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Methionine Guide: Benefits, Deficiency Symtoms

Milner (1979) and Burns and Milner (1981) found in their studies that methionine is an essential amino acid for optimum growth and nitrogen balance in immature Beagle dogs. Other studies have also DL-methionine supplement to be useful to treat bladder infections and prevent bladder stones in dogs.

The National Council’s Research on Pet Nutrition listed methionine as an essential ingredient that they must obtain from their diet.

Methionine is also listed as Methionine-cystine in some pet foods.

Methionine is an essential amino acid for both dogs and cats. It is required for numerous bodily functions, including proper digestion, absorption of nutrients, and proper liver function. Methionine also plays a role in the formation of several important compounds, including glutathione (an important antioxidant) and taurine (an important compound for heart health).

So what is Methionine?

Methionine is an essential sulphur-containing amino acid. It is required for the manufacture of other amino acids, enzymes, hormones, and vitamins. It is also required for proper absorption of vitamin B12 and folic acid.

Methionine plays a role in fat metabolism and prevents the build-up of fat in the liver. It also helps lower cholesterol levels and acts as an antioxidant.

Methionine is found in meat, fish, eggs, dairy products, nuts, and seeds. The best sources of methionine are liver and muscle meats.

Synthesis of Methionine:

Methionine is synthesized from oxaloacetate in the body, but this process is not very efficient. For this reason, it is important to include methionine-rich foods in the diet.

Oxaloacetate is first converted into homoserine as described above in the threonine biosynthetic pathway. This is then converted into cystathionine by the enzyme cystathionine.

Cystathionine is then converted into cysteine by the enzyme cystathionase. Cysteine can be used to synthesize glutathione, which is an important antioxidant.

Below is an image showing the 4 steps of methionine synthesis(source).

image showing process of methionine synthesis
Image showing process of methionine synthesis

Other reports also claim that taurine can be synthesized from methionine, Vitamin E and Cysteine.

Methionine can also be obtained from dietary supplements. Methionine supplements are available in tablet, capsule, and powder form.

Methionine supplements are safe for most people and pets. However, taking large doses of methionine can cause gastrointestinal distress and diarrhea. People with liver disease should avoid methionine supplements.

Is Methionine FDA-regulated?

Under Federal Regulation Notice 21 C.F.R § 582.1(b), FDA approved DL-methionine as a Generally Recognized As Safe (GRAS) ingredient for use in animal feed. Others include arginine, cysteine, lysine, tryptophan and others.

Below are all the amino acids recognized as GRAS under the following sections of 21 CFR;

Methionine link with Cysteine:

Methionine is required for the biosynthesis of cysteine, another important amino acid. Cysteine is required for the formation of glutathione, an important antioxidant. Methionine and cysteine are often found together in pet food products, listed as methionine-cystine (NRC, 2006, Page 126).

Uses of Methionine in pets – dogs and cats:

Treat bladder infection:

Methionine can be used to treat bladder infections and prevent bladder stones in dogs.

It works by acidifying urine to prevent struvite stones from forming as a result of high alkaline concentration. Because this neutralized pee is less harmful to grass, lawn-saver dog treats and those that combat the smell of pet urine residue may contain DL-methionine.

Liver disease:

Methionine can help to protect the liver from damage and improve liver function in dogs with liver disease. Liver disease is a common condition in dogs, and methionine can help to improve liver function and protect the liver from further damage. Read about symptoms of liver disease here.

Antioxidant:

Methionine is an antioxidant that helps to protect cells from damage. It also helps to prevent the build-up of fat in the liver. As an anti-inflammatory, it can help to reduce inflammation in the body.

Metabolism:

Methionine is required for the manufacture of other amino acids, enzymes, hormones, and vitamins. It is also required for proper absorption of vitamin B12 and folic acid. Methionine plays a role in fat metabolism and prevents the build-up of fat in the liver.

Itchy skin:

Methionine may help to relieve itchy skin in dogs.

Methionine Precautions:

Don’t give methionine supplements to dogs with liver, pancreatic, or kidney issues:

Methionine should not be given to dogs with liver, pancreatic, or kidney disease. It can worsen these conditions and should only be used under the supervision of a veterinarian. Read about these 8 dog foods that cause kidney failure in dogs.

Liver-Methionine can also increase the risk of gastrointestinal upset, so start with a lower dose and increase gradually as needed.

Pregnant dogs or puppies shouldn’t be given methionine:

You should also talk to your veterinarian before giving methionine supplements to puppies or pregnant dogs.

Methionine can interact with certain medications:

Methionine can interact with certain medications, including antacids, cholestyramine, and iron supplements. Talk to your veterinarian before giving methionine to your dog if they are taking any other medications.

