5 tips to stave off dementia as you age

Dementia is on the increase around the globe. Roughly 50 million people worldwide live with the disease, and the number is projected to reach a whopping 152 million by 2050, according to a report in The Lancet.^[]

With that kind of prediction, it might seem like getting dementia is a foregone conclusion for many of us.

The good news? A future diagnosis of dementia is by no means set in stone—in fact, neurocognitive health is highly dependent on the decisions you make today.

According to the authors of an article published in BMJ Neurology, “Ageing, genetic, medical and lifestyle factors contribute to the risk of Alzheimer’s disease and other dementias. Around a third of dementia cases are attributable to modifiable risk factors such as physical inactivity, smoking, and hypertension. With the rising prevalence and lack of neuroprotective drugs, there is renewed focus on dementia prevention strategies across the lifespan.”^[]

Here are five evidence-based ways to prevent dementia.

Physical activity

Exercise is a key means of preventing dementia, according to a study published in BMC Public Health—billed as the “first trial to examine the effects of a long exercise program (48 months) on cognitive performances.”^[]

The authors wrote that “several studies have shown that lifestyle modification and reduction of modifiable risk factors for AD [Alzheimer disease] offers a promising way of decreasing the risk of dementia. Physical inactivity is considered one of the seven main potentially modifiable risk factors for AD and explains approximately 13% (nearly 4.3 million) of AD cases worldwide.”

If successful, this trial may provide evidence for using long-term and multimodal exercise interventions for dementia prevention programs in the aging population.

The authors suggested that several potential mechanisms could mediate the link between exercise and decreased risk of dementia, including production of brain-derived neurotrophic factor (BDNF), enhanced insulin sensitivity, promotion of cardiovascular health, and decreased stress and inflammation.

The benefit of these factors could be especially important in the aging brain, and could someday serve as potential biomarkers to determine the effects of different exercise regimens on cognitive outcomes.

Diet

“It’s possible that eating a certain diet affects biological mechanisms, such as oxidative stress and inflammation, that underlie Alzheimer’s,” notes an article published by the National Institutes on Aging (NIA). “Or perhaps diet works indirectly by affecting other Alzheimer’s risk factors, such as diabetes, obesity, and heart disease. A new avenue of research focuses on the relationship between gut microbes—tiny organisms in the digestive system—and aging-related processes that lead to Alzheimer’s.”

Experts at the NIA point to two promising diets to possibly attenuate dementia risk: the Mediterranean diet and the MIND (Mediterranean–DASH Intervention for Neurodegenerative Delay). The Mediterranean diet includes fruits, vegetables, whole grains, legumes, fish, and unsaturated fats such as olive oils, as well as limited amounts of red meat, eggs, and sweets.

On the other hand, the MIND diet incorporates the DASH diet, which has been shown to decrease high blood pressure—a factor that plays a role in Alzheimer disease. The food groups covered by the MIND diet include leafy green vegetables, other vegetables, berries, whole grains, fish, poultry, beans, nuts, wine, and olive oil.

Hypertension

In a high-powered meta-analysis published in Lancet Neurology, researchers included data from six prospective studies (n=31,090) to determine the effect of antihypertensive medications (AHM) on dementia risk in dementia-free participants older than 55 years.^[]

“Over a long period of observation, no evidence was found that a specific AHM drug class was more effective than others in lowering risk of dementia,” they concluded. “Among people with hypertensive levels of blood pressure, use of any AHM with efficacy to lower blood pressure might reduce the risk for dementia. These findings suggest future clinical guidelines for hypertension management should also consider the beneficial effect of AHM on the risk for dementia.”

According to a report by the Lancet Commission, those aged 40 years or older should shoot for a systolic blood pressure of 130 mm Hg or less in midlife, with antihypertensive drugs the only known effective agents to prevent dementia.

Smoking

According to the Lancet Commission findings, smokers are at higher risk for dementia than are nonsmokers, as well as premature death before the age at which they may have developed dementia. Even older people who stop smoking can decrease their dementia risk.

With respect to the effect of second-hand smoke on dementia risk, the authors noted that research is limited. Nevertheless, they highlighted some research that indicated that in women aged between 55 and 64 years, second-hand smoke exposure was linked to increased memory deterioration that was dose-dependent. Of note, these findings persisted after accounting for covariates.

Heavy drinking

According to the authors of the aforementioned Lancet report, “An increasing body of evidence is emerging on alcohol's complex relationship with cognition and dementia outcomes from a variety of sources including detailed cohorts and large-scale record-based studies. Alcohol is strongly associated with cultural patterns and other sociocultural and health-related factors, making it particularly challenging to understand the evidence base.”

The authors highlighted different research findings that indicated that earlier onset of dementia (ie, aged 65 years or fewer) was closely associated with alcohol use. Additionally, heavy drinking was linked to atrophy of the right hippocampus on MRI. Notably, the right hippocampus plays a role in memory retrieval.

The bottom line

Fortunately, various lifestyle interventions could reduce the risk of dementia later in life. The key is to institute these changes earlier in life. In fact, unlike early-onset dementia, in late-onset dementia, the heritable component is uncertain.

“Early-onset familial Alzheimer disease is inherited in an autosomal dominant pattern, which means one copy of an altered gene in each cell is sufficient to cause the disorder. In most cases, an affected person inherits the altered gene from one affected parent,” according to the US National Library of Medicine.

"People who inherit one copy of the APOE e4 allele have an increased chance of developing the disease; those who inherit two copies of the allele are at even greater risk. It is important to note that people with the APOE e4 allele inherit an increased risk of developing Alzheimer disease, not the disease itself. Not all people with Alzheimer disease have the e4 allele, and not all people who have the e4 allele will develop the disease,” the authors added.