What is a Fat/Oil?
What’s the difference between a fat and an oil? Why are there so many to choose from? Which are best? Which fats should we avoid? Do fats make our dogs fat? In our blog today, we’ll address these and other fundamental questions.
Here’s the Science
First, let’s get some definitions straight. A fat is a substance that scientists call a lipid. It is made up of carbon, hydrogen and oxygen molecules, like carbohydrate, but fats are insoluble in water. Carbs are made up of precisely the same molecules, but they are arranged in such a way that the result is soluble in water, allowing you to add sugar to your tea and it dissolves making the entire cup a sugary brew.
Fats and oils are one of the three main food groups, along with proteins and carbohydrates. Dogs can survive without carbohydrates as these can be synthesised in the body, but fat and proteins are essential.
An oil is exactly the same as a fat but is liquid at room temperature. Thus, butter is a fat until it goes into the frying pan, at which point it becomes an oil, a liquid. For this blog, I’m going to use the words oils and fats. As you see, the terms are pretty interchangeable in the world of nutrition.
Oils are also known as triglycerides. Don’t worry, we’re not going to do a chemistry lesson, but I am going to show you how impressive the structure of oils are. They are all capital E shaped. The backbone of the letter, the upright, made of a glycerol molecule onto which three fatty acids are attached like a single flag pole bearing three flags, spaced apart, but one above the other. Different oils have different properties by using different fatty acids. Neat isn’t it!
In a study of oils and fats, we must mention the infamous Trans-fats. We’ve all heard of them and know they are bad for you, but why?
Most natural fatty acids are called ‘cis’ due to how the carbon chain is arranged. We won’t go too deep into the organic chemistry, suffice it to say they are natural and good! If, however, you bubble hydrogen through them to make an oil into something that looks like butter and has exceptional baking properties (think cooking margarine if you have a strong stomach), you damage the cis-fatty acids’ natural shape. These damaged, ‘trans’, fatty acids are pro-inflammatory and in humans, at least predispose to atherosclerosis, cancer and heart disease. They don’t do our pets any good either.
You’ll be pleased to know, though, that raw food is naturally low in trans-fats. Basically, the more you process a food, the more it is heated and manipulated, the more injurious elements are made as a consequence. The answer is to keep it raw, keep it as natural as possible.
Omega-3 and Omega-6 Fatty Acids
Fatty acids are identified according to their length and how many double bonds they have in the chain. Omega-3 fatty acids have a double bond three atoms away from the end of the chain. Omega-6 have the same bond, but six atoms down the chain, giving slightly different properties.
The standard Western diet for humans and animals is overly full of Omega 6 fatty acids because modern farming methods favour Omega-6. This is a problem because in the body Omega-6 is used to sustain inflammatory processes. You need them to react appropriately if you are injured or infected with a virus, for example. But equally, you need a good store of Omega-3 because they do the opposite – they are ANTI-inflammatory. An appropriate balance is needed for best health. This is why we all need to have more Omega-3 sources in our diet; to balance out the excess Omega-6 we all take daily.
In humans, in hunter-gatherer populations, the diet contains a 1:1 ratio of Omega 3 to 6. To counter our excess consumption of Omega-6, we just need to add Omega-3 oils to our diets. This is easy and usually takes the form of fish or flax oils which are naturally high in Omega-3.
Animal and Fish Fats/Oils
Animals use fats as a store of energy. A gram of fat stores over twice as much energy (calories) as a gram of protein or carb. It’s fat deposits that got our ancestors through long cold winters or times of famine. It’s fat deposits, ironically, that is killing millions of humans and dogs in the current obesity epidemic we see in the Western world. Fats are also used by the body for waterproofing our skin and for insulation against the cold. Think of fat whales or seals surviving in Antarctic oceans.
Why do fish have so much Omega-3 fatty acids? The answer, amazingly, is because they use it as anti-freeze in their blood when in icy ocean water. How clever is that?
Herring oil is becoming popular for dogs because it is believed to provoke histamine less than other marine oils, so it may be a good choice for itchy dogs. Krill oil is popular as it is very rich in EPA and DHA, the primary Omega-3 fatty acids. It also often contains astaxanthin, a red pigment thought in humans to help improve blood circulation, blood clotting and heart damage. It is favoured by ecologically conscious consumers because it is thought to impact the fish food-chain less than sourcing Omega-3s from larger fish. We are overfishing our oceans, so I’m all in favour of using Krill and other sources of Omega-3.
Going even further up the marine food chain, we come to the ultimate source of Omega-3 fatty acids: marine algae. These minute organisms synthesise complex chemicals like fatty acids using sunlight and CO2 dissolved in the oceans. Their use in human and pet supplements is relatively new but is an exciting addition to offering solutions for both global warming and over-fishing crises.
Humans can use all the fatty acids in plant oils, but dogs, being much more carnivorous, have not developed the necessary biochemical pathways. Some people think we should not give dogs flax oil, for example, because they metabolise it much less efficiently than us. Technically this is correct, but in practice, we see flax oil giving great benefits to dogs in terms of skin, joint and hormone health. At my practice, I usually suggest people alternate each month between marine and flax oils. It seems to be a winning formula.
Flax is not the only plant to have high levels of Omega-3, it’s just really convenient and has more per gram of oil, so is most peoples go-to non-animal Omega-3 source. There are others such as borage, starflower and hemp.
Coconut oil is a super-food! It is very high in saturated fats (the ones that supposedly give humans heart attacks and atherosclerosis), so most authorities recommend humans use it sparingly. In veterinary medicine, it seems to be a beneficial fat to add to food if one is trying to boost the calorie density if feeding a skinny dog, for example. If I were feeding a very very athletic dog, a working sled dog, for example, I would use animal fats for energy over coconut oil. When sourcing coconut oil, we always recommend organic product.
Fats and oils are essential as part of a raw food diet. Most are provided by varying meat sources as part of a balanced approach. It seems prudent, however, to add extra Omega-3 fatty acid sources from plant and marine sources to help the body control excessive inflammation. Inflammation is at the heart of most modern veterinary disease, from arthritis to obesity to cancer. Fresh, natural sources of ecologically appropriate oils seem like an important way to maintain our pets’ health.