The heart-brain connection: Hypertension is more than just heart health
By Dr. Romi Fung, NDFeatures Clinical Research Wellness alzheimer's dementia hypertension magnesium
According to the 2020 report by Statistics Canada, Alzheimer’s dementia deaths in Canada were ranked 9th for the leading cause of death. In comparison, cerebrovascular diseases were ranked as the 5th leading cause of death in Canada. It is interesting to observe that there is a likely correlation between Alzheimer’s dementia and cardiovascular disease, especially pertaining to the brain.
Vascular dementia is a decline in cognitive ability caused by conditions that reduce blood flow to the brain and its specific regions. As a result, this deprives the neural cells of oxygen and nutrients (Alzheimer’s Association, n.d.).
Vascular dementia is the second most common type of dementia, with Alzheimer’s disease being the most common (Alzheimer’s Society, n.d.). About 5-10% of people with dementia have vascular dementia alone; however, many experts believe that vascular dementia remains underdiagnosed even though it is recognized as common. It can be very common if you refer to the number of cardiovascular diseases that are prevalent that could be the underlying factors to vascular dementia and potentially Alzheimer’s Disease.
Looking at cardiovascular disease by the numbers, nearly 1 in 4 aged 20-79 had hypertension 140/90 in a report from 2012-2015 (Statistics Canada, 2020). According to the Centre for Disease Control and Prevention (CDC), only one in four adults with hypertension have their condition under control (CDC, 2022). With the uprise in cardiovascular diseases that coincide with the uprise in dementia cases, could they potentially be more correlated? Cardiovascular disease was associated with a double risk of dementia, and more than three-fold increased risk of vascular dementia (Eriksson et al., 2010).
Current conventional measures still focus on the idea of treating dementia using antipsychotics and pharmaceuticals without looking at underlying factors. Rather than putting the entire emphasis on the brain itself, a clinician should identify underlying factors that contribute to the brain, including cardiovascular health. The brain is a very vascular organ; although it consists of 2% of our body weight, the brain receives 20% of the body’s blood supply (Dafny, 2020).
There is growing evidence that there is a significant correlation between high blood pressure and incidence in dementia. In the Honolulu-Asia Aging Study where 3734 Japanese-American men were observed over a couple decades, researchers found that for every 10mmHg increase in systolic blood pressure, there was a nine percent increase in risk of cognitive impairment (Gelber et al., 2012). In other words, those who suffer from Stage 2 hypertension, or have blood pressure greater than 140/90mmHg, is at an approximate 20% increase risk of developing cognitive impairment if left untreated.
Cardiovascular disease can be highly prevented; treating for cardiovascular disease can also prove to benefit our cognitive health which further adds to the interconnectedness of our human organ systems. A meta-analysis conducted by Ding et al. (2019) referenced over 31,000 older adults aged 55+ that were treated for hypertension. Regardless of the antihypertensive medication, risk of dementia and developing Alzheimer’s disease were reduced by 12% and 16%, respectively (Ding et al., 2019).
It is interesting to note that screening for hypertension is very often underperformed. According to the World Health Organization (WHO), an estimated 46% of adults are unaware they have high blood pressure. In addition, less than half of adults with hypertension are properly diagnosed (WHO, 2021). Ensure that when seeing the older adult patient, to have a thorough assessment. Early detection, adequate first-line treatment and discussions of lifestyle factors are key.
Naturopathic approaches to hypertension
Controlling high blood pressure can reduce damage to the capillaries and vasculature of the brain. It is no reason why hypertension can be termed the ‘silent killer,’ as it may pertain to mortality, but also our brain health. There are many lifestyle recommendations when it comes to controlling high blood pressure that clinicians need to be discussing with their patients first and foremost before resorting to monotherapies including pharmaceuticals and nutraceuticals.
Salt reduction: Probably one of the first things that one would think of about high blood pressure is reducing salt. Salt makes it more difficult for the kidneys to remove water, which contributes to water retention in the blood and put more pressure on the heart and blood vessels. A meta-analysis in 2013 gathered a modest decrease of 5.8mmHg in systolic blood pressure from reducing six grams of salt intake after adjusting for age, ethnicity and pre-existing blood pressure status (He et al., 2013).
There are a couple considerations to sodium. With the convenience of processed and packaged foods, consumers do not realize how much sodium is contained in these foods even when they’re avoiding added sodium. Consuming a whole foods diet will have better control over how much sodium is consumed.
Potassium deficiency: Potassium may also be a factor in hypertension as it aids in the removal of sodium through urine, and also eases the tension in the blood vessels (Aburto et al., 2013). Could it be excess sodium, or a potassium deficiency? A systematic review by Aburto et al. (2013) compiled 22 randomized control trials and 11 cohort studies and observed a 7.16mmHg reduction in systolic blood pressure when 90-120mmol/day of potassium was consumed.
Potassium-rich foods include bananas, dates, dark chocolate, avocadoes, sweet potatoes and root vegetables. (Lanham-New & Lambert, 2012). There is the idea of the sodium:potassium relationship in food to consider as well. Food groups that have a high sodium:potassium ratio, meaning foods much higher in sodium than their potassium counterpart, are processed meats, white bread, and condiments (O’Halloran et all, 2016).
