Advances in pet nutrition andveterinary care have resulted in increasedlongevity of companion animals. Thisincreased life expectancy brings with itincreased wear and tear on the body,including the musculoskeletal system, andcan result in an increased risk of disordersinvolving joints and joint capsules. Thus,with advancing age, the risk fordevelopment of chronic, progressivediseases affecting, in particular, weight-bearing joints such as the knees, hips,back, and feet appears to be on theupswing in both human and petpopulations.

Most notable in this regard isosteoarthritis (OA). OA is the mostcommon form of arthritis. It is aprogressive, degenerative joint diseasecharacterized by changes in the synovialmembrane, including periarticularosteophyte production and degeneration

IN THIS ISSUE:Nutraceuticals and Joint Health ............................... 1Dangerous Foods........................ 4Ask the Vet ................................ 7

materials and promote their effects assynergistic. However, it is more difficult(and costly) to scientifically prove thatone particular substance is efficaciouswhen it is combined with otheringredients in a proprietary formula.Some evidence exists in the veterinaryliterature that such combination productshave a beneficial effect on joint health,yet conflicting results with the samenutrients have been reported in otherstudies.

M A Y 2 0 0 5 V O L U M E 3 , N U M B E R 2

A NEWSLETTER OF PRACTICAL MEDICINE FOR VETERINARY PROFESSIONALSA NEWSLETTER OF PRACTICAL MEDICINE FOR VETERINARY PROFESSIONALS

of articular cartilage. OA can range from mild to severe and results in pain,swelling, stiffness, and, over time, loss ofjoint mobility.

Several drugs have been developed andused to treat the pain and swelling ofOA-affected joints, but none has beenable to remedy the underlying loss ofcartilage that progressively occurs withthis disorder. This is a major reason whydietary chondroprotective supplements,which may help mitigate the loss ofcartilage, continue to gain popularity asbeing beneficial for OA.

Although most attention has beendirected to glucosamine and chondroitinsulfate, other products containing green-lipped mussel, methylsulfonylmethane(MSM), and trace minerals such as zinc,copper, and manganese are often alsofound in joint health supplements. Manyproducts use combinations of these

Nutraceuticals and Joint HealthJohn E. Bauer, DVM, PhD, DACVNComparative Nutrition LaboratoryDepartment of Small Animal Clinical SciencesCollege of Veterinary MedicineTexas A&M UniversityCollege Station, Texas

2 HARTZ® COMPANION ANIMALSM • MAY 2005 • VOL. 3, NO. 2

Consulting EditorsAlbert Ahn, DVM

Vice President of CorporateCommunications and VeterinaryOperationsThe Hartz Mountain Corporation

Bruce TrumanDivisional Vice President Animal Health and NutritionThe Hartz Mountain Corporation

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is produced for The Hartz Mountain Corporation by Veterinary Learning Systems, 780 Township Line Rd.,Yardley, PA 19067.

Copyright © 2005 The Hartz Mountain Corporation. All rights reserved.

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A NEWSLETTER OF PRACTICAL MEDICINE FOR VETERINARY PROFESSIONALSGLUCOSAMINE ANDCHONDROITIN SULFATEEffects on Joint Pain andOsteoarthritis

Among the chondroprotective agents,glucosamine is probably most frequentlymentioned. It is an amino sugar that isnaturally produced in the body.Glucosamine is a building block ofglycosaminoglycans (GAGs), which arepresent in joints, tendons, ligaments, skin,and even blood vessels. GAGs are high-molecular-weight molecules that holdwater and impart the joint capsule with theability to adapt to pressure changes duringweight bearing and absorb shock inducedby mechanical stress. As OA progresses,loss of cartilage occurs as a result ofdestruction of the GAGs and loss of theshock-absorbing property of the jointcapsule. It is believed that providingsupplemental glucosamine to joint tissuewill stimulate new GAG production. It hasbeen shown that not only can glucosaminebe absorbed via the gastrointestinal tract indogs after ingestion, but it also can betaken up by articular cartilage.1 Thus,dietary provision of glucosamine is believedto be an important component for thereplenishment of GAGs in the jointcapsule.

