Following in the popularity of the goji and acai berry, recent media reports are hailing the latest super berry on the block, the buffaloberry. It may then be timely to look at superfoods with an eye on science rather than an advantage to market sales.
We are bombarded with stories of the latest superfoods and their seemingly miraculous health benefits; foods that can slow down the ageing process, lift depression, boost our physical and mental capability, or the particular antioxidant packed fruit or vegetable that will destroy cancer cells. Whilst these claims are overstated, even the most sceptical of us who are aware that pretty much all types of fruit and vegetables are good, are likely to have been influenced by the superfood buzz and typically increased our consumption of such foods.
In reality ‘superfood’ is a marketing term. It has no scientific or technical definition. Indeed EU health claims legislation would prohibit the marketing of foods as a superfood unless it could be accompanied by a strictly assessed and authorised EU evidence-based claim on a specific health benefit. However, enter ‘superfood’ into an internet search and it will return millions of hits referring to well over 100 foods, Repeat the search in the internationally recognised scientific journal database, PubMed, and you get a total of three hits.
The widest use of the term refers to fruit and veg, and describes a food that is especially rich in phytochemicals, in particular antioxidant micronutrients, most recently lycopene in the buffaloberry. The idea that a single food item, packed with certain exotically named chemicals can confer remarkable health benefits is great for media headlines. But such claims around single foods curing and preventing diseases, fighting off cancer, even prolonging life are misleading.
Superfood Research
There is no smoke without fire, and certain studies have reported benefit of, for example, pomegranates in relation to heart disease or oily fish and blackcurrants in mental decline. But the researchers themselves don’t term them ‘super,’ and there are many reasons why the research, typically small with many limitations, is often not as promising as it first appears.
Much of the available evidence comes from cell culture or animal models, making any findings impossible to extrapolate in a meaningful way to the average person. Studying whether a chemical found in broccoli may kill cancer cells in a dish in the lab doesn’t mean that eating lots of a food containing this component will prevent you from getting cancer.
Even when research is conducted in people, superfood research tends to be limited as
- It tends to look only at short-term consumption or testing the compound in a food by way of a supplement
- It often tests chemicals and extracts in concentrations not found in the natural state and that are not reflective of intake in diets
- Disentangling the effect of one particular food or compound from the others that we consume in a complex diet is notoriously difficult.
- Eating certain foods may be closely associated with other factors like overall diet quality, physical activity, weight and socioeconomic status, and it may be these rather than the food in question that are conferring the benefit.
- Measuring food consumption accurately is problematic and often relies on self-reported biased recall.
Researchers may also use end points that are not the same as the health effects being reported, for example looking at changes in the blood flow to the brain, and extrapolating such findings to improved memory.
In short, few claims that a food has a miracle benefit live up to scrutiny.
The best level evidence would be from randomised controlled studies but looking at long-term effects of a particular food or nutrient with all other factors controlled such as in a laboratory setting is not feasible. Systematic reviews like those conducted by the World Cancer Research Fund provide a more substantive evidence base. Its report concluded that fruit and vegetables in general, as well as foods containing antioxidants such as lycopene, beta-carotene, and vitamin C, were probably associated with reducing the risk of a number of cancers. This should be compared to alcohol intake and body fatness which they report are convincingly associated with certain cancers.
Can increasing consumption of a superfood be bad?
Increasing fruit and vegetables is an important area of improving public health and nutrition, but seeking out large amounts of specific nutrients from any one source is not likely to be beneficial. Is broccoli more nutritious than other green vegetable for example? Dietitians often use the phrase ‘a rainbow on the plate’ reflecting that colour and variety are important. If consumers stick with only a narrow range of fruits and vegetables, or indeed consume large quantities of one, they are likely to miss out on the potential benefits of a wide range of phytonutrients. Understanding that such foods are healthy may be important, but understanding that a variety of these is better is also fundamental.
The idea of a superfood may also let people believe that they can somehow balance out other unhealthy habits. No single food in isolation can compensate for an unhealthy eating pattern. Including a superfood does not combat a diet high in calories, fat, sugar, salt and alcohol, or being overweight and having low levels of activity. Cocoa and red wine have both been cited as superfoods but contradictory reports make it difficult for the public to understand whether red wine and chocolate will save their life or kill them. In addition. cocoa can often be consumed with sugar and fat in the form of a chocolate treat. It is sobering when considering superfoods in context, that obesity and alcohol remain two common causes of ill health and premature death.
The trend for the more exotic foods not native to the UK may be contrary to the idea of sustainable diets using local and seasonal produce, many of which are also ‘super’ and cheaper.
Everyday fruits, vegetables wholegrains, lean meat, oily fish and dairy foods each have their own unique nutrient profile and contain individual factors that can be said to promote health and wellbeing. Couple this with avoiding excessive consumption of calories, processed refined foods and alcohol. While it might be tempting to believe in miracles, the reality is more straightforward. Instead of superfoods let’s concentrate on superdiets!