DASH Diet: Both sodium reduction and potassium intake ratio are elements of the Dietary Approaches to Stop Hypertension (DASH) diet, as well as incorporating foods higher in calcium and magnesium (Bensaaud et al., 2020). Appel et al. (1997) has observed participants undergoing the DASH diet to have their systolic and diastolic blood pressure reduced by 11.4 and 5.5 mmHg, respectively.
Nitric Oxide Production: Nitric Oxide (NO) helps support endothelium-depend vasodilation to maintain normal blood pressure (Sweazea et al., 2018). There are a few ways to generate NO. Dietary nitrates can contribute to NO generation via the nitrate-nitrite-NO pathway (Sweazea et al, 2018). Besides the common beetroot, vegetables that are particularly rich in nitrates include green leafy vegetables such as spinach and lettuce, as well as fennel, radishes, Chinese cabbage and parsley (Sweazea et al., 2018). .
Physical Activity: An important way to produce NO is physical exercise. Moderate-intensity aerobic exercise augments endothelium-dependent vasodilation in humans through the increased production of nitric oxide (Goto et al., 2003). Moderate intensity refers to approximately 50% of one’s VO2 max (Goto et al., 2003). It is interesting to note that Goto et al. (2013) suggests that high-intensity exercise, indicated as 75% of VO2 max, possibly increases oxidative stress.
Walking is a low-cost activity that has shown benefits in blood pressure. In a Cochrane report by Lee et al. (2021), there is moderate evidence suggesting that walking reduces systolic blood pressure by 4.11mmHg on average in participants aged 40 and under.
Nutraceuticals can be supplemental in supporting a healthy blood pressure.
Magnesium: A meta-analysis by Dibaba et al. (2017) of 11 RCTs show that magnesium supplementation had significantly lowered blood pressure, both systolic and diastolic values. The RDA requirement for magnesium for adults aged 18 and over is approximately 400mg (National Institutes of Health [NIH], 2022).
Garlic: There are two trials that showed a mean reduction of systolic and diastolic blood pressure by 10-12mmHg and 6-9mmHg, respectively (Stabler et al., 2012). Garlic has been shown to be similarly as effective as first-line antihypertensive medications. The active compound in garlic is allicin, or S-allycysteine, which likely exhibits prostaglandin-like effects (Rashid & Khan, 1985). In a dose-response trial by Reid et al. (2013), A dose of 480mg of aged garlic extract containing 1.2mg S-allycysteine lowered systolic blood pressure by 12mmHg in over 12 weeks.
Summary, implications in practice, and future considerations
It is very common to see a patient work with several health care practitioners for various conditions. Despite the collaboration between professionals, screening for the basics has become overlooked. Just screening patients even 18 and over with blood pressure can make a difference. If blood pressure is not well maintained, there are many considerations to take.
There is current research applying changes of the vasculature in the brain also reflecting in the eyes. A 2019 study in Ophthalmology Retina showed that there are small vessel changes in the retina of patients with later stages of dementia compared to healthy controls using Optical Coherence Tomography Angiography (Lee et al., 2020). Knowing that there are changes in vasculature that compromises the brain, this could be a potential screening tool for dementia.
Cardiovascular disease and dementia appear to have an intricate connection. Empowering patients to self-manage their blood pressure, along with other factors of cardiovascular health, can be a very powerful attempt in mitigating our risk for cognitive decline.
- Aburto, N. J. et al. (2013). Efefct of increased potassium intake on cardiovascular risk factors and disease: systematic review and meta-analyses. BMJ. doi: https://doi.org/10.1136/bmj.f1378
- Alzheimer’s Association. (n.d.). Vascular dementia. Retrieved from: https://www.alz.org/alzheimers-dementia/what-is-dementia/types-of-dementia/vascular-dementia/
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- National Institutes of Health. (2022). Magnesium. Retrieved from: https://ods.od.nih.gov/factsheets/Magnesium-HealthProfessional/
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- Ried, K., Frank, O. R., & Stocks, N. P. (2013). Aged garlic extract reduces blood pressure in hypertensives: a dose-response trial. European journal of clinical nutrition, 67(1), 64–70. https://doi.org/10.1038/ejcn.2012.178
- Stabler, S. N., et al. (2012). Garlic for the prevention of cardiovascular morbidity and mortality in hypertensive patients. Cochrane Database of Systematic Reviews. DOI: 10.1002/14651858.CD007653.pub2
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Dr. Romi Fung, ND, M.Sc, Ph.D (cand.) is a naturopathic physician practicing in Richmond, BC. A graduate of the Canadian College of Naturopathic Medicine, Romi helps patients living with dementia improve their quality of life by taking an integrative and functional approach; he believes that what happens in the body can also happen in the brain and there are several biochemical connections from chronic diseases correlated to cognitive decline. On top of his practice, Romi is currently a Ph.D. candidate in Aging and Health at Queen’s University, an Adjunct Clinical Faculty, and Academic Faculty teaching Traditional Asian Medicine at the Canadian College of Naturopathic Medicine – Boucher Campus. DrRomiFungND.com
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