Re: CRON reduces T3 thyroid hormone, tumor necrosis factor

[Guest guest]

Hi Dave:

Thank you. Interesting study. It suggests that the benefits of CRON

may NOT (not all of them at least) be derived from having less body

fat. Which dovetails nicely with Warren's post here a couple of

years ago asserting that among the 40% CRON mice, those that lived

the longest of all were the ones that had managed to preserve the

highest body fat mass.

(Can anyone provide a reference to that study, please? I don't think

we have it listed in the 'CRON studies' file, and it ought to be

there. TYIA)

The PMID # of the study to which Dave has alerted us is: 16720655.

And the full text is available free.

Rodney.

>

> summary:

>

> Researchers examined 28 members of the Calorie Restriction Society

who

> had been eating a CR diet for an average of six years.

>

> They found that CRON lowers concentrations of T3 thyroid hormone,

and

> also that CR decreases tumor necrosis factor alpha (TNF).

>

>

> ++++++++++++++++++++++++++++++

>

> link and full text:

>

> http://www.eurekalert.org/pub_releases/2006-05/wuso-cra053106.php

>

> Public release date: 31-May-2006

>

> Contact: Jim Dryden

> jdryden@...

> 314-286-0110

> Washington University School of Medicine

>

> Calorie restriction appears better than exercise at slowing primary

aging

>

> Investigators at Washington University School of Medicine in St.

Louis

> have found that eating a low-calorie yet nutritionally balanced diet

> lowers concentrations of a thyroid hormone called triiodothyronine

> (T3), which controls the body's energy balance and cellular

metabolism.

>

> The researchers also found that calorie restriction (CR) decreases

the

> circulating concentration of a powerful inflammatory molecule called

> tumor necrosis factor alpha (TNF). They say the combination of lower

> T3 levels and reduced inflammation may slow the aging process by

> reducing the body's metabolic rate as well as oxidative damage to

> cells and tissues.

>

> Previous research on mice and rats has shown that both calorie

> restriction and endurance exercise protect them against many chronic

> diseases including obesity, diabetes, cardiovascular disease and

some

> types of cancer. However, the research has shown that only CR

> increases the animals' maximum lifespan by up to 50 percent. These

> animal studies suggest that leanness is a key factor in the

prevention

> of age-associated disease, but reducing caloric intake is needed to

> slow down aging.

>

> For the new study, researchers examined 28 members of the Calorie

> Restriction Society who had been eating a CR diet for an average of

> six years. Although the CR group consumed fewer calories --

averaging

> only about 1,800 per day -- they consumed at least 100 percent of

the

> recommended daily amounts of protein and micronutrients. A second

> group of 28 study subjects was sedentary, and they ate a standard

> Western diet. A third group in the study ate a standard Western diet

> -- approximately 2,700 calories per day -- but also did endurance

> training. The researchers found reduced T3 levels -- similar to

those

> seen in animals whose rate of aging is reduced by CR -- only in the

> people on CR diets.

>

> But their serum concentrations of two other hormones -- thyroxin

(T4)

> and thyroid stimulating hormone (TSH) -- were normal, indicating

that

> those on CR were not suffering from the thyroid disease of clinical

> hypothyroidism. The findings are published online in the Journal of

> Clinical Endocrinology and Metabolism.

>

> Interestingly, body fat levels did not affect serum T3

concentrations.

> The people in the CR group and the endurance athletes had similar

> amounts and composition of body fat. But although the CR group had

> lower T3 levels, the exercise group had T3 levels closer to those

seen

> in the sedentary people who ate a standard Western diet.

>

> " The difference in T3 levels between the CR group and the exercise

> group is exciting because it suggests that CR has some specific

> anti-aging effects that are due to lower energy intake, rather than

to

> leanness, " says first author Luigi Fontana, M.D., Ph.D., assistant

> professor of medicine at Washington University in St. Louis and an

> investigator at the Istituto Superiore di Sanita, Rome,

Italy. " These

> findings suggest that although exercise helps prevent problems that

> can cut life short -- such as obesity, diabetes and cardiovascular

> disease -- only CR appears also to have an impact on primary aging. "

>

> Primary aging determines maximal length of life. Secondary aging, on

> the other hand, refers to diseases that can keep a person or an

animal

> from reaching that expected lifespan. Eliminating factors related to

> secondary aging allows more people to reach their projected length

of

> life. By slowing primary aging, CR may increase maximal lifespan.

>

> In a related study in 1997, co-investigator O. Holloszy, M.D.,

> professor of medicine at Washington University School of Medicine,

> reported in the Journal of Applied Physiology that in rats, CR

> extended life longer than exercise.

>

> " Sedentary rats who ate a standard diet had the shortest average

> life-spans, " Holloszy says. " Those who exercised by running on a

wheel

> lived longer, but animals on calorie restriction lived even longer. "

>

> Earlier this year, Fontana's group reported that CR seemed to

prevent

> or delay primary aging in the heart. Ultrasound examinations showed

> that the hearts of people on calorie restriction were more elastic

> than those of age- and gender-matched control subjects. Their hearts

> were able to relax between beats in a way similar to the hearts of

> younger people.

