Diabetes

• Long-known to lower LDL cholesteral, a new study shows oats also impact other markers that may be better measures of cardiovascular risk for those with diabetes or metabolic syndrome.
• An experimental study shows that whole grain foods significantly lower blood pressure compared to eating the equivalent refined grain foods.
• A review of population studies shows that the more whole grains you eat, the lower your risk of cardiovascular disease.

Eating oats lowers cholesterol on 3 markers

It’s long been known that eating oats can lower cholesterol levels, but the research focus has been on the effect on LDL cholesterol. However, there is growing evidence that two other markers provide an even more accurate assessment of cardiovascular risk:

• non-HDL cholesterol (total cholesterol minus HDL cholesterol)
• apolipoprotein B (apoB) — a lipoprotein that carries LDL cholesterol through the blood.

This is especially true for people with metabolic syndrome and Type 2 diabetes, since they typically don't have elevated LDL cholesterol levels.

In light of this, it’s good to see a review and meta-analysis of 58 clinical trials has concluded that eating oat fibre can reduce all three markers.

The reason is thought to lie in beta-glucan, a viscous soluble fibre, for which oats are a rich source. Oat bran contains twice as much as oat meal.

The review found that overall, LDL cholesterol was reduced by 4.2%, non-HDL cholesterol by 4.8% and apoB by 2.3%.

https://www.eurekalert.org/pub_releases/2016-10/smh-rse100616.php

Whole grain diet reduces cardiovascular disease risk

A study involving 33 overweight and obese adults who followed a whole grain diet for eight weeks and a refined grain diet during another eight week period, found that those on the whole grain diet saw a more than three-fold improvement in diastolic blood pressure compared to the refined grain diet.

This improvement equates to reducing the risk of death from heart disease by almost one-third, and the risk of death from a stroke by two-fifths.

Participants were under 50. Before age 50, an elevated diastolic blood pressure is associated with increased cardiovascular disease risk (diastolic is the bottom number, when you’re given a blood pressure reading).

Overall, there were substantial reductions in body weight, fat loss, systolic blood pressure, total cholesterol, and LDL cholesterol during both diet periods, but these differences were due to the people changing their normal dietary habits to carefully controlled diets. The order of diets was randomized, and there was a ten week period between them. The 33 participants included 6 men and 27 women.

The finding is supported by a meta-analysis of 45 different population studies that investigated whole grain intake in relation to risk of future illness or death due to specific causes. The review found that eating three more portions of whole grain foods a day was associated with a lower risk for all cardiovascular diseases and for dying of cancer, diabetes, and respiratory and infectious diseases. Three servings would be, say, two slices of whole-grain bread and one bowl of whole-grain cereal.

The benefits were dose-dependent, with the lowest risk found among those with the highest intake of whole-grain products: 7 to 7 ½ servings of whole grain products a day. This corresponds to 210-225 grams of whole grain products in fresh weight and about 70-75 grams of whole grains in dry weight.

https://www.eurekalert.org/pub_releases/2016-10/cc-ccs101816.php

http://www.eurekalert.org/pub_releases/2016-06/nuos-sso061516.php

Ho, H., Sievenpiper, J., Zurbau, A., Blanco Mejia, S., Jovanovski, E., Au-Yeung, F., . . . Vuksan, V. (2016). The effect of oat β-glucan on LDL-cholesterol, non-HDL-cholesterol and apoB for CVD risk reduction: A systematic review and meta-analysis of randomised-controlled trials. British Journal of Nutrition, 116(8), 1369-1382. doi:10.1017/S000711451600341X

Kirwan, J. P., Malin, S. K., Scelsi, A. R., Kullman, E. L., Navaneethan, S. D., Pagadala, M. R., … Ross, A. B. (2016). A Whole-Grain Diet Reduces Cardiovascular Risk Factors in Overweight and Obese Adults: A Randomized Controlled Trial. The Journal of Nutrition, 146(11), 2244–2251. https://doi.org/10.3945/jn.116.230508

Aune Dagfinn, Keum NaNa, Giovannucci Edward, Fadnes Lars T, Boffetta Paolo, Greenwood Darren C et al. Whole grain consumption and risk of cardiovascular disease, cancer, and all cause and cause specific mortality: systematic review and dose-response meta-analysis of prospective studies BMJ 2016; 353 :i2716 http://www.bmj.com/content/353/bmj.i2716

A study involving 1,818 Hispanic Americans has confirmed that diabetes, whether controlled or not, is linked to worse measures of cardiac structure and function, and also shows that this happens very early in the development of diabetes.

https://www.eurekalert.org/pub_releases/2016-10/cums-gia102116.php

Demmer, R. T., Allison, M. A., Cai, J., Kaplan, R. C., Desai, A. A., Hurwitz, B. E., … Rodriguez, C. J. (2016). Association of Impaired Glucose Regulation and Insulin Resistance With Cardiac Structure and Function. Circulation: Cardiovascular Imaging, 9(10), e005032. https://doi.org/10.1161/CIRCIMAGING.116.005032 

A meta-analysis of 40 epidemiological studies from 1999 to 2016 has concluded that that people in the highest category of dietary magnesium consumption had a 10% lower risk of coronary heart disease, 12% lower risk of stroke and a 26% lower risk of type-2 diabetes compared to those in the lowest category. A dose–response analysis revealed that a 100 mg/day increase in dietary magnesium intake is significantly associated with a 7%, 22%, and 19% decrease in the risk of stroke, heart failure, and type 2 diabetes, respectively.

