Researchers conducted a systematic review on human studies up to May 2014 to evaluate dietary patterns and their effect on cognitive decline and dementia in older adults. Four of six cross-sectional studies, six of 12 longitudinal studies, one trial, and three meta-analyses indicated that a better observance of the Mediterranean diet can lead to less cognitive decline, dementia, or Alzheimer’s disease. All six cross-sectional studies and six of eight longitudinal studies pointed to the link between other healthy dietary patterns and reduced cognitive decline and/or a reduced risk of dementia.
Overall, there was a general emphasis on fruits, vegetables, fish, and limited intake of meat, saturated fats, and refined sugar. There were some studies, however, that showed different effects of certain dietary patterns on men and women. One study found that higher intake of vegetables/fruits and snacks/drinks/milk patterns reduced risk of cognitive impairment in women, but not in men. Another study showed an increased risk of cognitive impairment in women but a lowered risk in men with the Mediterranean diet.
Due to the varying methodology among the studies, further research is needed to develop more targeted guidelines to prevent or postpone cognitive decline, study authors conclude.
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