In his regular help and advice column, Paul Boland looks at how dietary modifications and supplements can reverse the effects of liver disease in dogs.
The liver is an amazing organ with an extraordinary number of functions: it eliminates toxins; it produces proteins, urea, coenzyme Q10, cholesterol, bile acids and albumin; it maintains sugar and fat levels; it’s even involved in drug metabolism.
In fact, the liver is so resilient with such a reserve capacity that it can regenerate itself more than almost any other organ, and even if it malfunctions on a number of occasions, it can recover.
Animals usually only show signs of liver disease when more than 70% of liver cells (hepatocytes) are dead or damaged.
The most common causes of canine liver disease include some form of hepatitis, poisoning by a pharmaceutical drug or other type of toxin or, less commonly, biliary tract disease or some form of cancer. Rare causes include infectious canine hepatitis, hepatic cysts, inherited glycogen storage disease (where the enzyme that converts glycogen stored in the liver into glucose is missing, causing glycogen build- up in the liver), amyloidosis (when amyloid protein is abnormally deposited about the body) and massive necrosis (rapid and widespread death of hepatocytes).
The usual first signs that something’s wrong with your dog’s liver are general symptoms like anorexia, depression, lethargy, weight loss, poor or unkempt coat, vomitingand/ordiarrhoea. Amorespecific signpost of liver involvement is when the vet finds signs of abdominal liver enlargement, jaundice, bleeding problems, more frequent drinking and urinating, and behavioural changes like confusion caused by hepatic encephalopathy (an accumulation in the brain of toxic substances ordinarily removed by the liver). On clinical examination, in addition to an enlarged liver there may be fluid in the abdominal cavity (although this may also be seen in right-sided heart failure).
When liver cells are damaged, they release excess liver enzymes and bile acids that then show up as elevated on blood tests. To test this, your vet will carry out a bile acid stimulation test by measuring bile acids before a fatty meal and again an hour later. Your vet may also opt for ultrasound and radiography to view the liver and look for any liver enlargement or decrease in size, displacement of other abdominal organs and free fluid in the abdominal cavity. In some cases it may even be necessary to order a liver biopsy.
I treat all cases of liver disease with a three-pronged approach: modifying the diet; prescribing specific supplements; and asking owners to make their dog as comfortable and stable as possible until its liver function is improved.
I normally recommend dietary changes to ensure that a dog with liver disease receives the calories and nutrition necessary to support liver regeneration and deal adequately with the effects of toxic accumulations in the brain. In general, a diet that steers clear of preservatives and additives will benefit most dogs, but many other factors also need to be considered.
There are commercially made diets specifically designed for dogs with liver disease that include very high-quality, easily digestible ingredients aimed at reducing the demands placed on the liver. Although these diets are readily available, it is relatively easy and considerably cheaper to design such a diet yourself.
Protein metabolism creates circulating ammonia, which places a strain on the liver, so it’s important to monitor the amount and to give him less than usual. Aim for a mix of 20% protein and 60% of fats, with carbohydrates making up the remaining 40%.
I also suggest you give your dog non- meat protein sources like plant protein, dairy products and eggs as an alternative to meat sources. Cottage cheese, ricotta cheese and yoghurt will be easier to digest than meat, but if you’re going to serve up flesh food, opt for lean meat or white fish. For fats, choose rapeseed oil, and for carbs offer your dog grains, rice and pasta, which lower the production and absorption of ammonia, remove bile acids, bind toxins and prevent constipation.
Salt should also be restricted in dogs that retain excess fluid in their abdomens due to liver disease.
I routinely prescribe supplements of the herb milk thistle and the amino acid dl-methionine in animals with liver disease. Silymarin is the active constituent in milk thistle, and its therapeutic effects in liver disease apparently include causing an alteration in the outer membranes of certain liver cells to prevent penetration of toxins while stimulating liver regeneration. In fact, one study even suggests that silymarin might have anti-inflammatory and immune-modulating effects that may be beneficial in liver disease.1
Silymarin is composed of four flavonolignans called silibinin (silybin), isosilybin, silychristin and silydianin. Silybin makes up roughly 70% of silymarin, which is why many of the very expensive veterinary liver-support products are standardized and use just silybin. But in my opinion this is a mistake, as the beneficial effects of silymarin are attributed to the entire silymarin family and not just a single component. The four flavonolignans work in synergy to protect the liver, while silybin and silychristin working together appear to have regenerative effects on kidney cells.
I recommend that you give your dog a daily dose of at least 100 mg of milk thistle per 10 kg of body weight. dl-Methionine, a sulphur-containing amino acid, plays a role in many cellular functions and is part of a ‘methioninecycle’ that forms other amino acids, including cysteine, taurine and glutathione. Failure to maintain the smooth functioning of the methionine cycle is thought to result in liver damage, as glutathione prevents free radical damage to the liver and taurine plays a role in bile acid conjugation. Along with milk thistle, I also recommend that you give at least 20 mg/day of dl-methionine for every 10kg of bodyweight.
Incidentally, these two supplements also help protect the liver against the side- effects of medications. In my view, any animal taking phenobarbital for seizures, corticosteroids for allergies and immune diseases, chemotherapy drugs and even some heartworm drugs should be given these supplements as well.
Natural stem cell enhancers
Science is discovering new uses for adult stem cells every day and these have the potential to revolutionize medicine. Unfortunately, many of the techniques used are invasive and costly or may involve the use of embryonic stem cells. Fortunately, there are ways to increase the body’s own store of adult stem cells naturally.
In my practice, I’ve recently been using natural stem cell enhancers that cause the bone marrow to release millions more adult stem cells than usual. Granulocyte colony- stimulating factor (G-CSF)—a drug that stimulates the production of white blood cells (granulocytes) to prevent infection and fever due to low white cell counts — prompts adult stem cells in bone marrow to duplicate and the replicated cells are then released into the bloodstream, where they then migrate to the liver and replace any damaged or dead liver cells.
Until recently, it was thought that adult stem cells from bone marrow only differentiated into (change into and replace) certain white blood cells, but recent research shows they are involved in global repair systems of virtually any cell within the body. Attracted by molecules released by damaged cells, the stem cells migrate through capillary walls into the damaged cells, changing themselves into that specific cell and then multiplying thousands of times to replace the damaged cells in that damaged tissue or organ. Adult stem cells are essential for this regeneration process in the liver and, once the diseased cells are regenerated, many of the signs of liver disease disappear.
The natural way to increase adult stem cells is to give your dog supplements containing an aquatic botanical called Aphanizomenon flos-aquae (AFA), a typeofblue-greenalgae.AFAcontainsa molecule called MobilinTM, which appears to act on bone marrow in the same way as G-CSF does. I’ve used this product with great success in my practice for many conditions, including liver disease.