Nut consumption and risk of type 2 diabetes, cardiovascular disease, and all-cause mortality: a systematic review and meta-analysis.
BACKGROUND
Epidemiologic studies have shown inverse associations between nut consumption and diabetes, cardiovascular disease (CVD), and all-cause mortality, but results have not been consistent.


OBJECTIVE
We assessed the relation between nut intake and incidence of type 2 diabetes, CVD, and all-cause mortality.


METHODS
We searched PubMed and EMBASE for all prospective cohort studies published up to March 2013 with RRs and 95% CIs for outcomes of interest. A random-effects model was used to pool risk estimates across studies.


RESULTS
In 31 reports from 18 prospective studies, there were 12,655 type 2 diabetes, 8862 CVD, 6623 ischemic heart disease (IHD), 6487 stroke, and 48,818 mortality cases. The RR for each incremental serving per day of nut intake was 0.80 (95% CI: 0.69, 0.94) for type 2 diabetes without adjustment for body mass index; with adjustment, the association was attenuated [RR: 1.03; 95% CI: 0.91, 1.16; NS]. In the multivariable-adjusted model, pooled RRs (95% CIs) for each serving per day of nut consumption were 0.72 (0.64, 0.81) for IHD, 0.71 (0.59, 0.85) for CVD, and 0.83 (0.76, 0.91) for all-cause mortality. Pooled RRs (95% CIs) for the comparison of extreme quantiles of nut intake were 1.00 (0.84, 1.19; NS) for type 2 diabetes, 0.66 (0.55, 0.78) for IHD, 0.70 (0.60, 0.81) for CVD, 0.91 (0.81, 1.02; NS) for stroke, and 0.85 (0.79, 0.91) for all-cause mortality.


CONCLUSIONS
Our meta-analysis indicates that nut intake is inversely associated with IHD, overall CVD, and all-cause mortality but not significantly associated with diabetes and stroke. The inverse association between the consumption of nuts and diabetes was attenuated after adjustment for body mass index. These findings support recommendations to include nuts as part of a healthy dietary pattern for the prevention of chronic diseases.
From the Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety, Tongji Medical College, Hua Zhong University of Science and Technology, Wuhan, China (CL, YZ, YD, ZS, SC, MY, and LL); the Ministry of Education Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Wuhan, China (CL, YZ, YD, ZS, SC, MY, and LL); and the Department of Nutrition and Epidemiology, Harvard School of Public Health, Boston, MA (FBH).
Cheng
C
Luo
From the Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety, Tongji Medical College, Hua Zhong University of Science and Technology, Wuhan, China (CL, YZ, YD, ZS, SC, MY, and LL); the Ministry of Education Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Wuhan, China (CL, YZ, YD, ZS, SC, MY, and LL); and the Department of Nutrition and Epidemiology, Harvard School of Public Health, Boston, MA (FBH).
Yan
Y
Zhang
From the Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety, Tongji Medical College, Hua Zhong University of Science and Technology, Wuhan, China (CL, YZ, YD, ZS, SC, MY, and LL); the Ministry of Education Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Wuhan, China (CL, YZ, YD, ZS, SC, MY, and LL); and the Department of Nutrition and Epidemiology, Harvard School of Public Health, Boston, MA (FBH).
Yusong
Y
Ding
From the Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety, Tongji Medical College, Hua Zhong University of Science and Technology, Wuhan, China (CL, YZ, YD, ZS, SC, MY, and LL); the Ministry of Education Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Wuhan, China (CL, YZ, YD, ZS, SC, MY, and LL); and the Department of Nutrition and Epidemiology, Harvard School of Public Health, Boston, MA (FBH).
Zhilei
Z
Shan
From the Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety, Tongji Medical College, Hua Zhong University of Science and Technology, Wuhan, China (CL, YZ, YD, ZS, SC, MY, and LL); the Ministry of Education Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Wuhan, China (CL, YZ, YD, ZS, SC, MY, and LL); and the Department of Nutrition and Epidemiology, Harvard School of Public Health, Boston, MA (FBH).
Sijing
S
Chen
From the Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety, Tongji Medical College, Hua Zhong University of Science and Technology, Wuhan, China (CL, YZ, YD, ZS, SC, MY, and LL); the Ministry of Education Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Wuhan, China (CL, YZ, YD, ZS, SC, MY, and LL); and the Department of Nutrition and Epidemiology, Harvard School of Public Health, Boston, MA (FBH).
Miao
M
Yu
From the Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety, Tongji Medical College, Hua Zhong University of Science and Technology, Wuhan, China (CL, YZ, YD, ZS, SC, MY, and LL); the Ministry of Education Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Wuhan, China (CL, YZ, YD, ZS, SC, MY, and LL); and the Department of Nutrition and Epidemiology, Harvard School of Public Health, Boston, MA (FBH).
Frank B
FB
Hu
From the Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety, Tongji Medical College, Hua Zhong University of Science and Technology, Wuhan, China (CL, YZ, YD, ZS, SC, MY, and LL); the Ministry of Education Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Wuhan, China (CL, YZ, YD, ZS, SC, MY, and LL); and the Department of Nutrition and Epidemiology, Harvard School of Public Health, Boston, MA (FBH).
Liegang
L
Liu
D002318:Cardiovascular Diseases / Q000453:epidemiology*; D016208:Databases, Factual; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology*; D004032:Diet; D006801:Humans; D015994:Incidence; D009754:Nuts; D012307:Risk Factors; D012680:Sensitivity and Specificity