A biochemical basis for the use ofglucosamine in treating chronicinflammatory diseases has also beenshown using the rat model oflipopolysaccharide-inducedinflammation.2 That study found thatglucosamine inhibits inducible nitricoxide synthesis, which when produced inexcess, mediates the pathogenesis of OA.Furthermore, a randomized, placebo-controlled clinical trial of human OApatients evaluated the long-term effectsof glucosamine sulfate (1,500 mg/dayPO).3 Both symptom- and structure-modifying effects were found, suggestingthat the compound could mitigate OA.This trial also concluded that theglucosamine sulfate product used was safebecause no significant differences inadverse events compared with placebowere found. Another study of 200 human

subjects found no progressive joint spacenarrowing of the tibiofemoral joint(determined radiographically) withglucosamine sulfate compared with thatoccurring with a placebo.4 Subjects wereadministered 1,500 mg glucosaminesulfate daily for 3 years. Improvement ofpain and stiffness indexes was also foundin the treatment group. In a smaller trial,46 human subjects were prescribed 2,000mg of glucosamine/day for 12 weeks;marked improvements in self-reportedpain relief (88% given glucosamine versus17% given placebo) were noted.5 Theauthors suggested that glucosaminesupplementation can provide some degreeof pain relief and improved function inindividuals who experience regular kneepain caused by cartilage injury and/orOA. The trends also indicated that with a dose of 2,000 mg/day, mostimprovements are seen after 8 weeks.

A major review of several randomized,placebo-controlled clinical trialsconducted on both glucosamine andchondroitin supplementation alsodemonstrated high efficacy ofglucosamine on joint-space narrowingand improvement of pain and stiffnessindexes.6 Chondroitin was found to beeffective on other outcomes used toevaluate pain and mobility, and safetyappeared excellent for both compounds.Taken together, these studies showstructural efficacy of glucosamine andsimilar symptomatic efficacies for bothcompounds. However, it was concludedthat the relatively sparse data onglucosamine and joint-space narrowingand the absence of data on structuraleffects of chondroitin point to the needto investigate time, dose, patientcharacteristics, and structural efficacy fora more accurate assessment of these twocompounds for OA.6

In spite of the mostly positiveoutcomes in human trials, the long-termbenefit of glucosamine supplements totreat human knee-joint OA has recentlycome into question by Canadianresearchers. Their recently publishedstudy looked at whether oral glucosamine

could prevent painful flare-ups over a 6-month period in patients who had alreadytaken the supplement for an average of 2years and who had experienced at leastmoderate improvements in knee pain.7

Using a dose not exceeding 1,500mg/day, it was found that subjects’ painflared as quickly and severely as those inthe placebo group. Thus, these data donot support a benefit against symptomswith continued use of oral glucosamine.7

Interest in glucosamine and chon-droitin sulfate dietary supplementation

HARTZ® COMPANION ANIMALSM • MAY 2005 • VOL. 3, NO. 2 3

continues to be high, especially becausethe number of individuals with arthritisappears to be increasing. It is expectedthat similar interest in these supplementswill exist for companion animals as well.However, no long-term safety studies ofthe chondroprotective agents in dogs orcats have been reported in the literature.

The continued interest in thesesupplements awaits the publication ofresults from an ongoing study supportedby the National Institutes of Healthcalled the Glucosamine/ChondroitinArthritis Intervention Trial (GAIT),scheduled for completion in November2005. This study is a 24-week, placebo-controlled, parallel, double-blinded trialwith 1,588 subjects evaluated at 13clinical centers. The efficacy ofglucosamine alone, chondroitin alone, andthe two in combination will be comparedwith placebo in treating OA knee pain.

Effects on Glucose MetabolismAlthough most clinical trials have

found the safety of glucosamine andchondroitin supplements to be excellent,some concerns related to glucosemetabolism exist. Glucosamine infusionsin both ducks and dogs have beenreported to cause hyperglycemia due tothe release of glucagon immunoreactivityand possible insulin suppression.3,8 Thedose used in this instance may have beenhigher than that generally used as adietary supplement. Nonetheless, inhumans, glucosamine infusions producedacute insulin resistance,9 and glucosaminemay also induce or exacerbate insulinresistance.10

By comparison, a recent placebo-controlled, double-blinded, randomizedclinical trial looked at the effects ofglucosamine–chondroitin sulfatesupplementation for 90 days on glycemiccontrol in human outpatients with type 2diabetes mellitus. Although a smallnumber of patients were excluded becauseof comorbidities, adverse effects andchanges in diabetes management werenot seen, including mean hemoglobinA1c concentrations.11 Oral glucosamine

supplementation did not result inclinically significant alterations in glucosemetabolism in these diabetic patients inthis single study. Clearly, additionalstudies are needed to help confirm thesefindings.

