Are certain foods genuinely super — do their nutritional benefits really live up to the hype? Joanthan Emery finds out
Depending on your take, superfoods are either the royal road to vibrant health and fitness, an outright rip-off, or an occasional but worthwhile addition to your diet.
One thing’s for certain — the £100bn superfood industry continues to go from strength to strength.
First it was all about spinach, broccoli and garlic, then blueberries, pomegranates and kale took centre stage, only to have their thunder stolen by the exotic allure of açai, goji berries, chia seeds and spirulina.
The appeal of these modern-day cure-alls is obvious. After all, who wouldn’t like boundless energy, glowing skin, protection from the diseases of ageing, and even enhanced exercise performance?
To those of us who stress our bodies in the name of sport, the promises of improved recovery and boosted immune function can seem like a godsend.
However, the term ‘superfood’ is a marketing label with no scientific definition, which raises the question: how can we separate the healthy from the merely hyped?
A 2014 study conducted on behalf of the US Centers for Disease Control provides some useful guidance (see box opposite). The study ranked 41 foods by nutrient density according to the presence of 17 key health-promoting nutrients.
Not all fats are bad
The results were both surprising and reassuring. Top of the list was supermarket staple watercress, with spinach in fifth place and kale beaten into 15th place behind the likes of chicory and Romaine lettuce. And while strawberries came in at 35, the much-hyped blueberry didn’t even make the shortlist.
The study’s one major limitation was that it failed to account for phytonutrients (see box below), the diverse family of plant compounds which have been found to protect against a range of degenerative diseases.
However, since the vivid pigments of many fruits and vegetables are good indicators of phytonutrient content, hedging your bets is as easy as filling your plate with a rainbow of colours.
Acclaimed food writer Michael Pollan has criticised the “ideology of superfoods” and the “nutrient-by-nutrient science that takes the nutrient out of the context of food”.
In other words, just because a food is particularly high in one or two nutrients does not make it a magical panacea.
Instead, eating a wide range of common-or-garden fruits and vegetables is better both for you and your wallet.
Eat right, ride right
Superfoods are often marketed on the antioxidant power of their phytonutrients, in particular polyphenols. Sometimes this is expressed as an Oxygen Radical Absorbency Capacity (ORAC) score.
However, the only dietary antioxidants shown to quench free radicals in the human body, as opposed to in a test tube, are vitamins A, C and E.
While polyphenols are thought to be protective against heart disease, cancer and neurodegenerative disease, scientists haven’t determined why. One theory gaining ground is that they act as mild stressors, provoking the body to ‘fight back’ by fortifying its own disease protection defences.