Have you ever wondered about the health benefits and nutritional properties of avocados? I am a strong believer that it is important for everyone to have a general idea or at least a healthy curiosity as to what the nutritional properties of the food you are consuming are, and what the resulting health effects, be it good to not so good, will be once the food has been broken down in our bodies. So, in a nutshell, what are these health effects that everyone is raving about in the media when it comes to avocados, and that are often termed "superfoods" in the press?
Whistle-stop tour into the history of avocados and interesting facts:
Monounsaturated fatty acids (MUFAs):
Scientific evidence suggests that avocados promote a healthy heart. A major contributing factor in delivering this health effect may be the rich content of MUFAs naturally present in avocados. The research indicates that MUFA contained in avocados may enhance the bioavailability and absorption in the body of fat-soluble vitamins and phytochemicals. Furthermore, a number of clinical trials pinpoint the fact that avocados may have an important role to play in maintaining healthy blood lipid profiles. The mechanisms by which this physiological effect may be brought about is via the role of MUFAs in potentially reducing levels of low-density lipoprotein (LDL-cholesterol), often referred to as the 'bad' cholesterol. Generally, I am against ascribing such black and white attributes to nutrition i.e. 'good' or 'bad', as nutrition is composed of a complex interplay of many interrelated factors involving complex biological processes. However, this simplistic outlook does have some scientific foundations, as LDL-cholesterol is the type of cholesterol that has been been strongly linked with detrimental vascular consequences including the promotion of heart disease. On the other hand, avocados have also been shown to improve high-density lipoprotein (HDL-cholesterol) status, the so-called 'good-cholesterol', which has not been associated with similar negative health outcomes as LDL-cholesterol. In fact, a healthy level of HDL-cholesterol may be essential in preventing a cardiovascular incidence, such as stroke or heart attack. So, consuming avocados may contribute to help keeping heart disease at bay.
Avocados are rich in a range of micronutrients (vitamins and minerals):
Powerful Antioxidant and Anti-inflammatory
Avocados are rich in phytochemicals (such as carotenoids, phenolic antioxidants and phytosterols), which are naturally occurring compounds, many of which act as antioxidants in the body and have been shown to incur numerous potential health benefits. Antioxidants are present in food and are extracted once consumed in order to bring about a plethora of health effects in the body, including the combating of oxidative stress and inflammation. Indeed, these processes have been implicated in a range of chronic diseases, for example cancer, coronary heart disease and ageing. Antioxidants act by protecting us from harmful substances called free radicals, which are generated when we convert food into energy. Free radicals are also generated in other non food-mediated ways, such as by smoking and exposure via the air. Free radicals are harmful as they have the potential to cause damage to cells and alter genetic make-up. How exactly do antioxidants work? Antioxidants work by preventing the formation of free radicals, or scavenging them after they have been already generated. Each antioxidant will have its own specific function in the body, and each is involved in a highly complicated chemical pathway.
A deeper look into the different types of phytochemicals:
The carotenoid phytochemicals have been associated with enhanced cardiovascular health via the reduction of LDL-cholesterol. The phenolic antioxidants have been associated with enhanced blood flow and endothelial health, by inhibiting platelet aggregation to help maintain vascular health. Phytosterols, also naturally present in avocados, are known to have various bioactive properties. The most important documented benefit is their blood cholesterol-lowering effect via partial inhibition of intestinal cholesterol absorption. As such, phytochemicals are thought to play a key role in promoting cardiovascular health.
Avocados are rich in dietary fibre as they are composed of about 80% dietary fibre. This helps to maintain a healthy digestive system. By improving bowel function, dietary fibre can reduce some disorders such as haemorrhoids and may protect against colon cancer. Soluble fibre may also slow digestion and absorption of carbohydrates and consequently reduce the spike in blood glucose that follows a meal and ensuing insulin response. Furthermore, the research indicates that dietary fibre may have a role in prevention of coronary heart disease by improving the blood lipid profiles by reducing total cholesterol levels and LDL-cholesterol. Other benefits of fibre are also good to note: fibre can add bulk to your diet, without adding calories. It can have a satiating effect on appetite and help in weight management.
