Re: Eating affects previous fat eaten uptake

[Guest guest]

Hi Al:

It is not entirely clear to me what the implications of this study

might be.

Having said that, I get the impression it is arguing that meals at

more frequent intervals may result in higher average daily blood

lipid levels because of 'synergistic' effects when one meal follows

another by a comparatively short period of a few hours.

Since higher lipid levels may not be desirable, if this study is

confirmed by others these results might imply that there is a benefit

to be had from eating only a single meal a day.

So, is my above summary (in plain english) approximately right, or is

it off base?

Thanks,

Rodney.

--- In , Al Pater <old542000@y...>

wrote:

> Hi All,

>

> Eating a meal apparently affects the uptake of fat that was

previously eaten.

>

> The pdf is corrupted for the below.

>

> Their BMI was an average of 26.6 and they were 62 years old on

average.

>

> The areas under the curves for the times 0-27 minutes and 270-

600 minutes were:

> TAG, 374±66 and 563±116. For Apo B-48, they were: 254±52 and

376±87. for RE, they

> were: 120±36 and 53±66.

>

> Meal ingestion provokes entry of lipoproteins containing fat

from the previous

> meal: possible metabolic implications

>

> K. D. R. R. Silva, J. W. , C. M. , et al.

> European Journal of Nutrition ISSN: 1436-6207 (Paper) 1436-6215

(Online) Issue:

> Online First 05 November, 2004

>

> Summary

> Background Prolonged and exaggerated postprandial plasma

triacylglycerol (TAG)

> concentrations are considered as an independent risk factor for

coronary artery

> disease. Western populations eat many meals at regular intervals,

and can be in a

> postprandial state for at least 17h of a 24h period. After

consuming 2 meals an

> early plasma TAG peak has been observed after the second meal, the

origin of which

> is unclear.

> ... Methods Postprandial plasma lipaemic responses of 17

healthy postmenopausal

> women were studied by giving a test breakfast followed by a lunch.

Watermiscible

> retinyl palmitate (RP) was added to the breakfast, but not the

lunch test meal.

> Plasma TAG, retinyl esters (RE) and apo B–48 were determined for a

10h period

> following breakfast.

> Results In response to the test meals, RE, apo B–48 and TAG

showed multiple peaks.

> Despite omission of RP from the lunch, RE showed an early peak

response after

> ingestion of lunch in 15 of 17 subjects. The peak response after

lunch of all three

> markers appeared significantly earlier compared with their

respective peak responses

> after the breakfast (P < 0.0001). The area of RE response after

lunch was

> significantly correlated with the RE lipaemic response to the

breakfast (r = 0.67; P

> < 0.004) and to the fasting TAG concentration (r = 0.48; P < 0.05).

> Conclusions Since the lunch did not contain RP, the distinctive

second influx of

> RE after lunch was believed to have originated from the breakfast.

This, together

> with the fact that all three markers showed an earlier response to

the lunch than

> the breakfast, supports the view that ingestion of a second meal

provokes entry of

> fat from the previous meal, from an as yet unidentified site (gut,

enterocytes,

> lymph). The results indicate that the degree of TAG storage from

previous meals

> might be a function of TAG tolerance and provide a possible site of

regulation of

> the entry of fat into the systemic circulation.

>

> Al Pater, PhD; email: old542000@y...

>

> __________________________________________________

>

[Guest guest]

This is probably a meaningless paper due to poor experimental design.

The fact that the article did not even consider " de novo " synthesis of

fatty acids seems to be a weakness in the paper. As we have discussed

before, palmitic acid is the end product of carbohydrate metabolism.

So, even if you have a fat-free lunch, the body is going to create

palmitic acid triglycerides from the carbs.

Proper experimental design would use radioactively labeled

carbohydrates or fats so that it would be possible to determine the

source of the fat molecules: the breakfast, the lunch, or de novo

metabolism of carbohydrates from the lunch.

Tony

De novo fatty acid metabolism:

http://www.reactome.org/cgi-bin/eventbrowser?DB=gk_current & ID=76209 &

> > Hi All,

> >

> > Eating a meal apparently affects the uptake of fat that was

> previously eaten.

> >

> > The pdf is corrupted for the below.

> >

> > Their BMI was an average of 26.6 and they were 62 years old on

> average.

> >

> > The areas under the curves for the times 0-27 minutes and 270-

> 600 minutes were:

> > TAG, 374±66 and 563±116. For Apo B-48, they were:

254±52 and

> 376±87. for RE, they

> > were: 120±36 and 53±66.

> >

> > Meal ingestion provokes entry of lipoproteins containing fat

> from the previous

> > meal: possible metabolic implications

> >

> > K. D. R. R. Silva, J. W. , C. M. , et al.

> > European Journal of Nutrition ISSN: 1436-6207 (Paper) 1436-6215

> (Online) Issue:

> > Online First 05 November, 2004

> >

> > Summary

> > Background Prolonged and exaggerated postprandial plasma

> triacylglycerol (TAG)

> > concentrations are considered as an independent risk factor for

> coronary artery

> > disease. Western populations eat many meals at regular intervals,

> and can be in a

> > postprandial state for at least 17h of a 24h period. After

> consuming 2 meals an

> > early plasma TAG peak has been observed after the second meal,

the

> origin of which

> > is unclear.

> > ... Methods Postprandial plasma lipaemic responses of 17

> healthy postmenopausal

> > women were studied by giving a test breakfast followed by a

lunch.

> Watermiscible

> > retinyl palmitate (RP) was added to the breakfast, but not the

> lunch test meal.

> > Plasma TAG, retinyl esters (RE) and apo B–48 were determined

for a

> 10h period

> > following breakfast.

> > Results In response to the test meals, RE, apo B–48 and TAG

> showed multiple peaks.

> > Despite omission of RP from the lunch, RE showed an early peak

> response after

> > ingestion of lunch in 15 of 17 subjects. The peak response after

> lunch of all three

> > markers appeared significantly earlier compared with their

> respective peak responses

> > after the breakfast (P < 0.0001). The area of RE response after

> lunch was

> > significantly correlated with the RE lipaemic response to the

> breakfast (r = 0.67; P

> > < 0.004) and to the fasting TAG concentration (r = 0.48; P <

0.05).

> > Conclusions Since the lunch did not contain RP, the distinctive

> second influx of

> > RE after lunch was believed to have originated from the

breakfast.

> This, together

> > with the fact that all three markers showed an earlier response

to

> the lunch than

> > the breakfast, supports the view that ingestion of a second meal

> provokes entry of

> > fat from the previous meal, from an as yet unidentified site

(gut,

> enterocytes,

> > lymph). The results indicate that the degree of TAG storage from

> previous meals

> > might be a function of TAG tolerance and provide a possible site

of

> regulation of

> > the entry of fat into the systemic circulation.

> >

> > Al Pater, PhD; email: old542000@y...

> >

> > __________________________________________________

> >