ANTIOXIDANTS ANTIOXIDANTSCommon Uses
Anti-inflammatory, arthritis, allergies, asthma, cancer
Certain vitamins and minerals function in the body to reduce oxidation. Oxidation is a chemical process that occurs within the body’s cells. After oxidation occurs, certain by-products such as peroxides and “free radicals” accumulate. These cellular by-products are toxic to the cells and surrounding tissue. The body removes these by-products by producing additional chemicals called antioxidants that combat these oxidizing chemicals.
In disease, excess oxidation can occur and the body’s normal antioxidant abilities are overwhelmed. This is where supplying antioxidants can help. By giving your pet’s body extra antioxidants, it may be possible to neutralize the harmful by-products of cellular oxidation.
There are several antioxidants that can be used to supplement pets. Most commonly, the antioxidant vitamins A, C, and E, and the minerals selenium, manganese, and zinc are prescribed. These are all found in Part Two, under their own individual listings. Other antioxidants, including superoxide dismutase, glutathione, cysteine, Coenzyme Q10, Ginkgo biloba, bilberry, grape seed extract, and pycnogenol may also be helpful for a number of disorders.
Also called pycnogenols or bioflavonoids, this class of water-soluble plant-coloring agents, which contain naturally occurring polyphenolic compounds, are found in plants (most often products containing proanthocyanidins are made from grape seed or pine bark). While they don’t seem to be essential to life, it’s likely that people and pets need them for optimal health. These compounds are used for their antioxidant effects against lipid (fat) peroxidation. Proanthocyanidins also inhibit the enzyme cyclooxygenase (the same enzyme inhibited by aspirin and other nonsteroidal medications); cyclooxygenase converts arachidonic acid into chemicals (leukotrienes and prostaglandins), which contribute to inflammation and allergic reactions. Proanthocyanidins also decrease histamine release from cells by inhibiting several enzymes.
The actions of the proanthocyanidins make them useful in treating pets with various inflammatory disorders including allergies, asthma, and arthritis.
Inhibiting enzymes involved in the destruction of collagen (callagenase, elastase, hyaluronidase) is a proposed mechanism of proanthocyanidins in the treatment of arthritis, in addition to the anti-inflammatory actions.
Proanthocyanidins, by augmenting the immune system (via enhancement of T-lymphocyte activity and modulation of neutrophil and macrophage responses), are often recommended for use in the treatment of pets with cancer.
This antioxidant is promoted as an anti-arthritis agent in people. Pycnogenol is a group of chemicals from the bark of pine trees native to southern France and is a mixture of bioflavonoids, which inhibit the prostaglandins that cause inflammation. (Bioflavonoids isolated from grape seed are also recommended for arthritic disorders for their anti-inflammatory effect.) In addition to its use in people to help control arthritis, it is also suggested for use in patients suffering from adult attention deficit disorder.
Some research suggests that pycnogenol seems to work by enhancing the effects of another antioxidant, vitamin C. Other research suggests that the bioflavonoids can work independently of other antioxidants; as is the case with many supplements, there probably is an additive effective when multiple antioxidants are combined. People taking pycnogenol often report feeling better and having more energy; this “side effect” may possibly occur in our pets as well.
Quercetin is a natural antioxidant bioflavonoid found in red wine, grapefruit, onions, apples, black tea, and, in lesser amounts, in leafy green vegetables and beans. Quercetin protects cells in the body from damage by free radicals and stabilizes collagen in blood vessels.
Another intriguing finding is that quercetin may help prevent immune cells from releasing histamine, the chemical that initiates the itching, sneezing, and swelling of an allergic reaction. Based on this very preliminary research, quercetin is often recommended as a treatment for allergies and asthma. This recommendation is based on test-tube research showing that quercetin prevents histamine release from mast cells (allergy cells). It also may block other substances involved with allergies, although there is no evidence so far that taking quercetin supplements will reduce your pet’s symptoms.
In people, quercetin may help protect against heart attacks and strokes.
Quercetin supplements are available in pill and tablet form. One problem with them, however, is that they don’t seem to be well absorbed by the body. A special form called quercetin chalcone appears to be better absorbed. Test-tube and animal research also suggests that quercetin might be able to help prevent tumors in hamsters or enhance the effects of cancer-fighting drugs. An animal study found that quercetin might protect rodents with diabetes from forming cataracts. Another intriguing finding of test-tube research is that quercetin seems to prevent a wide range of viruses from infecting cells and reproducing once they are inside cells. One study found that quercetin produced this effect against herpes simplex, polio virus, flu virus, and respiratory viruses. However, none of this research tells us whether humans or pets taking quercetin supplements can hope for the same benefits. Much more research needs to be done on the use of quercetin for these conditions.
In people, a typical dosage of proanthocyanidins is 200 to 400 mg 3 times daily. Quercetin may be better absorbed if taken on an empty stomach. The suggested dosage of proanthocyanidin complex in pets is 10 to 200 mg given daily (divided into 2 to 3 doses). The suggested dosage of biflavonoid complex in pets is 200 to 1,500 mg per day (divided into 2 to 3 doses.) The actual dosage of each product will vary with the product and the pet’s weight and disease condition.
In general, antioxidants can be useful for a variety of conditions. Because some types of chemotherapy and radiation therapy may rely on cellular oxidation for their effects, antioxidants should not be used without veterinary supervision in pets with cancer undergoing chemotherapy or radiation therapy. For a greater discussion on the use of high doses of antioxidants in the therapy of various diseases in pets, called orthomolecular medicine, see Part Four, Other Complementary Therapies.
Quercetin appears to be quite safe. Maximum safe dosages for young children, women who are pregnant or nursing, or those with serious liver or kidney disease have not been established; similar precautions are probably warranted in pets.