We have been told that vegetable fats or oils are healthier for us than animal fats, but do we know the difference between these various vegetable fats?
Firstly, to distinguish between fats and oils, we may think that oils are healthier, and most oils are vegetable oils. Fats, by definition, are solid at room temperature and oils are liquid. This relates to their chemical composition, and most fats are saturated, having single bonds between the carbon atoms, and oils are unsaturated, having a number of double bonds. The higher the number of double bonds, the lower the melting point.
So we may wonder about coconut oil, which may be solid or liquid at room temperature depending on the season. Similarly, olive oil becomes solid when refrigerated, but this does not make it less healthy. In fact, nowadays, butter has been vindicated as being better for our health when used in cooking, than most polyunsaturated oils
Where do trans fats come from?
Like the essential ω3 and ω6 fatty acids, trans fatty acids come only from our food. They cannot be made in the body. Although a small amount of these fats are found in foods such as full-fat dairy and beef, 80-90% of trans fats come from the partial hydrogenation of liquid vegetable oils to make then into products which are solid at room temperature, such as margarine. This has been linked to increased levels of low density lipoproteins (LDL’s) and very low density lipoproteins (VLDL’s). These increase the likelihood of arteriosclerosis (hardening of the arteries) and blocking the arteries leading to heart attacks and stroke. Trans fats also raise triglycerides (free fatty acids) in the blood and promote systemic inflammation.
The trans fat found in beef and dairy raise both HDL (high density lipoprotein), also known as “good cholesterol” and LDL cholesterol, whereas industrial fats only raise LDL. The foods containing the highest amounts of trans fats include commercially produced cakes, biscuits, pies, pastries (when made with margarine and shortening), French fries, chips and margarine. The heating of polyunsaturated oils (corn, soy, safflower, sunflower, peanut, corn) to high temperatures also produces trans fats and this also oxidises them forming carcinogenic products. The frying and grilling of meats also produces trans fats.
How do we protect ourselves from the effects of trans fats?
To counteract the inadvertent intake of trans fats, it is advisable to take 2-3g (2,000-3,000mg) EPA+DHA fish oil each day or, for vegetarians, coconut oil, nuts and seeds. Fish oils decrease inflammation in the body as do anti-oxidants (such as turmeric) and bitter vegetables (such as chicory, kale, radicchio, asparagus).
Probiotics colonise the gut better when combined with fish oils. Fermenting foods provides probiotics. This was originally a way of preserving foods but it also enhances the immune system.