Re: Calcium as Part of a Normal Protein Diet May Increase Fecal Fat and Energy Excretion

[Guest guest]

Hi Al:

Thank you. That nicely ties up the loose end associated with the

calcium/weight loss anomaly. So the law of conservation of energy is

not being violated. Phew!

My bet is that similar studies/analyses will likely yield similar

explanations for other apparently anomalous situations, such as

people who: " eat like a horse and never put on weight " , or those

who: " eat next to nothing and cannot lose weight " , and others.

We have previously discussed the possibility that variations in

intestinal absorption may be a factor, so it is nice to see that

confirmed. At least in the particular case studied.

Rodney.

--- In , " Al Young " <acyoung@r...>

wrote:

>

>

> Medscape Medical News 2005. © 2005 Medscape

>

>

>

>

> March 29, 2005 - Calcium, taken along with a normal protein diet,

increases

> fecal fat and energy excretion, according to the results of a

randomized

> crossover study published in the April issue of the International

Journal of

> Obesity. The investigators suggest that this may help explain

weight loss

> from high-calcium diets.

>

> " Observational studies have shown an inverse association between

dietary

> calcium intake and body weight, and a causal relation is likely, "

write R.

> sen, MD, from the Royal Veterinary and Agricultural University

in

> Frederiksberg, Denmark, and colleagues. " However, the underlying

mechanisms

> are not understood. "

>

> Ten subjects each received three isocaloric one-week diets

containing low

> calcium and normal protein (LC/NP; 500 mg calcium; 15% of energy

from

> protein), high calcium and normal protein (HC/NP; 1,800 mg of

calcium; 15%

> of energy from protein), and high calcium and high protein (HC/HP;

1,800 mg

> of calcium; 23% of energy from protein).

>

> Although calcium intake did not affect 24-hour energy expenditure

or fat

> oxidation, fecal fat excretion increased approximately 2.5-fold

during the

> HC/NP diet compared with the LC/NP and the HC/HP diets (14.2 vs 6.0

and 5.9

> g/day; P < .05). The HC/NP diet also increased fecal energy

excretion

> compared with the LC/NP and the HC/HP diets (1,045 vs 684 and 668

kJ/day; P

> < .05). Calcium intake did not affect levels of blood cholesterol,

free

> fatty acids, triacylglycerol, insulin, leptin, or thyroid hormones.

>

> Study limitations include not testing the effect of calcium on

appetite and

> energy intake, so it is possible that calcium may also have

metabolic

> effects resulting in suppression of energy intake. Effects on

energy

> metabolism also could not be excluded due to the short duration of

the

> study.

>

> " A short-term increase in dietary calcium intake, together with a

normal

> protein intake, increased fecal fat and energy excretion by

[approximately]

> 350 kJ/day, " the authors write. This observation may contribute to

explain

> why a high-calcium diet produces weight loss, and it suggests that

an

> interaction with dietary protein level may be important. "

>

> The Danish Dairy Board and the Danish Ministry of Food,

Agriculture, and

> Fisheries supported this study.

>

> Int J Obesity. 2005;29:292-301