Page 920 - Small Animal Clinical Nutrition 5th Edition

952 Small Animal Clinical Nutrition

lizing. Differences in absorption of the cation and anion por-
Table 46-17. Effect of urinary pH on urine saturation values in tion of a salt are important.Intestinal absorption of calcium and
VetBooks.ir Food Urinary pH CaOx RSS Struvite RSS magnesium is relatively low. However, absorption of accompa-
healthy cats (n = 6).*
NaHCO 3 6.81 ± 0.33 b 0.78 ± 0.53 a 7.98 ± 4.62 b nying anions can be high and influences urinary pH. Non-
Control 6.18 ± 0.26 a 0.71 ± 0.28 a 1.61 ± 1.11 a metabolizable anions (e.g., chloride, phosphate and sulfate)
NH Cl 5.81 ± 0.14 a 1.66 ± 0.58 b 1.16 ± 0.25 a absorbed in excess of their accompanying cations are acidifying.
4
Key: NaHCO = sodium bicarbonate, NH Cl = ammonium chlo- For example, ammonium chloride, calcium chloride and calci-
4
3
ride, CaOx = calcium oxalate, RSS = relative supersaturation.
*Significant differences within columns indicated by different um sulfate decrease urinary pH, and magnesium oxide and cal-
superscripts. Adapted from Stevenson AE, Wrigglesworth DJ, cium carbonate increase urinary pH.
Markwell PJ. Urine pH and urinary relative supersaturation in Urinary pH plays a critical role in managing cats with stru-
healthy adult cats In: Rodgers AL, Hibbert BE, Hess B, et al, eds.
IXth International Symposium on Urolithiasis. Cape Town, South vite disease but appears less important in cats with calcium
Africa, 2000: 818-820. oxalate uroliths. Struvite is highly soluble and is, therefore, less
likely to precipitate in acidic urine (pH <6.5). Alterations in
urinary pH have a proportionally greater effect on changing
struvite activity product than changes in crystalloid (e.g., mag-
Table 46-18. Oxalate content of selected human foods.*
nesium) concentrations. Decreasing urinary pH, therefore, is
Product Moderate to the most reliable means of producing urine undersaturated for
categories high oxalate Low oxalate struvite. Although acidifying foods have been associated with
occurrence of calcium oxalate uroliths in cats, changes in uri-
Milk and dairy – Milk**
products Cheese** nary pH values over the physiologic range appear to have little
effect on solubility of calcium oxalate (Figure 46-17) (Ver-
Meats Liver Beef
Sardines Bacon plaetse et al, 1985; Yu and Gross, 2007; Stevenson et al, 2000).
Ham One study showed that pH changes between 4 and 11 had
Lamb minimal effect on calcium oxalate solubility (Verplaetse et al,
Shellfish
Poultry 1985). In a study of healthy cats fed three foods to produce dif-
ferent urinary pH values, reducing urinary pH from 6.81 to
Fruits Apples (green) Apples (red) 6.18 had no significant effect on urine saturation for calcium
Apricots Coconut (fresh)
Bananas Cranberries oxalate (0.78 vs. 0.71) but significantly decreased struvite satu-
Cherries Melons ration (Table 46-17) (Stevenson et al, 2000).
Berries (most) Peaches The recommended urinary pH range for dissolving struvite
Oranges/tangerines
Pears uroliths is 5.8 to 6.2. To decrease risk for recurrence of struvite
Peel (lemon/lime/orange) uroliths or urethral plugs, urinary pH should be 6.0 to 6.4;
Pineapple however, to decrease risk for recurrence of calcium oxalate
uroliths, urinary pH should be at least 6.2.Thus, foods for pre-
Vegetables Beans Asparagus
Carrots Avocado vention of both struvite and calcium oxalate urolithiasis should
Celery Broccoli** produce a urinary pH between 6.2 to 6.4.
Green beans Cabbage
Green peppers Corn (sweet)
Greens (collards, Cucumber Fatty Acids
mustard, turnips) Urinary bladder inflammation is characteristic of most lower
Peas
Soybean products urinary tract disorders including FIC and urolithiasis. Long-
Spinach chain omega-3 (n-3) fatty acids such as eicosapentaenoic acid
Sweet potatoes (EPA) and docosahexaenoic acid (DHA) have potent antiin-
Tofu
Tomatoes flammatory properties. These dietary fatty acids are absorbed
and incorporated into cell membranes, including those of the
Breads/ Bagels Bread (white) urinary bladder, where they may alter production of inflam-
grains/nuts Bread (whole wheat) Tortilla (corn)
Cornbread Pasta (boiled) matory mediators. Antiinflammatory effects of omega-3 fatty
Fig newtons Popped popcorn acids such as EPA have been demonstrated in dogs with
Fruitcake Rice (white) osteoarthritis and patients with dermatitis. Effects of omega-
Grits
Oatmeal 3 fatty acids have not been evaluated in cats with various
Most nuts lower urinary tract disorders; however, they appear to have
Rice (brown) beneficial urinary effects in studies of other species.
*For information about oxalate content of additional foods see Administration of EPA to rats prevented experimentally
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**High in calcium, therefore, may not be ideal for cats with induced nephrocalcinosis and significantly decreased urinary
calcium oxalate uroliths. calcium excretion compared with a placebo (Buck et al, 1991).
In a second part of the study, 12 human patients with recur-
rent calcium oxalate uroliths and hypercalciuria had signifi-