In part one of this article, we covered the prevalence of Alzheimer’s disease and the risk factors that we can’t change and the ones we can. In this article we will discuss dietary factors as well as the role sleep can play in prevention.
Our dietary habits turn out to be a very large player in preventing Alzheimer’s. Registered dietician Joanna Morris says that certain dietary patterns appear to protect against cognitive decline. She says that historically, the Mediterranean diet and the Dietary Approaches to Stop Hypertension (DASH) diet have been widely studied for heart disease prevention, but more recent research has also focused on their ability to decrease dementia risk. In a prospective study in the American Journal of Clinical Nutrition, both diets were associated with a decrease in cognitive decline over an 11-year period. Higher adherence to the Mediterranean diet has also been associated with lower levels of inflammatory markers and therefore may decrease oxidative stress in the brain (Singh et al. 2014).
After evaluating a study evaluating a new dietary pattern developed to focus on brain health, Martha Clare Morris, ScD, of Rush University created the Mediterranean-DASH Intervention for Neurodegenerative Delay—also known as the MIND diet—which uses a three-pronged approach:
- Emphasizing plant-based, whole foods, and olive oil as the primary oil
- Limiting animal products and saturated fat
- Promoting one fish meal a week because of the strong link between omega-3 and brain health (Morris et al. 2015).
Morris followed 923 people, aged 58–98, over 4.5 years to see who would develop dementia, and then she compared how closely they followed the MIND, Mediterranean, or DASH diets based on scales of adherence. The MIND diet was associated with a 53% risk reduction for those with the strictest diet adherence and a 35% reduced risk for those with moderate diet adherence. The DASH and Mediterranean diets elicited significant reductions in cognitive decline only with the highest level of adherence. Always adhering strictly to a new way of eating isn’t easy, so its good news to see that moderate adherence to the MIND diet might be protective.
The MIND diet’s specific recommendations may explain its effectiveness. The MIND diet recommends at least two servings of flavonoid-rich berries and a minimum of six servings of vitamin-rich leafy greens per week.
The DASH and Mediterranean diets, however, recommend eating a lot of nonspecific vegetables and fruit, which are still beneficial but may not be as imperative for brain health. According to Morris, evidence from the MIND study shows that those who ate the most amount of leafy greens were 11 years younger in cognitive age than those who ate the least. People benefit from including kale, mustard greens, romaine lettuce, spinach and other leafy greens on their weekly menus.
According to the Center for Alzheimer’s Research, recent studies have linked lack of sleep and poor quality of sleep to developing Alzheimer’s. While a sound night’s sleep has long been advised for a sound body, the new research adds to a growing body of evidence linking sleep to brain health. It’s long been known that people with Alzheimer’s disease tend to sleep poorly and spend more time awake at night. But scientists have been uncertain whether poor sleep contributes to Alzheimer’s onset, or if troubled sleep is actually an early symptom of Alzheimer’s. The new studies shed further light on the links between sleep and dementia.
In one study, researchers at the Johns Hopkins Bloomberg School of Public Health in Baltimore found that getting less sleep or sleeping poorly was tied to an increase in brain levels of beta-amyloid, a toxic protein that builds up and forms plaques in the brains of those with Alzheimer’s. The researchers studied 70 older adults. Using brain scans, they found that those who said they got the least sleep, under five hours a night, or who slept fitfully had higher levels of beta-amyloid in the brain than those who slept over seven hours a night. The findings appeared in the journal JAMA Neurology.
The researchers couldn’t say whether poor sleep caused the accelerated buildup of beta-amyloid, or the accumulation was a cause of poor sleep. It’s also possible that both may be true: That poor sleep may cause beta-amyloid accumulation, and that enhanced beta-amyloid in turn disrupts sleep.
“These findings are important, in part because sleep disturbances can be treated in older people,” said Dr. Adam Spira, the study’s lead author. “To the degree that poor sleep promotes the development of Alzheimer’s disease, treatments for poor sleep or efforts to maintain healthy sleep patterns may help prevent or slow the progression of Alzheimer’s disease.”
Additional research suggests that one reason why poor sleep may be linked to Alzheimer’s is that sleep may help to clear toxic molecules from the brain. Researchers at the University of Rochester Medical School found that when mice slept, the cells in their brains literally shrank, making more room for the flow of fluids through the brain. This increased flow of fluid acted something like the jet sprays in a dishwasher, flushing away harmful waste products like beta-amyloid.
In a third study, scientists at the University of Toronto found that sound sleep seemed to blunt a gene that predisposes to the development of Alzheimer’s disease. For the study, researchers tested nearly 700 elderly men and women, monitoring their sleep and cognitive status at regular intervals. None had dementia at the start of the study.
Over the next six years, 98 of the participants developed Alzheimer’s, and 201 died. Their brains were examined for evidence of the plagues of Alzheimer’s disease. The researchers found that those who slept most soundly showed the greatest preservation of memory and thinking skills. Among study participants who died, the poor sleepers were more likely to exhibit the characteristic brain plaques and tangles of Alzheimer’s disease. Earlier studies have shown that poor sleep can lead to memory and thinking problems, even in healthy people. People with a common breathing disorder called sleep apnea, which causes sleepers to awaken briefly hundreds of times during the night, has also been linked to memory problems and an increased risk of dementia. Poor sleep, as well as sleep apnea, is a common problem in the elderly, and it doesn’t necessarily mean you will get Alzheimer’s.
We can’t control all of the risk factors, but we can control many of them. Menachem’s problems came from a different problem altogether. And his doctor emphasized to him that there is much we can do to take care of our brain and help arrest cognitive decline, let alone dementia and Alzheimer’s.
Following our recommendations will greatly reduce your chances of contracting any form of dementia and will “add hours to your day, days to your year, and years to your life.”