Introduction

Source :
C. Rutgers1 and V. Biourge
Department of Veterinary Clinical Sciences
The Royal Veterinary College, United Kingdom
Royal Canine Research Center, France

Diets for dogs with liver disease should be formulated for your dog based on the specific diagnosis provided by your veterinarian. The diet should be calibrated based on the digestive capacity of the diseased liver.

There are three goals for a canine liver disease diet:

1. Supply adequate energy and nutrients to fulfill basic requirements and prevent malnutrition
2. To limit further liver damage by preventing accumulation of copper and free radicals
3. To support liver cell regeneration
4. To prevent or minimize possible complications, such as abnormal brain function caused by passage of toxic substances from the liver to the blood (called hepatic encephalopathy) and the buildup of fluid in your dog's abdomen (called ascites)

Protein is Essential for a Canine Liver Disease Diet

Canine liver disease diet should contain normal amounts of high quality protein, at least 20% of daily calories. The exception to this is if your dog has hepatic encephalopathy, a condition in which the liver disease has advanced so far that the brain has become affected. In this case, a low-protein diet is recommended.

High-quality proteins are better digested and have an amino acid content close to the levels your dog needs. Foods that come from animals or from plants such as soy isolates, wheat gluten and dairy products are better tolerated than meat proteins in people which may be the case with dogs. Most veterinarians recommend that owners feed their dogs a mix of animal based and plant proteins since the use of soybean or lactose-containing dairy protein diets are not liked by some dogs and can cause diarrhea.

Non-Protein Calories

Non-protein calories help to prevent the use of protein (amino acids) for energy and reduce the need for your dog's body to manufacture glucose in the liver by converting protein molecules (called gluconeogenesis).

Normally, energy is from fat since it is a something dog's like to eat and is a concentrated source of energy. Dogs with liver disease can tolerate larger quantities of fat in their diet (30 - 50% of calories).

Fiber and Canine Liver Disease Diet

Moderate amounts of soluable and insoluble dietary fiber can help a dog with liver disease. Soluble fiber such as beet pulp and gums lowers the production and absorption of ammonia and helps the growth of beneficial bacteria. Fiber (both soluble and insoluble) also helps your dog rid itself of bile acids. Insoluble fibers (lignin, cellulose, hemicellulose) help to normalizing transit time for feces, prevent constipation and bind toxins.

Vitamin and Herbal Supplements for a Canine Liver Disease Diet

A canine liver disease diet should include vitamin supplements that act as antioxidants. Liver diseases cause greater generation of free radicals and oxidant stress. Supplementation with antioxidants helps to reduce liver injury.

B Vitamins: are often recommended at double the normal maintenance dose since this is a clinically supported approach in humans.

C Vitamins: Vitamin C is a antioxidant and should be part of a dog's diet with liver disease. Most dog foods meet the daily requirement for vitamin C. Do not overdose vitamin c since it could increase the intake of copper. Additional supplementation should only be necessary if your dog's liver is having trouble with in case where fat is not be digested normally (fat malabsorption).

Vitamin E: may prevent canine liver disease from getting worse by reducing free radical or oxidant injury. A water-soluble form of Vitamin E is preferred, since the absorption of fat-soluble vitamins may be decreased in some forms of liver disease.

Vitamin K: helps with blood clotting and is recommended in cases of chronic liver disease. The liver produces clotting factors, and it does not produce or store vitamin K as well when it is diseased.

Zinc: A canine liver disease diet should also be supplemented with zinc since it is an anti-oxidant. It also reduces the risk of abnormal brain function caused by passage of toxic substances from the liver to the blood (called hepatic encephalopathy). Zinc reduces the accumulation of copper in the liver.

Adenosylmethionine (SAMe): may be helpful in reducing liver injury. Normally produced by the liver, SAMe is necessary for many functions of liver cells. It is also an anti-oxidant. Providing your dog with an oral supplement helps to to improve antioxidant function and has anti-inflammatory properties.

Phosphatidylcholine (PC): is a components of bile required for normal bile acid transport and a building block for cell membranes. There are no clinical studies showing that it is helpful in dogs (it is helpful in humans).

Silymarin: a component of milk thistle is thought to have antioxidant and helps with free radicals for various types of liver disease. It also helps with toxicity. There are a few studies that support its use for dogs. Suggested doses range from 50 to 250 mg/day

Minerals and Supplements to Avoid

Potassium: Diets for dogs with liver disease should avoid potassium. If your dog is not eating and therefore not getting any potassium your veterinarian may choose to give your pet the mineral through intravenous fluids.

Sodium: Moderate restriction of dietary sodium if recommended for dogs that have a lower than normal appetite or if your pet has hypertension.