In dogs, an anecdotal report using anoral dose of glucosamine (1,000 mg/day,duration unspecified) in an 11-year-oldLabrador retriever noted urinaryincontinence, polyuria, and polydipsia, allof which abruptly returned to normalwhen the dose was reduced to 500mg/day.12 However, serum glucoseconcentration tested using a midday,nonfasted sample was normal, andfollow-up tests were not conducted. Bycontrast, one study in rats was unable todemonstrate adverse effects ofglucosamine or chondroitin sulfate onglucose metabolism.13 Until more usagedata are obtained, caution is advised andmore frequent monitoring in cases ofdiabetes or possibly even obese animalsprone to type 2 diabetes should beemployed when glucosamine is beingused for OA or related problems in suchpatients.

COMBINATION PRODUCTSWith respect to other

chondroprotective agents, data exist thatsupport an interactive, or synergistic,effect between glucosamine andchondroitin sulfate in helping maintainjoint health. Combinations ofglucosamine with other productscontaining mucopolysaccharides or othersubstances may also help alleviate jointproblems or rebuild degeneratingcartilage. One proprietary product inparticular that combines glucosaminewith chondroitin sulfate and manganeseascorbate has been subjected to severalcell culture and animal studies in dogsand other target species.14–17 Survey dataof practicing veterinarians have providedinformation that pain relief as well asmobility was good to excellent with thistype of combination product.15

Other substances that may benefitjoint health include MSM and green-

lipped mussel extracts. A purportedbenefit of MSM is that it is a bioavailablesource of sulfur, which is a component ofseveral structural compounds found injoints.18 The use of MSM in dogs or catshas yet to be evaluated. One human trialadministered a combination of 500 mgglucosamine and 500 mg MSM for 12weeks and concluded that this particularcombination therapy showed betterefficacy in reducing pain and swellingthan either alone.19 An extract of green-lipped mussel combined with a mixture ofGAGs, n-3 fatty acids, and possibly othercompounds has been shown to benefitdogs exhibiting chronic lameness.20

However, another dog study was unableto confirm this finding.21 Additionalproprietary combinations have also beenevaluated. 22,23 In these cases, potentialbenefits of glucosamine may be furtherenhanced by the addition of other knowncollagen-matrix components or evenantiinflammatory agents.

IN SUMMARYChondroprotective agents such as

GAG precursors are often derived fromvarious animal species. As such, they maycontain other proteins that carry apotential for allergic reactions. Asadditional findings of both proprietarymixtures and single substances arereported, further confidence in the safeand efficacious use of chondroprotectivematerials, in certain clinical cases, willdevelop. However, at present, caution isadvised with the use of these agents indogs and cats, especially in the absence ofrelated long-term safety data. It appearsthat initial relief of some signs associatedwith OA may exist. However, long-termbenefits of their use to minimize painfulflare-ups await further study.

References1. Setikar I, Giacchetti C, Zanolo G:

Pharmacokinetics of glucosamine in the dog and inman. Arzneimittelforschung 36:729–735, 1986.

2. Meininger CJ, Kelly KA, Li H, et al: Glucosamineinhibits inducible nitric oxide synthesis. BiochemBiophys Res Commun 279:234–239, 2000.

3. Reginster JY, Deroisy R, Rovati LC, et al: Long-term effects of glucosamine sulphate on

(continues on page 6)

4 HARTZ® COMPANION ANIMALSM • MAY 2005 • VOL. 3, NO. 2

increased heart rate, hyperactivity,tremors, and potentially death. Othereffects seen with chocolate overdoseinclude diarrhea, lethargy, increasedthirst, increased urination, and vomiting.Although theobromine and caffeine havean LD50 of 100 to 200 mg/kg, signs canmanifest well below this dose: Mild signscan be seen at doses higher than 20mg/kg, moderate signs above 40 mg/kg,and severe signs above 60 mg/kg.1

The amount of methylxanthines inchocolate varies with the type ofchocolate. Generally, the more bitter thechocolate is, the more toxic it can be(Table 1). In fact, unsweetened bakingchocolate contains about seven timesmore theobromine than milk chocolate,while white chocolate (a combination ofcocoa butter, sugar, butterfat, milk solids,and flavorings but no cocoa beans)contains negligible amounts ofmethylxanthines.

