Re: Re: Amino acids - methionine restriction

[Guest guest]

>>>If proven, this would change the practice of CRON. We would be fine

tuning our calorie restriction by making sure to also restrict

methionine (and perhaps protein).

More on restricting protein in CR... (abstract and mass media press

article) from the WUSTL group. Notice the comment in the mass media

article on the " vegans "

Regards

Jeff

Aging Cell. 2008 Oct;7(5):681-7. Long-term effects of calorie or protein

restriction on serum IGF-1 and IGFBP-3 concentration in humans Fontana

L, Weiss EP, Villareal DT, Klein S, Holloszy JO.

Reduced function mutations in the insulin/IGF-I signaling pathway

increase maximal lifespan and health span in many species. Calorie

restriction (CR) decreases serum IGF-1 concentration by ~40%, protects

against cancer and slows aging in rodents. However, the long-term

effects of CR with adequate nutrition on circulating IGF-1 levels in

humans are unknown. Here we report data from two long-term CR studies (1

and 6 years) showing that severe CR without malnutrition did not change

IGF-1 and IGF-1 : IGFBP-3 ratio levels in humans. In contrast, total and

free IGF-1 concentrations were significantly lower in moderately

protein-restricted individuals. Reducing protein intake from an average

of 1.67 g kg(-1) of body weight per day to 0.95 g kg(-1) of body weight

per day for 3 weeks in six volunteers practicing CR resulted in a

reduction in serum IGF-1 from 194 ng mL(-1) to 152 ng mL(-1). These

findings demonstrate that, unlike in rodents, long-term severe CR does

not reduce serum IGF-1 concentration and IGF-1 : IGFBP-3 ratio in

humans. In addition, our data provide evidence that protein intake is a

key determinant of circulating IGF-1 levels in humans, and suggest that

reduced protein intake may become an important component of anticancer

and anti-aging dietary interventions. PMID: 18843793

Science News

Oct 25, 2008

Diet details may influence longevity: cutting protein may be as

important as cutting calories

Tina Hesman Saey

Beefing about your diet probably won't lengthen your life, but a new

study suggests that cutting down on beef and other protein-laden foods

might.

A group of researchers at Washington University in St. Louis, led by

Luigi Fontana and Holloszy, is investigating how nutritious,

calorie-restricted diets affect people. Cutting 25 percent or more

calories from the diets of rodents, dogs, worms and other animals has

been shown to prolong life. But no one knows whether restricting

calories in people will also make them live longer.

Previous studies from the same group have shown that members of the

Calorie Restriction Society, who have voluntarily followed a

calorie-restricted diet for years, have improved cardiovascular health

compared with people of the same age who eat 20 to 30 percent more calories.

In their latest study, in the October Aging Cell, the scientists found

that people who eat a high-nutrition, minimal calorie diet don't get all

the benefits from calorie restriction that rodents do. But restricting

proteins along with calories seems to mimic the full effect seen in

other animals.

This new study focused on the diet's effect on amounts of insulin-like

growth factor, or IGF-1. The growth factor stimulates cells to grow, and

high levels have been linked to cancer. Lowering levels of the growth

factor may be a key step in slowing down aging.

In previous studies, rodents on a calorie-restricted diet showed a drop

in IGF-1. The researchers examined IGF-1 levels in people who followed a

calorie-restricted diet, but the diet did not lower IGF-1 levels.

" It was a little surprising, " says Andrzej Bartke of Southern Illinois

University School of Medicine in Springfield. " IGF-1 reduction is kind

of a textbook response to caloric restriction, and in this study it

didn't happen. "

Vegans--people who do not eat meat, milk, eggs or other animal

products--did have slightly lower levels of IGF-1, even though their

diets are higher in calories. However, the vegans did not have all the

cardiovascular benefits that people on calorie restriction do.

Fontana and his colleagues realized that the vegans get only about 10

percent of their calories from protein, while people in the

calorie-restriction group get nearly a quarter from protein.

Six members of the Calorie Restriction Society agreed to lower their

protein consumption to slightly below the recommended daily intake.

After three weeks on the lower-protein diet, IGF-1 levels in these

volunteers' blood dropped 25 percent on average. The result suggests

that caloric restriction works differently in people than rodents and

that restricting protein consumption is important to achieve maximal

health benefits, Fontana says.

" This study says, 'Pay attention: Too many proteins can increase your

risk of getting cancer, and it can speed up your aging,' " Fontana says.

The findings suggest that diet composition may be as important as

calorie consumption for controlling aging, Bartke says. But the

importance of IGF-1 to longevity is not as clear in humans as in

rodents, because while rodents often die of cancer, people die more

often of heart disease.

COPYRIGHT 2008 Science Service, Inc.

COPYRIGHT 2008 Gale, Cengage Learning

[Guest guest]

We have been assessing this question of methionine for a long time now. But the answers are not in yet. Vegans and vegetarians don’t live any longer than health-conscious meat eaters. If methionine were be all and end all, they would. See our files for the studies on this.