Canine Liver Disease Diet Prepared at Home

These two diets were created by veterinary professionals for dog's with liver disease problems:

Home Canine Liver Disease Diet#1 (1000 g diet)

• Chicken, breast with skin 220 g
• Rice, cooked 680 g
• Carrots (boiled, drained) 60 g
• Wheat bran 20 g
• Rapeseed oil 20 g

Home Canine Liver Disease Diet#2: (1000 g diet)

• Beef, minced meat, 15% fat 100 g
• Tofu 400 g
• Rice, cooked 440 g
• Carrots (boiled, drained) 30 g
• Wheat bran 10 g
• Rapeseed oil 20 g

Appetite Problems

If your dog has little or no appetite you can try warming your dog's food a bit to make it more appetizing. Try feeding small amounts several times a day. If that doesn't work, your dog may need to be force fed with a syringe or a feeding tube may need to be placed.

Your dog also needs to be getting plenty of fluids. If your dog is not drinking on his own, he may need to get IV or subcutaneous fluids to prevent dehydration.

SAMe [S-Adenosylmethionne]

S-Adenosylmethionine (SAMe) is a substance produced by the body from the amino acid methionine. SAMe affects all cells in the body, but especially liver cells. Through three chemical processes in the liver, SAMe is converted into very important compounds:

1. Through a process called transsulfuration, SAMe is converted into glutathione, a powerful antioxidant. Glutathione plays a major role in protecting hepatocytes (liver cells) from damage from waste products that the liver removes from the blood stream and detoxifies (reduces toxic properties). Other cells in the body, such as red blood cells (RBC's) are also protected. Transsulfuration also produces taurine and other compounds that aid in the movement of bile acids out of the liver.
2. Through transmethylation, SAMe helps to stabilize cell membranes and promote the secretion of bile.
3. Through aminopropylation, SAMe is converted into other antioxidants and methylthioadenosine, which has anti-inflammatory and analgesc properties.

These three processes that rely on SAMe all aid in supporting the structure and function of the liver, and also play an important role in nutritional pathways, cell replication, and protein synthesis (formation of protein from smaller proteins and/or amino acids).

Normally, the liver produces SAMe from the amino acid methionine, which is present in the animal's food. If the liver is damaged, less SAMe is produced, and thus less glutathione is produced. With less of this antioxidant, even more liver cells become damaged and a vicious cycle is started.

By giving an animal with liver dysfunction "pre-made" SAMe, the liver can produce more glutathione and protect itself from further damage. The increased glutathione may also help in the healing and repair of cells.

Even though SAMe is produced from methionine, it is not beneficial to give an animal with liver damage additional methionine; in fact, it can be harmful.

SAMe has been recommended for animals with various forms of liver disease including hepatic lipidosis (fatty liver), cirrhosis, leptospirosis, toxicities from acetominophen (Tylenol) and other non-steroidal anti-inflammatories (NSAID), hepatic fibrosis, cholangiohepatitis, and certain breed-specific liver diseases. It may also be useful in pets receiving long-term treatments for diseases such as epilepsy, in which the medication used is metabolized by the liver.

Some researchers believe that SAMe may be helpful in other conditions related to the damage of cell membranes. Such conditions may include:

1. Diabetes
2. Cushing's disease
3. Pancreatis
4. Inflammatory bowel disease
5. Certain anemias
6. Autoimmune disorders
7. Certain heart conditions

The effectiveness of SAMe in these conditions has not been determined through controlled research studies.

SAMe is considered a dietary supplement and is available in an oral form. There are important considerations in giving SAMe:

1. Give SAMe on an empty stomach. Do NOT give SAMe with a meal, since food will decrease the body's absorption of SAMe from the digestive system. Give SAMe at least one hour before feeding your pet. You may give the SAMe in a small treat or bite of food. You do not need to withhold water.
2. SAMe can cause irritation of the throat and esophagus if it is not quickly swallowed and moved to the stomach. This is especially true for cats. For this reason, give your pet a small amount (one teaspoon) of water after giving the SAMe to help your pet swallow. You may wish to try tuna water or other liquid your cat likes; however, do not use milk.

SAMe is not a stable compound, being adversely affected by moisture and other environmental conditions. This is one reason it cannot be incorporated in high levels in pet foods. SAMe should be stored at room temperature in a childproof container, out of reach of children and pets. It should be protected from humidity and moisture (e.g., do not store in the bathroom). If the tablet comes in a foil pack, do not open it and remove a tablet until ready to use.

SAMe has been shown to be very safe, and there are usually no side effects if it is given correctly. Vomiting may occur in rare instances.

Thus far, there have been no adverse reactions resulting from giving SAMe with other supplements or medications in dogs and cats.

-Adenosylmethionine (SAMe) may also be helpful in reducing oxidative injury (Davidson, 2002). It is a precursor of glutathione, an important hepatic antioxidant enzyme that is often reduced in dogs with liver disease. Oral administration helps to replenish hepatic glutathione stores and may thus improve antioxidant function. In addition, SAMe has anti-inflammatory properties (Center et al, 2002).