Early treatment, includingdecontamination procedures (such asinducing emesis and administeringactivated charcoal), monitoringcardiovascular health, and providingsupportive care, is extremely helpful incases of chocolate poisoning. In addition,fluid diuresis may help enhance

Dangerous FoodsProblems Resulting from Ingestionand Appropriate Treatments

Pet owners often give table scraps totheir pets as a special treat. This seems tobe especially true on holidays, because petowners often include their pets in theircelebrations. Unfortunately, some types ofhuman food can be toxic to pets, so it isimportant that veterinarians and their staffbe aware of these dangerous foods and howto respond if a pet has consumed them.

The best way to avoid seriousproblems caused by pets consumingdangerous foods is through poisonprevention. Veterinary staff can educatepet owners using educational displays,newsletter items, and on-holdmessaging. However, if a pet eats adangerous food item, prompt action canhelp avoid a potentially life-threateningproblem.

ChocolateA mixture of cocoa beans and cocoa

butter, chocolate contains theobromineand caffeine, which are both classified asmethylxanthines. Dogs are sensitive tothe effects of methylxanthines, whichcompetitively inhibit cellular adenosinereceptors, resulting in central nervoussystem (CNS) stimulation andtachycardia.1 Depending on the amountconsumed, methylxanthines can cause

Jill A. Richardson, DVMAssociate Director, Consumer Relations and Technical ServicesHartz Mountain CorporationSecaucus, New Jersey

Table 1: Amount of Methylxanthines in Certain Types of Chocolate

Type of Chocolate Caffeine (mg/oz) Theobromine (mg/oz)

Milk chocolate 6 44–56Semisweet 22 138Baking chocolate (unsweetened) 33–47 393

elimination.1 It should be noted, however,that the bladder wall can reabsorbcaffeine, which may increase the durationof clinical signs. Therefore, the veterinarystaff should take extra steps, such ascatheterization or frequent walking, tokeep the patient’s bladder empty.1

Grapes and RaisinsSome types of grapes and raisins have

been shown to cause kidney failure indogs when consumed in large amounts.2

The basis of this kidney failure is unclearbut is currently being studied in theveterinary community. The exact amountof grapes or raisins that may cause renalfailure is not known, so any amount couldpotentially be dangerous.

Recommended treatment for recentingestion includes inducing emesis andadministering activated charcoal.2 Thesesteps should be followed by fluid diuresisfor 48 hours, during which the patientshould be monitored for azotemia.2 If theanimal shows signs of renal failure, fluidsand supportive care should be continued.

Macadamia NutsAccording to a retrospective study,

clinical signs commonly reported in dogsingesting macadamia nuts include ataxia,depression, hyperthermia, tremors,vomiting, and weakness.3 In most cases,dogs developed clinical signs within thefirst 12 hours after ingestion.3 These signshave only been seen in dogs, and the exactcause for dogs’ sensitivity to macadamianuts is unknown. The lowest dose reportedto cause clinical effects is 2.4 g/kg.3

HARTZ® COMPANION ANIMALSM • MAY 2005 • VOL. 3, NO. 2 5

members of the Allium family is n-propyldisulfide, which is thought to causeoxidative damage to erythrocytes, resultingin hemolysis and potentially anemia.5

In one study, dogs were given5 g of whole garlic/kgintragastrically once a day for7 days. On days 9 to 11, thedogs had decreasederythrocyte counts,hematocrits, and hemoglobinconcentrations. Heinz bodiesand eccentrocytes, along with anincrease in erythrocyte-reducedglutathione concentrations, were alsodetected; however, none of the dogsdeveloped hemolytic anemia.6

In another study, dogs developedhemolytic anemia after being fed 30 g/kgof onions once daily for 3 days.7 Heinzbody hemolytic anemia was seen in a dogthat ingested Chinese chive (Alliumtuberosum) and garlic (Allium sativum).8 Inaddition, toxicoses caused by ingestion offresh, dried, or powdered plant materialhave been reported in dogs and cats.Commercial baby food containing onionpowder has also been reported to causetoxicity in cats. Clinical signs associatedwith onion poisoning include hemolyticanemia, hemoglobinuria, pallor, vomiting,and weakness.

