Mattson MP, Wan R (2005) Beneficial effects of intermittent fasting and caloric restriction on the cardiovascular and cerebrovascular systems. J Nutr Biochem. 16(3):129-37.
Abstract
Intermittent fasting (IF; reduced meal frequency) and caloric restriction (CR) extend lifespan and increase resistance to age-related diseases in rodents and monkeys and improve the health of overweight humans. Both IF and CR enhance cardiovascular and brain functions and improve several risk factors for coronary artery disease and stroke including a reduction in blood pressure and increased insulin sensitivity. Cardiovascular stress adaptation is improved and heart rate variability is increased in rodents maintained on an IF or a CR diet. Moreover, rodents maintained on an IF regimen exhibit increased resistance of heart and brain cells to ischemic injury in experimental models of myocardial infarction and stroke. The beneficial effects of IF and CR result from at least two mechanisms--reduced oxidative damage and increased cellular stress resistance. Recent findings suggest that some of the beneficial effects of IF on both the cardiovascular system and the brain are mediated by brain-derived neurotrophic factor signaling in the brain. Interestingly, cellular and molecular effects of IF and CR on the cardiovascular system and the brain are similar to those of regular physical exercise, suggesting shared mechanisms. A better understanding of the cellular and molecular mechanisms by which IF and CR affect the blood vessels and heart and brain cells will likely lead to novel preventative and therapeutic strategies for extending health span.
Showing posts with label 2005. Show all posts
Showing posts with label 2005. Show all posts
Wednesday, January 20, 2010
Alternate-day fasting in nonobese subjects
Heilbronn LK, Smith SR, Martin CK, Anton SD, Ravussin E. (2005) Alternate-day fasting in nonobese subjects: effects on body weight, body composition, and energy metabolism.Am J Clin Nutr.81(1):69-73
http://www.ajcn.org/cgi/content/full/81/1/69
Abstract
Background: Prolonged dietary restriction increases the life span in rodents. Some evidence suggests that alternate-day fasting may also prolong the life span.
Objective: Our goal was to determine whether alternate-day fasting is a feasible method of dietary restriction in nonobese humans and whether it improves known biomarkers of longevity.
Design: Nonobese subjects (8 men and 8 women) fasted every other day for 22 d. Body weight, body composition, resting metabolic rate (RMR), respiratory quotient (RQ), temperature, fasting serum glucose, insulin, free fatty acids, and ghrelin were assessed at baseline and after 21 d (12-h fast) and 22 d (36-h fast) of alternate-day fasting. Visual analogue scales were used to assess hunger weekly.
Results: Subjects lost 2.5 ± 0.5% of their initial body weight (P < 0.001) and 4 ± 1% of their initial fat mass (P < 0.001). Hunger increased on the first day of fasting and remained elevated (P < 0.001). RMR and RQ did not change significantly from baseline to day 21, but RQ decreased on day 22 (P < 0.001), which resulted in an average daily increase in fat oxidation of ≥15 g. Glucose and ghrelin did not change significantly from baseline with alternate-day fasting, whereas fasting insulin decreased 57 ± 4% (P < 0.001).
Conclusions: Alternate-day fasting was feasible in nonobese subjects, and fat oxidation increased. However, hunger on fasting days did not decrease, perhaps indicating the unlikelihood of continuing this diet for extended periods of time. Adding one small meal on a fasting day may make this approach to dietary restriction more acceptable.
http://www.ajcn.org/cgi/content/full/81/1/69
Abstract
Background: Prolonged dietary restriction increases the life span in rodents. Some evidence suggests that alternate-day fasting may also prolong the life span.
Objective: Our goal was to determine whether alternate-day fasting is a feasible method of dietary restriction in nonobese humans and whether it improves known biomarkers of longevity.
Design: Nonobese subjects (8 men and 8 women) fasted every other day for 22 d. Body weight, body composition, resting metabolic rate (RMR), respiratory quotient (RQ), temperature, fasting serum glucose, insulin, free fatty acids, and ghrelin were assessed at baseline and after 21 d (12-h fast) and 22 d (36-h fast) of alternate-day fasting. Visual analogue scales were used to assess hunger weekly.
Results: Subjects lost 2.5 ± 0.5% of their initial body weight (P < 0.001) and 4 ± 1% of their initial fat mass (P < 0.001). Hunger increased on the first day of fasting and remained elevated (P < 0.001). RMR and RQ did not change significantly from baseline to day 21, but RQ decreased on day 22 (P < 0.001), which resulted in an average daily increase in fat oxidation of ≥15 g. Glucose and ghrelin did not change significantly from baseline with alternate-day fasting, whereas fasting insulin decreased 57 ± 4% (P < 0.001).
Conclusions: Alternate-day fasting was feasible in nonobese subjects, and fat oxidation increased. However, hunger on fasting days did not decrease, perhaps indicating the unlikelihood of continuing this diet for extended periods of time. Adding one small meal on a fasting day may make this approach to dietary restriction more acceptable.
Reuters Health:Fasting Every Other Day Cuts Weight, Ups Crankiness
originally published February 1st, 2005 via womenfitness.net
http://www.womenfitness.net/news/wt_managment/fasting_every_other_day.htm
Fasting Every Other Day Cuts Weight, Ups Crankiness
NEW YORK (Reuters Health) - Shunning food every other day may be a feasible way to slash calories -- if you and those around you don't mind the crankiness that comes with it, according to researchers.
Their study of 16 nonobese men and women looked at the effects of alternate-day fasting, an eating plan that interspersed fasting days with "feasting" days that allowed participants to eat as much as they wanted.
The researchers were interested in whether food deprivation every second day would be easier on people than counting calories on a daily basis, lead author Dr. Eric Ravussin told Reuters Health.
