Spinach may cause Alzheimer's disease in at-risk people, research suggests.
The salad leaf's iron-rich content may damage the brain similar to how the compound causes metal to rust, according to the researchers.
People with high levels of iron alongside the protein amyloid, which has previously been associated with Alzheimer's, are more likely to experience rapid cognitive decline, a study found.
Those with high amyloid but low iron levels are less at-risk of the disease, the research adds.
Removing such 'rust' from the brain could prevent or delay the degenerative condition, the researchers add.
Rusting in the brain
Lead author Dr Scott Ayton from the University of Melbourne, said: 'The rusting you see on iron metal is the same rusting reaction that occurs in the brain,' The Express reported.
Although iron is important for energy, it can cause cellular stress and their subsequent death.
The researchers plan to conduct a five-year trial investigating whether an anti-iron drug could treat Alzheimer's.
Treatments that focus on altering amyloid levels have had limited success.
Dr Ayton said: 'Given the data from our study, it seems reasonable to hypothesise that lowering iron in the brain would slow the progression of the disease, but we can only know that by testing it, which is what we are now going to do.'
Do not cut back on dietary iron
The researchers do not recommend people cut back on their dietary iron intake to reduce their Alzheimer's risk.
This is because the amount of the iron in the brain appears unrelated to levels in the blood or a person's food intake.
Dr Ayton said: 'We don't have any evidence that the amount of iron you eat, or the amount that is measured in your blood, has any impact on the amount of iron in your brain, so we are not recommending people change what they eat based on our research.'