Confused about fat? Do we need it in our diet? Grace Forsythe fills us in on the facts about fats...
People are confused — bad science and poor journalism have not helped our understanding of fat, lumping the good and the bad in the same basket. Many now fear any type of fat, worrying that it’s always bad for our health and that it causes unwanted weight gain. But not all fat is bad…
Do we really need fat?
Fat is essential for health and plays many roles in the body, from helping us to absorb vitamins A, D, E and K, to building the membrane of each of our cells. It also protects our vital organs by providing padding around them, insulates our bodies and provides us with energy.
One fat we don’t need, however, is saturated fat as our bodies can make all we need. Diets high in saturated fat increase the risk of many health problems and diseases, including obesity, high blood cholesterol, heart disease, stroke, type 2 diabetes and cancer. Saturated fat actually has 10 times the power to raise blood cholesterol than dietary cholesterol.
The main sources of saturated fat are animal products — meat, eggs, dairy, pies, pastries, processed foods, fatty spreads and coconut oil and palm fat. Man-made trans fats are much rarer in foods now than they used to be, once it became clear how damaging they are to our health. We have no need for them and they increase the risk of heart disease and stroke. Trans fats are twice as bad as saturated fat for blood cholesterol!
Low levels of trans fats are found naturally in dairy products, lamb and beef fat but they can also be found in some processed foods, such as biscuits, cakes, pastry and shortening as a result of manufacturers partially hydrogenating unsaturated vegetable oils. This converts them into a solid or semi-solid state that increases the shelf life of these processed foods but does your health no favours — it’s wise to check the ingredients list!
Not all fats are bad, though, and some polyunsaturated fats are essential in the diet as the body cannot produce them: linoleic acid (LA) is an omega-6 fat found in seeds, nuts, corn and soya oils and can be converted into other important omega-6 fatty acids in the body. Alpha-linolenic acid (ALA) is an omega-3 fat that can be obtained from flaxseed/linseed (the richest source), walnuts, hempseed, rapeseed oil and soya beans. The body converts ALA to the longer-chain omega-3 fats EPA and DHA, which are required for healthy brain function. These can also be obtained from some species of vegan (algae-based) omega-3 supplements.
Oily fish are a source of EPA and DHA, which they get from eating algae naturally rich in omega-3s. However, all the world’s oceans are polluted so they also contain toxins such as mercury, polychlorinated biphenyls (PCBs) and dioxins. Fear not, you can get your omega-3s from the same place as the fish — algae. Vegan EPA and DHA supplements are available online and in health shops but the algae for these are usually grown in controlled conditions away from the sea so it doesn’t impact on marine ecosystems or deprive fish of their natural food.
The bonus of algae supplements is that toxin levels are virtually non-existent, unlike in fish oil supplements. Monounsaturated fats, including omega-7 and omega-9 fatty acids, are not classed as ‘essential fatty acids’ as the body can produce them from other unsaturated fats. Good sources include olive oil, peanut oil, rapeseed oil, avocados and most nuts.
Omega-3 fat that can be obtained from flaxseed, walnuts, rapeseed oil and soya.
Concerns about cholesterol
A small amount of cholesterol in the body is essential for health, but you don’t need to eat any in your diet as your body can produce as much as you need. Large amounts of cholesterol in the diet are bad for you. Because animals also naturally produce cholesterol, it follows that animal products contain it. Plant-based foods, including every type of fruit and vegetable, pulses (peas, beans and lentils), wholegrains, nuts and seeds and avocados are all cholesterol-free.
Cholesterol has to be transported to and from the cells by special carriers called lipoproteins. Two types of lipoprotein are often mentioned in connection with cholesterol. Low-density lipoprotein (LDL), too much of which in the blood can lead to the build-up of fatty plaques that can block the arteries, reducing blood flow to the heart and brain. For this reason, LDL is often called ‘bad’ cholesterol.
High-density lipoprotein (HDL) tends to carry cholesterol away from the arteries and back to the liver where it is eliminated from the body and a high HDL level seems to protect against heart disease. It follows that HDL cholesterol is referred to as ‘good’ cholesterol.
A weighty subject
We gain weight when we take in more calories than we need. They can come from fat, protein or carbohydrate. Protein and carbohydrate both provide four calories per gram, whereas fat provides nine calories per gram. So, when eating the same amount of protein, carbohydrate or fat, you will always get more calories from fat. But don’t avoid monounsaturated and polyunsaturated fats — just eat them in moderation.
Many studies have found that some high-fat foods, such as nuts, can help prevent weight gain and even encourage weight loss. One study showed that those who ate two portions of nuts a week were 31 per cent less likely to gain excess weight than those who ate none. This may be because nuts can reduce hunger and make you feel full for longer. They also contain fibre, so some of the fat is not absorbed and is carried into the bowel.
You should be able to get all the healthy fats you need from eating a varied, vegan diet including ground flaxseed, hempseed, rapeseed oil for cooking and some nuts — especially walnuts — and seeds.
Having a diet high in omega-3s may help protect against heart disease and stroke, inflammatory diseases and neurodegenerative diseases, such as Alzheimer’s. Avoiding animal foods rich in saturated fat, while including some foods containing unsaturated fat, such as avocados, nuts, seeds and a small amount of plant oil, is a simple and effective way to protect your health.
Grace Forsythe is a Health Campaigner at Viva! Health, which is part of the charity Viva!, Europe’s largest vegan campaign group. They monitor scientific research linking diet to health. vivahealth.org.uk