Chemists Develop Foolproof New Test to Track the Fats We Eat

Michelle Donovan wrote . . . . . . . . .

A team of researchers at McMaster has developed a reliable and accurate blood test to track individual fat intake, a tool that could guide public health policy on healthy eating.

Establishing reliable guidelines has been a significant challenge for nutritional epidemiologists until now, because they have to rely on study participants faithfully recording their own consumption, creating results that are prone to human error and selective reporting, particularly when in the case of high-fat diets.

For the study, published in the Journal of Lipid Research, chemists developed a test, which detects specific non-esterified fatty acids (NEFAs), a type of circulating free fatty acid that can be measured using a small volume of blood sample.

“Epidemiologists need better ways to reliably assess dietary intake when developing nutritional recommendations,” says Philip Britz-McKibbin, professor in the Department of Chemistry & Chemical Biology at McMaster and lead author of the study

“The food we consume is highly complex and difficult to measure when relying on self-reporting or memory recall, particularly in the case of dietary fats. There are thousands of chemicals that we are exposed to in foods, both processed and natural,” he says.

The study was a combination of two research projects Britz-McKibbin conducted with Sonia Anand in the Department of Medicine and Stuart Phillips in the Department of Kinesiology.

Researchers first assessed the habitual diet of pregnant women in their second trimester, an important development stage for the fetus. The women, some of whom were taking omega-3 fish oil supplements, were asked to report on their average consumption of oily fish and full-fat dairy and were then tested with the new technology. Their study also monitored changes in omega-3 NEFAs in women following high-dose omega-3 fish oil supplementation as compared to a placebo.

Researchers were able to prove that certain blood NEFAs closely matched the diets and/or supplements the women had reported, suggesting the dietary biomarkers may serve as an objective tool for assessment of fat intake.

“Fat intake is among the most controversial aspects of nutritional public health policies given previously flawed low-fat diet recommendations, and the growing popularity of low-carb/high-fat ketogenic based diets,” says Britz-McKibbin.

“If we can measure it reliably, we can begin to study such questions as: Should pregnant women take fish oil? Are women deficient in certain dietary fats? Does a certain diet or supplement lead to better health outcomes for their babies?”

Researchers plan to study what impact NEFAs and other metabolites associated with dietary exposures during pregnancy, might have on childhood health outcomes in relation to the obesity, metabolic syndrome and chronic disease risk later in life.

Source: Brighter World

Western Diet Rich in Fat and Sugar Linked to Skin Inflammation

A Western diet rich in fat and sugar may lead to inflammatory skin diseases such as psoriasis, a study by UC Davis Health researchers has found.

The study, published today in Journal of Investigative Dermatology, suggests that dietary components, rather than obesity itself, may lead to skin inflammation and the development of psoriasis. A common and chronic skin disease, psoriasis causes skin cells to form scales and red patches that are itchy and sometimes painful.

Diet and Skin Inflammation

Previous studies have shown that obesity is a risk factor for the development or worsening of psoriasis. The Western diet, characterized by a high dietary intake of saturated fats and sucrose and low intake of fiber, has been linked to the increased prevalence of obesity in the world.

“In our study, we found that short-term exposure to Western diet is able to induce psoriasis before significant body weight gain,” said Sam T. Hwang, professor and chair of dermatology at UC Davis and senior author on the study.

For the UC Davis Health study, which used a mouse model, Hwang and his colleagues found that a diet containing both high fat and high sugar (mimicking the Western diet in humans) was required to induce observable skin inflammation. In four weeks only, mice on Western diet had significantly increased ear swelling and visible dermatitis compared to mice fed a controlled diet and those on high fat diet alone.

“Eating an unhealthy diet does not affect your waistline alone, but your skin immunity too,” said Zhenrui Shi, visiting assistant researcher in UC Davis Department of Dermatology and lead author on the study.

Bile Acids and Skin Inflammation

The study detailed the mechanisms by which inflammation happens following a Western diet. It identified bile acids as key signaling molecules in the regulation of skin immunity. Bile acids are produced in the liver from cholesterol and metabolized in the intestine by the gut microbiota. They play an important role in dietary lipid absorption and cholesterol balance in the blood.

The study found that cholestyramine, a drug used to lower cholesterol levels by binding to bile acids in the intestine, helped reduce the risk of skin inflammation. The finding suggests that bile acids mediate the development of psoriasis. The binding of cholestyramine to bile acids in the gut and its subsequent release through the stool allows for lowering of skin inflammation.

