This is an advanced reading page for interested readers. It contains a detailed discussion on the risk factors and preventive factors for dementia. It discusses how to make sense of the various reports we read on the topic. If you want an overview on dementia risk, please check the section Risk factors for dementia and what we can do of our page on diagnosis.
The idea of getting dementia is frightening for most of us. We want to avoid dementia. Unfortunately, media articles give confusing information. Sometimes we hear that dementia can happen to anyone. At other times, an article claims that we can prevent dementia by eating a particular herb or doing some particular activity. We want to stay safe from dementia but we don’t want to do things that don’t work or may even harm us.
This page contains detailed discussions for readers trying to understand the risk factors for dementia. The page is for readers who want to reduce their chance of dementia by making suitable changes in their diet, exercise, and daily activities. The page does not discuss ongoing research and studies. Persons interested in the latest research should subscribe to reliable research sites.
- Basic understanding of terms like risks, prevention, correlations, causation, etc.
- Finding ways an individual can completely avoid dementia is very unlikely; we therefore must try to reduce the risk of dementia.
- Consolidated suggestions on risk factors, as available in published reports and authoritative sites.
- Evaluating media reports related to ongoing Alzheimer’s/ dementia research findings.
- Deciding on lifestyle choices.
- Data on some modifiable factors currently under discussion.
Dementia risk reduction is often discussed using words like “prevention”, “risk reduction”, “risk factors”, and “protective factors.” Articles often use these terms in different ways. Sometimes there are contradictions within the same article.
Popular media use of the word “prevention” is misleading. Most people use “prevention” to mean that the chance of getting something has dropped to zero. When an article headline says: “Do this one thing to prevent dementia” readers think the author is assuring them that they will never get dementia if they do that activity regularly. Such articles often quote a study to support the claim. This makes the claim seem scientifically proven. But this is wrong. A single study cannot be used to make such a drastic claim.
Scientific papers and articles use “prevention” more precisely.
Some standard, authoritative dementia and Alzheimer’s sites are meant for individuals. These discuss what people can do to reduce their risk of dementia. They do not claim that there is any certain way for an individual to remain safe from dementia. The Alzheimer’s Association has a page discussing risks at Prevention and Risk of Alzheimer’s and Dementia Opens in new window. It says (web-page quote reconfirmed March 2022):
Researchers around the globe are exploring how to prevent Alzheimer’s. While Alzheimer’s prevention has no definitive answers at this time, research has shown that we can take action to reduce our risk of developing it.
Some scientific papers and published reports look at dementia incidence and prevalence at a population level. Such reports use “prevent” in a different context. The word “prevention” is used by policy makers in the context of entire populations (not individuals). The focus is delaying dementia onset for the population on an average. Chapter 1 of World Alzheimer’s Report 2014: Dementia and Risk Reduction: An analysis of protective and modifiable factors Opens in new window explains this. A quote:
…prevention of dementia is commonly conceived as the delay of the clinical onset of the disease rather than a slowing or avoidance of the development of the underlying neuropathology. Similar to other chronic diseases primary prevention of dementia corresponds, ideally, to ‘delay until death’ of symptomatic onset, or, failing that, a delaying or deferring of onset to older ages than that at which it would otherwise have occurred. An average five year delay in the age of onset would tend to reduce population prevalence by 50%, hence greatly reducing its impact in the general population.
The report explains that the global burden can be tackled by delaying dementia onset at a population level. They do not use “prevention” for what individuals can do to completely avoid dementia. The report says:
There is no evidence strong enough at this time to claim that lifestyle changes will prevent dementia on an individual basis.
When viewing interventions at the population level, it is useful to see interventions for dementia risk reduction along with other health-based recommendations. As the WHO May 2019 report, Risk reduction of cognitive decline and dementia: WHO Guidelines Opens in new window points out in its foreword,
As many of the risk factors for dementia are shared with those of non-communicable diseases, the key recommendations can be effectively integrated into programmes for tobacco cessation, cardiovascular disease risk reduction and nutrition.
