Resveratrol’s antioxidant and anti-inflammation actions shown previously only in vitro and in laboratory animals have now been observed in a small human study.
State University of Buffalo New York and Kaleida Health researchers found that supplementation with a plant extract containing resveratrol suppressed generation of free radicals called reactive oxygen species (ROS) and reduced expression of two major proinflammatory pathways.
Writing in their study, published in Journal of Clinical Endocrinology and Metabolism, the researchers state that they have demonstrated for the first time in humans “comprehensive effects on ROS generation and inflammation” and the “antiaging action of resveratrol.”
In the trial, two groups of 10 healthy adults were randomized to receive placebo or 200 milligrams of Japanese knotweed extract (Polygonum cuspidatum) supplying 40 milligrams of resveratrol daily. Fasting blood samples were collected before, during and after six weeks of supplementation. Subjects chosen were not on any antiinflammatory drugs.
The researchers’ data showed clear suppression of ROS generation and reduced expression of TNF-alpha and IL-6, which are regulated by NFkB, that led to falling levels of C-reactive protein, which are all involved with inflammatory response.
In parallel, the extract reduced expression of two major proinflammatory enzymes, JNK-1 and IKK-beta.
Resveratrol’s effects on reducing oxidative stress and inflammation are thought to take place because it activates production of SIRT1, one of a family of proteins that is positively associated with influencing fat metabolism, slowing aging, and extending lifespan in response to calorie restriction and fasting in yeast and animals.
Chronic oxidative stress and inflammation are implicated as factors that accelerate aging because of damage caused to cellular components including membranes, mitochondria and DNA.
Source: Ghanim H, Sia CL, Abuaysheh S, Korzeniewski K, Patnaik P, Marumganti A, Chaudhuri A, Dandona P. An Antiinflammatory and Reactive oxygen Species Suprressive Effects of an Extract of Polygonum Cuspidatum Containing Resveratrol. J Clin Endocrin Metab. 2010; 10:12.
Showing posts with label calorie restriction. Show all posts
Showing posts with label calorie restriction. Show all posts
11 April 2010
Does low-calorie dieting cause you to "yo yo" because of lowered metabolism?
This post came out of a question from someone who asked a question related to whether or not eating a very low calorie diet would lead to a "yo yo" effect caused by lowered metabolism, stoping weight loss and causing weight gain upon eating normally again.
There is no evidence suggesting that a "yo yo" effect would occur from low-calorie dieting, nor would lowering calories too far "stop" weight loss altogether. Truth is, calorie restriction does reduce metabolic rate, you would lose weight at a rate that is lower than normally expected, but if you started eating normally again, your metabolism would speed back up again.
In 2006, Heilbronn et al. studied the effects of calorie restriction (CR) on metabolism. The researchers published in JAMA the results of a six-month randomized controlled trial on CR and how it made an impact on biomarkers of metabolism as well as longevity and oxidative stress in overweight adults.
The subjects were paid and placed in one of the following groups: a control group, a CR group (25% reduction from baseline), a CR group with exercise (12.5% reduction, 12.5% increase activity), and what they called a very-calorie diet (890 kcal/d) followed by weight management at 15 percent weight reduction.
By the third month, metabolism had slowed (measured in part with plasma T3 levels) in both CR and very low-calorie diets. At six months, metabolism had slowed in the CR, CR with exercise, and very low-calorie diet groups.
Everyone lost weight in the intervention groups. Those on the very-low calorie diet lost the most, but they also lost the most muscle. From that same study, the researchers were the first to find reduced oxidative stress and DNA damage from CR in humans.
So, what do we know? We know that if you also drop even to 500-800 kcal per day that, despite slower metabolism (your body's survival mechanism), you still would lose weight albeit at a lower rate (as stated before).
What some researchers have tried to do since then to "trick" the body to not slow metabolism. They do it by staggering the calories with alternate-day CR/fasting or intermittent CR/fasting. These are interesting topics of research and may show up as new weight-loss fads of the future.
I don't recommend people drop calories or lose weight too quickly because it leads to too much loss of hard-earned muscle and, possibly, gallstones (if you're not drinking enough water and eating small meals throughout the day). In my experience, I've also seen quite a few people go lower than 800 calories per day for weeks and end up without energy, getting sick and looking pretty frail.
It's best, I think, to stick with losing only 1-2 pounds per week (by dropping calories steadily and increasing activity to keep muscle up) and then eventually keeping diet within 800-1200 kcal/d range.
There is no evidence suggesting that a "yo yo" effect would occur from low-calorie dieting, nor would lowering calories too far "stop" weight loss altogether. Truth is, calorie restriction does reduce metabolic rate, you would lose weight at a rate that is lower than normally expected, but if you started eating normally again, your metabolism would speed back up again.
In 2006, Heilbronn et al. studied the effects of calorie restriction (CR) on metabolism. The researchers published in JAMA the results of a six-month randomized controlled trial on CR and how it made an impact on biomarkers of metabolism as well as longevity and oxidative stress in overweight adults.
The subjects were paid and placed in one of the following groups: a control group, a CR group (25% reduction from baseline), a CR group with exercise (12.5% reduction, 12.5% increase activity), and what they called a very-calorie diet (890 kcal/d) followed by weight management at 15 percent weight reduction.
By the third month, metabolism had slowed (measured in part with plasma T3 levels) in both CR and very low-calorie diets. At six months, metabolism had slowed in the CR, CR with exercise, and very low-calorie diet groups.
Everyone lost weight in the intervention groups. Those on the very-low calorie diet lost the most, but they also lost the most muscle. From that same study, the researchers were the first to find reduced oxidative stress and DNA damage from CR in humans.
So, what do we know? We know that if you also drop even to 500-800 kcal per day that, despite slower metabolism (your body's survival mechanism), you still would lose weight albeit at a lower rate (as stated before).
What some researchers have tried to do since then to "trick" the body to not slow metabolism. They do it by staggering the calories with alternate-day CR/fasting or intermittent CR/fasting. These are interesting topics of research and may show up as new weight-loss fads of the future.
I don't recommend people drop calories or lose weight too quickly because it leads to too much loss of hard-earned muscle and, possibly, gallstones (if you're not drinking enough water and eating small meals throughout the day). In my experience, I've also seen quite a few people go lower than 800 calories per day for weeks and end up without energy, getting sick and looking pretty frail.
It's best, I think, to stick with losing only 1-2 pounds per week (by dropping calories steadily and increasing activity to keep muscle up) and then eventually keeping diet within 800-1200 kcal/d range.
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