The study is also interesting because it helps explain human studies showing that people who incorporate medium chain ‘fatty acids’, such as those found in coconut oil, into their diets can lose body fat.

Dr Nigel Turner and Associate Professor Jiming Ye, from Sydney’s Garvan Institute of Medical Research, compared fat metabolism and insulin resistance in mice fed coconut oil and lard based diets. Their findings are now published online in the international journal Diabetes.

“The medium chain fatty acids, like those found in coconut oil, are interesting to us because they behave very differently to the fats normally found in our diets,” said study leader Nigel Turner.

“Unlike the long chain fatty acids contained in animal fats, medium chain fatty acids are small enough to enter mitochondria – the cells’ energy burning powerhouses – directly, where they can then be converted to energy.”

“Unfortunately the downside to eating medium chain fatty acids is that they can lead to fat build up in the liver, an important fact to be taken into consideration by anyone considering using them as a weight loss therapy.”

Fat storage is determined by the balance between how much fat is taken in by cells and how much of this fat is burned for energy. When people eat a high fat diet, their bodies attempt to compensate by increasing their capacity to oxidise fat. The medium chain fatty acid (coconut oil) diet was more effective at increasing the oxidative capacity of muscle than the long chain fatty acid (lard) diet leading to less fat storage in muscle and better insulin action.

According to Turner, the lard-based diet used in this research is similar to the diet eaten by people in the Western world. “Its fatty acid composition is about 40% saturated fats, 40% monounsaturated fats and 20% polyunsaturated fats, of which the vast proportion is omega-6, rather than omega-3,” he said.

“Obese humans usually eat 40-50% of their calories as fat. Our mice were fed 45% of their calories as fat.”

“No high fat diet is good, and the normal dietary combination of long chain fats leads to an overload that our bodies can’t cope with. Therefore high consumption of common dietary fats is contributing directly towards the global escalation of obesity and Type 2 diabetes.”

“If someone is trying to prevent weight gain, we can see they may benefit from substituting oils containing medium chain fatty acids for other oils in their diet, as long as consideration is given to the potential problem of excess fat in the liver. Other natural dietary alternatives, such as fish oil, might be helpful because the fatty acids in fish oil are thought to exert a lot of their beneficial effects through improving fat oxidation in the liver.”

Source
Garvan Institute of Medical Research

More importantly, according to two new studies led by a University of Utah human geneticist, fruit flies use the same molecular mechanisms as humans to help maintain proper balances of cholesterol and a key form of stored fat that contributes to obesity. The findings mean that as researchers try to learn more about the genetic and biological processes through which people regulate cholesterol and fat metabolism, the humble fruit fly, also called Drosophila, can teach humans much about themselves.

“Not a lot is known about these regulatory mechanisms in people,” says Carl S. Thummel, Ph.D., professor of human genetics at the U of U School of Medicine and senior author on the two studies. “But we can learn a lot by studying metabolic control in fruit flies and apply what we learn to humans.”

High cholesterol and obesity, which affects an estimated 25 percent to 30 percent of the U.S. population, are linked to heart disease, diabetes, and other diseases that take huge tolls on health and add billions of dollars to the nation’s medical bills. Understanding the processes that regulate cholesterol and fat in humans could be critical for addressing those health risks in people, Thummel believes.

The two studies identify a nuclear receptor, DHR96, which plays a critical role in regulating the balance or homeostasis of cholesterol and another fat molecule called triacylglycerol (TAG). Nuclear receptors are proteins that sense the presence of chemical compounds within cells. DHR96 corresponds closely to a nuclear receptor in humans, called LXR, that is known to regulate cholesterol levels.

In a study published Dec. 2 in Genes & Development, Thummel and colleagues at the U of U and two Canadian universities show that DHR96 helps regulate cholesterol in fruit flies by binding with this compound. When this binding occurs, it allows DNA to be read, which switches genes on and off that help maintain proper levels of cholesterol, according to Thummel, who also holds an H.A. and Edna Benning Presidential Endowed Chair in Human Genetics.

The researchers used a technique developed by University of Utah biologist Kent Golic, Ph.D., in which they silenced or disabled the DHR96 protein so it couldn’t function in fruit flies. They then grew flies in which DHR96 was silenced. Depending on what the fruit flies were fed, lean or fat diets, they had either too little or too much cholesterol. Flies fed too little cholesterol died, while those with too much developed hypercholesterolemia or chronically excessive cholesterol levels. At the same time, flies in which DHR96 functioned normally maintained a proper level of cholesterol.

