The issue of low-purine diets raises most questions for the owner of a dog with leishmaniosis. In principle, it is not always necessary to feed a low-purine diet if the dog is well and has no problems with xanthine sediment or stones. In that case, care should be taken to ensure that the diet contains as little purine as possible. There is no upper or lower limit for purines and should be considered on an individual basis.

Basic information about nutrition

The dog is a carnivore, i.e. it eats meat. If we look at its ancestor, the wolf, we can see quite well from its eating habits how the dog would eat in the wild. The wolf feeds on small mammals, insects, fish, etc., depending on where it lives. According to Professor Rodríguez de la Fuente, the Iberian wolf, for example, has the following food sources:

• 35% large herbivores (mouflon, deer)
• 24% sheeps
• 14% rabbits
• 9% mouse
• 7% scavenger
• 5% reptiles and birds
• 4% insects & herbs
• 2% other carnivores (fox, domestic dog)

If we then look at the composition of a prey animal (e.g. a rabbit), we can better understand the division or composition of the home-made feed: The rabbit consists of 48% muscle meat and fatty tissues, 21.5% fur and stomach and intestinal contents, 7.5% pure bone and 23% blood and viscera. BARF according to the German school is given with the following distributions: 80% animal content and 20% fruit/vegetables/carbohydrates. This 20% replaces the fibre content of the actual prey animal, such as fur and stomach contents. The 80% animal content is further subdivided into 15-20% meaty bones, which is approximately 10% pure bones. Flesh-bearing bones ideally consist of 50% meat and 50% bone, e.g. carcasses or necks. Offal constitutes about 10-15% of the animal portion. The rest should consist of meat and fat. It should be noted that fat is the dog’s most important source of energy and should be contained in the meat, so a fat content of 15-25% of the muscle meat is the target. The 20% vegetarian ration should consist of 75-80% vegetables and 20-25% fruit. If carbohydrates are fed, these account for about 30%. These are the percentages of the ideal diet for a healthy dog. We will see that these percentages cannot be fully maintained on a low purine diet. If cooked for the dog, the percentage of meaty bones should be added to the percentage of meat and supplemented with bone meal or other calcium replacer. Bones should never be fed cooked, as their structure changes, they become brittle and can cause serious internal injuries. In addition, vitamin B should be added to the cooked diet, as meat loses it in the cooking process. Depending on the dog and its activity, 2-4% of its body weight should be provided daily. Puppies and pregnant or lactating bitches should receive up to 8% of their body weight.

Purine content of food

In some dogs taking allopurinol, a low purine diet should be used. In addition, a diet containing a high oxalate content should be avoided, as dogs with xanthine stones are unfortunately also prone to oxalate stones.

Meat and offal

There is meat with a higher purine content and meat with a lower purine content. In principle, meat rich in fat has less purines than lean meat. Fat contains practically no purine. Meat contains hardly any oxalate and therefore does not need to be taken into account in the oxalate calculation. Chicken meat is generally low in purines and should be provided without skin. Chicken breast with skin has a content of 73mg/100g and chicken thigh with skin 46mg/100g. Chicken breast without skin has a content of 50mg/100g. Eggs are almost completely free of purine and oxalate. Lamb or sheep meat has less purines and can be well used. Muscle meat has an average purine content of 76mg/100g. Lamb meat has a higher percentage and contains between 61 and 81 mg/100g. Duck is a meat with a lower purine content, with an average of 58 mg/100g. In this case, you should also consider removing the skin. Rabbit has an average purine content of 60 mg/100 g, which also makes it one of the less purine-rich meats. Beef is also low in purines. Veal fillet has approximately 46mg/100g, veal shoulder 46mg/100g, veal brisket only 38mg/100g and roast beef 59mg/100g. Turkey is also not a meat rich in purines, so turkey cutlet has about 50mg/100g. And turkey leg approx. 63mg/100g. The skin must be removed. Game meat has varying levels of purines, so roe deer meat tends to have a relatively low purine content (44mg/100g). Deer has a higher content at 67mg/100g. Pheasant has an approximate content of 62mg/100g. Goose has a slightly higher purine content, the average content is 69mg/100g. Horse meat is a high purine meat and contains approximately 83mg/100g. Pork should only be fed cooked and has a purine content of between 48 and 63mg/100g.

