A study indicates that women who followed blood pressure-lowering diets in their middle years were roughly 17 percent less likely to report memory loss and other indicators of cognitive decline decades later.
The new findings, led by researchers from NYU Grossman School of Medicine, suggest that adopting the Dietary Approaches to Stop Hypertension, or DASH diet, in midlife may improve cognitive function later in life for women, who account for more than two-thirds of those diagnosed with Alzheimer's disease, the most common form of dementia.
The findings, which were published in the journal Alzheimer's & Dementia, have implications for the estimated 6.5 million Americans over the age of 65 who will be diagnosed with Alzheimer's disease in 2022. This figure is anticipated to more than double by 2060.
"Subjective complaints about daily cognitive performance are early predictors of more serious neurocognitive disorders such as Alzheimer's," said Yu Chen, PhD, MPH, professor in the Department of Population Health and senior author of the study.
"With more than 30 years follow-up, we found that the stronger the adherence to a DASH diet in midlife, the less likely women are to report cognitive issues much later in life."
The DASH diet includes a high consumption of plant-based foods that are rich in potassium, calcium, and magnesium and limits saturated fat, cholesterol, sodium, and sugar.
Longstanding research shows that high blood pressure, particularly in midlife, is a risk factor for cognitive decline and dementia.
The investigators analysed data from 5,116 of the more than 14,000 women enrolled in the NYU Women's Health Study, one of the longest-running studies of its kind that examines the impact of lifestyle and other factors on the development of the most common cancers among women, as well as other chronic conditions.
The researchers queried the study participants' diet using questionnaires between 1985 and 1991 at study enrolment when the participants were, on average, 49 years old.
The participants were followed for more than 30 years (average age of 79) and then asked to report any cognitive complaints. Participants who did not return questionnaires were contacted by phone.
Self-reported cognitive complaints were assessed using six validated standard questions that are indicative of later mild cognitive impairment, which leads to dementia.
These questions were about difficulties in remembering recent events or shopping lists, understanding spoken instructions or group conversation, or navigating familiar streets.
Of the six cognitive complaints, 33 percent of women reported having more than one. Women who adhered most closely to the DASH diet had a 17 percent reduction in the odds of reporting multiple cognitive complaints.
"Our data suggest that it is important to start a healthy diet in midlife to prevent cognitive impairment in older age", said Yixiao Song, a lead author of the study.
"Following the DASH diet may not only prevent high blood pressure but also cognitive issues," said Fen Wu, PhD, a senior associate research scientist who co-led the study.