Dietary supplements such as vitamins do nothing to boost brain health and are simply a waste of money for healthy people, experts have said.

According to figures from the US, sales of so-called “memory supplements” doubled between 2006 and 2015, reaching a value of $643m, while more than a quarter of adults over the age of 50 in the US regularly take supplements in an attempt to keep their brain in good health.

But while bottles, packets and jars line the shelves of health food shops – with claims that they help maintain brain function or mental performance – a worldwide panel of experts says at present there is little evidence that these supplements help healthy older people, and that they could even pose a risk to health.

“There is no convincing evidence to recommend dietary supplements for brain health in healthy older adults,” they write. “Supplements have not been demonstrated to delay the onset of dementia, nor can they prevent, treat or reverse Alzheimer’s disease or other neurological diseases that cause dementia.”

However, the team note a lack of certain nutrients, such as vitamins B9 and B12, appear to be linked to problems with cognitive function or brain health, and that supplements might prove useful in people with deficiencies. About 20% of people over the age of 60 in the UK are thought to be lacking in vitamin B12.

But the experts stress it is important to consult a doctor before starting any supplements, and that it is better to get nutrients from a healthy diet.

At present, the team say, they cannot recommend healthy people take supplements for brain health – although they stress further research is needed. Their top recommendation is simple. “Save your money,” they write.

The report by the Global Council on Brain Health looks at the evidence for a range of supplements, including B vitamins, omega-3 fatty acids, vitamin D, caffeine, coenzyme Q10 and ginkgo biloba.

The team found that few supplements which make claims about brain health have actually been tested for their impact. Where studies do exist they offer little or mixed evidence that supplements improve brain function or prevent dementia.

“The big problem is that these things are being marketed to people as if they have evidence,” said Linda Clare, professor of clinical psychology of ageing and dementia at the University of Exeter and a member of the team behind the report.

The team advise taking a sceptical view of such products, saying many are marketed with exaggerated claims about their impact on mental functions. They also stress that such pills, powders and capsules are usually not subject to the same safety and efficacy tests as medications.

However, Clare stressed the report only looked at the impact of supplements on brain health. “The message is not that all supplements are wrong for everything,” she said.

The report echoes recent findings by the Cochrane collaboration. Their study, looking at evidence for effects of vitamin and mineral supplements on cognitive function in over-40s, found no convincing effect for B vitamins, selenium, zinc, vitamin E, omega-3, and only tentative evidence of any benefit from long-term use of beta‐carotene or vitamin C supplements.

Caroline Abrahams, charity director at Age UK, said of the new report: “These eminent experts have concluded it doesn’t do any good to take supplements to promote your brain health in later life so our advice to older people is to save your money and spend it on a healthy diet, full of delicious fruit and vegetables instead.”

David Smith, professor emeritus of pharmacology at the University of Oxford, said that while the report was sensible, there were debates about what constituted a vitamin deficiency – for example, low “normal” levels might still have a negative impact on brain health. He also noted that while consuming a Mediterranean diet was good for the brain, as people got older they might not be as able to absorb nutrients from food, while medications could potentially lead to deficiencies. What’s more, plants contain no vitamin B12, so people on a vegan diet should consider fortified foods or supplements.

Smith added that while the report called for more high-quality research to improve the evidence base, there was a significant stumbling block. “The problem is that the authorities and drug companies seem to be reluctant to support such trials on vitamins, partly because there is no obvious financial benefit and because no patents can be filed,” he said.

Experts say there are many other steps individuals can take to keep sharp as they age – including not smoking, sleeping well, exercising and keeping socially engaged and mentally stimulated.

Prof Gill Livingston of University College London added that people should also get their blood pressure and hearing checked to prevent dementia. “Drugs for high blood pressure are currently the only known effective preventive medication for dementia,” she said.