By David Dunaief, M.D.
When you hear the word dementia, what is your reaction? Is it fear, anxiety or an association with a family member or friend? The majority of dementia is Alzheimer’s, which comprises about 60 to 80 percent of dementia incidence (1). There is also vascular dementia and Parkinson’s-induced dementia, as well as others. Then there are precursors to dementia, such as mild cognitive impairment, that have a high risk of leading to this disorder.
There is good news! A recent study, the Health and Retirement Study (HRS), a prospective (forward-looking) observational study, suggested that dementia incidence has declined (2). This was a big surprise, since predictions were for significant growth. Dementia declined by 24 percent from 2000 to 2012. There were over 10,000 participants 65 years old and older at both the 2000 and 2012 comparison surveys. There was also a decrease in mild cognitive impairment that was statistically significant. However, the reason for the decline is not clear. The researchers can only point to more education as the predominant factor. They surmise that more treatment and prevention of risk factors for cardiovascular disease may have played a role.
So how is dementia defined?
According to the American Psychiatric Association’s DSM-5 (“Diagnostic and Statistical Manual of Mental Disorders,” Fifth Edition), dementia is a decline in cognition involving one or more cognitive domains. In addition to memory, these domains can include learning, executive function, language, social cognition, perceptual-motor and complex attention (3).
What can be done to further reduce dementia’s prevalence?
Knowing some of the factors that may increase and decrease dementia risk is a good start. Those that raise the risk of dementia include higher blood pressure (hypertension), higher heart rate, depression, calcium supplements in stroke patients and prostate cancer treatment with androgen deprivation therapy (ADT).
What abates risk?
This includes lifestyle modifications with diet and exercise. A diet shown to be effective in prevention and treatment of dementia is referred to as the MIND (Mediterranean–DASH intervention for neurodegenerative delay) diet, which is a combination of the Mediterranean-type and Dietary Approaches to Stop Hypertension (DASH) diets. Surprisingly, there is also a cocktail of supplements that may have beneficial effects.
How does medication to treat dementia, specifically Alzheimer’s, fit into this paradigm?
It is not that I was ignoring this issue. Our present medications are not effective enough to slow the disease progression by clinically significant outcomes. But what about the medications in the pipeline? The two hottest areas are focusing on tau tangles and amyloid plaques. Recently, drugs targeting tau tangles from TauRx Therapeutics and amyloid plaques from Eli Lilly failed to achieve their primary clinical end points during trials. There may be hope for these different classes of drugs, but don’t hold your breath. The plaques and tangles may be signs of Alzheimer’s dementia rather than causes. Several experts in the field are not surprised by the results.
Let’s look at the evidence.
The quandary that is blood pressure
If ever you needed a reason to control high blood pressure, the fact that it may contribute to dementia should be a motivator. In the recent Framingham Heart Study, Offspring Cohort, a prospective observational study, results showed that high blood pressure in midlife — looking specifically at systolic (top number) blood pressure (SBP) — increased the risk for dementia by 70 percent (4). Even worse, those who were controlled with blood pressure medications in midlife also had significant risk for dementia.
There were 1,440 patients involved in the study over a 16-year period with an examination every four years. Then, those patients who were free of dementia were examined for another eight years. Results showed a 107-patient incidence of dementia, of which half were on blood pressure medications. And when there was a rapid drop in SBP from midlife to late in life, there was a 62 percent increased risk, to boot. Thus, the moral of the story is that lifestyle changes to either prevent high blood pressure or to get off medications may be the most appropriate route to reducing this risk factor.
Prostate cancer inflates dementia risk
Actually, the title above does not do justice to prostate cancer. It is not the prostate cancer, but the treatment for prostate cancer, androgen deprivation therapy (ADT), that may increase the risk of dementia by greater than twofold (5). Treatment duration played a role: those who had a year or more of ADT were at higher risk. ADT suppresses production of the male hormones testosterone and dihydrotestosterone. The study involved over 9,000 men with a 3.4-year mean duration; however, it was a retrospective (backward-looking) analysis and requires a more rigorous prospective study design to confirm the results. Thus, though the results are only suggestive, they are intriguing.
Calcium supplements — not so good
In terms of dementia, the Prospective Population Study of Women and H70 Birth Cohort trial has shown that calcium supplements, especially when given to patients who have a history of stroke, increase the risk of dementia by greater than sixfold (6). Those who had white matter lesions in the brain also had an increased risk. The population involved 700 elderly women, with 98 given calcium supplements. How do we reduce this risk? Easy: Don’t give calcium supplements to those who have had a stroke. This brings more controversy to taking calcium supplements, especially for women. You are better off getting calcium from foods, especially plant-based foods.
The MIND diet to the rescue
In a recent study, results showed that the MIND diet reduced the risk of Alzheimer’s dementia by 53 percent in those who were adherent. It also showed a greater than one-third reduction in dementia risk in those who only partially followed the diet (7). There were over 900 participants between the ages of 58 and 98 in the study, which had a 4.5-year duration. When we talk about lifestyle modifications, the problem is that sometimes patients find diets too difficult to follow. The MIND diet was ranked one of the easiest to follow. It involves a very modest amount of predominantly plant-based foods, such as two servings of vegetables daily — one green leafy. If that is not enough, the MIND diet has shown the ability to slow the progression of cognitive decline in those individuals who do not have full-blown dementia (8).
To whet your appetite, a recent study involving transgenic growth hormone mice (which have accelerated aging and demonstrate cognitive decline) showed a cocktail of supplements helped decrease the risk of brain deterioration and function usually seen with aging and in severe Alzheimer’s dementia (9). The cocktail contained vitamins, minerals and nutraceuticals, such as bioflavonoids, garlic, cod liver oil, beta carotene, green tea extract and flax seed. Each compound by itself is not considered to be significant, but taken together they seem to have beneficial effects for dementia prevention in mice.
The reasons for dementia may involve mitochondrial dysfunction, oxidative stress and inflammation that are potentially being modified by these supplements. Hopefully, there will be more to come on this subject. It comes down to the fact that lifestyle modifications, whether in terms of reducing risk or slowing the progression of the disease, trump current medications and those furthest along in the drug pipeline. There may also be a role for a supplement cocktail, though it’s too early to tell. The MIND diet has shown some impressive results that suggest powerful effects.
References: (1) uptodate.com. (2) JAMA Intern Med. online Nov. 21, 2016. (3) uptodate.com. (4) American Neurological Association (ANA) 2016 Annual Meeting. Abstract M148. (5) JAMA Oncol. online Oct. 13, 2016. (6) Neurology. online Aug. 17, 2016. (7) Alzheimers Dement. 2015;11:1007-1014. (8) Alzheimers Dement. 2015;11:1015-1022. (9) Environ Mol Mutagen. online May 20, 2016.
Dr. Dunaief is a speaker, author and local lifestyle medicine physician focusing on the integration of medicine, nutrition, fitness and stress management. For further information, visit www.medicalcompassmd.com or consult your personal physician.