They found that the diet plan was indeed "feasible," at least for the duration of the 3-week study. Overall, the men and women lost an average of 5 pounds, while shedding some body fat.
On the other hand, Ravussin said, "most people were not happy" -- a major problem being the crankiness that erupted on the fasting days and did not abate over the 3 weeks.
Ravussin and his colleagues at the Pennington Biomedical Research Center in Baton Rouge, Louisiana, report the findings in the American Journal of Clinical Nutrition.
Uncovering the most tolerable ways for people to cut calories is not just a matter of trimming waistlines. A number of studies, Ravussin explained, have now shown that calorie restriction can extend the lives of everything from yeast and worms to rodents and, possibly, monkeys.
There are a number of theories on why limiting food might make for a longer, healthier life. One idea, Ravussin noted, is that slowing the rate of metabolism reduces the generation of oxygen free radicals, potentially cell-damaging molecules that are a normal byproduct of the metabolic process.
No one knows if calorie counting can extend human life as it does for some animals. Ravussin and his colleagues are currently conducting a trial, sponsored by the National Institutes of Health, which is examining how long-term dietary restriction affects people's health and longevity.
Studying dietary restriction in people is, of course, far more complicated than studying it in lab rats. The ongoing trial is investigating how calorie cutting affects "biomarkers of longevity" in people, such as levels of blood sugar and insulin, a hormone key in regulating blood sugar.
The trial is testing several methods of dietary restriction -- from pure calorie cutting to burning extra calories through exercise -- to see which are most viable.
In the current study, Ravussin's team evaluated the effects of alternate-day fasting, an approach not included in that trial. They wanted to see if the eating plan was feasible and whether it influenced biomarkers of longevity, as well as participants' weight and metabolism.
As mentioned, every other day for 3 weeks the men and women subsisted on calorie-free beverages and sugarless gum. On the days in between, they ate whatever they wanted.
According to Ravussin, participants were not able to "make up" for what they didn't eat on fasting days, and consequently, they generally lost a few pounds and some fat mass. In addition, their insulin levels declined by an average of about 57 percent.
However, the researchers also found that many participants said they were irritable on food-free days, and they did not appear to get used to having an empty stomach every other day.
Calorie restriction, Ravussin noted, is the only behavior that has so far been shown to prolong life. "There is a ton of data suggesting that this is the only way to the 'fountain of youth', if you want," he said. If the current findings are any indication, the researcher added, alternate-day fasting may not be the easiest path to that fountain.
SOURCE: American Journal of Clinical Nutrition, January 2005.
http://www.womenfitness.net/news/wt_managment/fasting_every_other_day.htm
Fasting Every Other Day Cuts Weight, Ups Crankiness
NEW YORK (Reuters Health) - Shunning food every other day may be a feasible way to slash calories -- if you and those around you don't mind the crankiness that comes with it, according to researchers.
Their study of 16 nonobese men and women looked at the effects of alternate-day fasting, an eating plan that interspersed fasting days with "feasting" days that allowed participants to eat as much as they wanted.
The researchers were interested in whether food deprivation every second day would be easier on people than counting calories on a daily basis, lead author Dr. Eric Ravussin told Reuters Health.
They found that the diet plan was indeed "feasible," at least for the duration of the 3-week study. Overall, the men and women lost an average of 5 pounds, while shedding some body fat.
On the other hand, Ravussin said, "most people were not happy" -- a major problem being the crankiness that erupted on the fasting days and did not abate over the 3 weeks.
Ravussin and his colleagues at the Pennington Biomedical Research Center in Baton Rouge, Louisiana, report the findings in the American Journal of Clinical Nutrition.
Uncovering the most tolerable ways for people to cut calories is not just a matter of trimming waistlines. A number of studies, Ravussin explained, have now shown that calorie restriction can extend the lives of everything from yeast and worms to rodents and, possibly, monkeys.
There are a number of theories on why limiting food might make for a longer, healthier life. One idea, Ravussin noted, is that slowing the rate of metabolism reduces the generation of oxygen free radicals, potentially cell-damaging molecules that are a normal byproduct of the metabolic process.
No one knows if calorie counting can extend human life as it does for some animals. Ravussin and his colleagues are currently conducting a trial, sponsored by the National Institutes of Health, which is examining how long-term dietary restriction affects people's health and longevity.
Studying dietary restriction in people is, of course, far more complicated than studying it in lab rats. The ongoing trial is investigating how calorie cutting affects "biomarkers of longevity" in people, such as levels of blood sugar and insulin, a hormone key in regulating blood sugar.
The trial is testing several methods of dietary restriction -- from pure calorie cutting to burning extra calories through exercise -- to see which are most viable.
In the current study, Ravussin's team evaluated the effects of alternate-day fasting, an approach not included in that trial. They wanted to see if the eating plan was feasible and whether it influenced biomarkers of longevity, as well as participants' weight and metabolism.
As mentioned, every other day for 3 weeks the men and women subsisted on calorie-free beverages and sugarless gum. On the days in between, they ate whatever they wanted.
According to Ravussin, participants were not able to "make up" for what they didn't eat on fasting days, and consequently, they generally lost a few pounds and some fat mass. In addition, their insulin levels declined by an average of about 57 percent.
However, the researchers also found that many participants said they were irritable on food-free days, and they did not appear to get used to having an empty stomach every other day.
Calorie restriction, Ravussin noted, is the only behavior that has so far been shown to prolong life. "There is a ton of data suggesting that this is the only way to the 'fountain of youth', if you want," he said. If the current findings are any indication, the researcher added, alternate-day fasting may not be the easiest path to that fountain.
SOURCE: American Journal of Clinical Nutrition, January 2005.
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