The term ‘superfood’ is pasted across mainstream media and marketing campaigns. Vivid colours and imagery of idealised healthy living captivates consumers into buying the latest product, which promises to prevent cancer or miraculously deliver on fitness goals.

But how much truth underlies the polished campaigns? Is there robust science to back it up?

Whilst superfoods are not strictly defined by science, they are generally accepted to be nutrient dense foods which deliver health benefits. This includes blueberries, salmon, pomegranate juice, kale and ginger, to name but a few.

Among their arsenal lies antioxidant properties, a wealth of vitamins and fibre. Antioxidants are molecules which help to protect cells from oxidative damage from free radicals, which may result from natural metabolism or external factors such as smoking. Thus, they can protect against DNA damage which may otherwise lead to cancer.

The humble blueberry is often hailed as a superfood due to its natural antioxidant effects, which have been shown to combat colonic cancer cells. In vitro studies have shown that polyphenols found in berries reduce cellular proliferation and aid apoptosis of the cancer cells. In rats, berry extracts were found to reduce ageing biomarkers including aspartate transaminase, an enzyme indicating liver damage, and inflammatory agents such as IL-6.

Encouraging research in humans has hinted at the benefits of blueberries; one study found a significant reduction in myocardial infarction risk among young and middle-aged women who ate more than 3 portions of blueberries or strawberries per week, compared to those whose intake was less than monthly.

Another superfood, praised for its effects in reducing cardiovascular disease and alleviating joint pain, is salmon. Salmon is high in Omega-3 fatty acids; a polyunsaturated fat which our bodies cannot produce themselves. This has been shown to reduce the risk of cardiac disease through a range of mechanisms involved in regulating lipid synthesis, heart rate, vessel function and inflammation. Another attribute of salmon is its wealth of B vitamins. One of their key roles is to maintain proper neurological functioning, often acting as essential coenzymes in metabolic processes such as the citric acid cycle.

Whilst the health benefits of eating superfoods are undeniable, controversy surrounds the marketing of products to naïve consumers by manipulating scientific evidence. Herein lies a conflict of interest, as superfood status often commands a higher price point.

The relevancy of certain studies in promoting superfoods frequently comes into question. Often the dosage used is physiologically unattainable in a true diet or may prove to have adverse effects in such quantity. Similarly, experiments conducted in vitro or in rats overlook the combinatorial effects of eating other foods and possible attenuating effects of the human digestive system. Additionally, short-term research is vulnerable to claims that the health benefits quoted are transient in nature.

The title, superfood, can be misleading; suggesting that alternative nutritional choices are detrimental to health. In contrast, the benefits of certain foods often increase when eaten in combination with others. For example, carotenoids found in carrot and spinach are absorbed quicker when accompanied by a source of fat, such as a salad dressing.

In some cases, nutrient powerhouses lose their assets through the treatments used in preparation for consumption. Slogans like ‘1 of your 5 a day’ tend to gloss over the high sugar content that often accompanies superfood juices.

A prime example of inaccurate media, the French paradox painted a picture that seemed too good to be true: French people had lower cases of coronary heart disease despite their high-fat diet. Jumping on this correlation, papers proclaimed the finding that polyphenols in red wine could cause cardiovascular benefits. However, later studies have pivoted to reveal the significant contribution of the Mediterranean diet to the lower disease risk. It has also been highlighted that the quantity of red wine needed to deliver a sufficient concentration of polyphenols would be toxic.

Ultimately, the narrative that certain foods hold the key to healthy living is untrue. The title ‘superfood’ is more of a marketing slogan than a scientific definition. A more realistic proposition is that a balanced diet encompassing a range of food types – in moderation – is an important factor in formulating a healthy lifestyle.

Image: Eiliv Aceron on Unsplash