Traditional Asian diet lowered insulin resistance in Asian Americans

Lipidology_NP_NutritionWhy are Asian Americans at higher risk of developing type 2 diabetes than Caucasian Americans, and prone to develop the disease at lower body weights? One part of this puzzle may lie in the transition from traditional high-fiber, low-fat Asian diets to current westernized diets, which may pose extra risks for those of Asian heritage, says George King, M.D., Senior Vice President and Chief Scientific Officer at Joslin Diabetes Center and the senior author of the study.

A Joslin randomized clinical trial now has demonstrated that both Asian Americans and Caucasian Americans at risk of type 2 diabetes who adopted a rigorously controlled traditional Asian diet lowered their insulin resistance. (A leading risk factor for developing the disease, insulin resistance is a condition in which the body struggles to use the hormone insulin, which helps to metabolize sugar.)

Moreover, when both groups of participants then switched to consuming typical western fare, the Asian Americans experienced greater increases in insulin resistance than did the Caucasian Americans, says Dr. King, senior author on a paper on the study published in the journal PLOS One.

The 16-week pilot trial was completed by 24 East Asian Americans and 16 Caucasian Americans, who had an average age of 34 and were either of normal weight or overweight but not obese. All the volunteers had a family history of type 2 diabetes or another indication of diabetes risk such as gestational diabetes.

For the first eight weeks, all the participants ate a traditional high-fiber East Asian diet with 70% of calories fromcarbohydrates, 15% from protein and 15% from fat, and providing 15 g fiber/1,000 kcal. The food was prepared fresh by local chefs and delivered every two days. “Three meals and one snack were included each day, and we made sure that they were nutritious as well as very tasty,” says Ka Hei Karen Lau, a Joslin dietitian and certified diabetes educator.

For the second eight weeks, 33 of the volunteers (20 Asian Americans and 13 Caucasian Americans) transitioned to a typical low-fiber western diet with 50% of calories from carbohydrates, 16% from protein and 34% from fat, and providing 6 g fiber/1,000 kcal. Seven volunteers (4 Asian Americans and 3 Caucasian Americans) stayed on the traditional Asian diet to act as controls for the study.

Meeting with the trial participants every two weeks, the Joslin team adjusted individual diets as needed to keep their weights relatively steady, so that changes in their metabolism were not driven primarily by changes in weight.

Maintaining those steady body weights for trial participants was a challenge, King remarks. “It was almost impossible to prevent people from losing weight on the Asian diet, and that was not because the food wasn’t good!” he says. “And almost everybody gained weight on the western diet, and we had to work very hard so they didn’t gain too much.”

The researchers suggested that the combination of high fiber and low fat in the traditional diet may help to explain the decrease in insulin resistance, especially for the Asian American participants.

Additionally, those on the traditional Asian diet lowered their LDL cholesterol, a potential benefit for cardiovascular health.

“These results were very exciting for Asian Americans,” Lau says. “We are at high risk for diabetes, but we can use diet to help prevent it.”

Joslin’s Asian Clinic now promotes a traditional Asian diet and shares suitable recipes with patients.

The researchers hope to follow up the pilot trial with a larger trial that compares results of a traditional Asian diet with a westernized Asian diet and does not try to control participant weight.

Asian Americans have about 20% higher risks of developing type 2 diabetes than Caucasian Americans. More than half of the adults in the world with the disease live in Southeast Asia and the Western Pacific, the researchers pointed out, and about 10% of adults in China now suffer from diabetes.

http://www.medicalnewstoday.com/releases/282735.php

Picture courtesy to www.just-like.net

Sugar substance ‘kills’ good HDL cholesterol

LipidologyScientists at the University of Warwick have discovered that ‘good’ cholesterol is turned ‘bad’ by a sugar-derived substance.

The substance, methylglyoxal – MG, was found to damage ‘good’ HDL cholesterol, which removes excess levels of bad cholesterol from the body.

Low levels of HDL, High Density Lipoprotein, are closely linked to heart disease, with increased levels of MG being common in the elderly and those with diabetes or kidney problems.

Supported by funding from the British Heart Foundation (BHF) and published in Nutrition and Diabetes, the researchers discovered that MG destabilises HDL and causes it to lose the properties which protect against heart disease.

