You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet.

Antioxidants are added to foods to prevent deterioration and prolong shelf-life

Once a food has been manufactured chemical changes can occur which make the food unfit to eat. Exposure to oxygen from the atmosphere leads to a process called oxidation and this can make fat turn rancid which makes the food unpalatable, destroys fat-soluble vitamins  (A,D,E and K) - and produces unpleasant waste products  that can make the food  potentially dangerous if eaten. So, all foods have a recommended shelf life after which they should be discarded. 

Foods that are high in energy content often contain relatively high concentrations of fats or oils, and these are particularly liable to undergo oxidation - especially if the food is stored at warm environmental temperatures.

One way to prevent or delay oxidation and prolong the shelf life of foods is to add substances called antioxidants to the food. These work either by taking up oxygen or by preventing the formation of , or by removing , undesirable chemicals called "free radicals" which are produced in the food. Chemically antioxidants work by one of the following mechanisms :

• They donate electrons
• They donate hydrogen
• They scavenge oxygen
• They scavenge free radicals

Antioxidants can be synthetic (eg butylated hydroxyanisole -BHA) or natural products - and a commonly used natural antioxidant is Vitamin E which is also beneficial to the animal because it is an essential  nutrient.

Consumers are concerned about the safety of "additives" in foods and a frequently asked question is "Are antioxidants harmful?". Well, all food additives for human consumption have to satisfy the regulatory authorities that they are safe before they are allowed to be added to a food - and antioxidants added to pet foods in the USA and EC are used in human foods as well and have to comply with statutory safety regulations.

Last updated : September 2013