Finding ways an individual can completely avoid dementia is very unlikely; we therefore must try to reduce the risk of dementia
Cognitive decline occurs due to an accumulation of many factors. The report referred to earlier, World Alzheimer’s Report 2014: Dementia and Risk Reduction: An analysis of protective and modifiable factors explains this. A quote:
…marked inter-individual differences in cognitive health in late-life are observed at a population-level. These differences may in part be a function of the level of exposure to a number of factors across the entire life course and are usually termed risk or protective, depending on whether, in general, they are associated with an increased or reduced future likelihood of cognitive impairment and dementia in populations.
Because the clinical onset of dementia is likely to be the end stage of the accumulation of neuropathological damage over several years, the latency between the initiation of the process and detection of the onset of dementia is likely to be very long.
Dementia symptoms happen because of many factors and their impact grows over time. This impact then crosses a threshold where the symptoms are visible. Keeping this in mind, it is clear that any simplistic suggestion like ‘do a su-do-ku a day and keep dementia at bay’ cannot be correct.
Also, many medical conditions can cause dementia symptoms. Even if researchers find a way to avoid one medical condition, that does not safeguard an individual against all other conditions that can cause dementia. For example, even if researchers find how to completely avoid all variations of Alzheimer’s Disease, the individual can still get one or more of the several other dementia-causing diseases. So an article that keeps using “prevent Alzheimer’s” interchangeably with “prevent dementia” is clearly suspicious. In any case, research has not yet shown any way to prevent Alzheimer’s in an individual.
As prevention is not possible, we, as individuals, need to look at ways to reduce our risk of getting dementia. We can do this in two ways: (1) reduce or cut out known risk factors (2) increase things known to be protective factors.
Many risk factors are beyond our control. So we focus on information on modifiable risk factors to reduce our individual probability of developing dementia. Modifiable risk factors are often considered in four key domains: developmental, psychological and psychosocial, lifestyle and cardiovascular conditions.
We also need to know if we have an increased risk of dementia because of factors beyond our control. If our risk is higher, we will be more careful about factors that we can still control. For example, many risk factors are associated with the stage of life, like childhood development. Adults cannot change their childhood development. But if they realize that their risk of dementia is higher because of their childhood, they will be more careful about avoiding risk factors now. They will also adopt more protective measures. Research on dementia risk factors is ongoing. Individuals who understand the conclusions can make better choices.
Prioritization matters. We lead busy lives. We cannot follow every “good” advice we get. We have to see what may be effective and what is practical for us. We cannot waste effort and energy on dramatic, misleading headlines. We cannot change our actions just because of a single study. After all, the results of a single study are likely to be rejected in later studies. We should not get misled by claims about a miracle cure by someone who is selling that alleged cure.
The rest of the page explains ways to consider available data. It suggests sites where analysis of multiple studies and claims may be viewed.
Scientists look at results of multiple studies to identify risk factors and protective factors. This is called a meta study. A specific study may find a correlation of a factor with dementia, but this may be a “false positive” or a “false negative.” The result may also be because of a flaw in the experiment design or a bias in the sample. Authoritative bodies therefore look for results that are proven in multiple studies. This makes sure that their recommendations are reliable.
Here are some web resources of national and international Alzheimer’s Disease associations and research bodies:
- Alzheimer’s Association, USA, describes the three main risk factors for Alzheimer’s that cannot be changed as age, family history and heredity. It also suggests factors that can be changed. Risk factors and genetic components of risk are explained on this page: Risk factors for Alzheimer’s Opens in new window. This page lists the major factors that we can control. It explains the complex interactions that cause Alzheimer’s. It suggests working on avoiding head trauma, maintaining good heart health, and using general strategies for overall healthy aging.
- Alzheimer’s Disease International has a page discussing risk factors, Risk Factors Opens in new window.
- Alzheimer’s Australia has a page on risk reduction Opens in new window.
Here are some important published reports on risk reduction:
- In February 2014, Alzheimer’s Disease International (ADI) published a report, “Nutrition and dementia: A review of available research Opens in new window“. This report discusses the role of right nutrition in the life of persons with dementia. It reviews dietary factors across the life course in terms of the risk of late onset dementia. It includes suggestions on nutrition-related actions.
