Fatty acids, especially oils from coldwater fish, have been recommended in people for lowering triglycerides, reducing secondary cardiovascular disease (and probably primary disease), decreasing heart arrhythmias, decreasing blood pressure, and improving rheumatoid arthritis. They are also possibly helpful in preventing stroke and treating cancer, allergies, and mild depression. Since fish oil taken for many months can lower vitamin E, most products contain added vitamin E.
In pets, fish oil may be beneficial for heart disease, cancer, allergies, arthritis, kidney disease, and autoimmune diseases. I use high doses (2-4 times the label dose) in my patients and most can have their conventional medications lowered.
Side effects of fatty acid supplementation are rare. Fish oil may decrease platelet aggregation and prolong bleeding time. Contamination of fish meat (not oil) with methylmercury can occur. The human literature reports that fish oil may slightly increase LDL (bad) cholesterol although this does not seem to be common or of any significance in most cases. The human literature also reports multiple cases of bleeding (in the brain) when high dose doses is combined with ginkgo. I have not seen any side effects in my patients except the very rare case in a few dogs that smelled fishy.
Milk thistle is a well-known liver tonic. Milk thistle extract provides liver protection by stabilizing the cell membranes of the liver cells, aids in detoxification of toxins (especially those absorbed from the gastrointestinal tract,) stimulates protein synthesis and regeneration of damaged liver cells (actually helping the diseased cells to heal,) and also acts as an antioxidant.
Milk thistle is one of my favorite supplements for just about any disease, as the liver is involved in all disease processes. Many of my holistic clients like extra liver support during treatment with any conventional medications, including when they administer monthly heartworm and flea medications. Milk thistle is very safe to use and I’ve never seen any side effects from its use. Based upon general safety guidelines in people, it’s probably best not to use it in pregnant animals without veterinary supervision. According to some herbalists, long term use can result in depressed liver function unless chronic liver disease is present. Milk thistle is not recommended for use in normal pets but rather those that have diseases of the liver or affecting the liver.