Diet

A Finnish study involving 2,189 healthy men aged 42-60 found that over 19 years, 417 men (19%) were diagnosed with type 2 diabetes. Those with high omega-6 polyunsaturated fatty acid concentrations in their blood were 46% less likely to develop diabetes. When analyzed, it turned out that this association depended on linoleic and arachidonic acid concentrations only; high serum gamma-linolenic and dihomo-γ-linolenic acid concentrations were linked to a higher risk.

The serum linoleic acid concentration is determined by the person's diet, and the main sources of linoleic acid are vegetable oils, nuts and seeds. Arachidonic acid is present in meat and eggs; however, the human body can also make arachidonic acid from linoleic acid.

Gamma-linolenic acid and dihomo-γ-linolenic acid are mainly formed in the human body from linoleic acid, but their concentrations in serum are very low.

Linoleic acid is the most common omega-6 fatty acid, and has been linked to a reduced risk of cardiovascular diseases as well as type 2 diabetes.

http://www.eurekalert.org/pub_releases/2016-03/uoef-hso032416.php

Teymoor Yary, Sari Voutilainen, Tomi-Pekka Tuomainen, Anu Ruusunen, Tarja Nurmi, Jyrki K Virtanen 2016. Serum n-6 polyunsaturated fatty acids, delta-5- and delta-6-desaturase activities and risk of incident type 2 diabetes in men: The Kuopio Ischaemic Heart Disease Risk Factor Study. American Journal of Clinical Nutrition, Published online March 24, 2016 http://ajcn.nutrition.org/content/early/2016/03/23/ajcn.115.128629.abstract

Lower salt generally lowers blood pressure, but it turns out this may not apply in all instances. A mouse study suggests that a low-salt diet can increase the risk of hypertension if you have a disrupted circadian rhythm. Sleep disorders, shift work, disease, and aging are all potential signs of or triggers for circadian dysfunction.

A 24-hour blood pressure check may reveal that blood pressure is not falling, as it should, during the night. Nondipping blood pressure is estimated as high as 53% in patients being treated for hypertension. It may be that, for those with a disrupted circadian rhythm, the timing of antihypertensive medication should be different.

http://www.eurekalert.org/pub_releases/2016-02/mcog-wab020116.php

Pati, P., Fulton, D. J. R., Bagi, Z., Chen, F., Wang, Y., Kitchens, J., … Rudic, R. D. (2016). Low-Salt Diet and Circadian Dysfunction Synergize to Induce Angiotensin II–Dependent Hypertension in Mice. Hypertension, 67(3), 661–668. http://doi.org/10.1161/HYPERTENSIONAHA.115.06194

A review of recent neutral studies questioning the benefits of omega-3s for heart health suggests that the findings may have been due to a number of design issues, rather than a lack of substantiated clinical benefits in cardiovascular disease. The issues include such things as:

• aggressive cardiovascular drug treatment overshadowing the benefits of long-chain omega-3s
• high background long-chain omega-3 intake at study initiation
• too few subjects in the study
• treatment duration too short
• insufficient LC omega-3 dosage
• increase in omega-6 fatty acid intake during the study
• failure to assess the LC omega-3 status of the subjects prior to and during treatment
• lack of clarity concerning which mechanisms were expected to produce benefits

The existing body of gold-standard research showing omega-3s may reduce cardiovascular death risk, maintain healthy blood pressure and improve triglyceride levels also makes it difficult to conclude that EPA and DHA consumption does not contribute to a healthy heart.

http://www.eurekalert.org/pub_releases/2016-02/g-phb012916.php

Rice, H. B., Bernasconi, A., Maki, K. C., Harris, W. S., von Schacky, C., & Calder, P. C. (2016). Conducting omega-3 clinical trials with cardiovascular outcomes: Proceedings of a workshop held at ISSFAL 2014. Prostaglandins, Leukotrienes and Essential Fatty Acids (PLEFA), 107, 30–42. http://doi.org/10.1016/j.plefa.2016.01.003

Telomeres are the protective caps at the ends of chromosomes that affect how quickly cells age. With age, they shorten, and as their structural integrity weakens, the cells age and die quicker. Telomere length thus is a biomarker of cellular age. Stress is also thought to shorten telomere length.

A year-long study that looked at the effects of three healthy behaviors in 239 post-menopausal, non-smoking women has found that women who engaged in lower levels of healthy behaviors showed a significantly greater telomere shortening for every major life stressor that occurred. However, stress didn't lead to greater shortening in those women who maintained active lifestyles, healthy diets, and good quality sleep.

Shorter telomeres have become associated with a broad range of aging-related diseases, including stroke, vascular dementia, cardiovascular disease, obesity, osteoporosis diabetes, and many forms of cancer.

http://www.eurekalert.org/pub_releases/2014-07/uoc--hlm072414.php

Puterman, E., Lin, J., Krauss, J., Blackburn, E. H., & Epel, E. S. (2015). Determinants of telomere attrition over 1 year in healthy older women: stress and health behaviors matter. Molecular Psychiatry, 20(4), 529–535. http://doi.org/10.1038/mp.2014.70

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

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

A review of studies investigating lifestyle interventions that can delay or prevent the onset of type 2 diabetes in people with prediabetes and focusing specifically on ones that looked at gender differences, found that both men and women benefited equally from the interventions. The review of 12 studies found that those who received lifestyle interventions (including diet and exercise) were 40% less likely to progress to type 2 diabetes after 1 year, and 37% less likely to progress after 3 years.

People involved in lifestyle interventions also experienced greater weight reductions, and greater reductions of fasting plasma glucose.

http://www.eurekalert.org/pub_releases/2014-11/d-bit112614.php

Glechner, A., Harreiter, J., Gartlehner, G., Rohleder, S., Kautzky, A., Tuomilehto, J., … Kautzky-Willer, A. (2014). Sex-specific differences in diabetes prevention: a systematic review and meta-analysis. Diabetologia, 58(2), 242–254. http://doi.org/10.1007/s00125-014-3439-x

A new class of lipids produced in human and mouse fat has been discovered, and these ones seem to be good for you. Following the discovery that diabetes-resistant mice had dramatically higher levels of these “fatty acid hydroxy fatty acids (FAHFAs)”, levels were found to be low in pre-diabetic humans. Moreover, when mice with the equivalent of type 2 diabetes were given this lipid, blood sugar levels dropped and insulin levels rose. FAHFAs also seem to reduce inflammation.

FAHFAS are found in low levels in a wide range of vegetables, fruits and other foods, as well as being (unlike omega-3 fatty acids) produced and broken down inside the body.

http://www.eurekalert.org/pub_releases/2014-10/si-sda100814.php

Yore, M. M., Syed, I., Moraes-Vieira, P. M., Zhang, T., Herman, M. A., Homan, E. A., … Kahn, B. B. (2014). Discovery of a Class of Endogenous Mammalian Lipids with Anti-Diabetic and Anti-inflammatory Effects. Cell, 159(2), 318–332. http://doi.org/10.1016/j.cell.2014.09.035