Methionine supplement side effects in dogs and cats:

The most common side effect of methionine is gastrointestinal upset, including diarrhea, vomiting, and abdominal pain. If these effects persist or worsen, talk to your veterinarian.

ethionine can also cause liver damage in some dogs. If you notice any signs of liver disease, such as yellowing of the eyes or skin, increased thirst or urination, loss of appetite, or lethargy, talk to your veterinarian.

Common side effects are;

  • Loss of appetite
  • Vomiting
  • Diarrhea

How to Give Your Dog DL-Methionine 

Chewable tables:

Give the chewable tablet directly to your dog or crumble it over their food.

Powder:

Add the powder to your dog’s food.

Liquid:

Add the liquid to your dog’s food or water bowl.

Is methionine safe in pet food?

Yes, methionine is safe in pet food. The National Council’s Research on Pet Nutrition listed methionine as an essential ingredient that they must obtain from their diet.When you see it listed on pet food labels, it is usually in the form of DL-methionine, which is the synthetic form of methionine.

It is not only a required nutrient but AAFCO has specified minimum amounts dogs and cats must receive in their diet on a daily basis.

What are the benefits of giving methionine to my pet?

Methionine has many benefits for dogs and cats. It can help to treat bladder infections, prevent bladder stones, and protect the liver from damage. It also plays a role in fat metabolism and helps to prevent the build-up of fat in the liver. Methionine is also an antioxidant that helps to protect cells from damage.

Best Methionine Supplements for Dogs

You can purchase Methionine supplements for dogs on various online retailers such as 1800petmeds and from Amazon.

PetHonesty GrassGreen Grass Burn Spot Chews for Dogs

PetHonesty’s GrassGreen soft chews for dogs are the perfect solution, targeting the root cause of grass burn and yellow spots. With natural ingredients like cranberry, probiotics and apple cider vinegar, GrassGreen helps maintain normal and healthy digestion for your dog – and reduces the amount of nitrogen in their urine to keep your grass green. Methionine supplement is also included to help reduce grass burn from dog urine.

Methionine Supplement Dosage

You can find 500 mg chewable tablets in most vet stores and according to wagwalking.com, below are the generally recommended daily DL-methionine dosage;

  • For small-breed dogs weighing 15 pounds or less, give them 1/2 to 4 tablets daily.
  • For medium breeds weighing 15 to 33 lbs, give them 2 to 7 tablets daily
  • Give 4 to 13 tablets daily for large breeds weighing between 33 to 66 lbs.

According to PetHonesty, dogs should take approximately a half tablet per 10 pounds of body weight each day. This is, of course, dependent on your dog’s weight and health. DL-methionine in excessive quantities can be toxic or even deadly, thus it’s critical that you follow your veterinarian’s instructions carefully.

Methionine toxicity in dogs:

Methionine is safe for dogs when used as directed. However, methionine can be toxic in large doses. If you suspect your dog has ingested too much methionine, contact your veterinarian immediately. Symptoms of methionine toxicity include vomiting, diarrhea, loss of appetite, and lethargy.

DL-methionine Overdose:

Methionine is safe for most people and pets. However, taking large doses of methionine can cause metabolic acidosis, low potassium levels, osteoporosis, or hemolytic anemia accompanied by gastrointestinal distress and diarrhea. Metabolic acidosis is a condition in which the body produces too much acid. This can lead to kidney stones and bone loss.

Dog overdose from DL-methionine causes low potassium levels. The imbalances in potassium can lead to high blood pressure, heart arrhythmias, and kidney damage.

Osteoporosis: Methionine overdose can increase the risk of osteoporosis. Osteoporosis is a condition in which the bones become weak and fragile.

Hemolytic anemia: Methionine overdose can cause hemolytic anemia, a condition in which the red blood cells are destroyed. This can lead to fatigue, shortness of breath, and heart arrhythmias.

How much methionine should I give my cat?

The amount of methionine that you should give your dog or cat will depend on their weight and the condition that you are treating. Always follow the dosage instructions on the supplement label.

According to AAFCO, the minimum amount to feed your cat on a dry matter basis is 0.62% of their diet for kittens and 0.2% for adult cats and the maximum recommended is 1.5% of their diet. The AAFCO table below shows more details.

How much methionine should I give my dog?

Dogs need less methionine compared to cats, almost half the dosage that cats need. AAFCO recommends that you feed puppies a minimum of 0.35% of their diet on a dry matter basis. They also recommend a minimum of 0.33% of their diet on a dry matter basis for adult dogs and have not set a maximum.

Research on Methionine efficacy:

Urinary infection study:

One study found DL-Methionine to be effective in acidifying dog urine and preventing stone formation. It worked by acidifying urine to prevent struvite stones from forming as a result of high alkaline concentration.

Another human study found similar results.

Liver disease study:

A study done on dogs with the liver disease found that methionine supplementation improved liver function. The study found that methionine could help to protect the liver from damage and improve liver function in dogs with liver disease.