Table 3.
Effect of Seed Consumption on CVD Outcomes Based on Selected Meta-analyses of Findings of Epidemiologic Studies and Randomized Clinical Trials
| Author (year) (reference) | Type of study | n | Population | Follow-up | Outcomes | Effect of increased seed consumption* (numbers between brackets are 95% confidence intervals) |
|---|---|---|---|---|---|---|
| Whole grains | ||||||
| Ye (2012) (45) | Meta-analysis of 8 cohort studies | 298,592 | Generally healthy | 6 to 14 y | Incident CVD | RR=0.79 (0.74-0.85) |
| Meta-analysis of 6 cohort studies | 288,319 | Generally healthy | 6 to 12 y | Incident T2DM | RR=0.74 (0.69-0.80) | |
| Meta-analysis of 21 RCTs | Not available | Healthy or patients with HC or hypertension | 4 to 16 wk | Lipid profile | Δ Total cholesterol: –0.83 mmol/L (–1.24 to –0.42) Δ LDL-cholesterol: –0.72 mmol/L (–1.34 to –0.11) |
|
| Glycemic control | Δ Fasting glucose: –0.93 mmol/L (–1.65 to –0.21) | |||||
| de Munter (2007) (46) | Meta-analysis of 6 cohort studies | 286,125 | Generally healthy populations | 6 to 18 y | Incident T2DM | 21% (13%-28%) risk reduction for a 2-serving/d increment |
| Nuts | ||||||
| Kris-Etherton (2008) (47) | Pooled analysis of 4 U.S. prospective studies | 135,604 | CVD-free men and women | 6 to 17 y | Incident CHD | RR=0.65 (0.47-0.89) |
| Banel & Hu (2009) (48) | Meta-analysis of 13 walnut RCTs | 365 | Subjects with normal lipids or HC | 4 to 24 wk | Lipid profile | Δ Total cholesterol: –0.27 mmol/L (–0.38 to –0.15) Δ LDL-cholesterol: –0.24 mmol/L (–0.34 to –0.14) |
| Sabaté (2010) (49) | Pooled analysis of 27 nut RCTs | 583 | Subjects with normal lipids or HC | 3 to 8 wk | Lipid profile | Δ Total cholesterol: –0.28 mmol/L (–0.37 to –0.20) Δ LDL-cholesterol: –0.26 mmol/L (–0.34 to –0.19) |
| Pulses | ||||||
| Bazzano (2011) (50) | Meta-analysis of 10 RCTs | 268 | Subjects with normal lipids or HC | 3 to 8 wk | Lipid profile | Δ Total cholesterol: –0.31 mmol/L (–0.42 to –0.19) Δ LDL-cholesterol: –0.21 mmol/L (–0.30 to –0.12) Δ Triglycerides: –1.67 mmmol/l (–3.63 to 0) (Results as SMD)† |
| Sievenpiper (2009) (51) | Meta-analysis of 11 RCTs of pulses alone | 253 | Subjects with T2DM, normoglycemia or HC | 1 to 96 wk | Glycemic control | Fasting glucose: –0.82 (–1.36 to –0.27) Fasting insulin: –0.49 (–0.93 to –0.04) |
| Meta-analysis of 19 RCTs of pulses in low-GI diets Meta-analysis of 11RCTs of pulses in high-fiber diets |
72 641 |
Subjects with type-1 diabetes, T2DM or normoglycemia Subjects with type-1 diabetes, T2DM or normoglycemia |
2 to 52 wk 1.4 to 156 wk |
HbA1c: –0.28 (–0.42 to –0.14) Fasting glucose: –0.32 (–0.49 to –0.15) HbA1c: –0.27 (–0.45 to –0.09) |
||
| Chocolate | ||||||
| Buitrago-Lopez (2011) (52) | Meta-analysis of 5 prospective studies | 60,455 | CVD-free men and women (patients with prior CHD in one study) | 8 to 16 y | Incident CVD | RR=0.63 (0.44-0.90) |
| Stroke | RR=0.71 (0.52-0.98) | |||||
| Larsson (2012) (53) | Meta-analysis of 5 prospective studies | 131,3455 | CVD-free men and women (patients with prior CHD in one study) | 8 to 16 y | Stroke | RR=0.81 (0.73-0.90) |
| Tokede (2011) (54) | Meta-analysis of 10 RCTs | 320 | Healthy subjects or subjects with CVD risk factors | 2 to 12 wk | Lipid profile | Δ Total cholesterol: –0.16 mmol/L (–0.30 to –0.02) Δ LDL-cholesterol: –0.15 mmol/L (–0.27 to –0.03) |
| Hooper (2012) (55) | Meta-analysis of 21 RCTs reporting lipid outcomes | 290 | Healthy subjects or subjects with CVD risk factors | 2 to 26 wk | Lipid profile | Δ LDL-cholesterol: –0.07 mmol/L (–0.14 to –0.0) Δ HDL-cholesterol: 0.03 mmol/L (0.0-0.06) |
