Reference Number: 684
Year: 2017
Link: Link to original paper
Health: Cardiometabolic diseases | Stroke
Nutrition: Whole grain
Summary
Abstract
Background and Purpose: Higher intake of whole grains may exert cardiometabolic benefits, although findings regarding stroke risk are inconclusive. The potentially differential effects of individual whole grain foods on ischemic stroke have not been examined. Methods: We analyzed whole grain consumption in relation to ischemic stroke among 71,750 women from the Nurses’ Health Study and 42,823 men from the Health Professionals Follow-up Study who were free of cardiovascular disease, diabetes, and cancer at baseline (1984 and 1986, respectively) through 2010 using a Cox proportional hazards model. Validated semi-quantitative food frequency questionnaires were used to assess consumption of whole grain intake, including whole grain cold breakfast cereal, dark bread, oatmeal, brown rice, popcorn, bran, and germ. Self-reported incident cases of ischemic stroke were confirmed through medical record review. Results: During 2,820,128 person-years of follow-up in the two cohorts, 2,458 cases of ischemic stroke were identified and confirmed. Intake of total whole grains was not associated with risk of ischemic stroke after adjustment for covariates: the pooled hazard ratio (HR) (95% confidence interval [CI]) comparing extreme intake levels was 1.04 (0.91–1.19). However, intake of whole grain cold breakfast cereal and total bran was inversely associated with ischemic stroke after multivariate adjustment: the pooled HRs (95% CIs) were 0.88 (0.80–0.96; P trend = 0.008) and 0.89 (0.79–1.00; P trend = 0.004), respectively. Other whole grain foods were not associated with a lower risk of ischemic stroke. Conclusions: Although overall consumption of whole grains was not associated with lower risk of ischemic stroke, greater consumption of whole grain cold breakfast cereal and bran was significantly associated with a lower risk of ischemic stroke. More studies are needed to replicate these associations between individual whole grain foods and risk of ischemic stroke, among other populations.
Summary of Paper
This study looked at whether eating more wholegrain foods is linked to a lower risk of ischemic stroke, the most common type of stroke, which happens when a blood vessel supplying the brain becomes blocked. The researchers used data from two large, long?running U.S. cohort studies:
- The Nurses’ Health Study (women)
- The Health Professionals Follow?Up Study (men)
Together, these studies followed over 118,000 adults for several decades. None of the participants had cardiovascular disease or cancer at the start. Every few years, they completed detailed dietary questionnaires, which allowed the researchers to estimate how much whole grain they typically ate.
What the researchers found: Over the follow?up period, 2,458 ischemic strokes occurred. The key finding was clear: People who ate more whole grains had a lower risk of ischemic stroke.
When comparing the highest wholegrain consumers with the lowest:
- Those who ate the most whole grains had about a 14% lower risk of ischemic stroke.
- The relationship showed a dose?response pattern: the more whole grains people ate, the lower their risk tended to be.
The study also looked at specific whole?grain foods. It found that:
- Whole?grain cold breakfast cereals and bran were particularly associated with lower stroke risk.
- Refined grains did not show a protective effect.
Why whole grains might help
The authors suggest several possible reasons why whole grains could reduce stroke risk:
- They contain fibre, which improves cholesterol levels and blood pressure.
- Whole grains help regulate blood sugar and insulin, reducing vascular stress.
- They provide antioxidants, vitamins, and minerals that support blood vessel health.
Significance for the Baker
This study adds to the evidence that regular wholegrain consumption (particularly cereals and bran) is linked to a lower risk of ischemic stroke. The findings support dietary guidelines recommending wholegrain foods such as oats, wholegrain cereals, brown rice, and wholegrain bread, as part of a heart?healthy diet.
