What’s so super about avocados?

The avocado rose, delicious served on toast with a screw of black pepper and lemon juice, is the latest and prettiest way to eat one the world’s healthy ‘superfoods.’

And you don’t get much more super than avocados. Since they were first introduced to the UK over 40 years ago, avocados have become a staple of the British diet. We love their smooth creaminess and nutty buttery taste and eat more than 35 million of the green fruits each year. And it’s not just our taste buds which are benefiting from our fondness for avocado vinaigrette and guacamole. Multiple scientific studies have linked avocados with health benefits ranging from anti-ageing to warding off heart disease and even cancer.

“Avocado is an extraordinary food and can offer significant benefits as part of a healthy lifestyle,” says Sue Baic, a registered dietitian and co-author of Nutrition for Dummies. “It contains a lot of nutrients that we need in a convenient package which tastes great and keeps well.” So what’s in an avocado? “Beneath the inedible skin is a fruit which is largely made up of monounsaturated fat, one of the healthiest form of fats which is also found in rapeseed and olive oils. Half a large avocado contains 180 calories and counts as one of your recommended five daily portions of fruit and vegetables,” says Baic. “Avocados are also chock-full of other beneficial nutrients including potassium and vitamin E. They are naturally low in salt and contain fibre. In addition, they contain hundreds of powerful antioxidant plant chemicals – many of which are believed to have widespread health benefits. “

Tantalisingly, there may be many more announcements of health boons linked to eating avocados on the horizon. “There are over 200 types of plant steroids (phytosterols) – although avocados contain large amounts of several of these active chemicals, we really don’t yet know enough about what they do,” says Professor Donald Singer, a member of the British Pharmacological Society. “In laboratory tests, sterols reduce the growth of cells which could mean they have an action against inflammation and cancer, although this is yet to be tested robustly in humans.” There is also theoretical evidence that these sterols and other chemicals in avocados could help to reduce the pain and inflammation caused by osteoarthritis. “We know enough about them to know that they have very powerful properties in the test-tube. Now, we have to carry out rigorous studies on humans to see if the effects are felt outside the laboratory too.”

Heart health

Avocados, which contain monounsaturated fatty acids, may be able to help lower levels of ‘bad’ LDL cholesterol while boosting ‘good’ HDL cholesterol in the body. High levels of HDL cholesterol seem to protect against heart attack while LDL cholesterol clogs up arteries. In one study, scientists discovered that people who ate avocados every day for three months dramatically cut their levels of LDLs. “Replacing saturated fats with monounsaturated fats has been shown to lower LDL cholesterol which is going to have heart health benefits. There is also a small but significant boost to HDL cholesterol too,” says Linda Main, dietetic advisor for cholesterol charity, Heart UK. “We are not quite sure why this happens although it may be that monounsaturated fats improve the function of LDL receptors in the liver. These recognise LDL circulating in the body and take it out of circulation.”

Avocados also contain high levels of potassium – a third again more than bananas weight for weight- which is essential for protecting the vascular system and helps to regulate the heart as it pumps blood around the body.

Weight control

People who are trying to lose weight can expect to feel ‘fuller’ and eat less if they make sure that avocados are part of their diet, according to a study published in the journal, Cell Metabolism. This is because they contain unsaturated fats which trigger production of a compound in the small intestine that curbs hunger pangs.

Rob Beale, head of sport, health and fitness Uk and Europe for David Lloyd Leisure, says that avocados are recommended eating as part of their wellbeing course, “Avocados are a great source of essential nutrients and healthy fats such as oleic acid, which may help in lowering cholesterol levels, and the ideal choice for any weight loss programme.

They contain enough calories in healthy fat to nourish but not to induce excess weight gain – if eaten in moderation on a regular basis – and in fact possess properties that have been shown to speed up metabolism.”

Osteoarthritis

Around 8.5 million people in the UK suffer from osteoarthritis, which is a painful condition disease caused by cartilage loss in the joint. Research has found that a combination of avocado and soybean oil may reduce the pain and inflammation of osteoarthritis. This is because both foods contain chemicals called phytosterols, or plant steroids. These seem to act as anti-inflammatories and reduce pain. Jo Cumming, head of information and helpline manager at Arthritis Care says that the compound is ‘very interesting’ although it is not yet available to buy in the UK. “It does sound promising and people are quite excited about this. In studies, it significantly reduced pain and improved walking. It also had very minor adverse effects.”

Eating raw avocado may also give benefits because the fruit is rich in Vitamin E, a powerful antioxidant. “As part of a Mediterranean-style diet, avocados have an important role to play, alongside lots of other kinds of fruit and vegetables, olive oil and oily fish,” says Cumming.

Reducing wrinkles

Victoria Beckham swears by a facemask made of mashed avocado and a study published in the International Journal of Cosmetic Science found that certain avocado sugars including D-manno-heptulose may help to boost epidermis collagen.

“Nutrients from avocados will not penetrate the skin, although the flesh may help to moisten and soften the epidermis temporarily,” says Sue Baic of the BDA.

Anti-cancer

Diets rich in fruit and vegetables of all types do have a protective effect against certain types of cancer, including oral cancer, cancer of the gullet, stomach and lung.

A study carried out by researchers at Ohio State University and published in 2007 did suggest that avocados may help to prevent mouth cancer. Extracts from Hass avocados were found to kill some oral cancer cells and prevent pre-cancerous cells from developing.

However, human trials still need to be done, and the US scientists tested an extract in laboratory conditions – hardly the same as eating raw avocados.

Healthy birth

Avocados contain high amounts of the B vitamin, folic acid (or folate) which protects against birth defects such as spina bifida and anencephaly. Folate is an important regulator of embryonic and fetal nerve formation and helps to reduce the risk of giving birth too early.

Rosie Dodds, senior policy advisor at NCT, the UK’s largest charity for parents, said: “The government recommends all women who are considering pregnancy take a 400 microgram folic acid tablet every day until the 12th week of pregnancy. Even if you didn’t take folic acid beforehand, it is worth starting as soon as you find out that you are pregnant. It’s also a good idea to eat more foods containing folic acid, such as green leafy vegetables, wholemeal bread and brown rice.”