You exercise, you limit your fatty and sugary foods, and you don’t smoke and drink only on occasion. Clearly you are living a healthy lifestyle and wish to maintain it. With soaring rates of obesity in the UK and the prediction that by 2035 75% of the population will be overweight, it is only natural that you would want to take control of your health. I’m the same. But this makes “superfoods” appealing; the idea of a type of a food with a high nutritional content to confer a significant health benefit over other foods. But is there any truth to it?
This term superfood was coined by the authors of the book Superfood (1990); Michael Van Straten and Barbara Griggs. Since then the bandwagon has accumulated various foods all conferring some health advantage: kale, wheatgrass, quinoa, chocolate and the all-time favourites with high levels of antioxidants; blueberries, pomegranate and acai berries.
Antioxidants and Aging
Antioxidants are said to be the key to preventing cancer and slowing down the aging process. However studies have revealed a level of complexity when it comes to antioxidants and all is not as it seems.
Reactive oxidant species (ROS) which include superoxide, hydroxyl radical and hydrogen peroxide are produced naturally in the body and erodes the telomeres at the end of each chromosome contributing to the aging process. It was therefore suggested that if antioxidants mop up the ROS that therefore they would slow down aging. This gave antioxidants a hero-like status while ROS was something that had to be destroyed, but this is too simplistic a picture
ROS are essential for numerous reasons. They maintain healthy livers so as to prevent insulin sensitivity and therefore type2 diabetes, and the immune system uses them to attack bacteria and cancer cells. ROS levels are maintained by the enzyme Keap1 ubiquitin which destroys the transcription factor Nrf2 (responsible for turning on the antioxidant genes). Should ROS levels increase to a high amount, Nrf2 turns on the antioxidant system to destroy the ROS. This cycle ensures that our bodies will naturally maintain ROS levels and in fact we produce powerful antioxidants to do this job.
As it turns out we do need to intake some antioxidants from outside sources, namely vitamin C and E from the food we eat. But in terms of supplements (because that industry jumped on the bandwagon with glee), we shouldn’t really be taking them. As James Watson writes about in the New Scientist it is quite possible that the intake of additional antioxidants promotes cancer. A large study looking at how vitamin E could prevent cancer actually had to be halted when the men who were taking it were found to have an increase in the incidence of prostate cancer. In another study it was found that if you already have cancer, by taking supplements you are actually increasing the risk of it developing further. What this means is that consuming healthy fruit and vegetable to obtain vitamins is all we need to do. But Watson even asks the question if consuming any antioxidant rich food could lead to cancer! Finding this out will not be easy.
One of the reasons why this isn’t going to be easy is because experiments conducted on how certain nutrients affect cells and physiology is largely conducted on animal models. This will only identify the health properties of a nutrient and the mechanism by which it works. But there isn’t any assurance that the nutrients will have the same effect in people. Analysing diets and how nutrients affect different people is complicated because everyone has different genes, diets and lifestyles. Additionally many of the studies conducted on foods focus upon the nutrient in isolation. Co-consumption of nutrients actually increases the body’s capacity to absorb them, for instance beta-carotene and fat go well together, and a medically qualified friend of mine has told me in the past that if you wish to absorb iron, have some vitamin C with it. Finally, studies need to be carried out on people who eat particular foods long-term as usually investigations only look at short-term benefits. This reveals that actually there is no such thing as a “superfood” (European Food Information Council and The Conservation).
Indeed however some foods will have nutrients at high levels which do promote health. The Channel 4 programme Superfoods: The Real Story highlights some foods that do contain health promoting components, including broccoli and my personal favourite xylitol, which is said to reduce dental plaque. I told my dentist that I had found the chewing gum Peppersmith containing xylitol and he applauded it. You can find out what the scientific evidence says about your favourite food here from this NHS website. Suffice to say, everything comes with a disclaimer: It is the cocoa in chocolate that would provide the benefit of lowering blood pressure, but this has to be weighed up against the fats and sugars that are added in, and wheatgrass has not been found to confer any extra benefit above that of any other fruit or vegetable.
The truth is there is no one specific food that is the miracle cure. All foods (apart from junk food) will have nutrients that the body requires. It is because of this that the term “superfood” was banned by the EU in 2007, unless of course it can be proven. If not, be prepared for a lawsuit!
So the bottom line is simple: Superfood is a myth and the only thing we need to do is just eat a healthy, balanced diet, don’t smoke, or drink in excess, make sure to exercise….and occasionally allow yourself a treat!