Avoiding bad cholesterol may help burn extra flab more than anything else.
If you’re obese and also high on cholesterol, there is some bad news for you. Scrimping on food or hitting the gym regularly will be less helpful in dislodging the fat tucked away in the tummy if the level of low-density lipoprotein (LDL), or bad cholesterol, increases considerably in your body.
The nexus between LDL and reduced burning of fat was discovered recently by a team of researchers from the Swedish medical university Karolinska Institutet, Stockholm.
Higher order animals like humans retrieve energy stored as fat — free fatty acids — in a layer under the skin when there is a drop in the availability of glucose, the body’s primary source of energy. But the process gets hampered badly when there are higher levels of bad cholesterol in the body, showed the Swedish scientists who studied the inhibitory role of cholesterol in fat turnover in lab-cultured human human tissues and mice.
“Our study clearly shows that bad cholesterol inhibits the breakdown of fat stored in the adipose cells in the body,” said Johan Björkegren, who led the study. The study appeared recently in the journal PLoS ONE.
“Scientists have long known that when food intake is restricted, the liver sends signal to the white adipose tissues to release free fatty acids at higher rates.” Such fat is processed in the liver to meet the energy requirement of the body. The process also results in the production of cholesterol. In a healthy person, there is always a fine balance between the production of cholesterol and the release of fats from the adipose tissues.
But, much to their surprise, the Swedish scientists found that when there is a higher level of cholesterol, the release of fat from the tissues may remain the same but the liver will process less fat. The excess fat, then, will remain in the bloodstream, triggering the synthesis of more cholesterol. “This forms a vicious cycle,” Björkegren told Knowhow.
But, the Swedish researcher said, there is no need to lose heart. Cholesterol-busting medication such as statins can increase the turnover of fat. Similarly, cutting the intake of bad cholesterol from food may benefit an obese person on two counts: he or she may be able to reduce the risk of heart diseases such as atherosclerosis, and it enhances the process of weight reduction.
While the Swedish study clearly indicated the negative role played by cholesterol in obesity, another study reported at a recent meeting of the American Heart Association showed how cholesterol clogged the arteries of obese children, making the blood vessels look more like those of 45-year-olds.
WHY DIETING FAILS:Dieting summons ready energy from fat deposits in the body but the liver lacks the ability to process more fat. The result: the extra fat stays in the blood, producing more cholesterol.
“There’s a saying that ‘you’re as old as your arteries,’ meaning that the state of your arteries is more important than your actual age in the evolution of heart disease and stroke,” said Geetha Raghuveer, associate professor of paediatrics at the University of Missouri-Kansas City School of Medicine. The scientists, who used ultrasound to measure the thickness of the inner walls of the carotid arteries in the neck that link the brain to the heart, were surprised to see the fatty build-up of plaque. Such plaque deposit — called carotid artery intima-media thickness (CIMT) — within arteries feeding the heart muscle and the brain can lead to heart attacks and strokes, Raghuveer, who led the study, said.
The scientists studied 70 boys and girls with an average age of 13. Most of these children had abnormal levels of one or more types of cholesterol — elevated levels of LDL or low levels of good cholesterol (HDL) or high triglyceride levels.
The children’s “vascular age” — the age at which level of thickening would be normal for their gender and race — was about 30 years more than their actual age, she said.
“Vascular age was advanced the furthest in the children with obesity and high triglyceride levels. So the combination of obesity and high triglycerides should be a red flag to the doctor that a child is at high risk of heart disease,” Raghuveer said.
She said further studies are needed to determine whether artery build-up will decrease if children lose weight, exercise or are treated for abnormal lipids.
One factor that gives rise to hope, according to Raghuveer, is that unlike in adults these plaques haven’t hardened or calcified in children. So the same treatments that help improve vessel walls and blood flow in adults can help children even more, she observed.
Sources: The Telegraph (Kolkata, India)
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