Magnesium-rich foods include spices, nuts, beans, cocoa, whole grains and green leafy vegetables.

Magnesium deficiency is relatively common, estimated to affect between 2.5% and 15% of the population. The recommended dietary allowance of magnesium is 350mg/day for an average male adult and 300mg/day for an average adult female, with an additional 150mg/day during pregnancy and lactation

https://www.biomedcentral.com/about/press-centre/science-press-releases/08-12-16

https://www.eurekalert.org/pub_releases/2016-12/bc-dma120516.php

Fudi Wang et al. 2016. Dietary magnesium intake and risk of cardiovascular disease, type 2 diabetes, and allcause mortality: A dose-response meta-analysis of prospective cohort studies. BMC Medicine, DOI: 10.1186/s12916-016-0742-z

Data from 3,349 participants in the PREDIMED Study who were free of diabetes at baseline but at high cardiovascular risk, has found that those who consumed higher amounts of saturated fatty acids and animal fat had a twofold higher risk of developing type 2 diabetes over 4.5 years than those with a lower intake of saturated and animal fat. 266 participants developed diabetes during the period.

They also found that those who had a higher intake of legumes (lentils, chickpeas, beans and peas) had a 35% lower risk of developing type 2 diabetes compared to those eating the least amount. The main benefit came from lentils, with chickpeas running second. Those with a higher intake consumed at least 28.75 grams/day (equivalent to 3.35 servings/week).

There was also a positive benefit when half a serving per day of foods rich in protein or carbohydrates (such as eggs, bread, rice and baked potato) was replaced with a similar amount of legumes.

Legumes are rich in B vitamins, with beneficial minerals such as calcium, potassium and magnesium. They have long been thought to protect against type 2 diabetes.

https://www.eurekalert.org/pub_releases/2017-02/uriv-csa021617.php

https://www.eurekalert.org/pub_releases/2017-03/uriv-tco033017.php

Guasch-Ferré, M. et al. 2017. Total and subtypes of dietary fat intake and risk of type 2 diabetes mellitus in the Prevención con Dieta Mediterránea (PREDIMED) study. Total and subtypes of dietary fat intake and risk of type 2 diabetes mellitus in the Prevención con Dieta Mediterránea (PREDIMED) study Am J Clin Nutr 2017 105: 3 723-735; First published online February 15, 2017. doi:10.3945/ajcn.116.142034

Becerra-Tomás N, Díaz-López A, Rosique-Esteban N, Ros E, Buil-Cosiales P, Corella D, Estruch R, Fitó M, Serra-Majem Ll, Arós F, Lamuela-Raventós R.M, Fiol M, Santos-Lozano J.M, Diez-Espino J, Portoles O, Salas-Salvadó J, PREDIMED study investigators. "Legume consumption is inversely associated with type 2 diabetes incidence in adults: a prospective assessment from the PREDIMED study". Clinical Nutrition (2017). http://dx.doi.org/10.1016/j.clnu.2017.03.015.

A study folowing nearly 500 patients with existing cardiovascular disease for more than two decades has found that insulin resistance is linked to faster cognitive decline in both diabetic and non-diabetic patients.

Executive function and memory were particularly affected.

Insulin resistance is a condition in which cells fail to respond normally to the hormone insulin, and so require higher levels of insulin to get the amount of glucose they need. But without sufficient insulin, excess glucose builds up in the bloodstream, leading to prediabetes, diabetes, and other serious health disorders.

Exercising, maintaining a balanced and healthy diet, and watching your weight, will help you prevent insulin resistance.

https://www.eurekalert.org/pub_releases/2017-03/ip-irm032317.php

Lutski M, Weinstein G, Goldbourt U, Tanne D. Insulin Resistance and Future Cognitive Performance and Cognitive Decline in Elderly Patients with Cardiovascular Disease. J Alzheimers Dis. 2017 Mar 10. doi: 10.3233/JAD-161016

A number of studies have pointed to a link between depression and type 2 diabetes, but a new study indicates that this is not as straightforward as it seemed. The large Canadian study involving 2,525 adults aged 40-69 has found that it is not depression alone that increases the risk of developing diabetes, but depression in conjunction with metabolic risk factors such as obesity, high blood pressure and unhealthy cholesterol levels,.

