Bones in Space

 

 

 

 

 

When extra calcium is absorbed, that calcium is temporarily stored in the bones and deported from the bones as soon as there is the opportunity to do so. (1) When little calcium is consumed, dietary calcium absorption rate is greater and there is less calcium to deport. (2)

 

Bone cells are destroyed due to exercise, which stimulates the bones to hold on to more calcium to be better able to cope with future burdening.

The bones will deport more calcium if there is no loading of the bones since there seems to be no need to hold on to it.

 

Bone-mineral density (BMD) in astronauts decreased 1% to 2% each month, on the average, but the lower weight-bearing bones appeared more sensitive than the upper ones. (3) However, BMD of the skull, a non-weight bearing bone, does not decrease at all. (4)

In the MIR 97- mission high calcium intake and vitamin D supplementation led to decreased bone formation and increased bone-calcium deportation. (5) Bone-calcium absorption is reduced during immobilization, (6) but is incresased when the body is physically active. (7)

 

There 'apparently' was less need for minerals in the bones because the bones experienced no burdening in space and thus BMD decreased.

No matter how much calcium was consumed, the bones did not hold it because ‘there was no need to do so’. Apparently not just the deportation of calcium was increased, but even calcium absorption and bone-formation were also decreased to prevent the need for subsequent calcium deportation.

The bones appear to be sensitive to this stimuli according to the need for adaptation given earthly circumstances, which is different for the legs, the arms, the head, etc.

So the bones “are not stupid”. They hold the calcium they need and they deport what is not needed.

 

All the redundant calcium that is consumed is always deported too. The more calcium that is processed, the sooner the cells that do the processing will be worn out, eventually causing osteoporosis.

 

 

 

 

© 2000 Copyright Artists Cooperative Groove Union U.A.     

 

 

 

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Excessive Calcium Causes Osteoporosis

 

 

 

Sources

Abstracts of these sources can be found at The National Library of Medicine

 

(1) Bronner F., et al, Development and regulation of calcium metabolism in healthy girls. J. Nutr. 1998 / 128 (9) / 1474-1480. , O'Brien K.O., et al, Variables related to urinary calcium excretion in young girls. J. Pediatr. Gastroenterol. Nutr. 1996 / 23 (1) / 8-12. , Lee, W.T. et al, A follow-up study on the effects of calcium-supplement withdrawal and puberty on bone acquisition of children. Am. J. Clin. Nutr. 1996 / 64 (1) / 71-77.

(2) O'Brien, K.O. et al, Increased efficiency of calcium absorption from the rectum and distal colon of humans. American Journal of Clinical Nutrition 1996 / 63 (4) / 579-583.

(3) Collet P, et al, Effects of 1- and 6-month spaceflight on bone mass and biochemistry in two humans. Bone 1997 /20 (6) / 547-551.

(4) Miyamoto A, et al, Medical baseline data collection on bone and muscle change with space flight. Bone 1998 / 22 (5 Suppl.) / 79S-82S.

(5) Heer M, et al, Calcium metabolism in microgravity. Eur. J. Med. Res. 1999 /  4 (9) / 357-360.

(6) Branca F., Physical activity, diet and skeletal health. Public Health Nutr. 1999 / 2 (3A) / 391-396.

(7) Zittermann A, et al, Exercise-trained young men have higher calcium absorption rates and plasma calcitriol levels compared with age-matched sedentary controls. Calcif. Tissue Int. 2000 / 67 (3) / 215-219.