>

> This latest study targeted another marker of primary aging. The

> thyroid gland produces critical hormones that play an indispensable

> role in cell growth and development as well as in lipid and

> carbohydrate metabolism. T4 is the main product secreted by the

cells

> of the thyroid gland, but most actions of thyroid hormone are

> initiated by T3. Fontana says T3 controls body temperature, cellular

> metabolism and to some extent, it also appears to be involved with

> production of free radicals, unstable molecules that can damage

cells.

> All are important aspects of aging and longevity. In fact, a 2002

> study in Science magazine from researchers at the National Institute

> on Aging observed that men with lower body temperatures tended to

live

> longer those with higher body temperatures.

>

> Fontana says lower levels of T3, cholesterol and the inflammatory

> molecules TNF and C-reactive protein, combined with evidence of

> " younger " hearts in people on calorie restriction, suggest that

humans

> on CR have the same adaptive responses as did animals whose rates of

> aging were slowed by CR.

>

> Holloszy and Fontana are getting ready to launch a 2-year study to

> look at the effects of calorie restriction. Later this year, they

will

> begin recruiting volunteers between the ages of 25 and 45 who are

> willing to go on a CR diet for 24 months.

>

> Called the Comprehensive Assessment of the Long Term effects of

> Reducing Intake of Energy (CALERIE) study, the goal is to get some

> clues about whether putting a normal weight person on calorie

> restriction will lower their levels of inflammation and their serum

> concentrations of T3, improve their heart function and change other

> markers of aging, as Fontana and Holloszy have observed in members

of

> the Calorie Restriction Society.

>

> " We want to learn whether calorie restriction can reverse some of

> these markers of aging in healthy people, " Holloszy says. " It's

going

> to be many years before we know whether calorie restriction really

> lengthens life, but if we can demonstrate that it changes these

> markers of aging, such as oxidative damage and inflammation, we'll

> have a pretty good idea that it's influencing aging in the same way

> that CR slows aging in experimental animals. "

>

> ###

>

> Fontana L, Keline S, Holloszy JO, Premachandra BN. Effect of long-

term

> calorie restriction with adequate protein and micronutrients on

> thyroid hormones. Journal of Clinical Endocrinology and Metabolism,

> first published ahead of print May 23, 2006 as doi: 10.1210/jc 2006-

0328.

>

> This research was supported by was supported by the National

> Institutes of Health.

>

> Related articles:

>

> Fontana L. Excessive adiposity, calorie restriction and aging in

> humans. Journal of the American Medical Association, vol. 293:13,

> April 5, 2006.

>

> Meyer TE, Kovacs SJ, Ehsani AA, Klein S, Holloszy JO, Fontana L.

> Long-term caloric restriction ameliorates the decline in diastolic

> function in humans. Journal of the American College of Cardiology,

> vol. 47:2, pp. 398-402, Jan. 17, 2006.

>

> Holloszy JO. Mortality rate and longevity of food-restricted

> exercising male rats: a reevaluation. Journal of Applied Physiology,

> vol. 82, pp. 399-403, Feb. 1997.

>

> Roth GS, Lane MA, Ingram DK, Mattison JA, Elahi D, Tobin JD, Muller

D,

> Metter EJ. Biomarkers of caloric restriction may predict longevity

in

> humans. Science, vol. 297, p. 811, Aug. 2, 2002.

>

> Washington University School of Medicine's full-time and volunteer

> faculty physicians also are the medical staff of -Jewish and

St.

> Louis Children's hospitals. The School of Medicine is one of the

> leading medical research, teaching and patient care institutions in

> the nation, currently ranked fourth in the nation by U.S. News &

World

> Report. Through its affiliations with -Jewish and St. Louis

> Children's hospitals, the School of Medicine is linked to BJC

HealthCare.

>

[Guest guest]

Does anyone find it odd that t3 levels are said to be lower in CR

than in the other 2 groups when a great majority of americans

actually suffer from mild to severe hypothyroidism? And that none of

the other 2 groups, especially not the group fed SAD can be said to

show very high T3 levels? Would CR lower T3 even more than levels

that require treatment in non CR folks? Would this not result in a

catabolic state??? I've often read that when there is hypothyroidism

there is an increase in estrogen levels. I wonder what were the cr

participants estrogen levels. I ask because after 4 years of moderate

CR my t3 levels are somewhat higher than the average person's and

cerrtainly higher than they were 4 years ago at 33 years. This seems

at odds with the report posted.

Regards.

--- In , " Rodney " <perspect1111@...>

wrote:

>

> Hi Dave:

>

> Thank you. Interesting study. It suggests that the benefits of

CRON

> may NOT (not all of them at least) be derived from having less body

> fat. Which dovetails nicely with Warren's post here a couple of

> years ago asserting that among the 40% CRON mice, those that lived

> the longest of all were the ones that had managed to preserve the

> highest body fat mass.