Offals

Their purine content is very high; for example, beef liver has an average purine content of 231mg/100g. This is why it is always advisable to minimise offal in a low-purine diet. However, offal, and especially liver, is the most important source of vitamins for dogs, so reducing offal not only reduces purines, but also important vitamins such as vitamin A. All of these cannot be completely replaced by a low purine diet. All of these cannot be completely replaced by other products. All of them cannot be fully supplemented with offal, but may be completely lacking. Offal usually contains very little oxalate, so it is not necessary to take it into account when calculating its content.

Fish

Fish with low purine content are: Cod, pike-perch, plaice, pike and sole. These fish are below 60mg/100g (without skin). Fish with a medium purine content are shrimps, salmon, haddock and halibut, whose purine content is between 60 and 80mg/100g. Tuna and sardines are very rich in purines and should not be fed, no matter whether fresh or canned. Fish contains hardly any oxalate and should therefore not be taken into account when calculating the oxalate content.

Dairy products

In general, dairy products have little or no purine, so they can be used in a low-purine diet. Sheep’s milk cheese and feta cheese have the highest purine content, with 13 mg/100 g. Therefore, dairy products such as yoghurt, cream cheese and quark can be included in a dog’s diet. Dairy products contain almost no oxalates and do not need to be taken into account in the calculation. Soy ‘dairy’ products have a high purine content and should not be used for the dog.

Carbohydrates

Carbohydrates and cereals, with a few exceptions, contain hardly any purines and are therefore widely used in low-purine diets. However, it should be noted that carbohydrates in large quantities can cause problems. Many dogs are allergic or intolerant to certain cereals or carbohydrates in general. In addition, dogs do not produce as much amylase (enzyme for digesting carbohydrates) as humans and the body needs much more energy for digestion. In addition, too much carbohydrate overloads the dog’s pancreas and can lead to physical discomfort. Carbohydrates should always be given cooked, never raw. Legumes are not suitable for the low-purine diet because they have a medium purine content. White beans or lentils, for example, contain about 53 mg/100 g of purines. Buckwheat also contains up to 62 mg/100 g. However, some cereals and carbohydrates contain relatively high levels of oxalate and this must be taken into account in the calculation: amaranth, wheat bran, to name a few. Seeds and nuts sometimes contain high levels of purines or oxalates and should therefore not be used: Sunflower seeds (↑ purine), poppy seeds (↑ purine), almonds (↑ oxalate), walnuts (↑ oxalate), cashews (↑ oxalate), cashew nuts (↑ oxalate).

Vegetables and fruits

All plant components are low in purines and can be used well in dog food. However, they must be broken down for the dog, i.e. boiled or steamed or shredded or grated into small pieces. If vegetables are given whole, the dog cannot digest them and excretes them. There are some vegetables that should not be used in dogs (healthy or with leishmaniasis): Aubergines, green or yellow peppers, green tomatoes, quinces, grapes and onions. Some vegetables are very rich in oxalates and should not be given to dogs with kidney or bladder stones:

• Spinach
• Swiss chard
• Parsley
• Rhubarb
• Portulaca
• Mint
• Sorrel
• Beetroot
• Berries of all kinds have a medium oxalate content and should be consumed infrequently, as should beans.

More recommendations

It is always important that the meat is of good quality. Meat with a lot of connective tissue or throat meat should not be fed, as this can lead to an increase in thyroid hormones and cause an excess of iodine. Muscle meat with sufficient fat is essential. An important point that should not be overlooked in the diet is good quality drinking water. Not all water tastes good to all dogs. But especially in the case of kidney or bladder stones, attention should be paid to a sufficient quantity of drink. In this case, salt-free broths, a little cream in the water or even non-alcoholic malt beer can help to cover the liquid needs. However, food should not be soaked, as this can cause the digestive juices to become too diluted and unable to be active enough for digestion to proceed smoothly. The body already receives fluids with fresh food, and fresh water should always be available during the day. If the dog does not drink enough (about 50 ml per kilo of body weight is normal), you should try to encourage him to drink with the above tips.