“When they lacked the DHR96 receptor, the flies were unable to maintain cholesterol homeostasis,” Thummel says. “This is similar to what happens in humans who have high cholesterol levels.”

Fruit flies are good for such research insights in large part because of the insects’ short life span – about 30 days – meaning their development and biological processes are more easily observed than in other, longer-lived models, such as mice. Fruit flies also are easy to manipulate genetically and are less expensive to study compared to mice or other models, according to Thummel. In addition, the mechanisms by which metabolism is controlled in fruit flies are very similar to those in mice or humans.

“We can do a lot more mechanistic studies in a fly than are possible in a mouse,” he says. “We can study metabolic pathways faster and more in-depth.”

Along with its important role in helping to maintain proper levels of cholesterol, DHR96 also plays an integral part in regulating dietary fat metabolism, Thummel and another U of U researcher report in a Dec. 2 study in Cell Metabolism.

In flies in which DHR96 was silenced, TAG levels were markedly reduced in the intestine, making the insects resistant to diet-induced obesity. But when DHR96 was overexpressed, meaning there were higher levels of the protein, it led to increased TAG levels and made the flies more prone to being overweight. These findings show that DHR96 is required for breaking down dietary fat in the intestine of fruit flies and provide insight into how dietary fat metabolism is regulated in Drosophila.

“This nuclear receptor plays a major role in sensing and regulating cholesterol and TAG uptake in the intestine in fruit flies,” Thummel says. “It functions similarly to the way LXR functions in humans, although we have a relatively poor understanding about how LXR controls these pathways.”

In his future studies, Thummel intends to learn more about how DHR96 regulates metabolism by studying the functions of the genes that it controls.

Source: Phil Sahm
University of Utah Health Sciences

According to Australia’s peak nutrition body, the Dietitians Association of Australia (DAA), more Australians eat pastries, cakes and chocolates, and less eat fruit, during the colder months1. Australia’s last national nutrition survey found more than 70 per cent of Australian adults indulge in less nutritious ‘cereal-based’ foods during the winter months1. Such foods included pizza, cakes, pastries, battered food, commercial hamburgers and biscuits.

But dietitians say choosing the right ‘comfort’ foods during winter can help you stay healthy and happy all year round.

DAA Spokesperson Lisa Renn said: ‘On short, cool days, it’s tempting to reach for fatty and sugary comfort foods. But any boost from these foods is usually short lived, so you end up with less energy – and more weight in the long term’.

Ms Renn, an Accredited Practising Dietitian, said the right comfort foods are lower in sugar, fat and kilojoules (energy). ‘Try nourishing foods like porridge with reduced-fat milk and fruit, chunky vegetable and lentil soups, and slow-cooked casseroles made with lean meat and vegetables like potato and carrot,’ said Ms Renn. She also recommends eating healthy, low glycaemic index (GI) foods for sustained energy, and maintaining regular physical activity to boost energy levels.

Try these tips from the DAA to stay energised this winter:

- Cook healthy soups and casseroles in bulk and freeze in meal-sized containers for a quick meal.
- Piping hot drinks can be a great way to stay warm. Use reduced-fat milk and limit added sugar.
- Keep up a regular exercise routine over winter. Rug up when heading outdoors and have bad weather options to fall back on, such as an exercise DVD.
- Warm up with a chunky vegetable soup and crusty wholegrain bread roll.
- Try a baked apple with reduced-fat custard for a healthy dessert.
- Curries or hearty casseroles make a tasty meal on cold winter nights. Choose lean cuts of meat and experiment with different vegetables.
- Baked potatoes are a great winter idea. Try topping potatoes with sliced mushrooms, reduced-fat cheese and chives.

1National Nutrition Survey, 1995 ABS catalogue number 4805.0. (Based on the period March to August, compared with other times throughout the year).

Source
Dietitians Association of Australia (DAA)

A research article published on November 14, 2009 in the World Journal of Gastroenterology describes the responses of 26 ED patients to F-S provocation. The research team, including Professors Kellow, Abraham and Hansen from the University of Sydney, Australia, monitored gastrointestinal symptoms and breath hydrogen concentration (a marker of small bowel absorption) for 3 h following ingestion of 50 g glucose on one day, and 25 g fructose/5 g sorbitol on the next day. Responses to F-S were compared to those of 20 asymptomatic healthy females.

