This common nutrient could be the secret weapon against dementia-and you can add it to your diet for just 24p

We've all heard that 'an apple a day keeps the doctor away'—and now a new study has found that the same can be said of potatoes, too. Researchers found that eating a diet rich in copper can help the body stave off dementia, and the mineral is naturally found in the patchy light brown skins of the pantry stalwart, which you can pick up for just pennies at a local greengrocer.  A new study published in medical journal Scientific Reports found that people who added copper to their daily diet experienced better cognitive function than those who ate relatively low levels. The researchers, from the Fourth Hospital of Hebei Medical University, China, found that 1.22mg of copper per day—approximately two medium sized potatoes—significantly boosted brain health and helped ward off disease. Speaking of the findings, lead author Professor Weiai Jia urged those who have a history of stroke in particular to add copper to their daily diet—and it can be in the form of potatoes, or other foods naturally packed with it, like wholegrains and beans. 'Dietary copper is crucial for brain health', he said. This is because copper—a naturally occurring trace element—triggers the release of iron which helps carry oxygen around the body—and protects the brain against cognitive decline. According to the NHS, the essential nutrient is also thought to be important for infant growth, brain development, the immune system and bone health, and recommends adults aged 19 to 64 try to consume 1.2mg of it a day. The richest dietary copper sources include potatoes, shellfish, nuts and seeds, wholegrains and chocolate Around 900,000 Britons are currently thought to have the memory-robbing disorder. But University College London scientists estimate this will rise to 1.7 million within two decades as people live longerThe scientists believe that copper-rich foods may help regulate the release of neurotransmitters in the brain that are closely related to learning and memory. Dementia affects an estimated one million people in the UK and has a variety of causes, such as Alzheimer's disease and reduced blood flow to the brain following a stroke, known as vascular dementia.The team said that the links between dietary copper intake and cognitive function are complex, but highlighted energy metabolism and neurotransmission as potential reasons why copper can help protect brain function. It is thought that a lack of copper may accelerate the cognitive collapse that is associated with dementia—for instance memory loss, language difficulties and problems with thinking and reasoning. However, the researchers warned that whilst copper is essential for optimal brain functioning, too much copper can be toxic.  Foods naturally rich in copper  Shellfish: Oysters, crab, and lobster Nuts and seeds: Cashews, sunflower seeds, almonds, and sesame seeds Organ meats: Beef liver and kidneysWhole grains: Quinoa, brown rice, oats, bulgur wheatDark chocolate: Look for a high cacao percentageLegumes: Lentils and beansVegetables: Potatoes, mushrooms, dark leafy greens—like spinach and kaleDried fruits: Prunes, apricots and raisins In the longitudinal study, using data from the National Health and Nutrition Examination Survey, 2420 American adults were analysed to see how dietary copper intake affected cognitive function, especially in participants with a history of stroke. According to the American Heart Association, having a stroke may triple someone's risk for developing dementia within the following year. Participants' were tracked for for four years and dietary copper intake was determined by averaging two 24 hour dietary recalls.Read More Experts pinpoint shocking dementia trigger in some TAP WATER - map shows worst-affected UK areas Cognitive function was also assessed by a range of golden metrics. Researchers concluded that those who consumed the most copper had the highest cognitive scores—after accounting for various confounding factors such as age, sex, alcohol intake and heart disease. The researchers concluded: 'Our findings indicate a potential association between dietary copper intake and enhanced cognitive function in American older adults, particularly among those with a history of stroke.' However, the researchers noted that further research is needed to confirm these findings, with a major drawback of the study being that they used self-reported dietary reviews. Alzheimer's Research UK analysis found 74,261 people died from dementia in 2022 compared with 69,178 a year earlier, making it the country's biggest killer.It comes as new research warns that millions of people could be up to a third more likely to develop the memory robbing disease because of their tap water. A groundbreaking study suggested earlier this year that people who live in 'softer water' areas of the UK may be at an increased risk of dementia because their water contains lower levels of minerals such as calcium, magnesium and copper. Scientists suggest that these minerals may have a protective effect on the brain with low levels of magnesium linked with a 25 per cent higher risk of Alzheimer's.