From blueberries to goji berries, garlic to green tea, we have all heard foods being referred to as ‘superfoods’. But what does this really mean? This article explains why some foods are described as ‘superfoods’ and the truth behind the hype.
This information was published by Bupa's health information team and is based on reputable sources of medical evidence. It has been peer reviewed by Bupa doctors. The content is intended for general information only and does not replace the need for personal advice from a qualified health professional.
All foods contain some nutrients. However, some foods are thought to have such a high content of certain nutrients that they have extra health benefits, so much so that they are referred to as 'superfoods'.
Despite its common use, there is no official scientific definition of the term 'superfood'. This has led to food companies claiming products to be 'superfoods' without explaining what makes them so beneficial or make other health claims such as 'good for your heart' or 'helps lower cholesterol'. Some of the foods most commonly referred to as 'superfoods' are those containing high levels of anti-oxidants, such as blueberries and goji berries.
Anti-oxidants are substances that reduce damage to your cells, caused by unstable molecules called free radicals. Anti-oxidants include beta-carotene, lycopene, selenium and vitamins A, C and E. These substances are naturally found in fruits and vegetables, as well as other foods such as nuts, meat and fish.
It's been claimed that anti-oxidants can help prevent a number of health problems, including cancer. It's even been suggested that their beneficial effects can help you live longer. However, despite research showing that anti-oxidants can reduce the growth of cancer cells, this has been done only in laboratory studies involving cells or animals. Studies in people haven't confirmed this effect. Also, a scientific review has found no evidence that anti-oxidant supplements prolong life. In fact, some anti-oxidant vitamin supplements (containing vitamin A or E) may actually be harmful.
Lycopene is a type of anti-oxidant that is thought to be particularly beneficial. It’s found in red fruits, including watermelon, grapefruit and tomatoes. Men whose diet contains high amounts of lycopene have been found to be at a lower risk of prostate cancer. However, scientists aren't sure whether the lycopene itself actually helps to prevent prostate cancer, or whether it's just a coincidence that men who have high levels happen to be less likely to develop cancer.
Although the evidence for particular health benefits of anti-oxidants is lacking, what we do know is that eating plenty of fruit and vegetables can help to reduce your risk of certain illnesses including some cancers.
It's thought that the beneficial effects of fruit and vegetables are due to a combination of things, rather than one specific component. So, rather than opting for so-called 'superfoods', try to eat at least five portions of a variety of fruit and vegetables a day. This should provide you with all the anti-oxidants you need. Only take supplements if your doctor or a registered dietitian recommends it.
Although 'superfood' isn’t an official term, there are certain foods that can be called functional foods. These have additional benefits above their basic nutritional value. Examples of some functional foods are discussed below.
Although functional foods may have health benefits, they are no substitute for a varied and balanced diet. You shouldn’t use functional foods as a substitute for any medicines that your doctor has prescribed you.
Prebiotics are carbohydrates that your digestive system can’t break down. These are good for your health as they encourage beneficial bacteria in your bowel to grow and prevent the growth of bacteria that are harmful to your bowel. Prebiotics are found naturally in certain foods, including leeks, onions, asparagus and artichoke. You can buy specially made products that contain prebiotics, such as yoghurts and yoghurt drinks.
These are live micro-organisms (mainly bacteria) that are thought to help keep your digestive system healthy. You can buy products, such as yoghurts, that contain probiotics. However, although they have been shown to help those with infectious diarrhoea, there isn't much scientific evidence to suggest that probiotic products have any benefits for healthy people.
Stanols and sterols
These are substances found in plants that can lower your levels of LDL (bad) cholesterol. They are added to certain food products such as margarines. If you have been told by your GP that you have high cholesterol levels, these products may help you to lower your cholesterol level. Always read the information on the packaging – these products are most effective if you take them as recommended by the manufacturer.
Dairy peptides are small proteins. They can help to control your blood pressure. Some foods do naturally contain dairy peptides, such as mature cheddar cheese, but there isn’t enough in them to be useful.
However, some drinks have been specially produced with dairy peptides added to them. These can help to control your blood pressure as part of a healthy balanced diet. You should only have these drinks if you have been told by your GP that you have high blood pressure. Always use them in combination with treatment and/or lifestyle changes recommended by your GP.
Omega-3 fatty acids
It's thought that long-chain omega-3 fatty acids may help to protect you against heart disease. They are also important if you're a woman who is pregnant or breastfeeding because they help your baby to develop healthily. These types of fats are found in oily fish, such as mackerel, fresh tuna and salmon.
Because of the health benefits, you should aim to eat two portions of fish a week, one of which should be oily. If you're pregnant you shouldn't eat any more than two portions of oily fish a week. This is because oily fish can contain low levels of pollutants, which can be harmful if they build up in your body over time.
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- Anti-oxidants and cancer prevention: factsheet. National Cancer Institute. www.cancer.gov, accessed 21 June 2010
- Bjelakovic G, Nikolova D, Gluud L, et al. Anti-oxidant supplements for prevention of mortality in healthy participants and patients with various diseases. Cochrane Database of Systematic Reviews, 2008(2). doi:10.1002/14651858.CD007176, www.cochrane.org
- Food and medical conditions. Food Standards Agency. www.eatwell.gov.uk, accessed 21 June 2010
- Adults. British Nutrition Foundation. www.britishnutrition.org.uk, accessed 12 May 2010
- Functional foods. British Nutrition Foundation. www.britishnutrition.org.uk, accessed 7 June 2010
- Functional foods. The British Dietetic Association. www.bda.uk.com, published March 2006
- Prebiotics. British Nutrition Foundation. www.britishnutrition.org.uk, accessed 7 June 2010
- Allen S, Okoko B, Martinez E, et al. Probiotics for treating infectious diarrhoea. 2003(4). doi:10.1002/14651858.CD003048.pub2, www.cochrane.org
- Fish and shellfish. Food Standards Agency. www.eatwell.gov.uk, accessed 25 June 2010
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