- In September 2014, Alzheimer’s Disease International (ADI) published a landmark report, World Alzheimer’s Report 2014: Dementia and Risk Reduction: An analysis of protective and modifiable factors. This report is referred to at several places on this page. You can view the report here: World Alzheimer’s Report 2014: Dementia and Risk Reduction: An analysis of protective and modifiable factors Opens in new window. This report presents a meta analysis of published research. It offers conclusions regarding factors that are correlated with dementia at a population level. It also says whether the correlation is strong enough to explore through more studies. The report suggests actions at the Governmental level to “prevent” (delay the onset of) dementia at a population level. (See explanation of “prevention” above.) The report does not suggest how individuals can reduce their own dementia risk. However, the insights in the report can be interesting for readers who want to understand more.
- In July 2017, the Lancet Commission on Dementia Prevention, Intervention, and Care published a 62 page detailed report consolidating expert opinion on the emerging knowledge of how to prevent and manage dementia. This report includes the key messages of the commission as well as supporting discussions, data, and references. Risk factors and prevention recommendations (and their basis) are included in this report. The report can be viewed/ downloaded using a (free) subscriber account on the Lancet site, at Dementia prevention, intervention, and care Opens in new window .
- In May 2019, World Health Organization (WHO) published a 96 page report with evidence-based guidance for a public health response to dementia. These are recommendations on lifestyle behaviours and interventions to delay or prevent cognitive decline and dementia.This is intended as a tool for health care providers, governments, policy-makers and other stakeholders to strengthen their response to the dementia challenge. The recommended interventions are identified as strong or conditional: Strong interventions are those that most individuals would want and should receive and while conditional recommendations are those where different choices may be appropriate for individuals and they may need help to decide. The report can be viewed/ downloaded from this page: Risk reduction of cognitive decline and dementia: WHO Guidelines Opens in new window .
- In August 2020, the Lancet Commission on Dementia Prevention, Intervention, and Care published an updated report, adding three risk factors to those already identified in its earlier 2017 report. The earlier report had identified modifiable factors as less education, hypertension, hearing impairment, smoking, obesity, depression, physical inactivity, diabetes, and low social contact. The 2020 report adds three more risk factors for dementia based on newer, convincing evidence. These are excessive alcohol consumption, traumatic brain injury, and air pollution. Read the report (or download it) at Dementia prevention, intervention, and care: 2020 report of the Lancet Commission Opens in new window.
Newspapers and magazines often carry reports of apparently sensational studies. They may even publish a contradictory report a few days later. This is very confusing for persons trying to decide on life changes to make. Remember that media reports are often misleading. Headlines, especially, are dramatic and written mainly to attract readers. The article may be written in a hurry. It may not be a correct summary of the scientific paper it quotes. Also, newspapers often sensationalize the results of a single study. They do not bother about whether the claims are supported or replicated by other studies.
Before changing your lifestyle because of a result that gives “hope,” look at the actual published study. How can you evaluate a report? Some possibilities:
- Find the abstract of the paper that the newspaper is quoting. Media reports often ignore the disclaimers and limitations of the study. But the paper abstracts will state these clearly. Abstracts can be seen by visiting the site of the journal that published the paper. Use the search facility to locate it.
- Read this article on how to evaluate a report: What Every Caregiver Should Know About Alzheimer’s Research Opens in new window (if link doesn’t work, see archived version here Opens in new window. This has questions you can consider to see whether the study is useful.
- Read this article for criteria to evaluate evidence: Does Drug X Really Work? Evaluating Medical Evidence Opens in new window.
One type of recommendation is taking some specific herb or food supplement. Impressive claims are made in a few articles. These articles are then duplicated across multiple Internet articles and seem to be all over the Internet. Here are some useful ways to verify claims:
- The National Center for Complementary and Alternative Medicine (NCCAM) is a US Government agency for scientific research. It has data on diverse medical and health care systems, practices, and products that are not part of conventional medicine. Visit their site Opens in new window. Two useful pages at the site are: Herbs at a glance Opens in new window and Health A to Z Opens in new window.
