Eating nuts every day may prevent disability, onset of dementia in older adults

Key takeaways:

• Study participants who ate nuts daily had significantly lower risk for death, onset of dementia or physical disability.
• Daily nut eaters with a suboptimal diet showed higher risk reductions.

Daily nut consumption among older adults corresponded with a sustained healthy lifespan that lacked adverse health outcomes like dementia or physical disabilities, results of a prospective cohort study suggest.

The findings — published in Age and Ageing — show an even stronger association between eating nuts daily and a disability-free lifespan among older adults who had a less-than-optimal diet.

The finding “was an important result,” Alice J. Owens, from the Monash University School of Public Health and Preventive Medicine in Australia, told Healio. “Incorporating a serving of nuts or nut pastes or butters into your diet on a regular basis is straightforward advice to give, so we hope that this might be considered by primary care providers.”

Prior studies have tied nut intake to several health benefits, including a reduced CVD risk and slower cognitive decline.

However, research on the links between chronic diseases and nut consumption “is dominated by studies in middle-aged adults, while longitudinal studies have largely focused on specific disease outcomes, such as CVD or cancer,” Owens and colleagues wrote.

In the study, the researchers aimed to assess the effects of daily nut consumption on disability-free survival (DFS) among a cohort of 9,916 Australian participants aged 70 years or older from the ASPREE Longitudinal Study of Older Persons.

The DFS outcome used “was a holistic one, being a composite of survival, free of dementia or persistent physical disability,” Owens explained. “We feel that this represents a health outcome that many older adults would find meaningful and relevant, as it supports the capacity to continue to live an independent and fulfilling life in older age.”

Participants had completed a 49-item food frequency questionnaire, which asked them to categorize nut intake as never or infrequent (one to two times a month), weekly (one to two times a week) or daily (once or several times a day).

The researchers also used dietary quality data categorized into quartiles.

At a median follow-up of 3.9 years, researchers recorded 997 composite endpoint events, 63.8% of which occurred among men.

The results showed a 23% risk reduction for reaching the DFS endpoint (HR = 0.77; 95% CI, 0.61-0.98) among those who ate nuts daily compared with those who ate nuts infrequently or never.

Meanwhile, subgroup analyses showed a 29% risk reduction for reaching the DFS endpoint (HR = 0.71; 95% CI, 0.51-0.98) among adults in the second dietary tertile who ate nuts daily vs. those who ate nuts infrequently or never.

Supporting nutrient and protein consumption “is important for limiting muscle loss and wasting in older age — something PCPs are acutely aware of for their older adult patients,” Owens said.

There were some study limitations noted by the researchers. For example, the data on nut consumption being self-reported may have increased the risk for recall bias.

Additionally, the types and quantity of nuts consumed were not determined, “but based on dietary research to date, I would say consuming a variety of nuts might be a good choice, but of course this will be dictated by availability,” Owens noted.

“The history of dietary research would suggest that there is not one 'magic ingredient' that can provide all our nutritional and preventive health needs, and that it is possible to have too much of a good thing,” she said. “Different nuts have different macro and micronutrient compositions, so if you are in a position to eat a variety of nuts over the year, you can get the benefits of that variety of nutrients. Choosing foods that are 'in season' also allows you to consume foods that have optimal nutritional content.”