>

> (Can anyone provide a reference to that study, please? I don't

think

> we have it listed in the 'CRON studies' file, and it ought to be

> there. TYIA)

>

> The PMID # of the study to which Dave has alerted us is: 16720655.

> And the full text is available free.

>

> Rodney.

>

[Guest guest]

Hi :

No. I don't find it odd at all.

My understanding is (please correct me, anyone, if you have some

medical qualifications or other good reason to do so!) that low T3 is

NOT a symptom of hypothyroidism. In hypothyroidism **T4** is

abnormally low and TSH is abnormally high.

As the study noted, T4 and TSH were both normal in this study's CR

subjects.

Rodney.

> >

> > Hi Dave:

> >

> > Thank you. Interesting study. It suggests that the benefits of

> CRON

> > may NOT (not all of them at least) be derived from having less

body

> > fat. Which dovetails nicely with Warren's post here a couple of

> > years ago asserting that among the 40% CRON mice, those that

lived

> > the longest of all were the ones that had managed to preserve the

> > highest body fat mass.

> >

> > (Can anyone provide a reference to that study, please? I don't

> think

> > we have it listed in the 'CRON studies' file, and it ought to be

> > there. TYIA)

> >

> > The PMID # of the study to which Dave has alerted us is:

16720655.

> > And the full text is available free.

> >

> > Rodney.

> >

>

[Guest guest]

Hi folks:

I am looking forward to living long enough to come across a study

which finds some negative effects resulting from CRON! ; ^ )))

Rodney.

> > >

> > > Hi Dave:

> > >

> > > Thank you. Interesting study. It suggests that the benefits

of

> > CRON

> > > may NOT (not all of them at least) be derived from having less

> body

> > > fat. Which dovetails nicely with Warren's post here a couple

of

> > > years ago asserting that among the 40% CRON mice, those that

> lived

> > > the longest of all were the ones that had managed to preserve

the

> > > highest body fat mass.

> > >

> > > (Can anyone provide a reference to that study, please? I don't

> > think

> > > we have it listed in the 'CRON studies' file, and it ought to

be

> > > there. TYIA)

> > >

> > > The PMID # of the study to which Dave has alerted us is:

> 16720655.

> > > And the full text is available free.

> > >

> > > Rodney.

> > >

> >

>

[Guest guest]

T3 is the active form of thyroid. That much is certain, for

everything else about thyroid is controversial, lacks consensus. When

TSH and TSH test come out inconclusive or point out to a problem, T3

test may be then ordered to complete diagnosis. T4 converts to T3 in

optimal conditions? T3 however remains the surest way to assess

thyroid function because it expresses thyroid function. Is it

possible that in CR there is little conversion? The need for thyroid

maybe lessened? A higher metabolic rate, charateristic of

hyperthyroid states would increase demand for calories. Does anyone

know if higher metabolism ditinguishes early cr practice, when one

sometimes feels very hungry? Does anyone know the average restriction

levels of the participants? Their dietary elements? Could something

there, common to all, also play a part in inhibiting thyroid

function?

> > >

> > > Hi Dave:

> > >

> > > Thank you. Interesting study. It suggests that the benefits

of

> > CRON

> > > may NOT (not all of them at least) be derived from having less

> body

> > > fat. Which dovetails nicely with Warren's post here a couple

of

> > > years ago asserting that among the 40% CRON mice, those that

> lived

> > > the longest of all were the ones that had managed to preserve

the

> > > highest body fat mass.

> > >

> > > (Can anyone provide a reference to that study, please? I don't

> > think

> > > we have it listed in the 'CRON studies' file, and it ought to

be

> > > there. TYIA)

> > >

> > > The PMID # of the study to which Dave has alerted us is:

> 16720655.

> > > And the full text is available free.

> > >

> > > Rodney.

> > >

> >

>

[Guest guest]

Hi :

Here is a link regarding diagnosis of thyroid problems:

http://www.endocrineweb.com/tests.html

Note the indications for low **T4** and/or high TSH. In a quick scan

of it I also notice a problem marked by a **HIGH** T3. But I did not

see a reference to low T3 being a problem. But I only scanned it

briefly.

Rodney.

> > > >

> > > > Hi Dave:

> > > >

> > > > Thank you. Interesting study. It suggests that the benefits

> of

> > > CRON

> > > > may NOT (not all of them at least) be derived from having

less

> > body

> > > > fat. Which dovetails nicely with Warren's post here a couple

> of

> > > > years ago asserting that among the 40% CRON mice, those that

> > lived

> > > > the longest of all were the ones that had managed to preserve

> the

> > > > highest body fat mass.

> > > >

> > > > (Can anyone provide a reference to that study, please? I

don't

> > > think

> > > > we have it listed in the 'CRON studies' file, and it ought to

> be

> > > > there. TYIA)

> > > >

> > > > The PMID # of the study to which Dave has alerted us is:

> > 16720655.

> > > > And the full text is available free.

> > > >

> > > > Rodney.

> > > >

> > >

> >

>