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Volkoren granen tegen en bij diabetes*
Uit twee studies blijkt dat het regelmatig eten van volkoren granen goed is in het voorkomen van en het verkleinen van de gevolgen van diabetes. Uit de eerste studie blijkt dat vooral volkoren granen van gerst en rogge en duidelijk minder de granen van tarwe zorgen voor een verbeterde insuline gevoeligheid. Gerst bevat veel vezels en zetmeel waarvan bij de fermentatie in de darmen bepaalde darmhormonen (GPLP-1) vrijkomen. Deze darmhormonen stimuleren de aanmaak van insuline en verhinderen de aanmaak van glucagon, een hormoon dat de bloedsuikerwaarden verhoogt. Hierdoor zijn de bloedsuikerwaarden lager en stabieler. Uit de tweede studie, onder een kleine 8.000 vrouwen met diabetes type –2 die 26 jaar gevolgd werden, blijkt dat zij die regelmatig volkoren granen eten wel 35% minder kans hebben om dood te gaan aan een hartziekte. Zij die dagelijks 10 gram aten hadden wel 64% minder kans om dood te gaan aan een hartziekte en 55% minder kans op doodgaan aan een andere oorzaak, dit in vergelijking met zij die nooit volkoren granen aten.
Whole grain barley products with low glycemic response provide favourable metabolic benefits
Evidence from observational studies indicates that diets rich in whole grain reduce risk of obesity and other diseases related to the metabolic syndrome e.g. type 2 diabetes and cardio-vascular disease. The mechanisms involved are only partially elucidated. Work within HEALTHGRAIN has revealed novel insights regarding some potential mechanisms.
Barley products rich in indigestible carbohydrates (dietary fibre and resistant starch), facilitated glycaemic regulation through a mechanism involving fermentation by gut micro-organisms. Fermentation was associated with release of specific gut hormones (GLP-1), with acknowledged benefits on a variety of parameters associated with reduced risk of the metabolic syndrome, including benefits on perceived satiety. GLP-1 is currently investigated for use as an antidiabetic, antiobesity drug, but appears to be produced endogenously in healthy subjects after intake of certain whole grain barley products rich in indigestible carbohydrates. Addition of whole grain barley products with slow glycemic response and rich in dietary fibre and resistant starch in test meals significantly improved insulin sensitivity in type 2 diabetic subjects as compared with whole grain wheat or white wheat.
Additionally, rye products generally produce a beneficial blood glucose profile following a meal, with a low and sustained blood glucose response. Rye products also induced lowered insulin response compared with white wheat, promoted higher post-meal satiety, and induced lowered voluntary energy intake at a subsequent meal. Studies within HEALTHGRAIN indicate that different rye genotypes vary with respect to benefits on glycaemic regulation and insulin demand.
The results are in favour of metabolic benefits of an increased consumption of in particular whole grain barley products with low glycemic response, and foods made of certain rye varieties. The results provide tools for tailoring of whole grain cereal products with magnified health benefits adjunct to the metabolic syndrome.
Source HEALTHGRAIN

Whole Grain, Bran Intake Associated With Lower Risk Of Death In Diabetic Women
Women with type 2 diabetes who ate the most bran in a study had a 35 percent lower risk of death from cardiovascular disease (CVD) and a 28 percent reduction in death from all causes than women who ate the least amount, researchers reported in Circulation: Journal of the American Heart Association. 
Bran is a component of whole grain rich in vitamins, minerals and fiber. 
"To my knowledge, this is the first study of whole grain and its components and risk of death in diabetic patients," said Lu Qi, M.D., Ph.D., senior author of the study. "Patients with diabetes face two to three times the risk of cardiovascular disease and premature death compared to the general population." 
Qi and his colleagues used data from 7,822 women diagnosed with type 2 diabetes, a condition in which the body usually produces insulin but can't use it efficiently to break down blood sugar. The women were diagnosed after age 30 and were enrolled in the Nurses' Health Study (NHS), a study of 121,700 U.S. female registered nurses that began in 1976. NHS participants answered questionnaires about their medical history, lifestyle and disease diagnoses every two years and completed food frequency questionnaires about every fours years. 
During up to 26 years of follow-up, 852 deaths occurred, including 295 from cardiovascular disease in the diabetic women. The researchers used data from the food frequency questionnaires to calculate consumption of whole grain and its sub-components of bran and germ, as well as cereal fiber, in grams per day. They then divided the women into five groups based on their consumption of whole grain and its components. Women who ate the most bran had 9.73 grams (median value) per day; those with the lowest consumption ate less than 0.8 grams (median value) per day. 
After adjusting for age, the women in the top 20 percent for consumption of whole grain, bran, germ and cereal fiber were at reduced risk of death from all causes and from CVD compared to the women in the bottom 20 percent, Qi said. However, after adjusting for a range of lifestyle and factors such as smoking and physical activity, only the association with bran remained statistically significant and independent of those factors. 
"These findings suggest a potential benefit of whole grain, and particularly bran, in reducing death and cardiovascular risk in diabetic patients," said Qi, assistant professor of medicine at Harvard Medical School and assistant professor of nutrition in the Harvard School of Public Health. 
Women in the highest group for added bran had a 55 percent risk reduction for death from all causes and a 64 percent reduction in risk of CVD mortality compared to those who ate no added bran, Qi said. Several possible mechanisms have been suggested for these findings. Additional investigations relating different sources of bran to beneficial effects on patients with type 2 diabetes are warranted in future studies. 
A previous study by Qi's research group found that high intakes of whole grain and its components might protect against systemic inflammation and dysfunction of the endothelium - the cells that line the blood vessels and play an important role in blood pressure regulation. 
"Diabetes is thought to be a chronic state of inflammation characterized by moderately increased levels of chemical markers for inflammation and endothelial dysfunction," Qi said. "Those markers have been found to be related to increased risk of CVD in both diabetic and non-diabetic populations. In our previous studies, we have reported that intakes of whole grains and subcomponents such as cereal fiber may lower these markers in diabetic patients." 
The American Heart Association recommends a dietary pattern rich in whole-grain, high fiber foods and that half of an individual's grain intake should come from whole grains. 
Co-authors are Meian He, M.D., Ph.D., lead author; Rob M. van Dam, Ph.D.; Eric Rimm, Sc.D.; and Frank B. Hu, M.D., Ph.D. Author disclosures are on the manuscript. 
The study was funded by the National Institutes of Health, the American Heart Association Scientist Development Award and the Boston Obesity Nutrition Research Center. 
Source
American Heart Association (Augustus 2010)