F-S provoked gastrointestinal symptoms in 15 ED patients but only in one healthy control. In contrast, only one ED patient displayed symptom provocation to glucose, which does not usually provoke gastrointestinal symptoms; this shows specificity of the F-S response. A greater symptom response was observed in the most underweight ED patients (BMI ≤ 17.5 kg/m2) compared to those with a BMI >17.5 kg/m2. There were no differences in psychological scores, prevalence of functional gastrointestinal disorders or breath hydrogen responses between patients with and without an F-S response.

The key findings of this study are that F-S provoked gastrointestinal symptoms in more than half of the female ED patients, a significantly greater proportion than that found in healthy individuals; the response was specific for F-S ingestion; and there was a greater symptom response in patients at lower BMI values. Consistent with this last finding, symptom provocation was more common in anorexia nervosa patients. Hence negative energy balance appears to play a role in F-S sensitivity in these patients. As fructose and sorbitol are likely to be commonly ingested by ED patients, representing a potential source of gastrointestinal distress that would impact negatively on their nutritional management, F-S provocative testing could prove valuable in identifying those patients with symptom sensitivity to these substances.

Reference: Friesen N, Hansen RD, Abraham SF, Kellow JE. Fructosesorbitol ingestion provokes gastrointestinal symptoms in patients with eating disorders. World J Gastroenterol 2009; 15(42): 5295-5299 http://www.wjgnet.com/1007-9327/15/5295.asp

Source: Jin-Lei Wang
World Journal of Gastroenterology

Selenium is a trace essential mineral with anti-oxidant properties. The body naturally absorbs selenium from foods such as vegetables, meat and seafood. However, when the balance is altered and the body absorbs too much selenium, such as through taking selenium supplements, it can have adverse affects.

A team led by Dr Saverio Stranges at the University’s Warwick Medical School has found high levels of selenium are associated with increased cholesterol, which can cause heart disease.

In a paper recently published in the Journal of Nutrition, the research team examined the association of plasma selenium concentrations (levels of selenium in the blood) with blood lipids (fats in the blood).

The researchers found in those participants with higher plasma selenium (more than 1.20 µmol/L) there was an average total cholesterol level increase of 8% (0.39 mmol/L (i.e. 15.1 mg/dL). Researchers also noted a 10% increase in non-HDL cholesterol levels (lipoproteins within your total cholesterol that can help predict the risk of someone suffering a heart attack or chest pain). Also, of the participants with the highest selenium levels, 48.2% admitted they regularly took dietary supplements.

The study was conducted among 1042 participants aged 19-64 in the 2000-2001 UK National Diet and Nutrition Survey. All participants were interviewed face-to-face to assess lifestyle factors such as diet and drinking habits. Blood samples were then taken for analysis.

Dr Saverio Stranges said although high selenium levels were not exclusively caused by people taking dietary supplements, the results of the study were concerning because the use of selenium dietary supplements had risen considerably in the UK in recent years. He said this was largely due to the perception that selenium can reduce the risk of cancer and other diseases.

He said: “This use has spread despite a lack of definitive evidence on selenium supplements efficacy for cancer and other chronic disease prevention. The cholesterol increases we have identified may have important implications for public health. In fact, such a difference could translate into a large number of premature deaths from coronary heart disease.

“We believe that the widespread use of selenium supplements, or of any other strategy that artificially increases selenium status above the level required is unwarranted at the present time. Further research is needed to examine the full range of health effects of increased selenium, whether beneficial or detrimental.”

Source: Kelly Parkes-Harrison
University of Warwick

Half of women fit into two other categories, the study says, and were found to be the least likely to be leaning toward fat. Both types of women in those groups are concerned about nutrition and like to eat healthy.

“The basic attitude that people have about food is related to the likelihood that they’re at risk for obesity and weight gain,” said researcher Dennis Degeneffe, a study co-author.

The study, which appears in the December issue of the journal Health Education & Behavior, placed 200 women into five groups based on their attitudes about food. The women had an average age of 46, were well-educated (two-thirds had a four-year degree or higher) and 86 percent were white.

The researchers then compared the groups of women by measurements such as percentage of body fat, waist size and body mass index (BMI).

Those deemed to be “concerned about nutrition” (determined to eat well) and “creative cooks” (focused on food for their families) scored the lowest in the weight categories. “Impulsive eaters” and “guilt-ridden dieters” scored the highest, with “busy cooking avoiders” in the middle.