Decontamination procedures such asinducing emesis and administeringactivated charcoal should be consideredwith recent ingestions. Afterward, theanimal should be monitored for azotemia,hemolysis, and/or decreased packed cellvolume. Whole-blood transfusions oradministration of oxygenated hemoglobinshould be considered for critical patients.Fluid diuresis is recommended in patientswith hemoglobinuria. Supportive careshould be administered until recovery.

Rising Bread DoughIngestion of rising bread dough can be

life threatening to dogs. The animal’s bodyheat will cause the dough to rise in thestomach. Ethanol is produced during therising process, and the dough may expandto several times its original size. Signs seen

Treatment includes decontaminationprocedures such as inducing emesis,administering activated charcoal, andadministering enemas. Additionalsupportive care should be given as needed.The prognosis in most cases is extremelygood. With prompt treatment, most dogsreturn to normal within 24 to 48 hours.3

Moldy FoodsMoldy foods may contain certain

tremorgenic mycotoxins such as penitremA and roquefortine C.4 Classified asneurotoxins, tremorgenic mycotoxins caninduce ataxia, muscle tremors, andconvulsions that can last for several days.4

While the exact mechanism of action isunknown, studies have shown thatpenitrem A inhibits the neurotransmitterglycine in mice.4 Severity of signs can varyfrom mild to severe, depending on theparticular strength of the mycotoxiningested. Intoxications have been reportedin many species; however, dogs that roamor have access to spoiled foods are more atrisk than other pets.

Treatment goals following tremorgenicmycotoxin ingestion include minimizingabsorption through decontaminationprocedures such as inducing emesis,performing lavage, and administeringactivated charcoal; controlling tremorsand seizures with methocarbamol; andproviding supportive care.4 With earlyaggressive treatment, prognosis is good.

Definitive diagnosis can be confirmedby mass spectrometry analysis of stomachcontents.4 Veterinary diagnosticlaboratories (VDLs) that perform the testinclude Michigan State and Iowa StateUniversities VDL. Analysis ofmycotoxins may take several days;therefore, it is not advised to wait forresults before initiating treatment.

OnionsOnions (raw, powdered, or cooked) can

be harmful to dogs and cats. Onions aremembers of the genus Allium. Othermembers of this genus include chives,garlic, leeks, and shallots. The primarytoxic principle in onions and other

with bread dough ingestion are associatedwith ethanol toxicoses and foreign bodyobstruction and may include severe

abdominal pain, bloating,depression, incoordination, and

vomiting.9

In cases of recentingestion in asymptomaticdogs, emesis could beinduced. Analgesia is

important in patientsexhibiting signs of pain.

Administering cool water via astomach tube or orally may stop the

dough from rising.9 In some cases,surgery may be required to remove thedough. Since ethanol can cause acidosis,it is important to monitor the acid–basebalance and correct it with sodiumbicarbonate if indicated.9

TobaccoTobacco products contain varying

amounts of nicotine; cigarettes contain 13to 30 mg and cigars 15 to 40 mg. Buttscontain about 25% of the total nicotinecontent. The minimum lethal dose indogs and cats is reported as 20 to 100mg. Signs often develop quickly (usuallywithin 15 to 45 minutes) and includediarrhea, emesis, excitation, salivation,and tachypnea. Cardiac arrest, collapse,coma, depression, muscle weakness,shallow respiration, tachycardia, andtwitching can follow the period ofexcitation. Death occurs secondary torespiratory paralysis.10

For recent ingestion in asymptomaticanimals, emesis can be induced. Neverattempt emesis in stimulated animalsbecause it may trigger a seizure.Activated charcoal has been shown to behelpful in adsorbing nicotine.10 Patientsshould be monitored closely and treatedsymptomatically. Artificial respiration isindicated in patients with respiratoryparalysis.

