Part 1 of this post covered why some people like to cook for their pets, and dealt briefly with what should be included at mealtimes. (Missed Part 1? Catch up here!) But is it better to cook, or serve your pets’ meals raw?
It should be remembered that there have been many studies which indicate that cooking food can be beneficial. Some people like to include an amount of fruit and vegetables in their dog’s diet, as it is well known that these contain a wide range of minerals, nutrients and vitamins that can benefit your canine companion – leaving aside the fiercely debated issue of whether or not your dog would eat these ingredients in the first place if let loose in the wild. Dealing firstly with vegetables, an article published by Scientific American (Fact or Fiction: Raw veggies are healthier than cooked ones) confirms that not all raw vegetables are healthier than those that have been heated. For example, cooked carrots, broccoli and spinach supply more antioxidants than when eaten raw, and boiling or steaming better preserves antioxidants than frying – although boiling was deemed the best method of serving these veggies for optimum goodness.
Furthermore, cooking carrots increases their levels of beta-carotene (the substance which gives them their color), which the body in turn converts to vitamin A – a very important necessity for vision, reproduction, bone growth and the immune system.
Similarly, when cruciferous vegetables such as broccoli, cauliflower and cabbage are heated, the compound indole is formed – and research has shown that this helps kill precancerous cells before they turn malignant.
Cooking or lightly steaming vegetables also breaks down their cellulose, allowing the dog’s body to better access all the goodness inside. With the cellulose still intact, most dogs will simply pass the veg matter in their stool.
Assuming that you are therefore one of those feeders who adds vegetables to your dog’s dinner, there is much to be said for going to the effort of cooking those veggies first before offering them at dinner time.
On the flip side, and in all fairness to those who maintain that raw is best, there is a down side to the cooking of vegetables. Heat has been shown to damage the enzyme tyrosinase, which breaks down glucosinates in broccoli in to a compound called sulforaphane. Sulforaphane is believed to block and kill pre-cancerous cells, and can assist the fight against the bacteria which causes ulcers and can lead to stomach cancer.
And despite the benefit of increased beta-carotene when cooking carrots, heating them has shown to lead to a total loss of polyphenols – which have antioxidant properties, and can reduce the risk of cardiovascular disease and cancer.
A well known disadvantage to cooking vegetables is that it can result in some vitamin and mineral losses, although surprisingly few vitamins are destroyed by heat – and heating alone will not destroy minerals (although they may be leached in water). For an in-depth look at this issue, see this very informative site. Vitamin C is soluble in water, highly unstable, and degrades when exposed to oxygen and heat, but a number of important facts should also be borne in mind:
- cooked vegetables will still retain as much as 50% of their vitamin C content even after heating;
- dogs, like most mammals (with the exception of humans and Guinea Pigs), produce their own vitamin C, so introducing this from an external source is not always necessary. However, as vitamin C production is reduced by, for example, stress or exertion, working dogs often benefit from an additional boost from their food.
- vitamin C is widely available in many fruits and vegetables and therefore any loss sustained through cooking can easily be made up from raw fruit or veg elsewhere in the garden; and
- as when cooking any fruit or vegetables, if you keep and use the water in which they were cooked, you will still be able to access some if not all of the nutrients lost through heating. You can therefore still benefit from the vitamins and minerals that have been dissolved or leached in to the cooking water.
This last point is equally applicable if you cook meat for your pet’s dinner. Whilst cooking has been shown to destroy the enzymes in meat, many nutrients are by and large unaffected, although some quantities can be reduced by up to 40% in some cases. As when cooking vegetables however, any vitamins or minerals lost in cooking can often still be found in the juices created by heat, and if this is poured over the meat your pet is still able to benefit from this goodness, and little is therefore lost.
Studies have shown that cooked meat actually can pack more nutritional value than meat served raw. Cooking appears to “unwind” the proteins in meat, making it easier to digest – and the body expends far less energy processing cooked meat as a result, as well as being able to absorb more energy from the food. Therefore it is easier to lose weight if eating a raw diet because more calories are burnt digesting the food, but conversely it is easier to maintain weight if eating a cooked meal.
In a similar vein, the body’s immune system is saved the trouble of fighting off food borne pathogens if the food is cooked first (thereby destroying harmful bacteria). However, those feeding a raw diet to their dogs often believe that because the body is not struggling to process an “unnatural” food such as kibble results in an immune system better able to deal with external issues such as allergies and fighting infection.
Taking all the above in to account, it would appear that it is not possible to infer one general rule, or to be able to state that cooking your dog’s food is definitively better or worse than serving it raw. There are pros and cons on both sides, with much depending on the type of food served (meat & vegetables/just meat etc) as well as the temperature and duration of cooking. The general view seems to be that which has always been the case: you should strive to serve your pet a varied and balanced diet consisting of a wide range of proteins, mineral and vitamins from different sources in order to ensure he or she receives the best nutrition for optimum health – whether you serve a cooked meal or opt for raw!