From: RJB112 <rjb112@...>

Reply-< >

Date: Sun, 14 Dec 2008 12:11:49 -0000

< >

Subject: [ ] Re: Amino acids - methionine restriction

The possible implications of the study that Al posted are very big.

..

[Guest guest]

Does anyone know if

S-adenosyl-L-methionine or SAMe supplementation (taken with B12, B6, folic)

is detrimental to longevity? Ann

From: Novick <jnovickrd@...>Subject: Re: [ ] Re: Amino acids - methionine restriction Date: Sunday, December 14, 2008, 7:53 AM

>>>If proven, this would change the practice of CRON. We would be finetuning our calorie restriction by making sure to also restrictmethionine (and perhaps protein).More on restricting protein in CR... (abstract and mass media press article) from the WUSTL group. Notice the comment in the mass media article on the "vegans"RegardsJeffAging Cell. 2008 Oct;7(5):681- 7. Long-term effects of calorie or protein restriction on serum IGF-1 and IGFBP-3 concentration in humans Fontana L, Weiss EP, Villareal DT, Klein S, Holloszy JO.Reduced function mutations in the insulin/IGF- I signaling pathway increase maximal lifespan and health span in many species. Calorie restriction (CR) decreases serum IGF-1 concentration by ~40%, protects against cancer and slows aging in rodents. However, the long-term effects of CR with adequate nutrition on circulating IGF-1 levels in humans

are unknown. Here we report data from two long-term CR studies (1 and 6 years) showing that severe CR without malnutrition did not change IGF-1 and IGF-1 : IGFBP-3 ratio levels in humans. In contrast, total and free IGF-1 concentrations were significantly lower in moderately protein-restricted individuals. Reducing protein intake from an average of 1.67 g kg(-1) of body weight per day to 0.95 g kg(-1) of body weight per day for 3 weeks in six volunteers practicing CR resulted in a reduction in serum IGF-1 from 194 ng mL(-1) to 152 ng mL(-1). These findings demonstrate that, unlike in rodents, long-term severe CR does not reduce serum IGF-1 concentration and IGF-1 : IGFBP-3 ratio in humans. In addition, our data provide evidence that protein intake is a key determinant of circulating IGF-1 levels in humans, and suggest that reduced protein intake may become an important component of anticancer and

anti-aging dietary interventions. PMID: 18843793Science NewsOct 25, 2008Diet details may influence longevity: cutting protein may be as important as cutting caloriesTina Hesman SaeyBeefing about your diet probably won't lengthen your life, but a new study suggests that cutting down on beef and other protein-laden foods might.A group of researchers at Washington University in St. Louis, led by Luigi Fontana and Holloszy, is investigating how nutritious, calorie-restricted diets affect people. Cutting 25 percent or more calories from the diets of rodents, dogs, worms and other animals has been shown to prolong life. But no one knows whether restricting calories in people will also make them live longer.Previous studies from the same group have shown that members of the Calorie Restriction Society, who have voluntarily followed a calorie-restricted diet for years,

have improved cardiovascular health compared with people of the same age who eat 20 to 30 percent more calories.In their latest study, in the October Aging Cell, the scientists found that people who eat a high-nutrition, minimal calorie diet don't get all the benefits from calorie restriction that rodents do. But restricting proteins along with calories seems to mimic the full effect seen in other animals.This new study focused on the diet's effect on amounts of insulin-like growth factor, or IGF-1. The growth factor stimulates cells to grow, and high levels have been linked to cancer. Lowering levels of the growth factor may be a key step in slowing down aging.In previous studies, rodents on a calorie-restricted diet showed a drop in IGF-1. The researchers examined IGF-1 levels in people who followed a calorie-restricted diet, but the diet did not lower IGF-1 levels."It was a

little surprising," says Andrzej Bartke of Southern Illinois University School of Medicine in Springfield. "IGF-1 reduction is kind of a textbook response to caloric restriction, and in this study it didn't happen."Vegans--people who do not eat meat, milk, eggs or other animal products--did have slightly lower levels of IGF-1, even though their diets are higher in calories. However, the vegans did not have all the cardiovascular benefits that people on calorie restriction do.Fontana and his colleagues realized that the vegans get only about 10 percent of their calories from protein, while people in the calorie-restriction group get nearly a quarter from protein.Six members of the Calorie Restriction Society agreed to lower their protein consumption to slightly below the recommended daily intake. After three weeks on the lower-protein diet, IGF-1 levels in these volunteers' blood dropped

25 percent on average. The result suggests that caloric restriction works differently in people than rodents and that restricting protein consumption is important to achieve maximal health benefits, Fontana says."This study says, 'Pay attention: Too many proteins can increase your risk of getting cancer, and it can speed up your aging,'" Fontana says.The findings suggest that diet composition may be as important as calorie consumption for controlling aging, Bartke says. But the importance of IGF-1 to longevity is not as clear in humans as in rodents, because while rodents often die of cancer, people die more often of heart disease.COPYRIGHT 2008 Science Service, Inc.COPYRIGHT 2008 Gale, Cengage Learning