References1. Gwaltney-Brant S: Chocolate intoxication. Vet Med

96(2):108–111, 2001.2. Means C: The wrath of grapes. ASPCA Anim Watch

22(2), 2002. (continues on page 8)

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osteoarthritis progression: A randomized, placebo-controlled clinical trial. Lancet 357:251–256, 2001.

4. Pavelka K, Gatterova J, Olejarova M, et al:Glucosamine sulfate use and delay of progression ofknee osteoarthritis: A 3-year, randomized, placebo-controlled, double-blind study. Arch Intern Med162:2113–2123, 2002.

5. Braham R, Dawson B, Goodman C: The effect of glucosamine supplementation on peopleexperiencing regular knee pain. Br J Sports Med37:45–49, 2003.

6. Richy F, Bruyere O, Ethgen O, et al: Structuraland symptomatic efficacy of glucosamine andchondroitin in knee osteoarthritis: A comprehensivemeta-analysis. Arch Intern Med 163:1514–1522,2003.

7. Cibere J, Kopec JA, Thorne A, et al: Randomized,double-blind, placebo-controlled glucosaminediscontinuation trial in knee osteoarthritis. ArthritisRheum 51:738–745, 2004.

8. Kajinuma H, Kuzuya T, Ide T, Tyler JM: Effectsof glucosamine on insulin and glucagon secretion indogs and ducks. Endocrinol Jpn 22:517–523, 1975.

9. Monauni T, Zenti MG, Cretti A, et al: Effects ofglucosamine infusion on insulin secretion andinsulin action in humans. Diabetes 49:926–935,2000.

10. Robinson KA, Sens DA, Buse MG: Pre-exposure to glucosamine induces insulinresistance of glucose transport and glycogensynthesis in isolated rat skeletal muscles.Diabetes 42:1333–1346, 1993.

17. McNamara PS, Barr SC, Erb HN, BarlowLL: Hematologic, hemostatic, andbiochemical effects in cats receiving an oralchondroprotective agent for thirty days. VetTher 1:108–117, 2000.

18. Parcell S: Sulfur in human nutrition andapplications in medicine. Altern Med Rev7:22–44, 2002.

19. Usha PR, Naidu MU: Randomised, double-blind, parallel, placebo-controlled study of oralglucosamine, methylsulfonylmethane and theircombination in osteoarthritis. Clin DrugInvestig 24:353–363, 2004.

20. Bui LM, Bierer TL: Influence of green lippedmussels (Perna canaliculus) in alleviating signsof arthritis in dogs. Vet Ther 4:397–407, 2003.

21. Dobenecker B, Beetz Y, Kienzle E: Aplacebo-controlled double-blind study on theeffect of nutraceuticals (chondroitin sulfateand mussel extract) in dogs with joint diseasesas perceived by their owners. J Nutr132(suppl):1690S–1691S, 2002.

22. Reynolds R, Wight A, Wilder H: Clinicalevaluation of Arthrotabs in dogs with mobilityproblems. Vet Times 28:8, 1998.

23. Read R, Sutherland J, Ghosh P: The matrixcomponents of the epiphyseal growth plateand articular cartilages from dogs treated withammonium tetrathiomolybdate, a copperantagonist. Aust J Exp Biol Med Sci64:545–562, 1986.

11. Scroggie DA, Albright A, Harris MD: The effect of glucosamine-chondroitinsupplementation on glycosylated hemoglobinlevels in patients with type 2 diabetes mellitus:A placebo-controlled, double-blinded,randomized clinical trial. Arch Intern Med163:1587–1590, 2003.

12. McCoy SJ, Bryson JC: High-doseglucosamine associated with polyuria andpolydipsia in a dog [letter]. JAVMA222:431–432, 2003.

13. Echard BW, Talpur NA, Funk KA, et al:Effects of oral glucosamine and chondroitinsulfate alone and in combination on themetabolism of SHR and SD rats. Mol CellBiochem 225:85–91, 2001.

14. Lippiello L, Idouraine A, McNamara PS, etal: Cartilage stimulatory and antiproteolyticactivity is present in sera of dogs treated with achondroprotective agent. Canine Pract24:18–19, 1999.

