Whole grain and refined grain consumption and the risk of type 2 diabetes: a systematic review and dose–response meta-analysis of cohort studies

Abstract

Several studies have suggested a protective effect of intake of whole grains, but not refined grains on type 2 diabetes risk, but the dose-response relationship between different types of grains and type 2 diabetes has not been established. We conducted a systematic review and meta-analysis of prospective studies of grain intake and type 2 diabetes. We searched the PubMed database for studies of grain intake and risk of type 2 diabetes, up to June 5th, 2013. Summary relative risks were calculated using a random effects model. Sixteen cohort studies were included in the analyses. The summary relative risk per 3 servings per day was 0.68 (95% CI 0.58-0.81, I(2) = 82%, n = 10) for whole grains and 0.95 (95% CI 0.88-1.04, I(2) = 53%, n = 6) for refined grains. A nonlinear association was observed for whole grains, p nonlinearity < 0.0001, but not for refined grains, p nonlinearity = 0.10. Inverse associations were observed for subtypes of whole grains including whole grain bread, whole grain cereals, wheat bran and brown rice, but these results were based on few studies, while white rice was associated with increased risk. Our meta-analysis suggests that a high whole grain intake, but not refined grains, is associated with reduced type 2 diabetes risk. However, a positive association with intake of white rice and inverse associations between several specific types of whole grains and type 2 diabetes warrant further investigations. Our results support public health recommendations to replace refined grains with whole grains and suggest that at least two servings of whole grains per day should be consumed to reduce type 2 diabetes risk.

“Let food be your medicine ….” Inclusion of wheat porridge, a whole grain meal, and legumes lowers postprandial glucose in diabetic patient

“…However, it deserves some attention because the present case study was carried for more than 2 years and the results obtained are consistent and encouraging. This study supports the suggestions made by Aune et al (2013), 'to include at least two servings of whole grains per day in the diet to reduce type 2 diabetes risk [16]. Wheat porridge, a whole grain meal, is easy for the patients to make and hence can be included in their diet.…”

Relation of total sugars, fructose and sucrose with incident type 2 diabetes: a systematic review and meta-analysis of prospective cohort studies

“…23,40 Many of these other food sources, which tend to be sweetened with sucrose, have either shown no association (e.g., cakes and cookies, 41 and sherbert 42 ) or a protective association (e.g., whole-grain cereals, fruit, yogurt and even ice cream [42][43][44] ) with type 2 diabetes (Appendix 2, available at www.cmaj.ca/ lookup/suppl/doi:10.1503/cmaj.160706/-/DC1). An inverse doseresponse gradient, similar to that for sucrose, has even been found for whole-grain cereals, fruit and yogurt.…”

“…An inverse doseresponse gradient, similar to that for sucrose, has even been found for whole-grain cereals, fruit and yogurt. [42][43][44] Taken together, lack of an adverse association between intakes of total sugars, fructose or sucrose and diabetes may reflect important contributions from these other food sources.…”

The Western Diet&ndash;Microbiome-Host Interaction and Its Role in Metabolic Disease

“…Intake of whole grains is associated with reduced risk of several non-communicable diseases, as opposed to refined grains [24,25]. A study on fish intake reported adverse effects on markers of metabolic syndrome from processed fish, whereas whole fish seems to protect [26].…”