diabetes

A very small study, involving eight healthy young men and women, has found that insulin sensitivity gets worse the longer you're awake during the night.

During the study, one group had just five hours of available sleep time each night for five nights before five nights with nine hours of available sleep time. The other group did the opposite, starting with nine hours of available sleep time, followed by five hours per night. Participants were allowed to eat whatever they wanted during the short-night testing period.

The simulated five-day workweek of five hours of sleep per night resulted in a 20% reduced oral and intravenous insulin sensitivity, and it took three consecutive nights of nine hours of available sleep time to restore oral insulin sensitivity to previous levels.

It's worth emphasizing that these were all young and very healthy people.

http://www.eurekalert.org/pub_releases/2015-11/uoca-los_1110415.php

Eckel, R. H., Depner, C. M., Perreault, L., Markwald, R. R., Smith, M. R., McHill, A. W., … Wright, K. P. (2015). Morning Circadian Misalignment during Short Sleep Duration Impacts Insulin Sensitivity. Current Biology, 25(22), 3004–3010. http://doi.org/10.1016/j.cub.2015.10.011

Data from 4.1 million British adults who were free of diabetes and cardiovascular disease at the start of the study has found that those with high blood pressure were almost 60% more likely to develop type 2 diabetes.

The strength of the association declined with increasing body mass index and age.

The finding strengthens previous research indicating that you are more at risk of diabetes if you have had high blood pressure, a heart attack or a stroke.

http://www.theguardian.com/society/2015/sep/29/study-gives-strongest-link-yet-between-blood-pressure-and-diabetes

Emdin CA, Anderson SG, Woodward M, Rahimi K. Usual Blood Pressure and Risk of New-Onset Diabetes: Evidence From 4.1 Million Adults and a Meta-Analysis of Prospective Studies. J Am Coll Cardiol. 2015;66(14):1552-1562. doi:10.1016/j.jacc.2015.07.059.

Newly available 2011-2012 data from the very large National Health and Nutrition Examination Survey (NHANES) has revealed that Asian Americans have the highest proportion of undiagnosed diabetes among all ethnic and racial subgroups studied, at 51%. Diabetes was also common in Asian Americans, at 21%. The ethnic group with the highest prevalence of diabetes was Hispanic-Americans, at nearly 23%, with 49% of that undiagnosed.

One major reason for the high rate of undiagnosed diabetes among Asian-Americans may be that this group seem to develop type 2 diabetes at a lower body mass index than expected. The American Diabetes Association recommends Asian Americans get tested for diabetes at a BMI of 23 or higher, a lower threshold than the general population.

About 1 in 5 non-Hispanic black adults had diabetes, with 37% undiagnosed. Non-Hispanic whites had the lowest prevalence at 11%, and the lowest proportion of undiagnosed, at just over 32%.

However, overall the prevalence of diabetes has risen among American adults: from nearly 10% in 1988 to over 12% in 2012.

http://www.eurekalert.org/pub_releases/2015-09/niod-mth090315.php

Your risk of developing type 2 diabetes is about three times greater if someone in your immediate family (parent, sibling) has it. In a study looking at the effects of exercise on this group, it was found that men who have a family member with type 2 diabetes had to expend more energy than a control group, to achieve the same benefits.

The study involved 35 unfit, slightly overweight but completely healthy men aged 30-45 who, for seven months, exercised regularly at a fitness centre. Half of them had relatives with type 2 diabetes, and half did not. (It's perhaps worth noting that 50 men began the study, but didn't continue — these were roughly evenly divided between the two groups.) Three hour-long exercise sessions were available each week, and participants went to 39 sessions on average (the range was large though: 11-107).

Those with family members with diabetes tended to go to the gym more often (group average was 59% more sessions), and this may be due to their increased motivation.

It must be emphasized that both groups lost weight, reduced their waist size, increased their fitness, and showed similar improvements in gene expressions. So exercise was a good idea for both groups. However, statistical analysis indicates that the at-risk group had to do more exercise than the control group to achieve the same benefit. The findings support earlier findings that those with close relatives with type 2 diabetes show smaller physiological changes to exercise, compared to those without such familial links.

http://www.eurekalert.org/pub_releases/2015-10/lu-eig100215.php

Ekman, C., Elgzyri, T., Ström, K., Almgren, P., Parikh, H., Nitert, M. D., … Hansson, O. (2015). Less pronounced response to exercise in healthy relatives to type 2 diabetic subjects compared with controls. Journal of Applied Physiology, 119(9), 953–960. http://doi.org/10.1152/japplphysiol.01067.2014

In a study involving 52 sedentary, overweight, middle-aged men and women (aged 45-65), both exercise and calorie restriction had positive — and equal — effects on insulin sensitivity, but a combination of both had twice as much benefit for glucoregulation as either single approach. All three programs were designed to achieve about the same amount of weight loss (6-8%).

The study also indicated that both exercise and calorie restriction improve regulation of glucose levels through weight loss, but also through mechanisms that are independent of weight loss.