References and Further Reading

Center, SA. S-adenosyl-methionine an antioxidant and anti-inflammatory nutraceutical. Presented at the 18th American College of Veterinary Medicine Annual Meeting, Seattle, WA; May 2000.
New approach to managing hepatic dysfunction: Roundtable on the use of s-adenosylmethionine, Part I. Veterinary Forum 2000; November: 40-45.
New approach to managing hepatic dysfunction: Roundtable on the use of s-adenosylmethionine, Part II. Veterinary Forum 2000; December: 44-49.
S-Adenosylmethionine. The Compendium on Continuing Education for the Practicing Veterinarian; August 2000: 600-603

Milk Thistle

Reproduced (with permission) from an article publised by Jean Hofve, DVM in "Whole Dog Journal" Volume 5, Number 7, July 2002:

This amazing herb is used to treat diabetes, liver failure, and IBD.

Milk thistle can be purchased in powder, capsule, and liquid extract form.

Milk thistle (Silybum marianum) is a flowering plant in the Aster family. A native of Europe, it has been used since the time of the Roman emperors as a liver tonic. Milk thistle is one of very few traditionally used herbs that has been widely accepted by conventional science to have significant medicinal value.

Today we know the active ingredient of milk thistle seed extract as a flavonoid compound called "silymarin." Most milk thistle extracts available today contain about 80 percent silymarin.

Uses in canines

Silymarin, which is itself a combination of several other active compounds, has been extensively studied around the world, and has been shown to be safe and effective in treating a variety of liver diseases and other conditions. It specifically protects the liver against toxins (including some drugs and heavy metals), activates protein synthesis, and stimulates growth of new liver cells to replace those that are dead or damaged. Milk thistle also has strong antioxidant (destroys oxygen free radicals) and anti-inflammatory actions.

Silymarin reaches high levels in the bile and liver (it also reaches significant levels in the lungs, pancreas, prostate, and skin). It can be used in the treatment of hepatic lipidosis, chronic hepatitis, cholangitis (inflammation of the bile ducts), and pericholangitis (inflammation of the tissue around the bile ducts). It may be useful in preventing or treating gallstones by thinning the bile. Many dogs with inflammatory bowel disease (IBD) have concurrent inflammation of the liver/bile system and the pancreas. This suite of symptoms is called "triaditis." Because milk thistle's beneficial actions concentrate on the liver and bile systems, it may also be helpful in dogs with IBD.

Milk thistle should be considered as an aid to healing after drug therapy, vaccinations, and infections such as canine parvovirus, as well as an potential adjunct treatment for cancer. Researchers at Case Western University concluded from their work that "silymarin possesses exceptionally high protective effects against tumor promotion . . . " One human study even suggests a role for milk thistle in diabetes mellitus through its normalizing effects on red blood cells. It may also help prevent diabetic neuropathy, a common complication of the disease that causes degeneration of the nerves controlling the hind limbs, which consequently produces weakness and an abnormal gait.

Milk thistle generally supports the immune system through its powerful antioxidant, free-radical scavenging action, its ability to preserve the supply of another important antioxidant, glutathione, as well as direct effects on immune cells. Glutathione, which is stored primarily in the liver, naturally declines over time, and depletion of this protein appears to accelerate the aging process.

While it's not exactly the fountain of youth, milk thistle clearly has wide-ranging positive effects throughout the body. However, before you add this potent herb to your dog's daily regimen "just in case" it might do some good, it's important to consider that some herbalists believe milk thistle is best reserved as a treatment for existing disease, rather than being used by itself in a healthy dog.

While moderate use of milk thistle is very safe, there is some experimental evidence to suggest that long-term ingestion of very high dosages of milk thistle will eventually suppress liver function.

Dosage and Administration

The standard dosage of milk thistle extract is based on a silymarin content of around 80 percent; most supplements contain anywhere from 50-500 milligrams (175 mg is typical). As with many supplements, it's probably better to buy a milk thistle derivative rather than a silymarin-only or other fractional supplement, since there may be other compounds found in the whole herb that significantly enhance the effects of what science has decided is the main player.

Because of its excellent safety record and lack of adverse drug interactions, when I'm treating a very sick dog with advanced liver disease, I do not hesitate to use up to 200 mg per 10 pounds of body weight of milk thistle extract daily. For most canine purposes, however, one-third to one-half of that dose is more than adequate. (Dogs with liver disease typically will not eat, but it's a simple matter to open up a capsule, mix the appropriate amount of powdered herb with a little blenderized food or baby food, and feed it to the dog in a syringe.) Too high a dose can cause an upset tummy, gas, or mild diarrhea; these are easily resolved by giving less.

Human research studies have shown that it is more effective to administer this herb in three or four small portions over the day than in one large daily dose. When it is not possible to split the daily dose and administer the fractional portions three or four times a day, give it at least twice a day.

The capsule form is easy to find - any health food store, and even most pharmacies and grocers, will have them in stock. The herb also comes in a liquid extract, but most human products contain a fair bit of alcohol. If you prefer a liquid preparation, get one specifically intended for use in animals.

Dr. Dodds recommends using milk thistle in the doses listed below to help heal the liver along with reducing phenobarbital (according to your vet) and feeding the liver cleansing diet.

Milk Thistle Dosage (from the newsletter "Healthy Pets - Naturally"):