| Meta-analysis of 6 RCTs reporting glycemic control | 91 | Healthy subjects or subjects with CVD risk factors | 2 to 26 wk | Glycemic control | Δ Insulin: –2.65 μU/mL (–4.65 to –0.65) Δ HOMA-IR: –0.67 (–0.98 to –0.36) |
|
| Meta-analysis of 22 RCTs reporting blood pressure | 918 | Healthy subjects or subjects with CVD risk factors | 2 to 18 wk | Blood pressure | Δ DBP: –1.60 mm Hg (–2.77 to –0.43) | |
| Meta-analysis of 11 acute RCTs on postprandial FMD | 373 | Healthy subjects or subjects with CVD risk factors | 90 to 150 min | FMD | Δ FMD: 3.19% (2.04-4.33) | |
| Meta-analysis of 11 chronic RCTs reporting FMD | 382 | Healthy subjects or subjects with CVD risk factors | 2 to 18 wk | FMD | Δ FMD: 1.34% (1.00-1.68) | |
| Ried (2012) (56) | Meta-analysis of 20 RCTs | 865 | Healthy subjects or subjects with CVD risk factors | 2 to 18 wk | Blood pressure | Δ SBP: –2.77 mm Hg (–−4.72 to –0.82) Δ DBP: –2.30 mm Hg (–3.46 to –0.93) |
| Coffee | ||||||
| Wu (2009) (57) | Meta-analysis of 21 cohort studies | 407,806 | Generally healthy | 4 to 32 y | Incident CHD | RR=0.82 (0.73-0.92) in women RR=0.87 (0.80-0.86) in men and women followed ≤ 10 y |
| Larsson (2011) (58) | Meta-analysis of 11 cohort studies | 479,689 | Generally healthy | 2 to 20.8 y | Incident stroke | RR=0.86 (0.78-0.94) for 2 cups of coffee/d RR=0.83 (0.74-0.92) for 3-4 cups/d RR=0.87 (0.77-0.97) for 6 cups/d RR=0.93 (0.79-1.08) for 8 cups/d |
| Mostofsky (2012) (59) | Meta-analysis of 5 cohort studies | 140,220 | Generally healthy or patients with myocardial infarction | 8 to 35 y | Incident congestive heart failure | RR=0.90 (0.82-0.99) for 3 to 4 cups/d RR=0.89 (0.81-0.99) for 4 to 5 cups/d |
| Huxley (2009) (60) | Meta-analysis of 18 cohort studies | 457,922 | Generally healthy | 2.6 to 20 y | Incident T2DM | 7% (9%-5%) risk reduction for each additional cup of coffee/d 25% (18%-31%) risk reduction for consumption of 3 to 4 cups of coffee/d |
| Meta-analysis of 6 cohort studies | 225,516 | Generally healthy | 8.4 to 12 y | Incident T2DM | RR=0.64 (0.54-0.77) for 3 to 4 cups/d of decaffeinated coffee | |
| Zhang (2011) (61) | Meta-analysis of 6 cohort studies | 172,567 | Generally healthy | 6.4 to 33 y | Incident hypertension | Habitual coffee consumption of >3 cups/d was not associated with an increased risk of hypertension compared with <1 cup/d Slightly elevated risk associated with light-to-moderate consumption of 1 to 3 cups/d (RR for comparison of 3 with 0 cups/d: 1.07 (0.97-1.20) |
CVD indicates cardiovascular disease; T2DM, type 2 diabetes mellitus; CHD, coronary heart disease; RR, relative risk; CI, 95% confidence interval; RCT, randomized controlled trial; HC, hypercholesterolemia; SMD, standardized mean difference; GI, glycemic index; HOMA-IR, insulin resistance index; FMD, flow-mediated dilatation; DBP, diastolic blood pressure; SBP, systolic blood pressure..
*
Risk ratios in meta-analyses of epidemiologic studies, usually adjusted for multiple confounders, are for highest versus lowest categories of consumption or increased servings/d, as specified. Outcome changes (Δ) are means for average doses of seeds or seed products in seed diets compared to control diets in meta-analyses of RCTs; only statistically significant changes are shown. Values between brackets are 95% confidence intervals.
†
SMDs are interpreted as follows: <0.4, small effect size; 0.4–0.7, moderate effect size; and >0.7, large effect size.