Higher whole-grain intake was associated with improvements in multiple cardiometabolic risk factors in a meta-analysis of randomized trials published Sept. 15 in EHJ. The largest effects were generally seen at whole-grain intakes of about 60-100 g/day.

Sina Naghshi, Dagfinn Aune, PhD, MSc, et al., analyzed 87 trials evaluating the effects of whole grains on cardiometabolic risk factors. Random-effects meta-analyses were used to estimate mean differences (MDs) with 95% CIs per 48 g/day increment of whole grains (dry weight; equivalent to approximately 90 g or three servings of fresh weight.

Primary outcomes included body weight (kg), LDL-C (mmol/L), fasting plasma glucose (FPG) (mmol/L) and adverse events.

Each 48 g/day increment in whole-grain intake was associated with high-certainty reductions in body weight (MD: −0.20 kg; n=41), waist circumference (−0.22 cm; n=27), total cholesterol (−0.10 mmol/L; n=54) and interleukin-6 (MD: −0.12 pg/mL; n=12).

Moderate-certainty reductions were observed for LDL-C (−0.07 mmol/L; n=52), triglycerides (−0.04 mmol/L; n=52), FPG (−0.03 mmol/L; n=44) and systolic blood pressure (−0.82 mmHg; n=32). On nonlinear analyses, the strongest effects were seen at intakes of 60-100 g/day for most outcomes, although some outcomes showed greater effects at higher intakes of up to 180-220 g/day.

The authors note that the findings should be “interpreted cautiously” given the currently limited evidence. “Further well-designed, longer-term trials are needed to more clearly define the intake range that may maximize health benefits,” they write.

“…the message from Naghshi et al. is reassuringly simple: encouraging patients to replace refined grain foods with minimally processed whole grains is likely to yield modest but meaningful improvements in body weight, waist circumference and blood lipids, perhaps particularly in individuals with type 2 diabetes,” write Cecilie Kyrø, PhD, Anne Tjønneland, PhD, DMSc and Anja Olsen, PhD, in an accompanying editorial. “Evidence from research into other disease endpoints indicates that the benefits of whole-grain foods extend substantially beyond cardiometabolic disease.”