What all this suggests is that, even if you're maintaining a healthy weight, how much you eat, and whether you exercise, are factors that have health implications.

http://www.eurekalert.org/pub_releases/2015-05/slu-ido050615.php

Weiss, E. P., Albert, S. G., Reeds, D. N., Kress, K. S., Ezekiel, U. R., McDaniel, J. L., … Villareal, D. T. (2015). Calorie Restriction and Matched Weight Loss From Exercise: Independent and Additive Effects on Glucoregulation and the Incretin System in Overweight Women and Men. Diabetes Care, 38(7), 1253–1262. http://doi.org/10.2337/dc14-2913

Sleep apnea is common among overweight and obese individuals, and many people with prediabetes have untreated sleep apnea, although few of them are aware of it.

A study involving 39 middle-aged, overweight or obese volunteers with prediabetes and sleep apnea has found that those who received two weeks of CPAP treatment improved their blood sugar control and the ability of insulin to regulate their blood sugar, and also had lower blood pressure and lower levels of the stress hormone norepinephrine.

Two-thirds of the volunteers received continuous positive airway pressure (CPAP) for eight hours during the night; the other 13 received a placebo to be taken before bedtime. They were told the study would compare the two treatments. All participants slept in the sleep laboratory and were closely monitored.

http://www.eurekalert.org/pub_releases/2015-04/uocm-esa042715.php

Sushmita Pamidi, Kristen Wroblewski, Magdalena Stepien, Khalid Sharif-Sidi, Jennifer Kilkus, Harry Whitmore, and Esra Tasali "Eight Hours of Nightly Continuous Positive Airway Pressure Treatment of Obstructive Sleep Apnea Improves Glucose Metabolism in Patients with Prediabetes. A Randomized Controlled Trial", American Journal of Respiratory and Critical Care Medicine, Vol. 192, No. 1 (2015), pp. 96-105. doi: 10.1164/rccm.201408-1564OC

A very small Israeli study, involving eight men and 10 women aged 30-70 with type 2 diabetes, has found that a big breakfast and a small dinner helped control blood sugar levels through the day.

Patients were randomly assigned to follow either a “B diet”, in which breakfast contained 2946 kilojoules, lunch 2523 kj, and dinner 858kj, or a “D diet”, which involved a 858 kj breakfast, 2523 kj lunch, and 2946 kj dinner. In other words, the same total amount of calories, in the same foods, was eaten by both groups, and lunch was the same for both, but the 'breakfast' and 'dinner' meals swapped timing.

After six days on the diet, patients ate their meals on the 7^th day at the lab, where glucose levels were repeatedly tested during the day. After a break of two weeks, each patient was put on the alternate diet, and the same procedure was followed.

It was found that blood glucose levels rose 23% less after the lunch preceded by a large breakfast.

http://www.eurekalert.org/pub_releases/2015-03/afot-abo031615.php

Jakubowicz, D., Wainstein, J., Ahrén, B., Bar-Dayan, Y., Landau, Z., Rabinovitz, H. R., & Froy, O. (2015). High-energy breakfast with low-energy dinner decreases overall daily hyperglycaemia in type 2 diabetic patients: a randomised clinical trial. Diabetologia, 58(5), 912–919. http://doi.org/10.1007/s00125-015-3524-9

Mouse and human immune cells have demonstrated that a compound produced by the body when dieting or fasting (β-hydroxybutyrate — BHB) directly inhibits a protein, NLRP3, which is part of a complex set of proteins that drive the inflammatory response in several disorders, including autoimmune diseases, type 2 diabetes, Alzheimer's disease, atherosclerosis, and autoinflammatory disorders.

BHB is produced in response to fasting, high-intensity exercise, caloric restriction, or consumption of the low-carbohydrate ketogenic diet.

The finding helps explain why calorie restriction reduces inflammation.

http://www.eurekalert.org/pub_releases/2015-02/yu-amo021315.php

Youm, Y.-H., Nguyen, K. Y., Grant, R. W., Goldberg, E. L., Bodogai, M., Kim, D., … Dixit, V. D. (2015). The ketone metabolite β-hydroxybutyrate blocks NLRP3 inflammasome-mediated inflammatory disease. Nature Medicine, 21(3), 263–269. http://doi.org/10.1038/nm.3804

Studies have found that low levels of magnesium increases the chance that you will develop type 2 diabetes, but a large study shows that this association is modified by genetic variations in magnesium-related ion channel genes. So, for example, among Hispanic American women with high magnesium intake, those with one particular variant had a 35% lower risk of developing type 2 diabetes.

The study involved 7,287 black women and 3,285 Hispanic women aged 50-79.

http://www.eurekalert.org/pub_releases/2015-01/bu-t2d010715.php

http://www.futurity.org/diabetes-magnesium-833412/

Chan, K. H. K., Chacko, S. A., Song, Y., Cho, M., Eaton, C. B., Wu, W.-C. H., & Liu, S. (2015). Genetic Variations in Magnesium-Related Ion Channels May Affect Diabetes Risk among African American and Hispanic American Women. The Journal of Nutrition, 145(3), 418–424. http://doi.org/10.3945/jn.114.203489