Emerging Research on the Impacts of Diet on Dementia

One of the most common remarks I hear in my family when talking about our older relatives is how so-and-so, whose physical health may be physically declining, is mentally speaking still “sharp as a tack.” Typically this is quipped in a thick Boston accent – as classic yankees, my family heralds the ability to keep their wits about them, if only for the ability to snap up with sarcastic one-liners, above almost anything else. Indeed, no matter where we might be from, to stay sharp into our older years and maintain the ability to connect with (and occasionally zing) our loved ones is a natural desire – and one reason that the prospect of Alzheimer’s disease and dementia can be such a difficult one to face.

THE STATE OF OUR STATE
Washington currently ranks as the state with the third highest rate of death from Alzheimer’s, a disease that today affects an estimated 5 million Americans. In Washington State, that number is unfortunately projected to grow an estimated 40% over the next 10 years, and nationwide to approach 16 million by 2050.^[1]

In facing these difficult statistics, many are looking to preventive measures in hopes that we can work toward helping more people enjoy sharp minds well into their golden years. As we near the culmination of our work with the Alzheimer’s Disease and Other Dementias workgroup here at the Bree Collaborative, one interesting insight that has risen to the surface is what we can individually do to prevent the onset of dementia and/or slow cognitive decline. The Lancet very recently published a series of papers calling prevention and management of dementia a priority for public health and listing education, hypertension, obesity, hearing loss, depression, diabetes, physical inactivity, smoking, and social contact as key areas for intervention.^[2],[3]

While nutrition and changes to diet are not included as one of these key areas, there is emerging research showing that what we eat matters. Below is a summary of some of this emerging evidence. These are not official recommendations, but rather meant to start the discussion and call for further research.

THE MEDITERRANEAN AND DASH DIETS
As Martha Clare Morris, a nutritional epidemiologist and mover and shaker in the field of dietary intervention for dementia, notes: “Effective diet intervention has the potential for population-wide effects with respect to delaying dementia onset, and there is very high public demand for dietary guidance for prevention of cognitive decline and Alzheimer’s disease.”^[4]

Morris and others have devoted much recent research into determining what components make up the most effective diet for preventing cognitive decline. For many years, attention honed in on two diets: the Mediterranean and the Dietary Approaches to Stop Hypertension (DASH). Key findings have shown an association between diets low in saturated fat and high in vitamin E, B vitamins, and n-3 fatty acid with slowed cognitive decline – components that are hallmarks of both the Mediterranean and the DASH diets. Both diets are founded on the philosophy of promoting anti-inflammatory nutrition while discouraging known inflammatory agents, neuroinflammation being commonly linked as a causal or exacerbating factor in Alzhiemer’s disease.^[5]

Now, revelations from further studies have helped researchers narrow in on what essentially is a hybridized version of these two, with key modifications to reflect the best available evidence for nutritional neuroprotection for the aging brain. This is known, appropriately, as the MIND (Mediterranean–DASH Intervention for Neurodegenerative Delay) diet. In one study, participants more closely following a MIND diet had significantly higher scores on the Mini-Mental State Examination (MMSE) and Clock Drawing Test (CDT), while participants on the DASH diet exhibited greater improvements in psychomotor speed.^[6]

THE MIND DIET
The MIND diet emphasizes a few key neuro-protectants: green leafy vegetables, berries, fish, and olive oil.

  – Green leafy vegetables: May have protective effects against cognitive decline.^[4] Lucky for local residents, dark leafy greens like kale and chard grow remarkably well in the Pacific Northwest.
  – Berries: Blueberry and strawberry consumption have been positively associated slower cognitive decline^[4] – one great reason to get out and visit some u-pick berry farms before our beautiful northwest summer is over.
  – Fish: Consumption of oily or fatty fish like salmon (with the exclusion of fried fish) has been associated with lower risk of incident dementia, stroke, and cognitive decline.^[7] Again, we can count ourselves lucky that the northwest is one of the most vibrant salmon regions in the country.
  – Olive oil: Animal studies have shown an association between a diet enriched with n-3 PUFA (polyunsaturated fatty acids), which are found in rich amounts in olive oil and other oils, learning and memory.⁵

People have also reported that the MIND diet is easier to follow than the Mediterranean and DASH diets. For example, the MIND diet specifies just two vegetable servings per day, two berry servings per week, and one fish meal per week. By contrast, the DASH and Mediterranean specifies three to four daily servings each for fruits and vegetables, and the Mediterranean diet specifies an impressive six or more servings fish each week.^[8] The data also suggests that even modest adherence to the MIND diet can offer significant benefit in preventing Alzheimer’s, while only strict adherence to the DASH and Mediterranean diets were associated with Alzheimer’s prevention.^[3]

