Page 831 - Small Animal Clinical Nutrition 5th Edition

862 Small Animal Clinical Nutrition

acid (Tables 40-3 and 40-6) (Lulich et al, 2001). The increase
Table 40-6. Selected human foods with minimal calcium or in the urine concentration of oxalic acid can be prevented by
VetBooks.ir oxalate content. concomitantly reducing calcium and oxalic acid in the food.
Low-calcium
Food items
foods Low-oxalate Caution: severe calcium restriction should be avoided to pre-
foods
Meats and eggs Eggs Beef vent negative calcium balance.The minimum requirement for
Poultry Eggs calcium in foods for healthy dogs is 0.2% DM and the mini-
Fish and shellfish* mum recommended allowance is 0.4% DM (NRC, 2006). For
Lamb
Pork prevention of recurrence of calcium oxalate uroliths, reduce
Poultry dietary calcium to 0.4 to 0.7% DM.
Vegetables Cabbage People with calcium oxalate uroliths are often cautioned to
Cauliflower
Mushrooms avoid milk and milk products because the carbohydrate compo-
Peas, green nent (lactose) of these products may augment intestinal absorp-
Radishes tion of calcium from any dietary source (Leman et al, 1969).
Potatoes, white
Milk and dairy products Cheese* Likewise, they are often discouraged from consuming foods
Milk* containing relatively high quantities of oxalic acid (Table 40-3).
Yogurt* Although there is agreement that excessive consumption of cal-
Fruits Apple
Avocado cium and oxalic acid should be avoided, the consensus of urol-
Banana ogists is that it is inadvisable to restrict dietary calcium unless
Bing cherries persistent absorptive hypercalciuria has been documented.
Grapefruit
Grapes, green Even then, only moderate restriction is advocated to minimize
Mangos development of negative calcium balance.
Melons
Cantaloupe Phosphorus
Casaba
Honeydew Studies of laboratory animals, dogs and people suggest that
Watermelon dietary phosphorus should not be overly restricted in patients
Plums, green or yellow
Breads, grains, nuts Almonds Bread, white with calcium oxalate urolithiasis because reduction in dietary
Macaroni Macaroni phosphorus is often associated with augmentation of intestinal
Pretzels Noodles calcium absorption and hypercalciuria (Brautbar et al, 1979). If
Rice Rice
Spaghetti Spaghetti calcium oxalate urolithiasis is associated with hypophospha-
Walnuts temia and normal serum calcium concentration, oral phospho-
Miscellaneous Popcorn Jellies rus supplementation should be considered. However, caution
Preserves
Soups with allowed must be used because excessive dietary phosphorus may predis-
ingredients pose hypercalciuric patients to formation of calcium phosphate
uroliths.
*Low in oxalate, but not low in calcium content.
Based on a recommended range for calcium (0.4 to 0.7%
DM) in foods for calcium oxalate urolith prevention in canine
minimum recommended allowance for protein in foods for patients, dietary phosphorus levels should be in the range of 0.3
healthy adult dogs is 10% DM (NRC, 2006). to 0.6% DM with a calcium-phosphorus ratio range of 1.1:1 to
2:1.The minimum recommended allowance for phosphorus in
Calcium and Oxalic Acid foods for healthy adult dogs is 0.3% DM (NRC, 2006).
Reduction of dietary calcium appears to be a logical therapeu-
tic goal because intestinal hyperabsorption of calcium has Sodium
been identified as one mechanism promoting hypercalciuria Sodium chloride can be added to food to increase thirst and
in dogs with calcium oxalate uroliths. However, reducing con- urine volume. However, excess sodium increases urine calcium
sumption of calcium may increase the availability of oxalic excretion and therefore is a risk factor for calcium oxalate and
acid for intestinal absorption and subsequent urinary excre- calcium phosphate urolithiasis, particularly if the urinary pH is
tion. As in the urinary bladder, calcium and oxalic acid in the high. For the same reason, if oral urinary alkalinizing agents are
intestinal lumen form a relatively insoluble complex, thereby used, potassium citrate may be a better choice than sodium
preventing the absorption of one another. This provides a bicarbonate. Supplemental sodium sources may also contribute
plausible explanation as to why an epidemiologic study evalu- to hypertension in salt-sensitive dogs.
ating risk factors for calcium oxalate urolith formation in peo- In people, high dietary sodium consumption also reduces
ple unexpectedly discovered that foods with higher calcium urine citrate concentration via sodium-induced bicarbonate
levels were associated with reduced risk for urolith formation loss. Daily urine calcium excretion of normal dogs consum-
(Curhan et al, 1993, 1997; Curhan, 2007). Therefore, in ing foods with 0.8% DM sodium was comparable to calcium
hypercalciuric patients, reduction in dietary calcium should be excretion observed in dogs with calcium oxalate uroliths
accompanied by an appropriate reduction in dietary oxalic (Lulich, 1991). Based on this evidence, we recommend mod-