Supercharging our immune systems with supplements seems to be a national obsession, with £36 million spent annually on vitamin C alone, according to the NHS. But which supplements – if any – can help keep us healthy in the winter months? We look at the science behind the claims and ask Dr Anne Mullen, lecturer in nutrition sciences at King’s College London, to comment.
The promise: Echinacea contains phytochemicals called alkylamides, which are thought to stimulate the body’s natural immune system.
The research: Nearly 1,000 published trials on this herb, many industry-funded, have had mixed results. A big review in 2009, by the independent Cochrane Collaboration, found that echinacea had no more effect in preventing colds than a placebo. However, preparations from one particular species (echinacea purpurea) might reduce the duration and severity of colds in adults. Dr Mullen says: “Echinacea supplements come in a variety of forms, which has made it difficult to evaluate their effectiveness.”
Verdict: Not proven for prevention but echinacea purpurea extract might help reduce cold symptoms.