kidney stones

[Vince]

Current evidence suggests that the consumption of low calcium- diets is associated with a higher overall risk for the development of calcium oxalate kidney stones than the consumption of too much calcium.(Parmar, Malvinder S. (2004). "Kidney stones". British Medical Journal 328 (7453): 1420–1424. doi:10.1136/bmj.328.7453.1420. PMID 15191979 )

This is perhaps related to the role of calcium in binding ingested oxalate in the gastrointestinal tract. As the amount of calcium intake decreases, the amount of oxalate available for absorption into the bloodstream increases; this oxalate is then excreted in greater amounts into the urine by the kidneys. In the urine, oxalate is a very strong promoter of calcium oxalate precipitation, about 15 times stronger than calcium.Normal calcium intake is >30mmol/day. There is equivocal evidence that calcium supplements increase the risk of stone formation.

Restricting the intake of food that is high in oxalate is only helpful in those patients who are absorbing excess oxalate ,i.e. a minority of patients as most oxalate excreted in the urine is actually made in the liver.


The formation of calcium phosphate stones can be associated with renal tubular acidosis or hyperparathyroidism.

Some researchers suggested that nanobacteria can cause the formation of kidney stones.(Ciftcioglu N, Bjorklund M, Kuorikoski K, Bergstrom K, Kajander EO. Nanobacteria: an infectious cause for kidney stone formation. Kidney Int 1999;56: 1893-8. [PubMed] )

 

[Vince]

Christopher Masterjohn wrote,"Lifeguards in the tropics can reach blood levels in the 50's and 60's naturally from sun exposure, suggesting these levels are "natural," although lifeguards in Israel have 20 times the rate of kidney stones as the general population. Kidney stones may be the most sensitive indicator of vitamin D toxicity and are a symptom of vitamin A and K[SUB]2[/SUB] deficiency. Thus, I suspect these levels are healthful in the context of a diet rich in vitamins A and K[SUB]2[/SUB], and if my levels were to reach this high in the summer sun while I were eating such a diet I certainly would not worry.

 

[Vince]

http://www.umm.edu/health/medical/reports/articles/kidney-stones#ixzz3RWqH0eoN

People with kidney stones face a higher risk for chronic kidney disease, particularly if they also have diabetes, high blood pressure, or frequent urinary tract infections. Having chronic kidney disease, in turn, can increase the risk for a heart attack. Researchers have found that in general, kidney stones increase the risk for a heart attack by more than a third (as well as the risk for certain other disorders), independent of their effect on chronic kidney disease.

 

[Vince]

"[SIZE=-1][SIZE=-1][SIZE=-1]Women taking a daily calcium (1,000 mg) and vitamin D (400 IU) supplement showed a 17% increase in kidney stones compared to women who did not receive the supplement (Wallace, Am J Clin Nutr 2011). The increased risk, however, is small, as only 0.35% of the women taking the calcium/vitamin D supplement reported kidney stones, compared to 0.30% of the women in the control group. A similar (17% to 20%) increase in kidney stones has been reported in studies with calcium supplementation alone, suggesting that calcium, rather than vitamin D, is the causative factor. The increased risk of kidney stones in women has been observed with calcium from supplements but not with calcium from dietary sources."[/SIZE][/SIZE][/SIZE]