Abstract
Objective
We conducted a systematic review and dose–response meta-analysis of prospective studies
to summarize findings on the associations between intakes of soy, soy isoflavones,
and soy protein and risk of mortality from all causes, cancers, and cardiovascular
diseases.
Methods
Online databases were systematically searched to identify relevant articles published
earlier than May 2018. We applied restricted cubic splines using random-effects analysis
to assess dose–response associations. Between-study heterogeneity was assessed by
I
2
value and Cochrane Q test. Potential publication bias was assessed by visual inspection of funnel plots
and Begg regression test.Results
In total, 23 prospective studies with an overall sample size of 330,826 participants
were included in the current systematic review and the meta-analysis. Soy/soy products
consumption was inversely associated with deaths from cancers (pooled relative risk
0.88, 95% CI 0.79 to 0.99; P=0.03; I2=47.1%, 95% CI 0.0% to 75.4%) and cardiovascular diseases (pooled effect size: 0.85,
95% CI 0.72 to 0.99; P=0.04; I2=50.0%, 95% CI 0.0% to 77.6%). Such significant associations were also observed for
all-cause mortality in some subgroups of the included studies, particularly those
with higher quality. In addition, higher intake of soy was associated with decreased
risk of mortality from gastric, colorectal, and lung cancers as well as ischemic cardiovascular
diseases. Participants in the highest category of dietary soy isoflavones intake had
a 10% lower risk of all-cause mortality compared with those in the lowest category.
We also found that a 10-mg/day increase in intake of soy isoflavones was associated
with 7% and 9% decreased risk of mortality from all cancers and also breast cancer
respectively. Furthermore, a 12% reduction in breast cancer death was indicated for
each 5-g/day increase in consumption of soy protein. However, intake of soy protein
was not significantly associated with all-cause and cardiovascular diseases mortality.
Conclusions
Soy and its isoflavones may favorably influence risk of mortality. In addition, soy
protein intake was associated with a decreased risk in the mortality of breast cancer.
Our findings may support the current recommendations to increase intake of soy for
greater longevity.
Keywords
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Biography
S. M. Nachvak is an associate professor of nutrition sciences, Department of Nutritional Sciences, Research Center for Environmental Determinants of Health (RCEDH) and Student of Research Committee, Health Institute, School of Nutritional Sciences and Food Technology, Kermanshah University of Medical Sciences, Kermanshah, Iran.
Biography
S. Moradi is an academic researcher, Department of Nutritional Sciences, Research Center for Environmental Determinants of Health (RCEDH) and Student of Research Committee, Health Institute, School of Nutritional Sciences and Food Technology, Kermanshah University of Medical Sciences, Kermanshah, Iran.
Biography
J. Anjom-shoae is an MSc student of nutrition sciences, Students’ Scientific Research Center and Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran.
Biography
J. Rahmani is a PhD student of nutrition sciences, Department of Community Nutrition, Faculty of Nutrition and Food Technology, National Nutrition and Food Technology Research Institute, Student Research Committee, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Biography
M. Nasiri is a PhD student of nursing, Student Research Committee and Department of Operating Room Nursing, School of Nursing and Midwifery, Shiraz University of Medical Sciences, Shiraz, Iran.
Biography
V. Maleki is a PhD student of nutrition sciences, Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran.
Biography
O. Sadeghi is an academic researcher, Department of Nutritional Sciences, RCEDH and Student of Research Committee, Health Institute, School of Nutritional Sciences and Food Technology, Kermanshah University of Medical Sciences, Kermanshah, Iran; and a PhD student of nutrition, Students' Scientific Research Center and Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran.
Article info
Publication history
Published online: July 02, 2019
Accepted:
April 16,
2019
Received:
November 7,
2018
Footnotes
Supplementary materials: Figures 1, 2, and 3 and Table 1, Table 2, Table 3, Figure 1, and 4 are available at www.jandonline.org
STATEMENT OF POTENTIAL CONFLICT OF INTEREST No potential conflict of interest was reported by the authors.
FUNDING/SUPPORT This study was supported jointly by the Students’ Scientific Research Center, Tehran University of Medical Sciences, Tehran, Iran, and Kermanshah University of Medical Sciences, Kermanshah, Iran (grant no. 97149).
Identification
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© 2019 by the Academy of Nutrition and Dietetics.