- A pictorial depiction is at: Snake Oil Supplements? (Information is Beautiful) Opens in new window. (claims to be based on data of 2015, may not be up-to-date or fully correct)
- An extremely useful resource is the Cochrane foundation. This presents an analysis across multiple published papers to comment on the usefulness (or otherwise) of some medicine or herb or approach. View their section on dementia at Cochrane Dementia and Cognitive Improvement Group Opens in new window, or search for relevant reviews/ review groups.
- Some authoritative sites have articles that demystify common dramatic claims. One example is Alzheimer’s Association UK’s page which discusses various risk factors as well as the various claims made about ways to prevent dementia: Risk factors and prevention Opens in new window, and another page that discusses the effectiveness or otherwise of various alternate therapies Opens in new window. On these two pages you will find links to detailed pages on popular topics like antioxidants, caffeine, coconut oil, turmeric, cinnamon, cannabis oil (CBD oil) , etc. Other reliable sites also have pages to debunk myths, such as Alzheimer’s Myths Opens in new window. This page talks of myths like the role of aluminum, flu shots, dental fillings, and aspartame.
To stay in touch with published results, here are some websites to consider. (You will need to be careful about how to interpret the results):
- Many national dementia bodies/ international bodies have newsletters you can subscribe to. For example you can subscribe to the newsletter of alz.org, or follow its blog Opens in new window.
- Frequent updates can also be obtained by subscribing to, or checking up the Science Daily site’s mind and brain pages Opens in new window or their dementia pages Opens in new window.
- Another site is the Alzheimer’s Research & Therapy website Opens in new window. This is a forum for translational research into Alzheimer’s disease. It publishes open access basic research with a translational focus, as well as clinical trials, research into drug discovery and development, and epidemiologic studies. This society is affiliated to Alzheimer’s Disease International (ADI).
Some published papers may be on medication. When reading research findings, remember that it takes many years for preliminary research results to result in medicines or detection methods that can be used for humans.
Many persons assume that “there is no harm” trying out a diet change suggested in a news article, even if the report mentions only one study showing a particular correlation. Scientifically speaking, one isolated research study cannot be the basis for a lifestyle change because the result may be reversed in another study. That is, the results can be considered correct only if they are seen in multiple studies.
Our bodies are very complex. what may work for one person may not work for another–it may even harm. So if one person reports on the Internet that something worked for her loved one, it cannot be assumed that it will work for anyone and cannot be harmful. Even herbs can harm us. They may not suit us. They may be toxic when consumed in the quantities we plan to use. They may conflict with our other medicines or may make our other medical problems worse. Before making changes to diet and lifestyle, you must discuss the proposed changes with a doctor who knows your medical history, family history, and current medicines.
There are many reasons to be cautious even for apparently “harmless” decisions. We can make only limited number of changes in our lives. Each change we make is an effort for us. If we make changes that do not help (or which can actually harm), we may miss better and more useful changes.
Here are some recent studies that could be useful while making life choices. Please note that but there is no certain way to prevent or delay dementia, and research is still underway for solutions. But some choices are worth considering even if they are not fully proven.
Tobacco use and dementia: The International Journal of Geriatric Psychiatry, published a study linking dementia and tobacco. The abstract can be read here: Tobacco use and dementia: evidence from the 1066 dementia population-based surveys in Latin America, China and India Opens in new window. It concludes:
Dementia in developing countries appears to be positively associated with history of tobacco smoking but not smokeless tobacco use. Selective quitting in later life may bias estimation of associations.
Smoking has been mentioned as a possible causal factor in the World Alzheimer’s Report 2014: Dementia and Risk Reduction: An analysis of protective and modifiable factors. An excerpt from the report summary:
The strongest evidence for possible causal associations with dementia are those of low education in early life, hypertension in midlife, and smoking and diabetes across the life course.
