Animal and vegetable fats compared — who wins?
For decades the opinion has been: animal fats are bad. The less we eat of them, the better — but is that the right attitude? Fats in general serve not only to insulate and store energy in our bodies, but also to improve the absorption of important vitamins, cell signalling, immune function and many other significant processes. Many people think that the main difference between vegetable and animal fats is the content of “bad” saturated fatty acids and cholesterol. But saturated fat and cholesterol also have their role in our bodily functions and should not be demonised out of hand.
Can you remember?
Let’s start with a brief recap on fats in general: Fats are found in the body mainly as free fatty acids or as fatty acids combined with glycerol (triglycerides) or in cholesterol. You can read more about this in our last article on dietary fats. Triglycerides are the storage form of fatty acids, cholesterols fulfil numerous important tasks in cell structure, vitamin and hormone production and cell signalling. The body can produce all saturated fatty acids itself, but unsaturated fatty acids are divided into non-essential and essential fatty acids: non-essential unsaturated fatty acids can be produced by the body itself, whereas essential unsaturated fatty acids (omega-3 and omega-6 fatty acids) must be obtained from food.
The better-known omega-3 fatty acids are mainly found in fish, linseed oil or walnuts. The omega-6 fatty acids (linoleic acid) are found in most vegetable oils, such as sunflower oil or maize germ oil, as well as in meat, dairy products or almonds. The fatty acids found in food are broken down in the cells with the help of so-called beta-oxidation or converted into each other as needed. If the body has enough energy available, the fatty acids are stored in the fat tissue in the form of triglycerides.
Animal vs. vegetable fats
What do margarine, oils and the like actually consist of? All vegetable and animal fat sources naturally contain an individual mixture of different saturated and unsaturated fatty acids. The more unsaturated fatty acids, the more liquid the oil. Animal foods do not always contain more of the “unhealthier” saturated fatty acids. Some plant foods even provide more saturated fatty acids than animal foods (coconut oil), as we mentioned in our previous article. Pork, for example, like olive oil, contains the monounsaturated fatty acid (MUFA) called oleic acid. However, unlike vegetable fats and oils, meat contains a lot of cholesterol and no phytochemicals that can enhance the beneficial effects of unsaturated fatty acids and buffer the often harmful effects of saturated fatty acids.
Both omega 3 and omega 6 are important for humans: the two fatty acids together control processes in the body, such as the immune defence: omega 6 sets the inflammatory process in motion, omega 3 helps to stop the inflammation.
What is often not properly communicated is that the two essential omega-6 unsaturated fatty acids for the body, linolenic acid (ALA) and linoleic acid (LA), are found in a variety of both plant and animal foods. It is fairly easy to consume both of the important fatty acids regardless of individual dietary preferences. However, there is one catch: our body must first produce the usable end products from ALA and LA: EPA, DHA and ARA. Animal products already contain these end products, so the body has nothing more to convert and an easy game.
However, none of the three end products are found in vegetable fat sources. EPA (eicosapentaenoic acid) is an omega-3 fatty acid that primarily has anti-inflammatory and healing functions. ARA (arachidonic acid) is an omega-6 fatty acid that is often thought to be a “bad” fatty acid because it promotes inflammation and is only found in animal foods (and algae). However, ARA is indispensable in defence and inflammatory processes and thus promotes healing processes.
Fat IQ
Our brains are extremely rich in fat. About two-thirds of the human brain is made up of fat, and a full 20 percent of that fat is a very special omega-3 fatty acid called DHA or docosahexanoic acid. Among many other functions, DHA is involved in the formation of the white matter that insulates our “brain wiring” and helps maintain the blood-brain barrier that protects the brain from unwanted external influences. DHA plays a “unique and indispensable role” in the “neuronal signalling essential for higher intelligence”, says Simon Dyall PhD, lipid research scientist at Bournemouth University, UK. Especially during pregnancy, there is a high demand for DHA, as a whole brain has to develop anew. It is unclear whether the consequences of a DHA deficiency in pregnancy can be completely reversed later. Lower levels of DHA are found in people with psychiatric disorders, such as autistic disorders and ADHD.
Plant foods contain absolutely no DHA
For those on a vegan diet, it is important to know that plant-based foods do not contain DHA. Vegetarians show 31% lower levels than omnivores, and vegans even 59% lower. The essential omega-3 fatty acid alpha-linolenic acid (ALA) is abundant in plant foods such as flaxseed, walnut and chia, but unfortunately the conversion to DHA seems to be quite difficult for the adult human body. Most studies found a conversion rate of less than 10 percent, some even 0%. Many scientists have thus advocated that DHA should be officially considered an essential omega-3 fatty acid instead of ALA. Even vocal proponents of plant-based diets, such as the authors of the recent EAT Lancet report, acknowledge that it is unclear how much ALA one needs to consume to meet DHA requirements.
DHA-rich (animal) sources include:
- Salmon, anchovies, mackerel, tuna, shrimp.
- Eggs
- Poultry meat
Vegetable fats lower the risk of death
That’s according to researchers at the Harvard T.H. Chan School of Public Health, who studied dietary data from more than 90,000 people over an average of 22 years. The risk of heart disease was lower when unhealthy saturated fat, refined carbohydrates or trans fats were replaced with monounsaturated fat from plant sources, but not with animal-based monounsaturated fat. A higher intake of the plant-based fats was associated with a 16% lower risk of death. In contrast, a higher intake of animal fats was associated with a 21% higher risk of dying from any cause.
Not all vegetable fats are super
Almost all processed foods, packaged snacks and ready meals are made with refined vegetable oils such as soybean or sunflower oil. Most vegetable oils today unfortunately contain unnatural amounts of LA (linoleic acid), which has been shown to reduce the production and effectiveness of DHA in the body. Excess linoleic acid (from both plant and animal sources) can trigger inflammation and slow healing. The best vegetable oils low in linoleic acid are olive oil, avocado oil, rapeseed oil and palm kernel oil, he said. But beware, a deficiency of gamma-linolenic acid in combination with certain enzyme defects is seen by researchers at the Efamol Research Institute in Canada as the cause of a number of diseases, such as:
- Neurodermatitis
- Multiple sclerosis
- Diabetes
In addition, a study from Japan establishes the connection between a deficiency of gamma-linoleic acid and premenstrual syndrome (PMS).
How to achieve a healthy ratio?
A healthy mix of fatty acids can be achieved through diet. For example, nutritionists of the Budwig Foundation consider a ratio of omega 6 to omega 3 fatty acids of 2:1 to 5:1 to be balanced. The German Nutrition Society recommends eating no more than 300 to 600 grams of meat per week. Vegetarians must also be careful: too much omega-6 fatty acid can quickly be ingested through vegetable oils such as sunflower oil. To compensate, fish with the healthy omega 3 should be regularly on the menu. Those who want to do without fish can resort to linseed oil, linseeds, sesame seeds, walnuts or pine nuts.
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(3) https://www.budwig-stiftung.de/service/omega-3omega-6.html
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(5) https://next.amboss.com/de/article/B60zMS#Z392a1b5ce103b66cd7a1630143668848
(6) https://www.deutsche-apotheker-zeitung.de/daz-az/2013/daz-31-2013/welches-fett-ist-erste-sahne
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