THE PATH THROUGH LIFE PROJECT
In Australia, the fascinating Personality and Total Health (PATH) Through Life Project is an ongoing study that seeks to track the lifespan course of cognitive ability, depression, anxiety, and substance use with more than 7,000 participants over the course of 20 years. This ambitious study seeks to identify both risk and protective factors in analyzing correlations between depression, anxiety, and substance use with cognitive ability and dementia. In one report, the researchers reiterated Moore’s early point, saying, “As no cure or treatment for dementia is currently available it is critical that, where possible, preventative actions be implemented.”^[9] Researchers are looking into the associations between magnesium, calcium, potassium as well as diet and risk of dementia, hypertension, stroke, and other outcomes.^[10],[11] The PATH Through Life project began in 2010 and is slated to run through 2030, so we can hope for revelations on this topic to continue as the project progresses.

We can be glad that so many brilliant minds are coming together in seeking ways of preserving the brilliant minds of us all and hopefully keep us wisecracking well into our later years, or what some like to call our second childhoods. The Bree Collaborative will continue to report on this and other related topics as we learn of them, thanks largely to the great work of our workgroup experts. In the meantime, here are some additional resources to explore:

ADDITIONAL RESOURCES:

– Read more about the MIND diet.
– Read more about the PATH Through Life Project.
– 13 Area Agencies on Aging (AAAs) across Washington State provide services including nutrition/meals and health promotion for individuals 60 years of age and older, as part of the Federal Older Americans Act (OAA) and State Senior Citizens Services Act (SCSA).
– The Office of Nutrition Services works to create opportunities for people with limited resources to make healthy nutrition choices.  We support healthy eating, breastfeeding, access to healthy foods, and physical activity through contracts with local health jurisdictions, community agencies, tribal organizations, and food retailers.
– Many home health services provide nutritional services.
– The Aging & Disability Network consists of Area Agencies on Aging statewide that provide an array of home and community services including nutrition.
– The Senior Nutrition Program exists for individuals not able to prepare nutritious meals due to limited mobility, cognitive impairment, lack of knowledge or skills, or lack of incentive to prepare and eat meals alone. With this service, nutritious meals are provided in community (congregate) settings or through home-delivery for individuals who have difficulty leaving their homes

[1] Alzheimer’s Association. Alzheimer’s Statistics Washington. Available: www.alz.org/documents_custom/facts_2016/statesheet_washington.pdf
[2] Frankish H, Horton R. Prevention and management of dementia: a priority for public health. Lancet. 2017 Jul 19. pii: S0140-6736(17)31756-7.
[3] Livingston G, Sommerlad A, Orgeta V, Costafreda SG, Huntley J, Ames D. Dementia prevention, intervention, and care. Lancet. 2017 Jul 19. pii: S0140-6736(17)31363-6.
[4] Morris MC. Nutrition and risk of dementia: overview and methodological issues. Ann N Y Acad Sci. 2016 Mar;1367(1):31-7.
[5] Akiyama H, Barger S, Barnum S, Bradt B, Bauer J, Cole GM, et al. Inflammation and Alzheimer’s disease. Neurobiol Aging. 2000 May-Jun;21(3):383-421.
[6] Morris MC, Tangney CC, Wang Y, Sacks FM, Bennett DA, Aggarwal NT. MIND diet associated with reduced incidence of Alzheimer’s disease.  Alzheimers Dement. 2015 Sep;11(9):1007-14.
[7] Morris M. Symposium 1: Vitamins and cognitive development and performance Nutritional determinants of cognitive aging and dementia. Proceedings of the Nutrition Study. 2012. 71, 1-13.
[9] Anstey KJ, Christensen H, Butterworth P, Easteal S, Mackinnon A, Jacomb T, et al. Cohort Profile: The PATH through life project. Int J Epidemiol. 2012 Aug;41(4):951-60.
[10] Cherbuin N, Kumar R, Sachdev PS, Anstey KJ. Dietary Mineral Intake and Risk of Mild Cognitive Impairment: The PATH through Life Project. Front Aging Neurosci. 2014 Feb 4;6:4
[11] Cherbuin N, Reglade-Meslin C, Kumar R, Jacomb P, Easteal S, Christensen H et al. Risk factors of transition from normal cognition to mild cognitive disorder: the PATH through Life Study. Dement Geriatr Cogn Disord. 2009;28(1):47-55.

Emily Wittenhagen
Program Assistant, Bree Collaborative