The Alzheimer’s Disease Association includes a link to the WHO publication TOBACCO & DEMENTIA (PDF file) Opens in new window. Some quotes:
Smoking is a risk factor for dementia, and quitting could reduce the dementia burden
…Second-hand smoke exposure may also increase the risk of dementia
…14% of Alzheimer’s disease cases worldwide are potentially attributed to smoking
Brain plasticity, memory training, and dementia:
Earlier it was believed that we are born with a fixed number of brain cells and that no new brain cells are created during our lifetimes. This was discarded years ago. We now know that we can grow new neurons. Our brains can be retrained. Research is being done to see whether training the brain can delay or prevent dementia. So far studies show that cognitive activity reduces the risk of dementia. But studies have not suggested any specific recommendations for changing our lifestyles. Researchers are interested in seeing if software programs and video games can help reduce the risk of dementia. This is especially important because there are several commercial products for “brain training.” Many persons assume such products will help. But this is not yet proven scientifically across studies.
The 2014 World Alzheimer’s Report on Risk Factors which examines several such studies. It points out that in someone with dementia, the brain changes associated with dementia have been going on for years, possibly even two decades, before the symptoms are serious enough to get a diagnosis. This makes it difficult to see the impact (or otherwise) of cognitive activities on dementia. The report discusses several studies. Its conclusion with respect to cognitive stimulation is:
Although evidence from prospective cohort studies is limited, consistent results form a large number of observational studies that measured cognitive activity in late-life seem to support the hypothesis that this may be beneficial for both brain structure and function. Dementia-related brain damage likely starts up to decades before the clinical onset of dementia, and the effects of incipient neuropathology on the level and type of intellectual activity is not known. As stated earlier, this is the main reason why the current corpus of evidence on cognitive activity and risk of dementia should be interpreted with caution.
The report suggests a possible connection between cognitive activity and dementia:
The observed lower cognitive activity levels in those who will go on to show clinical symptoms of dementia may in fact be a prodromal sign of the disease itself
That is, a reduction in cognitive activity could be happening because the person is already in the initial stages of dementia.
An important, relevant concept here is the possible advantage of Cognitive Reserve. (See Wikipedia page on cognitive reserve Opens in new window). Education helps building more cognitive reserve. This may explain the findings that higher education in early years correlates to lower dementia. It may also explain the claims on the benefits of bilingualism (Published papers: Delaying the onset of Alzheimer disease: bilingualism as a form of cognitive reserve Opens in new window, Bilingualism delays age at onset of dementia, independent of education and immigration status Opens in new window). If bilingualism is protective, that may be good news for Indians, as many people here know multiple languages. They can choose to actively speak more than one language and acquire the claimed protection. The World 2014 report states:
Brain and cognitive reserve, developed early in life and consolidated in midlife may buffer the expression of symptoms of dementia in the presence of neurodegenerative disease.
So far, the recommendation is to maintain a good level of intellectual activity and social connection through a range of activities and participation. The cognitive stimulus needs to be broad-based. It should not be confined to a few specific activities.
The Alzheimer’s Association site has a page on risks and prevention at: Prevention and Risk of Alzheimer’s and Dementia Opens in new window. This explains (excerpt rechecked March 2022):
A number of studies indicate that maintaining strong social connections and keeping mentally active as we age might lower the risk of cognitive decline and Alzheimer’s. Experts are not certain about the reason for this association. It may be due to direct mechanisms through which social and mental stimulation strengthen connections between nerve cells in the brain.
The Alzheimer’s Society UK has a page that explains brain training and shares information obtained from a study they are doing: Brain Training Opens in new window. The page states (excerpt rechecked March 2022):
Some studies have found that cognitive training can improve some aspects of memory and thinking, particularly for people who are middle-aged or older.
So far, no studies have shown that brain training prevents dementia. However, this is a relatively new area of research and most studies have been too small and too short to test any effect of brain training on the development of cognitive decline or dementia.
Evidence suggests that brain training may help older people to manage their daily tasks better, but longer term studies are needed to understand what effect, if any, these activities may have on a person’s likelihood of developing dementia.
They also discuss commercial products (excerpt rechecked March 2022):
There are a large number of commercial brain training games or products on the market, some of which have been tested in research studies but the majority have not. It is not possible to apply the results of studies that test a particular training package to all brain training games because they may be designed to challenge a different kind of brain function.
People should be cautious if they find commercial packages that claim they can prevent or delay cognitive decline as the evidence for this is currently lacking.
More studies are being considered to refine the understanding of brain training and improved cognition.