Further studies are needed to understand the mechanism behind diet-induced skin inflammation and the interaction between metabolism, microbes and immunity.

Source: UC Davis

Study: Fat Accumulates in the Lungs of Overweight and Obese People

Researchers have shown for the first time that fatty tissue accumulates in the airway walls, particularly in people who are overweight or obese.

Scientists already know that people who are overweight or obese are more likely to suffer with wheezing and asthma, but the reasons for this have not been completely explained.

The new study, published in the European Respiratory Journal, suggests that this fatty tissue alters the structure of people’s airways and this could be one reason behind the increased risk of asthma.

The study’s author is Mr John Elliot, a senior research officer at Sir Charles Gairdner Hospital in Perth, Western Australia. He said: “Our research team studies the structure of the airways within our lungs and how these are altered in people with respiratory disease.

“Looking at samples of lung, we spotted fatty tissue that had built up in the airway walls. We wanted to see if this accumulation was correlated with body weight.”

The researchers examined post-mortem samples of lung that had been donated for research and stored in the Airway Tissue Biobank. They studied samples from 52 people, including 15 who had no reported asthma, 21 who had asthma but died of other causes and 16 who died of asthma.

Using dyes to help visualise the structures of 1373 airways under a microscope, they identified and quantified any fatty tissue present. They compared this data with each person’s body mass index (BMI).

For the first time, the study showed that fatty tissue accumulates in the walls of the airways. The analysis revealed that the amount of fat present increases in line with increasing BMI. The research also suggests that this increase in fat alters the normal structure of the airways and leads to inflammation in the lungs.

Co-author, Dr Peter Noble, an associate professor at the University of Western Australia in Perth said: “Being overweight or obese has already been linked to having asthma or having worse asthma symptoms. Researchers have suggested that the link might be explained by the direct pressure of excess weight on the lungs or by a general increase in inflammation created by excess weight.

“This study suggests that another mechanism is also at play. We’ve found that excess fat accumulates in the airway walls where it takes up space and seems to increase inflammation within the lungs. We think this is causing a thickening of the airways that limits the flow of air in and out of the lungs, and that could at least partly explain an increase in asthma symptoms.”

The team are looking for new ways to study and measure fatty tissue in the lungs. They want to confirm the relationship with respiratory disease and to find out whether the effect can be reversed by weight loss therapy.

Professor Thierry Troosters is President of the European Respiratory Society and was not involved in the study. He said: “This is an important finding on the relationship between body weight and respiratory disease because it shows how being overweight or obese might be making symptoms worse for people with asthma. This goes beyond the simple observation that patients with obesity need to breathe more with activity and exercise hence adding to their ventilatory burden. The observation points at true airway changes that are associated with obesity.

“We need to investigate this finding in more detail and particularly whether this phenomenon can be reversed with weight loss. In the meantime, we should support asthma patients to help them achieve or maintain a healthy weight.”

Source: European Respiratory Society

Drinking Soda While Eating Burger Is Especially Fattening

Dennis Thompson wrote . . . . . .

Combining a sugary soda with your burger or fried chicken can really prime your body to pack on more pounds, a new study suggests.

Folks who had a sweetened drink with a high-protein meal stored more unused fat, compared to others who ate the same food with a sugar-free beverage, laboratory tests revealed.

Their bodies did not burn about a third of the additional calories provided by the sugary drink, researchers found.

The participants also burned less fat from their food, and it took less energy overall to digest the meal.

“If we are adding extra carbohydrates on top of what’s already in a meal, that will definitely have an effect on the body being able to use fat as an energy source, and it will more than likely go into energy storage,” said lead researcher Shanon Casperson. She’s a research biologist with the U.S. Department of Agriculture.

Sodas, sweetened coffee and iced tea drinks, fruit drinks, energy beverages and the like are leading sources of added sugar in the American diet, according to the U.S. Centers for Disease Control and Prevention. Six in 10 kids and half of adults drink at least one sugary beverage each day.

Food contains three major types of nutrients — carbohydrates, fats and protein. Casperson and her team wanted to see how extra carbs in the form of a sugary drink would affect metabolism of fats and proteins.

For the study, 27 healthy-weight adults were placed in a sealed “metabolic room” that carefully tracked how much oxygen was inhaled and carbon dioxide was exhaled, Casperson said. Urine samples were also collected.

“With those three variables, we are able to calculate the amount of nutrients they use” as well as the calories they burn every minute, Casperson said.

Participants spent two full days in the sealed room. On one day they ate two meals containing 15 percent protein, and on the other they ate two meals with 30 percent protein. The meals consisted of bread, ham, cheese, potatoes and butter, and each provided 17 grams of fat and 500 calories.