15. Anderson MA, Slater MR, Hammad TA:Results of a survey of small-animalpractitioners on the perceived clinical efficacyand safety of an oral nutraceutical. Prev VetMed 38:65–73, 1999.

16. Canapp SO Jr, McLaughlin RM Jr,Hoskinson JJ, et al: Scintigraphic evaluation ofdogs with acute synovitis after treatment withglucosamine hydrochloride and chondroitinsulfate. Am J Vet Res 60:1552–1557, 1999.

Neutraceuticals and Joint Health (continued from page 3)

Albert Ahn, DVM, is Vice President of Corporate Communicationsand Veterinary Operations at The Hartz Mountain Corporation.

ASK THE VET

HARTZ® COMPANION ANIMALSM • MAY 2005 • VOL. 3, NO. 2 7

WE WANT TO HEAR FROM YOU!• Have questions or comments? Call our Consumer

Relations Department at 800-275-1414 and ask to speak to a Hartz staff veterinarian or email us atfeedback@hartz.com.

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QA

Can garlic cause Heinz body hemolyticanemia in cats? If so, at what dose wouldthis be expected to occur?

Garlic, like onions, is in the genus Allium andcontains n-propyl disulfide, which can cause oxidativedamage to erythrocytes. However, there are nopublished studies showing Heinz body production incats following ingestion of garlic. There has been onepublished study1 that indicates a dose of 5,000 mgof garlic/kg body weight produced hematologicchanges in dogs. Because cats appear to be moresensitive to oxidative changes, one would assumesimilar effects would also be seen in cats.

Reference1. Lee KW, Yamato O, Tajima M, et al: Hematologic changes associated with

the appearance of eccentrocytes after intragastric administration of garlicextract to dogs. Am J Vet Res 61(11):1446–1450, 2000.

Articles found in the Hartz Companion AnimalSM

newsletter can be copied and distributed to your

colleagues, staff, and clients. Additional newsletters may

also be obtained by contacting us at feedback@hartz.com

or by phone at 800-275-1414.

QA

Is there a confirmed dosage forglucosamine to prevent degenerativejoint disease (DJD)?

Glucosamine is an amino-monosaccharide nutrientand is classified as a chondroprotective agent.Chondroprotective agents are used with the intent of healing cartilage, stimulating cartilage matrixsynthesis, and inhibiting enzymatic degradation of cartilage. Glucosamine is a precursor to thedisaccharide unit of glycosaminoglycans, whichcomprise the proteoglycan ground substance ofarticular cartilage. Glucosamine acts by providing theregulatory stimulus and raw materials for synthesis ofglycosaminoglycans in cartilage. According to currentinformation and research standards, there is not a known preventative dosage. However, based on the mechanism of action, using glucosamineprophylactically in dog breeds that are proneto DJD would be an excellent idea.

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3. Hansen SR: Macadamia nut toxicosis in dogs. VetMed 97(2):274–276, 2002.

4. Schell MM: Tremorgenic mycotoxin intoxication.Vet Med 95(4):283–286, 2000.

5. Cheeke PR: Natural Toxicants in Feeds, Forages, andPoisonous Plants, ed 2. Danville, IL, InterstatePublishers, 1998.

6. Lee KW, Yamato O, Tajima M, et al: Hematologicchanges associated with the appearance of

ingestion of Chinese chive (Allium tuberosum) andgarlic (Allium sativum) in a dog. JAAHA41(1):68–73, 2005.

9. Means C: Bread dough toxicosis in dogs. J VetEmerg Crit Care 13(1):39–41, 2003.

10. Plumlee KH: Nicotine, in Peterson ME, TalcottPA (eds): Small Animal Toxicology. Philadelphia,WB Saunders, 2001, pp 600–602.

eccentrocytes after intragastric administration ofgarlic extract to dogs. Am J Vet Res 61(11):1446–1450, 2000.

7. Ogawa E, Shinoki T, Akahori F, Masaoka T:Effect of onion ingestion on anti-oxidizing agentsin dog erythrocytes. Jpn J Vet Sci 48(4):685–690,1986.

8. Yamato O, Kasai E, Katsura T, et al: Heinz bodyhemolytic anemia with eccentrocytosis from

Dangerous Foods (continued from page 5)