“Women in the middle group tend to lead busy lifestyles and are often preoccupied with other activities and responsibilities, with eating generally taking a back seat,” said Degeneffe, a research fellow at the University of Minnesota’s Food Industry Center.

Cynthia Sass, a registered dietitian and author in New York City, said the categories defined in the study “truly parallel what I see with my clients and women I talk to regarding how food and nutrition fit into their lives.”

“I have found that women who have a big responsibility to take care of their families appear to do less well at taking care of themselves, food-wise,” she said. In some cases, she said, food helps them to feel rewarded and cope with their lives.

She urges them to focus on their own needs “because taking better care of themselves will help them have the physical and emotional wellness they need to continue taking care of their families.”

Treating these kinds of women can be tough, said Lona Sandon, an assistant professor at the University of Texas Southwestern and national spokesperson for the American Dietetic Association. “Health and nutrition may be important to them, but convenience often wins,” she said. “It is very challenging to come up with solutions to help these women lose weight if they are not willing or able to give up something else in their life.”

Health Education & Behavior, a peer-reviewed journal of the Society for Public Health Education (SOPHE), publishes research on critical health issues for professionals in the implementation and administration of public health information programs. For information, contact Laura Drouillard at (202) 408-9804.

Sudo, N, et al. Relationship between attitudes and indicators of obesity for midlife women. Health Education & Behavior 36(6), 2009.

Source: Health Behavior News Service

The research team studied a group of 13,475 women from the Nurses’ Health Study II. During 10 years of follow-up, 860 incident GDM cases were identified. After adjustment for known risk factors for GDM including age, family history of diabetes, parity, physical activity, smoking status, sugar-sweetened beverage intake, alcohol intake, prepregnancy BMI, and Western dietary pattern, intake of sugar-sweetened cola was positively associated with the risk of GDM. No significant association was found for other sugar-sweetened beverages or diet beverages.

“Compared with women who consumed less than 1 serving per month, those who consumed more than 5 servings per week of sugar-sweetened cola had a 22% greater GDM risk,” notes Dr. Chen.

Gestational diabetes mellitus (GDM), defined as glucose intolerance beginning during pregnancy, is one of the most common pregnancy complications. Women with GDM are at increased risk for complications and illness during pregnancy and delivery, as well as post-pregnancy type 2 diabetes. Children of mothers with GDM are at increased risk for obesity, glucose intolerance, and early onset diabetes.

Although the underlying mechanism remains unclear, available evidence suggests that the main defect in the development of GDM is relatively diminished insulin secretion coupled with pregnancy-induced insulin resistance. The researchers discuss a number of explanations of their findings. Consuming a large amount of sugar-sweetened beverages could contribute to a high glycemic load (GL) by providing a large amount of rapidly absorbable sugars. High-GL foods induce a greater plasma glucose response after eating which can result in insulin resistance and impaired beta cell function. (Pancreatic beta cells make insulin.) In addition, higher sugar intake itself may lead to impaired pancreatic cell function.

“We don’t know why significant association was only found in sugar-sweetened cola, but not other types of sugar-sweetened beverages – fruit drinks, other soft drinks, etc.,” says Dr. Chen. “One of the explanations could be the tremendous popularity of cola in the US.”

Previous studies in children and adults have shown that regular consumption of sugary drinks is associated with excess caloric intake, greater weight gain, and increased risk of obesity. Sugary drinks have also been linked to type 2 diabetes and other metabolic disorders.

“This is the first study on the impact of sugar-sweetened beverages on GDM risk,” notes Dr. Chen. “This finding is important because sugar-sweetened beverages are the leading source of added sugars in the American diet, particularly in the age group most likely to conceive. Cutting down sugary drinks is clearly an important way to reduce this common pregnancy complication.”

According to the National Health and Nutrition Examination Survey 1999-2001, from 1977 to 2001, soft drink intake increased from 4.1% to 9.8% for 19- to 39-year-olds. In percentage terms, soft drink intake was highest among this age group in comparison to other ages.

This study was supported by the National Institutes of Health and part of the work was done when Dr. Chen received an Intramural Research Training Award Fellowship under Dr. Cuilin Zhang (senior author) at the Division of Epidemiology, Statistics, and Prevention Research at the NICHD.

Source:
Leslie Capo
Louisiana State University Health Sciences Center