HDL damaged by MG is rapidly cleared from the blood, reducing its HDL content, or remains in plasma having lost its beneficial function.

Lead researcher Dr Naila Rabbani, of the Warwick Medical School, says that: “MG damage to HDL is a new and likely important cause of low and dysfunctional HDL, and could count for up to a 10% risk of heart disease”.

There are currently no drugs that can reverse low levels of HDL, but the Warwick researchers argue that by discovering how MG damages HDL has provided new potential strategies for reducing MG levels.

Commenting on the research’s implications Dr Rabbani said:

“By understanding how MG damages HDL we can now focus on developing drugs that reduce the concentration of MG in the blood, but it not only be drugs that can help.

“We could now develop new food supplements that decrease MG by increasing the amount of a protein called glyoxalase 1, or Glo 1, which converts MG to harmless substances.

“This means that in future we have both new drugs and new foods that can help prevent and correct low HDL, all through the control of MG.”

A potentially damaging substance, MG is formed from glucose in the body. It is 40,000 times more reactive than glucose it damages arginine residue (amino acid) in HDL at functionally important site causing the particle to become unstable.

Glo1 converts MG to harmless substances and protects us. MG levels are normally kept low in the body to maintain good health but they slowly increase with ageing as Glo1 slowly becomes worn out and is only slowly replaced.

Dr Rabbani says: “We call abnormally high levels of MG ‘dicarbonyl stress‘. This occurs in some diseases – particularly diabetes, kidney dialysis, heart disease and obesity. We need sufficient Glo1 to keep MG low and keep us in good health.”

 

http://www.medicalnewstoday.com/releases/281827.php

 

Socioeconomic status and gender are associated with differences in cholesterol levels

Integrative LipidologyA long-term lifestyle study reports differences between the sexes when it comes to fat profiles associated with socioeconomic status. Research in the open access journal BMC Public Health breaks down factors associated with social class and finds surprising inequalities between men and women.

The researchers found that men in social classes (based on occupation) with manual jobs had lowercholesterol levels than their counterparts in non-manual social classes. In contrast, women’s LDL-cholesterol levels were more closely tied to their educational level than men.

The study highlights the health inequalities that exist between the social classes, and the researchers believe that future interventions should focus on men and women separately and explore the reasons for these differences, in order to promote better health.

Researchers from University of Cambridge performed a cross-sectional study as part of the European Prospective into Cancer involving 22451 participants aged 39-79 years old from the from Norfolk cohort in the UK. Each participant indicated what their alcohol consumption was and their BMI was calculated. Participants completed a survey that measured socioeconomic status using three factors: social class, education level, and the level of deprivation in the area they lived. This is the first time that socioeconomic status has been looked at assessingthese three factors independently. Blood samples were also taken to determine the following lipid levels: total cholesterol, HDL-cholesterol, triglycerides, and LDL-cholesterol.

Kay-Tee Khaw, lead researcher, says: “There is a well-recognised social gradient in cardiovascular disease. We were interested in trying to understand reasons for the observed socioeconomic inequalities in health. However, there are different measures of socioeconomic status including occupational class, educational status and residential deprivation, which may relate differently to different domains of health.”

Overall, women were found to have higher total cholesterol levels than men. In men, socioeconomic status was not initially associated with total cholesterol level, but after taking age into account, , men in manual social classes were found to have slightly lower total cholesterol than those in non-manual jobs. Women with a lower education level were found to have higher total cholesterol compared to others.

When the team looked at HDL-cholesterol levels – the ‘good’ cholesterol – they found that women had higher levels than men. Men with more education and from higher occupational classes were found to have higher levels of HDL-cholesterols, but this was not linked to the deprivation in their area. However, when the results are adjusted for alcohol consumption – which is higher in the non-manual occupation group – this association lost statistical significance.

For LDL-cholesterol – the ‘bad’ cholesterol – again women were found to have higher levels than men. Women without educational qualifications beyond the age of 15 had significantly higher LDL-cholesterol than those who did even when accounting for BMI and alcohol use. Occupational class and level of deprivation were not linked to LDL-cholesterol in women. No association was found between the three socioeconomic indices and LDL-cholesterol levels in men.