Commonly discussed factors, myths, and data: Many articles carry claims of both risk and protective factors. These are usually unconfirmed by research, or have been rejected by research. Some topics often discussed are:
- Coconut oil: Coconut oil is used in many Indian homes. News that coconut oil may help in dementia is seen as a practical measure that can be used right away. The Internet has several articles on the alleged benefits of coconut oil. Most are related to the videos and presentations of Dr. Mary Newport. Dr. Newport is neonatologist who reported that her husband showed significant improvement for some time by using coconut oil for a “ketogenic diet.” She offered her scientific impression of why this must have worked. Her personal experience is often shared and assumed by laypersons to be sufficient proof that anyone can benefit from adding coconut oil. However, scientists consider the science behind the claims to be flawed, and the claims unproven, and say that coconut oil’s safety has not been established and it may even be detrimental for Alzheimer’s Disease patients. A demystification of coconut oil is available at the Alzheimer Society UK’s page: Coconut oil and dementia Opens in new window. The page also has an update about a study that was underway; it states: “Update (May 2017): The trial into coconut oil has sadly been discontinued due to difficulties recruiting enough people to take part.”.
Additionally, Axona, the product based on the theory of the alleged benefit of coconut oil components, has not fared well in research studies. It is not FDA approved (Wikipedia page on Axona Opens in new window). The “Nutrition and dementia” report has this to say about Axona: “Randomised controlled trials of Axona do not support any consistent or clinically significant cognitive benefit.
- Turmeric (Haldi) and its extracts curcumin and turmerone: Numerous popular press articles claim that turmeric (haldi) consumption in food can protect from Alzheimer’s. This especially interests Indians because turmeric is a common spice in Indian cooking. However, this claim is not supported by research. Curcumin, an extract of turmeric, is being studied for its possible protective effect. Turmerone, too, is being studied. But turmeric is not easily absorbed when we eat it. Eating haldi may not make enough curcumin available to the body. An explanation can be read at Alzheimer Society UK’s page: Turmeric Opens in new window.
- Cinnamon: Numerous articles claim that cinnamon can treat Alzheimer’s. Research on extracts of cinnamon is still underway. The Alzheimer Society UK’s page: Cinnamon Opens in new window explains this. It states (excerpts checked March 2022): Though studies have been done on the possibility of cinnamon preventing dementia, clinical trials are needed to assess its effect on people with dementia. Cinnamon is not recommended as a prevention or treatment for Alzheimer’s disease or dementia as it can be toxic. Some of the extracts of cinnamon may warrant investigation to try and establish new treatments.
- Cannabis, Cannabis oil, CBD oil: Some articles claim that cannabis can prevent/ treat dementia or help with its symptoms. Soem research has been done on cannabis, but while some initial benefits have been seen, it is not recommended yet as there is no clarity on required dosage and no data on safety, long term effects/ side effects. The Alzheimer Society UK’s page: Cannabis, CBD oil and dementia Opens in new window explains this, and adds (excerpts checked October 2022): The jury is still out on whether cannabis or its by-products could be used to treat dementia. A lack of strong research studies mean that dubious and anecdotal reports have taken the place of hard evidence.. There is some evidence that heavy, long-term use of cannabis could have a negative effect on our memory and thinking. Much more research needs to be done to tease apart any potential benefits and drawbacks. Another relevant document is this paper (PDF file) Opens in new window which explains the current understanding, links to several references, and states (checked Oct 2022), There is currently a very limited evidence base for medicinal cannabis in treatment of or behavioural management of patients with dementia or Alzheimer’s disease….The current limited evidence does not support a therapeutic effect of medicinal cannabis for management of behavioural disturbance in dementia.
- Possible risk of aluminum, silver dental fillings/ amalgam, flu shots, aspartame: These are myths. They are debunked here: Alzheimer’s Myths Opens in new window.
It is common to find articles on the Internet claiming that some herb or spice can prevent dementia. Usually these claims are not supported by studies. These articles are re-publications of previous, unverified articles. Or they assume that anything that is good for one disease must be good for another. Some articles assume that if one study has found the extract of a substance useful, then that substance taken directly in any small quantity will be useful. This is a wrong way of looking at research results. It is better to check the data carefully. Ways to check such claims are already given above. It is possible that some diet elements claimed to be good for dementia are also beneficial for other health conditions, but we need to evaluate the claims carefully, and the risks, and then decide what we want to change. We should be especially careful to avoid excesses as these may result in toxic effects.
