cholesterol

• 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 review and meta-analysis of studies from 1982 to 2015, evaluating relationships between egg intake and coronary heart disease (total of 276,000 subjects) and stroke (total of 308,000 subjects) has found that consumption of up to one egg per day had no association with coronary heart disease (CHD) and a 12% reduction of stroke risk.

The study follows on from a 2015 meta-analysis in which dietary cholesterol was shown to have no association with cardiovascular diseases, including coronary artery disease and stroke. Consistent with this, the 2015 Dietary Guidelines for Americans placed no daily limit on dietary cholesterol and noted eggs are an affordable, accessible, nutrient-rich source of high quality protein.

https://www.eurekalert.org/pub_releases/2016-11/enc-oep102816.php

Alexander, D. D., Miller, P. E., Vargas, A. J., Weed, D. L., & Cohen, S. S. (2016). Meta-analysis of Egg Consumption and Risk of Coronary Heart Disease and Stroke. Journal of the American College of Nutrition, 35(8), 704–716. https://doi.org/10.1080/07315724.2016.1152928

Research using data from 2131 participants in the 2008 U.K. Health Survey suggests that regular exercise can partly counteract the negative health effects of being sedentary. The analysis grouped people into the following categories:

• physically active and low sedentary 'busy bees' (18.6% of the sample)
• physically active and high sedentary 'sedentary exercisers' (36.7%)
• physically inactive and low sedentary 'light movers' (6.8%)
• physically inactive and high sedentary 'couch potatoes' (37.9%).

Overall, physical activity was significantly associated with lower BMI, lower waist circumference, lower HbA1c levels (HbA1c is a modified form of haemoglobin, commonly used to measure glucose concentration; higher levels indicate poorer control of blood glucose levels), and higher HDL-cholesterol (the 'good' cholesterol). Sedentary time was associated with lower HDL-cholesterol levels.

None of that is a surprise, of course. The interesting aspect of this study is its attempt to disentangle physical activity and sedentary time.

In comparison to the couch potatoes, both busy bees and sedentary exercisers had significantly lower BMI and HbA1c levels, and higher HDL-cholesterol levels.

Busy bees (but not sedentary exercisers) also had lower waist circumferences. Compared to couch potatoes, light movers had only one improvement: higher HDL-cholesterol levels.

What all this shows is not simply the importance of physical activity for health, but that physical activity offsets some of the evils of a high sedentary time. It also suggests that not being sedentary doesn't take you all that far — you still need to exercise.

http://www.eurekalert.org/pub_releases/2016-04/uol-ecs040516.php

Bakrania, K., Edwardson, C. L., Bodicoat, D. H., Esliger, D. W., Gill, J. M. R., Kazi, A., … Yates, T. (2016). Associations of mutually exclusive categories of physical activity and sedentary time with markers of cardiometabolic health in English adults: a cross-sectional analysis of the Health Survey for England. BMC Public Health, 16, 25. http://doi.org/10.1186/s12889-016-2694-9

A Czech study involving 146 people with mild to moderate risk of cardiovascular disease has found that moderate wine drinking was only protective in people who exercised.

Participants were randomly assigned to one year of moderate consumption of red wine (Pinot Noir) or white wine (Chardonnay-Pinot) from the same year and wine region of the Czech Republic. They had to keep a logbook on their consumption of wine and other alcoholic beverages, medication use, and amount and type of exercise. They were required to return the corks from the wine bottles to confirm that they had drank the wine rather than sold it.

The study was looking for a rise in HDL cholesterol, indicating a protective effect against cardiovascular disease. However, there was no change in HDL cholesterol levels by the end of the study in either the red or white wine groups. Nor did it appreciably affect blood glucose, triglycerides, or levels of inflammatory markers like C-reactive protein, although LDL cholesterol was lower in both groups while total cholesterol was lower only in the red wine group.

However, those participants who engaged in regular exercise at least twice a week did show an increase in HDL cholesterol, as well as a decrease in LDL and total cholesterol. This occurred in both red and white wine groups.

Of course, the study didn't include a control group of people engaging in regular exercise who didn't drink, so all we can really say (and it's certainly worth saying) is that moderate wine drinking doesn't seem to help protect against cardiovascular disease, and that despite all the hype around red wine, with its greater antioxidants and resveratol, there's no evidence it's any healthier than white wine.

http://www.eurekalert.org/pub_releases/2014-08/esoc-wop082614.php

http://www.theatlantic.com/health/archive/2014/09/working-with-the-wine-not-against-it/379504/

Taborsky M, Ostadal P, Petrek M. A pilot randomized trial comparing long-term effects of red and white wines on biomarkers of atherosclerosis (in vino veritas: IVV trial). Bratisl Lek Listy. 2012;113(3):156-158.