In the breakdown of the socioeconomic status factors, the researchers did not expect to see such differences in lipid levels in occupational social class of the women, especially as their social class was based on her partner’s occupational social class. They had expected this to be similar for men and women. They speculate that this may be because men in manual social classes may have more physical activity and no differences in body mass index compared to those in non-manual social classes, whereas women in manual social classes (defined by their partners’ occupation) may not have high physical activity and had higher mean body mass index compared to those in non-manual social classes. To address this limitation the team conducted a separate analysis based on the women’s own occupation and found similar results.

Kay-Tee Khaw says: “We observed sex differences in the lipid patterns according to social class and education. The association of some adverse lipid parameters with social class and in particular, educational status in women was much stronger than for men. If we wish to reduce health inequalities we need to understand the reason for these health inequalities. Future studies need to look at men and women separately and explore the reasons for these sex differences.”

http://www.medicalnewstoday.com/releases/281685.php

 

New culprit identified in metabolic syndrome

Integrative LipidologyA new study suggests uric acid may play a role in causing metabolic syndrome, a cluster of risk factors that increases the risk of heart disease and type 2 diabetes.

Uric acid is a normal waste product removed from the body by the kidneys and intestines and released in urine and stool. Elevated levels of uric acid are known to cause gout, an accumulation of the acid in the joints. High levels also are associated with the markers of metabolic syndrome, which is characterized by obesity,high blood pressure, elevated blood sugar and high cholesterol. But it has been unclear whether uric acid itself is causing damage or is simply a byproduct of other processes that lead to dysfunctional metabolism.

Published in Nature Communications, the new research at Washington University School of Medicine in St. Louis suggests excess uric acid in the blood is no innocent bystander. Rather, it appears to be a culprit in disrupting normal metabolism.

“Uric acid may play a direct, causative role in the development of metabolic syndrome,” said first author Brian J. DeBosch, MD, PhD, an instructor in pediatrics. “Our work showed that the gut is an important clearance mechanism for uric acid, opening the door to new potential therapies for preventing or treating type 2 diabetes and metabolic syndrome.”

Recent research by the paper’s senior author, Kelle H. Moley, MD, the James P. Crane Professor of Obstetrics and Gynecology, and her collaborators has shown that a protein called GLUT9 is an important transporter of uric acid.

DeBosch, a pediatric gastroenterologist who treats patients at St. Louis Children’s Hospital, studied mice to learn what happens when GLUT9 stops working in the gut, essentially blocking the body’s ability to remove uric acid from the intestine. In this study, the kidney’s ability to remove uric acid remained normal.

Eating regular chow, mice missing GLUT9 only in the gut quickly developed elevated uric acid in the blood and urine compared with control mice. And at only 6-8 weeks of age, they developed hallmarks of metabolic syndrome: high blood pressure, elevated cholesterol, high blood insulin and fatty liver deposits, among other symptoms.

The researchers also found that the drug allopurinol, which reduces uric acid production in the body and has long been used to treat gout, improved some, but not all, of the measures of metabolic health. Treatment with the drug lowered blood pressure and total cholesterol levels.

Exposure to uric acid is impossible to avoid because it is a normal byproduct of cell turnover in the body. But there is evidence that diet may contribute to uric acid levels. Many foods contain compounds called purines that break down into uric acid. And adding to growing concerns about fructose in the diet, evidence suggests that fructose metabolism in the liver also drives uric acid production.

“Switching so heavily to fructose in foods over the past 30 years has been devastating,” Moley said. “There’s a growing feeling that uric acid is a cause, not a consequence, of metabolic syndrome. And now we know fructose directly makes uric acid in the liver. With that in mind, we are doing further research to study what happens to these mice on a high-fructose diet.”

http://www.medicalnewstoday.com/releases/280853.php

 

 

Niacin for cholesterol now linked to death risk, dangerous side effects and no benefits

Integrative LipidologyAfter 50 years of being a mainstay cholesterol therapy, niacin should no longer be prescribed for most patients due to potential increased risk of death, dangerous side effects and no benefit in reducing heart attacks and strokes, writes Northwestern Medicine® preventive cardiologist Donald Lloyd-Jones, M.D., in a New England Journal of Medicine editorial.