Diet and supplements: In general,the Mediterranean diet is recommended. This is because it is supposed to be protective of the brain. It is also associated with better outcomes on many other parameters, such as lower risk of stroke, type 2 diabetes, cardiovascular problems, etc.
Many people also consider adding vitamin and antioxidant supplements. However, current studies do not show any dementia-related advantage of adopting these. As the World Alzheimer’s Report 2014 says:
There is currently insufficient evidence to confirm a relationship between the micro- and macro-nutrients described above (vitamin B6, vitamin B12, folate, vitamin C, vitamin E, flavonoids, omega-3, Mediterranean diet) and cognitive function. Although some studies have shown positive results, particularly those using cross-sectional designs, the findings have not been consistently supported in prospective cohort studies, and preventive interventions have generally failed the critical test of randomised controlled trials.
So a Mediterranean diet is worth considering because of the many other advantages and protection it offers, even if it may not protect against dementia. But supplements may not be of any use, and can actually harm. In fact, some studies were stopped because of higher rates of cancer development among those taking antioxidant supplements according to this Alzheimer’s Society UK’s page: Antioxidants and dementia Opens in new window). Any antioxidants we want are best obtained from our normal diet, and such antioxidants may also be found in sufficient amounts in a Mediterranean diet.
Common health problems and their control: Healthy ageing is supposed to help for a healthy brain. One possible way to reduce the chance of dementia is to avoid major health problems or keep them under control.
One such important health problem is diabetes. The correlation seen so far between diabetes and dementia is strong enough to make us more careful about avoiding or controlling diabetes. The World Alzheimer’s Report 2014 says:
Evidence reviewed in this section confirms a particularly strong and consistent association between diabetes in late-life and the subsequent onset of dementia. ……Evidence from health record linkage studies also suggests that diabetes in midlife may have an equivalent or even greater effect, and it may be that the duration of diabetes is an important risk determinant. The primary prevention of diabetes should also therefore be targeted. Diabetes seems to be a much stronger risk factor for vascular dementia than for Alzheimer’s disease, and cerebrovascular disease is likely to be an important mediating mechanism.
Hypertension in midlife is also correlated. As the report says:
We have identified particularly strong and consistent epidemiological evidence that … Hypertension in midlife increases the risk of dementia, particularly vascular dementia
The correlation is weaker for some other factors. The report says:
There is weak and inconsistent evidence that…
….Obesity in midlife may increase the risk of dementia and Alzheimer’s disease
….Dyslipidaemia in midlife (high total cholesterol) may increase the risk of dementia, particularly Alzheimer’s disease.
In general, cardiovascular health is very important because it is correlated with vascular dementia as well as Alzheimer’s Disease. Cardiovascular risk factors must be addressed to have better brain health and reduce the chances of dementia. This is often summarized as:
A good mantra is “What is good for your heart is good for your brain”
(from World Alzheimer’s report 2014).
Many lifestyle changes have not yet been studied in terms of their correlation with dementia. However, they are known to help improve cardiovascular health and so they are worth considering. This includes things like physical activity.
Key recommendations from the July 2017 Lancet report: A consolidation of emerging data and expert opinion, published by the Lancet Commission in July 2017 identifies 9 key modifiable risk factors to consider and try to address throughout the life course. These are basic education, hearing loss (partial or complete), smoking, depression, physical inactivity, social isolation, hypertension, obesity, and diabetes. Data is still being gathered for other possibly important aspects like diet and alcohol consumption. The report suggests increasing cognitive reserve, reducing brain damage, and reducing brain inflammation. Suggestions include things like preserved hearing, education, cognitive training, reducing obesity, stopping smoking, treating diabetes, hypertension and high serum cholesterol, treatment for inflammation, reducing depression and having a rich social network, opting for a diet like the Mediterranean diet, and, of course, exercise. Note that this report has probably the first firm identification of hearing loss as an important risk factor for dementia.