Each day, the participants had a sugary cherry-flavored drink with one meal and a sugar-free cherry drink with the other meal, Casperson said.

The sugar-sweetened drink decreased fat oxidation — the process that kick-starts the breakdown of fat molecules — by 8 percent, the researchers discovered.

Also, the sweetened drink consumed with a 15 percent protein meal decreased fat oxidation by an average 7.2 grams, while the same sugary drink with a 30 percent protein meal decreased fat oxidation by 12.6 grams.

The researchers think the extra load of carbohydrates in a soda might reduce the body’s need to process dietary fat for energy, since fat is more difficult to burn than sugar.

“It’s easier for the body to use carbohydrates as an energy source,” Casperson said. “When you provide the body with carbohydrates, it’s going to use that first.” Unburned fat then winds up deposited somewhere in a person’s body, such as the belly or hips.

The study provides much-needed nuance to the understanding of fast-food nutrition, said Erika Renick. She’s a bariatric dietitian with the Comprehensive Weight Loss Center at Staten Island University Hospital in New York City.

“While this was a small sample size, the study backs up what recent research has been pointing to — that adding protein to meals helps to keep us full and that sugary drinks can influence our food cravings,” Renick said.

“However, this study takes it a step further by suggesting that pairing sugar-sweetened drinks with protein-rich meals can encourage weight gain more than we originally understood,” Renick continued.

“This specific combination seems to decrease how well our bodies burn fat,” she said. “More research would need to be done, but steering people away from this combination could potentially be another tool when counseling people on weight management.”

Casperson isn’t sure why adding extra protein to a meal seemed to affect the reduction in fat burning. “That’s something we need to look at in future research,” she said.

The study appears in the journal BMC Nutrition.

Source: HealthDay


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Replacing Saturated Fat with Healthier Fat May Lower Cholesterol in Healthy Diet

The American Heart Association continues to recommend replacing saturated fats with poly- and mono-unsaturated vegetable oil to help prevent heart disease, according to a new American Heart Association advisory, published in the association’s journal Circulation.

Periodically, the evidence supporting limiting saturated fats has been questioned in scientific literature and the popular press. This advisory was commissioned to review the current evidence and explain the scientific framework behind the American Heart Association’s long-standing recommendation to limit foods high in saturated fats.

“We want to set the record straight on why well-conducted scientific research overwhelmingly supports limiting saturated fat in the diet to prevent diseases of the heart and blood vessels,” said Frank Sacks, M.D., lead author of the advisory and professor of Cardiovascular Disease Prevention at the Harvard T.H. Chan School of Public Health in Boston, Massachusetts. “Saturated fat increases LDL – bad cholesterol – which is a major cause of artery-clogging plaque and cardiovascular disease.”

Saturated fats are found in meat, full-fat dairy products and tropical oils such as coconut, palm and others. Other types of fats include poly-unsaturated fats, found in corn, soybean, peanut and other oils, and mono-unsaturated fats, found in olive, canola, safflower, avocado and other oils. The advisory reports that:

  • Randomized controlled trials that lowered intake of dietary saturated fat and replaced it with polyunsaturated vegetable oil reduced cardiovascular disease by approximately 30 percent –similar to that achieved by cholesterol-lowering drugs, known as statins.
  • Prospective observational studies in many populations showed that lower intake of saturated fat coupled with higher intake of polyunsaturated and monounsaturated fat is associated with lower rates of cardiovascular disease.
  • Several studies found that coconut oil – which is predominantly saturated fat and widely touted as healthy – raised LDL cholesterol in the same way as other saturated fats found in butter, beef fat and palm oil.
  • Replacement of saturated fat with mostly refined carbohydrate and sugars is not associated with lower rates of CVD.

“A healthy diet doesn’t just limit certain unfavorable nutrients, such as saturated fats, that can increase the risk of heart attacks, strokes and other blood vessel diseases. It should also focus on healthy foods rich in nutrients that can help reduce disease risk, like poly- and mono-unsaturated vegetable oils, nuts, fruits, vegetables, whole grains, fish and others,” Sacks said.

Examples of healthy dietary patterns include the Dietary Approaches To Stop Hypertension (DASH) diet and a Mediterranean-style diet, both of which emphasize unsaturated vegetable oils, nuts, fruits, vegetables, low-fat dairy products, whole grains, fish and poultry and limits red meat, as well as foods and drinks high in added sugars and salt.

Source: American Heart Association


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