The study found that those with metabolic symptoms but not depression were around four times more likely to develop diabetes than normally healthy people, while those with both depression and metabolic risk factors were more than six times more likely to develop diabetes. The combined effect of depression and metabolic symptoms was greater than the sum of the individual effects. But those with depression alone had no more risk than normally healthy people.

There are probably two main causes for this effect. One is that, as evidence shows, people suffering from depression are less likely to adhere to medical advice aimed at tackling metabolic symptoms. This makes the metabolic symptoms worse, which can exacerbate the symptoms of depression, and so it goes, in a horrible negative cycle.

The second reason is that some forms of depression are associated with changes in the body's metabolic systems which can lead to weight gain, high blood pressure and problems with glucose metabolism. Some antidepressant medications can also cause weight gain.

http://www.eurekalert.org/pub_releases/2016-04/mu-hdm041216.php

Schmitz, N., Deschenes, S. S., Burns, R. J., Smith, K. J., Lesage, A., Strychar, I., … Wang, J. L. (2016). Depression and risk of type 2 diabetes: the potential role of metabolic factors. Mol Psychiatry. Retrieved from http://dx.doi.org/10.1038/mp.2016.7

For two years, 70 obese postmenopausal women with normal fasting plasma glucose levels ate either a Paleolithic-type diet or a “prudent” diet. The Paleolithic-type diet was based on lean meat, fish, eggs, vegetables, fruits, nuts and berries, with rapeseed, olive oils and avocado as additional fat sources. The diet excluded dairy products, cereals, added salt and refined fats and sugar. 30% of the calories were supposed to come from protein, 30% from carbohydrates, and 40% from fats with high unsaturated fatty acid content. The prudent control diet had a markedly different target: 15% in protein, 30% in fat, and 55% in carbohydrates.

Both groups took part in 12 group sessions led by a dietitian, and kept ongoing records of their food intake.

Both groups lost significant body weight and had significantly less abdominal obesity, but the women eating the Paleolithic-type diet also had significantly lower levels of specific fatty acids associated with insulin resistance, compared with those on the prudent control diet. Presumably this reflects the marked change in the types of fats eaten. At the end of the two years, the women eating the Paleolithic-type diet reported that their intake of saturated fatty acids decreased by 19%, while monounsaturated fatty acids increased by 47% and polyunsaturated fatty acids by 71%.

http://www.eurekalert.org/pub_releases/2016-04/tes-apd040116.php

Data from 8,452 participants in the population-based Rotterdam Study found that, over eight years, 1,100 (13%) developed prediabetes and 798 (9.4%) developed diabetes. The risk of progressing from prediabetes to diabetes was up to 40% higher for those with low thyroid function. Even among those whose thyroid function was in the normal range at first measurement, progression from prediabetes to diabetes was 1.4 times higher for those in the lowest third of thyroid function levels compared with the highest third.

The average age of the participants was 65.

http://www.eurekalert.org/pub_releases/2016-04/tes-sll040116.php

A small, Israeli study involving 48 overweight and obese older adults with Type 2 diabetes (average age 59) has found that those who ate a large breakfast containing whey protein managed their diabetes better.

Participants in the study were randomly alloted to one of three diets that contained the same number of calories, and followed the pattern: large breakfast, medium-sized lunch and small dinner. They followed this diet for 23 months. The groups varied in the type of breakfast: primarily whey protein; other proteins such as eggs, soy and tuna; a meal high in carbohydrates or starch.

After 12 weeks, the group on whey protein lost the most weight: 7.6 kg (16.7 pounds), compared to 6.1 kg (13.4 pounds) for those on the other proteins, and 3.1 kg (6.8 pounds) for those in the carbohydrate group. Those on whey protein were also more satiated and less hungry throughout the day, with lower glucose spikes after meals compared to the other two diets, and their HbA1C also decreased more than with the other two diets.

http://www.eurekalert.org/pub_releases/2016-04/tes-lwp040116.php

Frailty, manifesting in weight loss and malnutrition, leading to decreased hyperglycemia and normalization of blood glucose levels, may develop in older diabetics. This in turn leads to an increased risk of hypoglycemia. Current guidelines suggest relaxed glycemic control in diabetic, frail elderly patients.

A British study reviewing the impact of frailty on blood glucose level normalization has suggested not simply a more relaxed glycemic control in frail elderly with diabetes, but that complete withdrawal of hypoglycemic medications may be necessary. The researchers recommend that doctors regularly review medications taken in this vulnerable population “with consideration of gradual reduction or complete withdrawal when frailty and significant weight loss emerge”.

The review is available free to read here: http://www.future-science.com/doi/full/10.4155/fsoa-2015-0016.

http://www.eurekalert.org/pub_releases/2016-03/fsg-dwn031516.php