Avocados contain an antioxidant called lutein that may protect against eye conditions such as cataracts and age-related macular degeneration, a leading cause of blindness in elderly people. Lutein is selectively taken up into the macula of the eye (the portion of the eye where light is focused on the lens).
Sophie's RD opinion- Although avocados may be higher in calories compared to other foods, if consumed in moderation as part of a healthy balanced diet you will really be able to take advantage of the nutritional benefits conferred by nutritionally dense avocados.
Mash up some avocado and use it as a healthy alternative in place of:
1 ripe tomato
2 avocados, very ripe but not bruised
1 small red onion, finely chopped
1 chilli - red or green - deseeded and finely chopped
Juice of 2 large limes
1. Use a knife to chop up the tomato very finely, then tip into a bowl.
Halve the avocados (saving a stone) and use a spoon to scoop out the flesh
into the bowl with the tomato.
2. Tip all the other ingredients into the bowl, then season with salt, pepper and lime juice.
Use a whisk to roughly mash everything together. If not serving straight away, sit
a stone in the guacamole - this will help to stop it from going brown - cover with
cling film and chill until needed.
3. Serve with raw vegetables (e.g. carrots, cucumber, celery, radishes)
Myth of fact: Is brown sugar really healthier than white sugar?
It is a common misconception that brown sugar is a healthy alternative to white sugar as people wrongly believe that it is more natural and less refined. However, this is not the case. On the contrary, brown sugar is actually just white sugar that has undergone an additional process where molasses, a black syrup by-product of sugar refining, has been re-incorporated into the sugar particles. Brown sugar is technically speaking more refined as it has undergone a greater degree of processing than white sugar to give it that different granular texture and flavour. Although research shows that the molasses contain a slightly elevated level of minerals, this is such a negligible quantity that it would not bring about health benefits in the body.
The World Health Organisation (WHO) recommends that added sugars should not exceed 10% of energy (calorie intake) from food and drinks each day. This is about 70g for men and 50g for women, but varies according age, size and how active you are.
TAKE HOME MESSAGE
It's all about moderation - consume foods and drinks containing high amounts of sugar in moderate amounts. Although sugars are found naturally in many food products, there is also a vast amount of hidden sugars that are added to many products to enhance the flavour.
Calorific and nutritionally poor - many foods that contain added sugar e.g. sweets, cakes, biscuits, fizzy drinks etc. will usually provide 'empty calories' as they contain only very small amount of nutrients in relation to the vast amount of calories they deliver. As such, these products will not bring about any health benefits.
Weight gain & associated detrimental health outcomes- moreover, excessive consumption of sugars can bring about weight gain and promote unfavourable health conditions associated with weight gain.
Check food labels- read the nutritional labels of food products to see how much sugar the product contains prior to purchasing as you may be in for a surprise!
The closer to the beginning of the ingredient list the sugar is the more sugar the product contains. Look for 'carbohydrates' (of which sugars) figure in the nutritional label to see the quantity of sugar the product contains per 100g.
Fat-free does not mean sugar-free - just because a product is labelled as 'fat-free' this does not mean it is 'sugar-free'. Ensure you have a good read of the food label.
Sugar’s many guises - There are lots of differing ways that added sugar can be listed on ingredients labels, so pay attention to the ingredients list (e.g. sucrose, glucose, fructose, maltose, molasses, hydrolysed starch, corn syrup, honey)
Read more about sugar here: BDA Sugar Factsheet
Sophie Bruno is a Registered Dietitian living and working in Brussels (Belgium). Read Sophie's foodie blog which will enable you to learn, increase your knowledge & cultivate yourself in the field of nutrition & health directly from Brussels