A Canadian study involving 141 people with Type 2 diabetes, who ate either a low glycemic index diet that included bread made with canola oil, or a whole wheat diet known to reduce the risk of cardiovascular disease, found that those on the canola bread diet experienced both a reduction in blood glucose levels and a significant reduction in LDL, or "bad," cholesterol. Moreover, the canola bread diet seemed to have the most significant impact on people who needed help the most — those whose HbA1c test measuring blood glucose over the previous two or three months was highest.

On the other hand, those on the whole wheat diet seemed to have better blood flow after 12 weeks than those on the canola bread diet.

http://www.eurekalert.org/pub_releases/2014-06/smh-rsb061314.php

Jenkins, D. J. A., Kendall, C. W. C., Vuksan, V., Faulkner, D., Augustin, L. S. A., Mitchell, S., … Leiter, L. A. (2014). Effect of Lowering the Glycemic Load With Canola Oil on Glycemic Control and Cardiovascular Risk Factors: A Randomized Controlled Trial. Diabetes Care, 37(7), 1806–1814. http://doi.org/10.2337/dc13-2990

A trial in which 163 overweight adults with elevated blood pressure were given one of four complete diets that contained all their food for five weeks has found that a low glycemic diet did not improve insulin sensitivity, lipid levels or blood pressure. But it's important to note than all diets were based on a healthful DASH-type diet, varying only in their glycemic index and carbohydrate proportions.

So, the trial found that a healthy diet with low–glycemic index carbohydrate-containing foods didn't improve insulin sensitivity, HDL cholesterol levels, LDL cholesterol levels, or systolic blood pressure any more than the healthy diet with high–glycemic index foods It did reduce plasma triglyceride levels slightly more.

In fact, the low–glycemic index with high-carbohydrate diet was worse than the high–glycemic index, high-carbohydrate diet — decreasing insulin sensitivity and increasing LDL cholesterol and LDL apolipoprotein B levels. This finding was unexpected and inconsistent with other research. However, a meta-analysis of 28 trials found that lowering glycemic index did not affect HDL cholesterol or triglyceride levels and lowered LDL cholesterol level only if fiber content was also increased.

In line with the researchers' previous findings, the DASH diet had slightly better effects when its carbohydrate content was reduced. When the same calories were instead supplied by unsaturated fat and protein, triglycerides and VLDL levels were substantially lowered and diastolic blood pressure slightly lowered.

As in previous trials, all the DASH-type diets lowered blood pressure and LDL cholesterol levels.

Previous research has shown inconsistent results on whether low glycemic index helped people lose weight.

http://www.eurekalert.org/pub_releases/2014-12/bawh-lgd121614.php

Sacks FM, Carey VJ, Anderson CM, et al. Effects of High vs Low Glycemic Index of Dietary Carbohydrate on Cardiovascular Disease Risk Factors and Insulin Sensitivity: The OmniCarb Randomized Clinical Trial. JAMA. 2014;312(23):2531-2541. doi:10.1001/jama.2014.16658.

Goff  LM, Cowland  DE, Hooper  L, Frost  GS.  Low glycaemic index diets and blood lipids: a systematic review and meta-analysis of randomised controlled trials. Nutr Metab Cardiovasc Dis. 2013;23(1):1-10.

Further analysis of data from a 2011 study on the effect of the 'portfolio diet' on cholesterol has found that it also lowered blood pressure by an average 2% more than the DASH diet, a diet specifically designed to reduce hypertension, which is associated with a 5-10 mm blood pressure improvement.

The Canadian study involved 241 participants with hyperlipidemia, of whom 82 were randomly assigned to a DASH-type diet (control group) and 159 to the portfolio diet. Compared to the control, the portfolio diet reduced systolic, diastolic and mean arterial blood pressure by 2.1 mm Hg, 1.8 mm Hg and 1.9 mm Hg, respectively. Blood pressure reductions were small at 12 weeks and only reached significance at 24 weeks.

The portfolio diet includes foods that have been shown to lower cholesterol including mixed nuts, soy protein, plant sterols (found in vegetable oils and leafy vegetables) and viscous or soluble fiber. Viscous fiber is found only in plant-based food; rich sources include asparagus, Brussels sprouts, sweet potatoes, turnips, apricots, mangoes, oranges, legumes and oat bran.

However, the DASH diet did have higher compliance rates.

http://www.eurekalert.org/pub_releases/2015-11/smh-cd110515.php

Jenkins, D.J.A. et al. 2015. The effect of a dietary portfolio compared to a DASH-type diet on blood pressure. Nutrition, Metabolism and Cardiovascular Diseases, 25 (12), 1132-1139. http://dx.doi.org/10.1016/j.numecd.2015.08.006