Dietary recommendations emphasize increased consumption of fruit, vegetables, and whole grain cereals for prevention of chronic disease.
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.
OBJECTIVE: Eating whole grains (WG) is recommended for health, but multiple conflicting definitions exist for identifying whole grain (WG) products, limiting the ability of consumers and organizations to select such products. We investigated how five recommended WG criteria relate to healthfulness and price of grain products. DESIGN: We categorized grain products by different WG criteria including: the industry-sponsored Whole Grain stamp (WG-Stamp); WG as the first ingredient (WG-first); WG as the first ingredient without added sugars (WG-first-no-added-sugars); the word ‘whole’ before any grain in the ingredients (‘whole’-anywhere); and a content of total carbohydrate to fibre of ≤10:1 (10:1-ratio). We investigated associations of each criterion with health-related characteristics including fibre, sugars, sodium, energy, trans-fats and price. SETTING: Two major grocery store chains. SUBJECTS: Five hundred and forty-five grain products. RESULTS: Each WG criterion identified products with higher fibre than products considered non-WG; the 10:1-ratio exhibited the largest differences (+3·15 g/serving, P < 0·0001). Products achieving the 10:1-ratio also contained lower sugar (-1·28 g/serving, P = 0·01), sodium (-15·4 mg/serving, P = 0·04) and likelihood of trans-fats (OR = 0·14, P < 0·0001), without energy differences. WG-first-no-added-sugars performed similarly, but identified many fewer products as WG and also not a lower likelihood of containing trans-fats. The WG-Stamp, WG-first and 'whole'-anywhere criteria identified products with a lower likelihood of trans-fats, but also significantly more sugars and energy (P < 0·05 each). Products meeting the WG-Stamp or 10:1-ratio criterion were more expensive than products that did not (+$US 0·04/serving, P = 0·009 and +$US 0·05/serving, P = 0·003, respectively). CONCLUSIONS: Among proposed WG criteria, the 10:1-ratio identified the most healthful WG products. Other criteria performed less well, including the industry-supported WG-Stamp which identified products with higher fibre and lower trans-fats, but also higher sugars and energy. These findings inform efforts by consumers, organizations and policy makers to identify healthful WG products.
The potential role of whole grain in preventing various mortality outcomes has been inconsistently reported in a wealth of prospective observational studies.
We studied the combined effects of wholegrain, fish and bilberries on serum metabolic profile and lipid transfer protein activities in subjects with the metabolic syndrome.
Studies of whole grain and chronic disease have often included bran-enriched foods and other ingredients that do not meet the current definition of whole grains. Therefore, we assessed the literature to test whether whole grains alone had benefits on these diseases.
High intake of whole grains has been associated with lower risk of coronary heart disease; however, the research that has been used to evaluate different effects of different whole-grain cereals (e.g., wheat, rye, and oats) has been sparse.
The levels of 26 mycotoxins were determined in 147 samples of the grain of cereals cultivated in five regions of Poland during the 2014 growing season. The HPLC-HRMS (time-of-flight) analytical technique was used. An analytical procedure to simultaneously determine 26 mycotoxins in grain was developed, tested and verified. Samples from eastern and southern Poland were more contaminated with mycotoxins than the samples from northern and western Poland. Toxins produced by Fusarium fungi were the main contaminants found. Some deoxynivalenol (DON) was found in 100% of the tested samples of wheat (Osiny, Borusowa, Werbkowice), triticale, winter barley and oats, while the maximum permissible DON level (as defined in the EU Commission Regulation No. 1881/2006) was exceeded in 10 samples. Zearalenone (ZEN), DON metabolites and enniatins were also commonly found. The presence of mycotoxins in grain reflected the prevailing weather conditions during the plant flowering/earing stages, which were favorable for the development of blight. Among all investigated wheat genotypes, cv. Fidelius was the least contaminated, while Bamberka, Forkida and Kampana were the most contaminated. However, the single-factor ANOVA analysis of variance did not reveal (at a statistical significance level α = 0.05) any differences between levels of mycotoxins in individual genotypes. Triticale was the most contaminated grain among all of the tested varieties. ZEN, DON and the sum of 3-acetyldexynivalenol and 15-acetyldeoxynivalenol (3- and 15-ADON) were found in 100% of the tested triticale samples at concentrations within the 4-86, 196-1326 and 36-374 µg·kg(-1) range, respectively. Of particular concern was the fact that some “emerging mycotoxins” (enniatins) (in addition to commonly-known and legally-regulated mycotoxins) were also found in the tested triticale samples (enniatin B (Enn-B), enniatin B1 (Enn-B1), enniatin A-1 (Enn-A1), 100% of samples, and enniatin A (Enn-A), 70% of samples). Depending on the toxin, they were found at levels between 8 and 3328 µg·kg(-1).
Cereal-based foods are key components of the diet and they dominate most food-based dietary recommendations in order to achieve targets for intake of carbohydrate, protein and dietary fibre. Processing (milling) of grains to produce refined grain products removes key nutrients and phytochemicals from the flour and although in some countries nutrients may be replaced with mandatory fortification, overall this refinement reduces their potential nutritional quality. There is increasing evidence from both observational and intervention studies that increased intake of less-refined, whole-grain (WG) foods has positive health benefits. The highest WG consumers are consistently shown to have lower risk of developing CVD, type 2 diabetes and some cancers. WG consumers may also have better digestive health and are likely to have lower BMI and gain less weight over time. The bulk of the evidence for the benefits of WG comes from observational studies, but evidence of benefit in intervention studies and potential mechanisms of action is increasing. Overall this evidence supports the promotion of WG foods over refined grain foods in the diet, but this would require adoption of standard definitions of ‘whole grain’ and ‘whole-grain foods’ which will enable innovation by food manufacturers, provide clarity for the consumer and encourage the implementation of food-based dietary recommendations and public health strategies.
Many children do not eat enough whole grains, which may have negative health consequences. Intervention research is increasingly focusing on nudging as a way to influence food choices by affecting unconscious behavioural processes. The aim of this field study was to examine whether the shape of bread rolls is able to shift children’s bread choices from white to whole wheat during breakfast to increase whole grain intake.