Effect of soy protein varying in isoflavone content on serum lipids in healthy young men.

Abstract

BACKGROUND:

Previous research supports a role for soy protein in reducing serum lipids; however, few studies involved healthy male subjects or focused on soy isoflavones (or did both).

OBJECTIVE:

The objective was to ascertain the effects of soy protein varying in isoflavone content on serum lipids in healthy young men.

DESIGN:

Thirty-five males (x +/- SD age: 27.9 +/- 5.7 y) consumed milk protein isolate (MPI), low-isoflavone soy protein isolate (low-iso SPI; 1.64 +/- 0.19 mg aglycone isoflavones/d), and high-isoflavone SPI (high-iso SPI; 61.7 +/- 7.4 mg aglycone isoflavones/d) for 57 d each, separated by 4-wk washout periods, in a randomized crossover design. Blood samples were collected at the beginning and end of each treatment period, and total, LDL, and HDL cholesterol; triacylglycerols; apolipoprotein (apo) B; apo A-I; and C-reactive protein (CRP) were measured in serum. Twenty-four-hour urine samples were collected for 3 consecutive days at the end of each treatment period and analyzed for isoflavones.

RESULTS:

Urinary isoflavones were significantly greater with consumption of the high-iso SPI than with that of the low-iso SPI or MPI. The differences between the 3 treatments with respect to individual serum lipids were not significant, but the ratios of total to HDL cholesterol, LDL to HDL cholesterol, and apo B to apo A-I were significantly lower with both SPI treatments than with MPI treatment.

CONCLUSION:

Soy protein, regardless of isoflavone content, modulates serum lipid ratios in a direction beneficial for cardiovascular disease risk in healthy young men.

• Authors: Brianne L McVeigh, Barbara L Dillingham, Johanna W Lampe, Alison M Duncan
• Journal: The American journal of clinical nutrition (Am J Clin Nutr) Vol. 83 Issue 2 Pg. 244-51 (Feb 2006) ISSN: 0002-9165 [Print] United States
• PMID: 16469981 (Publication Type: Journal Article, Randomized Controlled Trial, Research Support, Non-U.S. Gov't)

Chemical References

• Apolipoprotein A-I
• Apolipoproteins B
• Cholesterol, HDL
• Cholesterol, LDL
• Isoflavones
• Lipids
• Soybean Proteins
• Triglycerides
• C-Reactive Protein
• Cholesterol

Topics

• Adult
• Apolipoprotein A-I (blood)
• Apolipoproteins B (blood)
• C-Reactive Protein (metabolism)
• Cardiovascular Diseases (blood, prevention & control)
• Cholesterol (blood)
• Cholesterol, HDL (blood)
• Cholesterol, LDL (blood)
• Cross-Over Studies
• Dose-Response Relationship, Drug
• Humans
• Isoflavones (administration & dosage, blood, urine)
• Lipids (blood, chemistry)
• Male
• Risk Factors
• Soybean Proteins (administration & dosage, chemistry)
• Triglycerides (blood)