001 Nov;131(11 Suppl):3095S-108S
11694655
Am J Clin Nutr. 2003 Sep;78(3 Suppl):584S-592S
12936953
Br J Nutr. 2001 Mar;85(3):307-16
11299076
J Clin Endocrinol Metab. 1998 Jul;83(7):2223-35
9661587
Am J Clin Nutr. 2000 Sep;72(3):844-52
10966908
Menopause. 2001 Nov-Dec;8(6):433-40
11723417
J Clin Endocrinol Metab. 2003 Mar;88(3):1048-54
12629084
J Br Menopause Soc. 2003 Mar;9(1):17-21
12804308
J Bone Miner Res. 2002 Oct;17(10):1904-12
12369794
J Nutr. 2000 Jul;130(7):1675-81
10867035
J Med Food. 2003 Spring;6(1):1-11
12804015
J Am Coll Nutr. 2000 Apr;19(2 Suppl):83S-99S
10759135
Menopause. 2001 Sep-Oct;8(5):384-92
11528367
Menopause. 2003 May-Jun;10(3):196-202
12792289
Public Health Nutr. 1999 Sep;2(3A):391-6
10610078
Climacteric. 1998 Jun;1(2):124-9
11907915
JAMA. 2004 Jul 7;292(1):65-74
15238592
Nutr Rev. 2003 Apr;61(4):117-31
12795445
Cancer Epidemiol Biomarkers Prev. 2000 Aug;9(8):781-6
10952094
Menopause. 2004 May-Jun;11(3):290-8
15167308
J Nutr. 2003 Mar;133(3):862S-865S
12612170
Am J Clin Nutr. 2001 May;73(5):990-2
11333855
Am J Clin Nutr. 2003 Sep;78(3 Suppl):593S-609S
12936954
J Clin Endocrinol Metab. 1995 May;80(5):1685-90
7745019
J Nutr. 1996 Jan;126(1):161-7
8558297
Br J Nutr. 2002 Nov;88 Suppl 2:S225-32
12495464
Ann Med. 1997 Apr;29(2):95-120
9187225
Curr Opin Obstet Gynecol. 2000 Jun;12(3):189-97
10873119
Nutr Cancer. 1999;33(1):82-7
10227048
Eur J Nutr. 2004 Aug;43(4):246-57
15309425
J Am Coll Nutr. 2001 Oct;20(5 Suppl):354S-362S; discussion 381S-383S
11603644
J Natl Cancer Inst. 2003 Jun 18;95(12):906-13
12813174
Am J Clin Nutr. 1998 Dec;68(6 Suppl):1375S-1379S
9848502
J Clin Endocrinol Metab. 1999 Oct;84(10):3479-84
10522983
Menopause. 1999 Fall;6(3):233-41
10486794
J Steroid Biochem. 1987;27(4-6):1135-44
2826899
Br J Nutr. 2003 Jun;89 Suppl 1:S87-99
12725658
Am J Clin Nutr. 1998 Dec;68(6 Suppl):1364S-1368S
9848500
Am J Clin Nutr. 1998 Dec;68(6 Suppl):1358S-1363S
9848499
Am J Clin Nutr. 2000 Jun;71(6):1462-9
10837286
Maturitas. 2002 Aug 30;42(4):295-300
12191852
Osteoporos Int. 1993 Sep;3(5):242-8
8400605
Osteoporos Int. 2003 Oct;14(10):835-42
12920508