Lloyd-Jones’s editorial is based on a large new study published in the journal that looked at adults, ages 50 to 80, with cardiovascular disease who took extended-release niacin (vitamin B3) and laropiprant (a drug that reduces face flushing caused by high doses of niacin) to see if it reduced heart attack and stroke compared to a placebo over four years. All patients in the trial were already being treated with a statin medication.

Niacin did not reduce heart attacks and stroke rates compared with a placebo. More concerning, niacin was associated with an increased trend toward death from all causes as well as significant increases in serious side effects: liver problems, excess infections, excess bleeding, gout, loss of control of blood sugar for diabetics and the development of diabetes in people who didn’t have it when the study began.

“There might be one excess death for every 200 people we put on niacin,” said Lloyd-Jones, chair of preventive medicine at Northwestern University Feinberg School of Medicine and Northwestern Memorial Hospital. “With that kind of signal, this is an unacceptable therapy for the vast majority of patients.”

“For the reduction of heart disease and stroke risk, statins remain the most important drug-based strategy by far because of their demonstrated benefit and their good safety profile,” said Lloyd-Jones, who was a member of the task force that rewrote cholesterol treatment guidelines in 2013 for the American College of Cardiology and the American Heart Association.

Niacin should be reserved only for patients at very high risk for a heart attack and stroke who can’t take statins and for whom there are no other evidence-based options, Lloyd-Jones said.

Niacin raises “good” HDL (high density lipoprotein) cholesterol levels, and having high HDL levels means a lowered risk for cardiovascular events. But clinical trials have not shown that niacin reduced the risk ofcoronary heart disease or the broader cardiovascular disease specifically by raising HDL. Niacin also produces a modest reduction in low-density lipoprotein (LDL cholesterol) and a more substantial reduction in triglyceride levels, which might be expected to lower the risk of coronary heart disease, Lloyd-Jones notes in the article.

But the new study suggests that higher HDL levels only are a sign of lowered risk for heart attacks and stroke. Raising HDL levels with niacin does not appear to impact cardiovascular outcomes nor does lowering triglyceride levels, Lloyd-Jones points out.

“The recent niacin clinical trials offer important new evidence that raising ‘good’ cholesterol (HDL) levels on top of statin therapy does not have the positive outcome that had been hoped for,” said Neil Stone, M.D., the Robert Bonow MD Professor in Cardiology at Feinberg and a cardiologist at Northwestern Memorial Hospital. “Lowering ‘bad’ cholesterol (LDL) with an optimal intensity of tolerated statins and adherence to healthy lifestyle changes remains the most effective approach to prevent strokes and heart attacks for patients at risk of cardiovascular disease.”

http://www.medicalnewstoday.com/releases/279734.php

 

Heart disease a greatly increased risk for obese young Hispanics

LipidologyObesity is common among U.S. Hispanics and is severe particularly among young Hispanics, according to research in the Journal of the American Heart Association (JAHA).

The first large-scale data on body mass index (BMI) and cardiovascular disease risk factors among U.S. Hispanic/Latino adult populations suggests that severe obesity may be associated with considerable excess risk for cardiovascular diseases.

For U.S. Hispanics, the obesity epidemic “is unprecedented and getting worse,” said Robert Kaplan, Ph.D., lead author, and professor of epidemiology and population health at Albert Einstein College of Medicine in New York City. “Because young adults with obesity are likely to be sicker as they age, and have higher healthcare costs, we should be investing heavily in obesity research and prevention, as if our nation’s future depended upon it.”

Researchers reviewed data from a study of 16,344 people of diverse Hispanic origin in four U.S. cities (Bronx, Chicago, Miami and San Diego). Men were average age 40 and women were average age 41. People with Mexican roots were the largest group (about 37 percent of subjects), followed by those with Cuban (20 percent) and Puerto Rican (16 percent) backgrounds.

They found:

  • Overall 18 percent of women in the study and 12 percent of the men had levels of obesity that signal special concern about health risks, as defined by having a BMI above 35 (BMI is calculated based on height and weight).
  • The most severe class of obesity, (BMI greater than 40, or for a person 5′ 5″ tall, body weight over 240 pounds) was most common among young adults between 25 and 34 years of age, affecting one in twenty men and almost one in ten women in this age group.
  • More than half of the severely obese people had unhealthy levels of HDL cholesterol, the “good” cholesterol, and of inflammation, as measured by a marker called C-reactive protein.
  • About 40 percent had high blood pressure, and more than a quarter had diabetes. Kaplan/2

“This is a heavy burden being carried by young people who should be in the prime of life,” he said. “Young people, and especially men – who had the highest degree of future cardiovascular disease risk factors in our study – are the very individuals who tend to neglect the need to get regular checkups, adopt healthy lifestyle behaviors, and seek the help of healthcare providers.”

