renal lithiasis and nutrition 2003

7/28/2019 Renal Lithiasis and Nutrition 2003

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RENAL LITHIASIS ANDNUTRITION

Nutrition Related Disease


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Regulation of Calcium

Metabolism Minerals; serum concentration Calcium (Ca2+); 2.2-2.6 mM (total) Phosphate (HPO4

2-); 0.7-1.4 mM Magnesium (Mg2+); 0.8-1.2 mM

Organ systems that play an import role in Ca2+metabolism Skeleton GI tract Kidney

Calcitropic Hormones Parathyroid hormone (PTH) Calcitonin (CT) Vitamin D (1,25 dihydroxycholecalciferol) Parathyroid hormone related protein (PTHrP)


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Three Forms of Circulating

Ca2+


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Calcium Balance Intake = output Negative calcium

balance: Output > intake Neg Ca2+ balance leads to

osteoporosis

Positive calcium balance:Intake > output Occurs during growth Most people are

asymptomatic Classically affects skeleton,

kidneys, and GI tract

Triad of complaints: bones,stones, and abdominalgroans

Renal stones are most

common single presentingcomplaint

Usually due to an adenoma(tumor)

Calcium is essential, wecant synthesize it


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Major Mediators of Calcium and

Phosphate Balance

Parathyroid hormone (PTH)

Calcitriol (active form of vitamin D3)


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Protective and Problems

Foods High-Potassium Foods. A study of 46,000 men conducted by Harvard

University researchers found that a high

potassium intake can cut the risk of kidneystones in half. Potassium helps the kidneys retain calcium,

rather than sending it out into the urine.

Potassium supplements are not generallynecessary. Rather, a diet including regularservings of fruits, vegetables, and beanssupplies plenty of potassium.


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Main Purine Rich Animal

Foods


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Renal Calculi

Author: Sandy Craig, MD, Adjunct Associate Professor, Department of Emergency

Medicine, University of North Carolina at Chapel Hill, Carolinas Medical

Center Contributor Information and Disclosures, Updated: Oct 29, 2009

Calcium stones (75%): Recent data suggest that a low-protein, low-salt diet may bepreferable to a low-calcium diet in hypercalciuric stone formers for preventing stonerecurrences.3 Epidemiological studies have shown that the incidence of stone disease isinversely related to the magnitude of dietary calcium intake in first-time stone formers.There is a trend in the urology community not to restrict dietary intake of calcium inrecurrent stone formers. This is especially important for postmenopausal women in whom

there is an increased concern for the development of osteoporosis. Calcium oxalate,calcium phosphate, and calcium urate are associated with the following disorders:

Hyperparathyroidism - Treated surgically or with orthophosphates if the patient is not asurgical candidate

Increased gut absorption of calcium - The most common identifiable cause ofhypercalciuria, treated with calcium binders or thiazides plus potassium citrate

Renal calcium leak - Treated with thiazide diuretics Renal phosphate leak - Treated with oral phosphate supplements

Hyperuricosuria - Treated with allopurinol, low purine diet, or alkalinizing agents suchas potassium citrate

Hyperoxaluria - Treated with dietary oxalate restriction, oxalate binders, vitamin B-6, ororthophosphates

Hypocitraturia - Treated with potassium citrate Hypomagnesuria - Treated with magnesium supplements
http://emedicine.medscape.com/article/766906-overviewhttp://emedicine.medscape.com/article/444866-overviewhttp://emedicine.medscape.com/article/444683-overviewhttp://emedicine.medscape.com/article/444968-overviewhttp://emedicine.medscape.com/article/444968-overviewhttp://emedicine.medscape.com/article/444683-overviewhttp://emedicine.medscape.com/article/444866-overviewhttp://emedicine.medscape.com/article/766906-overview


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Oxalate Intake and the Risk for

Nephrolithiasis

(J Am Soc Nephrol 18: 21982204, 2007)

CONCLUSION

Our data do not support the contention that

dietary oxalate is a major risk factor for incidentkidney stones. The risk that was associated withoxalate intake was modest even in individualswho consumed diets that were relatively low incalcium. We hope that our study encouragesadditional research into the relations betweendietary oxalate, other dietary factors,endogenous oxalate production, urinary oxalate,and kidney stone formation.


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Mechanism of Urinary Calcium Regulation by Urinary

Magnesium and pH (J Am Soc Nephrol 19: 15301537,

2008)


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DASH-Style Diet Associates with Reduced Risk

for Kidney Stones (J Am Soc Nephrol 20: 2253

2259, 2009)

In conclusion, consumption of a DASH-stylediet is associated with a marked decrease inkidney stone risk


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Here are simple steps to help your

patients avoid kidney stones.

Encourage patients to drink plenty of water orother fluids, staying ahead of their thirst.

Diets including generous amounts of vegetables,fruits, and beans are rich in potassium and verylow in sodium.

If you prescribe calcium supplements, encouragepatients to take them with meals, rather thanbetween meals.

Encourage patients to avoid animal products(

renal lithiasis and nutrition 2003

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