The 'wonder food' is tempe, a fermented whole soybean produce, which can help improve memory in older people if it's eaten every day.
Researchers from Loughborough University believe the food's beneficial effects may be due to its high folate levels, which may also protect against the adverse effects of the phytoestrogens that are also in tempe.
Estrogen can increase the risk of dementia in women aged over 65.
Tofu is another food that is high in phytoestrogens, and this seems to impair memory, the same research team found. They looked at the diets and memory abilities of a group of 719 participants, aged between 52 and 98, who live in several regions of Java and Sudan.