Providing Nutritional Support for Liver Health in Pets

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The liver plays a central role in many physiologic processes, including macronutrient (eg, proteins, fats, carbohydrates) metabolism, lipid and cholesterol balance, vitamin storage, endocrine signaling, and immune system support. The liver also protects the body from toxic chemicals and is the primary organ of drug metabolism.^1,2

The clearance of xenobiotics (ie, drugs, toxins) occurs primarily through the cytochrome P450 family of enzymes that work to convert fat-soluble molecules into more water-soluble forms in what is known as phase I detoxification. This is followed by phase II reactions involving functional group conjugation, making the toxin increasingly less harmful; the process is then completed with phase III reactions that work to eliminate the toxin or drug from the body.³

Acute and chronic insults to the liver can result in functional cell damage and death. Known causes of liver disease include infectious agents, toxins, drugs, and/or excessive copper accumulation. An immune-mediated component may also be involved in some cases.⁴ Hepatic tissue damage from inflammation and free radical damage trigger fibrogenesis, which, if unresolved, can result in cirrhosis, decreased liver function, and even liver failure.^5,6

Diagnosing the exact etiology of hepatobiliary cell damage is challenging and can involve advanced imaging and invasive procedures such as liver biopsy and gall bladder aspirates. Even with appropriate diagnostic testing, many hepatic cases will be considered idiopathic. Understandably, some pet owners may be reluctant to pursue advanced diagnostics and/or invasive procedures for their pets.

Diagnostic procedures and certain drug therapies may sometimes be withheld in patients with liver disease due to concerns regarding adverse effects or concerns that the patient may not tolerate them due to age or other concurrent medical issues.

Fortunately, another approach to managing liver cases can be to provide specific nutritional support that ensures an adequate supply of resources for liver functions, cellular repair, and regeneration. Nutritional management can also support the essential steps of liver detoxification, help ameliorate liver cell injury, and/or reduce fibrogenesis. Several nutrients should be considered to help support the liver:

• Flavonoids are potent plant-based antioxidants that may help reduce inflammation and may help regulate key cellular enzyme pathways, as well as provide antimutagenic and anticarcinogenic functions.⁷ The fruit of the milk thistle plant (Silybum marianum, family Asteraceae) contains flavonoids that are proven liver protectants.⁸

• Curcumin exerts remarkable protective and therapeutic effects on oxidative-associated liver diseases through various cellular and molecular mechanisms, acting as a free radical scavenger and reducing the activity of reactive oxygen species.⁹

• Glutathione is essential to supporting detoxification reactions that occur during phase II within the liver cell.¹⁰ S-adenosyl-L-methionine (SAMe) is an important, metabolically active molecule that participates in multiple cellular reactions, and it is the precursor for the synthesis of glutathione.¹¹ SAMe is also an essential methyl donor required for methylation of nucleic acids, phospholipids, histones, biogenic amines, and proteins.¹² These transmethylation reactions are essential to life, health, and regeneration of body cells, and there is evidence that SAMe depletion occurs during chronic liver disease.^6,13

• N,N-dimethylglycine HCl may also help support liver function by enhancing liver detoxification, serve as a precursor to SAMe, and modulate immune responses within the liver as well as the entire body.¹⁴

Managing liver diseases can be difficult, as often the etiology is not determined, but using thoughtful nutritional support offers a strategy that may help prevent disease progression or even allow liver recovery.