Yet compared with the women, high blood pressure and diabetes, both risk factors for heart disease andstroke, appeared to be more tightly linked with severe obesity among men.

The findings for younger Hispanic adults, who are in their child-bearing and child-rearing years, suggest to Kaplan that healthcare providers should take a holistic, family approach to weight management. A host of biological and societal factors that affect parents’ weight could also affect their children, he said.

http://www.medicalnewstoday.com/releases/279406.php

 

Periodic fasting ‘may protect against diabetes in at-risk groups’

At the 2014 American Diabetes Association Scientific Sessions in San Francisco, CA, researchers present new findings on how diabetes risk in prediabetics may be combated by periodic fasting.

LipidologyIn people who have prediabetes, the amount of glucose in the blood is higher than normal but is not high enough to be classed as diabetes.

In 2011, researchers at the Intermountain Heart Institute at Intermountain Medical Center in Murray, UT, investigated how glucose levels and weight were effected by 1 day of water-only fasting in healthy people.

“When we studied the effects of fasting in apparently healthy people, cholesterol levels increased during the one-time 24-hour fast,” says Benjamin Horne, PhD, director of cardiovascular and genetic epidemiology at the Intermountain Medical Center Heart Institute and lead researcher on the new study.

 

“The changes that were most interesting or unexpected were all related to metabolic health and diabetes risk,” he adds.

“Together with our prior studies that showed decades of routine fasting was associated with a lower risk of diabetes and coronary artery disease, this led us to think that fasting is most impactful for reducing the risk of diabetes and related metabolic problems.”

Consequently, Dr. Horne and team began investigating the effects of fasting in prediabetics. Although Medical News Today does not have details on the number of participants included in the new study, the team has revealed that participants were between the ages of 30 and 69, and each subject also had at least three metabolic risk factors, such as:

  • A large waistline
  • A high triglyceride level
  • A low HDL cholesterol level
  • High blood pressure
  • High fasting blood sugar.

Body ‘feasts’ on bad cholesterol in fat cells, negating insulin resistance effects

The researchers found that during fasting days, the participants’ cholesterol went up slightly, as it had done in the previous study of healthy people. However, over a 6-week period, the cholesterol levels of the prediabetic participants actually decreased by about 12%.

“Because we expect that the cholesterol was used for energy during the fasting episodes and likely came from fat cells,” says Dr. Horne, “this leads us to believe fasting may be an effective diabetes intervention.”

After 10-12 hours of fasting, the body begins to scavenge other sources of energy throughout the body in order to sustain itself. The benefit to prediabetics, Dr. Horne’s team believes, is that because the body feasts on the LDL (or “bad”) cholesterol in fat cells it negates the effect of insulin resistance.

Insulin resistance is when insulin production becomes so high that the pancreas can no longer produce the body’s required levels of insulin, which causes blood sugar to rise.

“The fat cells themselves are a major contributor to insulin resistance, which can lead to diabetes,” Dr. Horne explains. “Because fasting may help to eliminate and break down fat cells, insulin resistance may be frustrated by fasting.”

Although fasting may protect against diabetes, Dr. Horne reminds that it is important to keep in mind that fasting did not achieve overnight results. He adds that more in-depth study is needed to define what the optimum length and frequency of fasting should be in prediabetics.

“Fasting has the potential to become an important diabetes intervention,” he says. “Though we’ve studied fasting and its health benefits for years, we didn’t know why fasting could provide the health benefits we observed related to the risk of diabetes.”

Recently, Medical News Today reported on a study conducted by the University of Southern California in Los Angeles that suggested prolonged fasting may “reboot” the immune system – protecting against the toxic effects of chemotherapy and triggering stem cell regeneration of new immune cells, as well as clearing out old and damaged cells.

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http://www.medicalnewstoday.com/articles/278264.php