A new candidate pathway for treating visceral obesity
Brown seems to be the color of choice when it comes to the types of fat cells in our bodies. Brown fat expends energy, while its counterpart, white fat stores it. The danger in white fat cells, along with the increased risk for diabetes and heart disease it poses, seems especially linked to visceral fat. Visceral fat is the build-up of fat around the organs in the belly.
So in the battle against obesity, brown fat appears to be our friend and white fat our foe.
Now a team of researchers led by Jorge Plutzky, MD, director of The Vascular Disease Prevention Program at Brigham and Women’s Hospital (BWH) and Harvard Medical School has discovered a way to turn foe to friend.
By manipulating the metabolic pathways in the body responsible for converting vitamin A-or retinol -into retinoic acid, Plutzky and his colleagues have essentially made white fat take on characteristics of brown fat. Their findings put medical science a step closer in the race to develop novel anti-obesity therapies.
The study will be published online on May 6, 2012 in Nature Medicine.
Retinoids, which are molecules derived from vitamin A metabolism, are responsible for many biological functions. One such function is the control of fat cell development and actions. A key step in retinoid metabolism occurs with help from an enzyme called retinaldehyde dehydrogenase 1, or Aldh1a1. The researchers saw that in humans and mice, Aldh1a1 is abundant in white fat cells, especially in the more dangerous visceral fat (sometimes referred to as abdominal fat or belly fat).
Visceral fat surrounds the organs and is connected with various diseases such as diabetes, hypertension, elevated triglycerides and the fast growing phenomenon known as metabolic syndrome.
Unlike stomach fat that is located under the skin, visceral fat proceeds as a lively endocrine organ releasing hormones that can lead to diabetes and insulin resistance.
To be diagnosed with intra-abdominal adiposity, your waist must be larger than 40 inches in men and 35 inches in women. The common apple-shaped body is greatly associated with elevated levels of visceral fat storage. Unlike subcutaneous fat which jiggles on the outside, visceral fat environs the organs and can’t be visually seen.
When Aldh1a1 was inhibited in white fat cells, those cells began acting like brown fat cells. One of the defining characteristics of brown fat is its ability to release energy as heat. Mice with either deficiency or inhibition of Aldh1a1 become protected against exposure to cold. The researchers saw this classic indicator of brown fat and its ability to generate heat by oxidizing fat (a chemical reaction involving oxygen) in their research.
Especially exciting for the prospects of targeting Aldh1a1 for therapeutic benefit, the researchers found that knocking down expression of the Aldh1a1 gene by injecting antisense molecules into mice made fat by diet resulted in less visceral fat, less weight gain, lower glucose levels, and protection against cold exposure as compared to control mice.
Having Tummy Steals Happiness and Makes You Older
Those who accumulate greasers in the abdominal area are more likely to feel unhappy and experience premature aging, and all due to hormonal changes what is known as visceral obesity.
What happens in these cases is that abdominal visceral fat increases the production of stress hormone, cortisol, and lower levels of endorphins, which are hormones that facilitate the feeling of happiness and wellbeing. This was explained by Dr. Ruben Bravo, nutrition specialist, in a note published by 20minutos.es.
Being overweight is never good, but when fat accumulates in the abdominal area, the health risks are greater because it is situated around vital organs. Visceral fat accumulates rapidly and is more difficult to remove than the one located in other parts of the body. According to Bravo, visceral obesity puts us at risk for Cardiovascular diseases, diabetes, hypertension and some cancers.
“Brown fat, and mechanisms that might allow white fat to take on brown fat characteristics, has been receiving increasing attention as a possible way to treat obesity and its complications,” said Plutzky. “Although more work is needed, we can add specific aspects of retinoid metabolism to those factors that appear involved in determining white versus brown fat.”
According to the Centers for Disease Control and Prevention, one-third of adults in the United States are obese. Current methods to reduce obesity include exercise, dietary therapy, medications and surgery.
Being overweight is never good, but when fat accumulates in the abdominal area, the health risks are greater because it is situated around vital organs. Visceral fat accumulates rapidly and is more difficult to remove than the one located in other parts of the body. According to Bravo, visceral obesity puts us at risk for Cardiovascular diseases, diabetes, hypertension and some cancers.
Previous studies suggest that people with central obesity, commonly identified as “apple-shaped bodies”, embraces a threefold increased risk of having a heart attack compared to those with general obesity or “pear-shaped. ” >> Body of apple? Your heart danger
To get rid of fat in the abdominal area and reduce health risks, it is necessary to combine a proper diet and aerobic and anaerobic. Bravo explained that the abs could be counterproductive to reduce the belly, so consult an expert would be best to find the right exercise routine to facilitate the burning of visceral fat.
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This research was supported by the National Institutes of Health grants HL048743, AR054604-03S1, 5P30DK057521-12; Mary K. Iacocca Professorship; National Institute of Diabetes and Digestive and Kidney Diseases; and Austrian Science Fund.
Brigham and Women’s Hospital (BWH) is a 793-bed nonprofit teaching affiliate of Harvard Medical School and a founding member of Partners HealthCare, an integrated health care delivery network. BWH is the home of the Carl J. and Ruth Shapiro Cardiovascular Center, the most advanced center of its kind. BWH is committed to excellence in patient care with expertise in virtually every specialty of medicine and surgery. The BWH medical preeminence dates back to 1832, and today that rich history in clinical care is coupled with its national leadership in quality improvement and patient safety initiatives and its dedication to educating and training the next generation of health care professionals.
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Lori J. Shanks
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Brigham and Women’s Hospital