Superfoods: are chia seeds and goji berries really good for you? Jebb agrees, but with reservations. It can undermine the concept of dietary variety - one type of food alone will not keep you healthy, we need a wide mix. They are often expensive, she says, and at a time when many of us are struggling to balance the household budget. Rather than buying pricey pomegranates and blueberries, "people may be better off spending the same amount of money on twice as much of cheaper foods." But according to the doctor and science journalist Michael Mosley, there are exceptions - berries in particular. "I do think that there is some evidence that blackberries and blueberries are good for the brain, and they are really low-calorie," he says. But he agrees that many superfoods are generally overrated. The most important thing is a rainbow diet, lots of different colours on your plate so you are getting lots of different phytonutrients. It's also crucial that the food be as fresh as possible, since the vitamin and mineral content tends to fall with storage. The verdict? Eat lots of fruit and vegetables. Fresh food is super food. And if you like the latest superfood, go for it. It's not roquette science. Wheatgrass Hype factor: High Generally taken as a tiny shot of bitter dark-green juice, this is the most macho of health drinks. It's not bad for you, but there's no scientific evidence for claims that it improves red blood cell production and circulation. Pound for pound, its nutrient content is about the same as that of spinach, but because it is juiced there's no fibre. I'd take eggs Florentine any day. From Crussh (crussh.com) and independent juice bars. Goji berries Reports that these protect against heart disease and cancer, as well as boosting immunity and brain activity, get short shrift on the NHS website: "Most of the research into these conditions is small-scale, of poor quality and performed in laboratories using purified and highly concentrated extracts of the goji berry." Expensive - and not very nice. Chia Hype factor: Medium high These seeds are from a mint-like plant that grows in Latin America, which has only recently been available in Britain but is much loved by Hollywood A-listers. Weight for weight, chia has up to eight times more omega-3 than salmon, say advocates. But it's a less useful kind of omega-3 than that in oily fish, and who'd eat a salmon-fillet-sized portion of these? Stick to sardines on toast. From Holland & Barrett branches. Quinoa Hype factor: Medium A seed that thinks it's a grain, quinoa can be used like couscous. It is higher in protein and lower in carbs than traditional "starches." More to the point, it is good to eat provided you rinse it well before cooking to get rid of the bitter residue. Best of all, it's a great gluten-free alternative. But concerns have been raised that the craze in the developed world has put the traditional market in Latin America under strain. Sea Buckthorn Hype factor: Medium low A wild plant that grows by the sea in most parts of Britain, it has bitter-tart orange berries. They have that irritatingly cool forage factor - they are free, so they're egalitarian, but also virtually impossible to get, so they're the ultimate in elitism. Now researchers at Edinburgh's Queen Margaret University claim they're high in vitamins C and E and full of antioxidants. The real pull as far as I'm concerned is that they are delicious, with a passion-fruit flavour that is gorgeous in jam or as a sauce for white-chocolate puds. En Place Sea Buckthorn and Lime Jam from fortnumandmason.com and The Meat Merchant, Moira, Northern Ireland BT67 0LZ Kale Hype factor: Low Cheap and suited to the British climate, kale is something we should all eat more of this winter. Those dark green leaves are loaded with vitamins, calcium and iron. Granted, iron from veg is not as easily assimilated as iron from meat, and badly cooked it tastes like cattle food. But kale can be delicious. Buy the whole plumelike leaves from the greengrocer so that it is easy to strip out the tough stems. Toss the leaves in olive oil and salt, spread on a baking tray and bake for 15 minutes or so at gas 4/200C to make kale crisps. Or substitute for its southern cousin, cavolo nero, in Italian recipes. Neal's Yard Remedies Michael Mosley's new television series, Pain, Pus and Poison, starts on BBC4 on October 3