“Getting to the Heart of Alzheimer Disease” is the title of a recent publication that connects brain and heart health in a very interesting way. For years, researchers have detected a connection between heart and cognitive health changes but weren’t able to identify many details. Considerable insight is now coming to light. Rates for Alzheimer’s disease and congestive heart failure continue to markedly rise. For the millions of Baby Boomers and consecutive generations, this is now the time to support healthy heart function to protect the brain.
Heart Failure and Alzheimer’s Disease Linked
When we think about the heart and adverse changes, heart attack, atherosclerosis, atrial fibrillation, and congestive heart failure are some concerns that usually come to mind. In Western thinking, heart health is often viewed from only a heart muscle and circulatory system perspective.
Likewise, loss of brain health and neurodegenerative changes seen in Alzheimer’s disease is customarily viewed in isolation of a brain only disease. There is more to congestive heart failure and Alzheimer’s dementia than only the changes observed within the confines of that particular organ system.
This new study published early January 2019 in the journal Circulation Research suggests a link between the heart and brain in patients with Alzheimer’s disease. Build-up of damaging amyloid beta deposits occur in both parts of the body as a result of reduced blood flow.
Congestive heart failure (CHF) and Alzheimer’s disease (AD) dementia in the elderly were previously thought to coexist as two separate disorders in the same person. Similar risk factors such as obesity, diabetes, and age overlap, but research shows us that it is more than that. Diminished blood flow changes, oxidative stress, and inflammation, stiffening of tissues, and decreased perfusion or oxygenation of tissues link these two disorders.
Diminished Blood Flow Theory
Nearly 25 years ago, researchers discovered that in the brains of patients with Alzheimer’s disease there were changes in very small blood vessels that led to decreased blood flow and perfusion throughout the brain. As research has progressed, the breakdown process is more fully understood.
It is now understood that brain perfusion is decreased by an estimated 20 percent in patients with Alzheimer’s disease. This is a significant issue as it results in diminished metabolism, adverse blood sugar metabolism, reduced oxygen exposure, and increased inflammation within the brain.
This in turn results in increased oxidative stress and a build-up of lactic acid within the brain. Mitochondria within the blood vessels and nerves become damaged from reactive oxygen species (ROS) free radicals. Subsequently, build-up of amyloid beta occurs and nerves become progressively damaged beyond repair and brain function deteriorates. The process continues and affects the blood brain barrier making it more permeable. Loss of the protective blood brain barrier allows toxins and inflammatory by-products from the brain inflammation to enter circulation in the body. All of these changes are thought to occur because of decreased blood flow in the brain.
Atherosclerosis, Blood Pressure, and Elevated Blood Sugar
It was historically thought that diminished blood flow in the brain was primarily due to atherosclerosis with thickening and stiffening blood vessels in the brain and elevated blood pressure. Additional factors that are now known to cause substantial reduction in blood flow to the brain are diabetes, high and low blood pressure, and aging.
Of these concerns, hypertension (high blood pressure) is currently considered the most problematic vascular risk factor for late onset Alzheimer’s disease. High blood pressure leads to tiny infarcts or injuries within brain blood vessels along with lack of blood flow in the brain and ultimately a build-up of tau proteins and amyloid beta.
Damaging Effects of Diminished Blood Flow from Heart to Brain
The recent findings in the January 2019 study expanded the picture of Alzheimer’s disease and amyloid beta build-up with diminished blood flow related with diastolic congestive heart failure. In this picture, diastolic heart failure and its weakened ability to pump blood leads to decreased blood flow in the brain. It was followed by decreased metabolism, toxic waste build-up, oxidative stress and inflammation in the brain that leads to neurodegeneration.
Investigation of brain tissues in patients with Alzheimer’s disease and heart failure (myocardial diastolic dysfunction), researchers found accumulation of several damaging proteins in both tissues. Ultimately, heart failure is thought to worsen brain inflammation and plaque build-up due to the impaired blood flow and oxidative stress stemming from changes in heart function.
In addition, elevated blood sugar adds layers of damages to the heart, brain, and blood vessels in the brain. There is also some evidence of increased genetic risk that are similar in both Alzheimer’s disease and congestive heart failure. Due to the diminished circulation in the brain and heart function, adverse blood brain barrier changes, and how cellular trash is managed, there is now evidence that amyloid beta can also build up not only in the heart, but also in the large intestine, skin, and muscles of Alzheimer’s patients.
There are different types of heart failure. Regarding Alzheimer’s and heart failure, research is focused on diastolic dysfunction. Diastolic congestive heart failure occurs when part of the heart is unable to accept blood return from another part of the heart in a normal manner and results in impaired relaxation of the heart, or stiffening of tissues. With this disorder, there are four grades of dysfunction. Grade I is considered a "normal" finding as it is found in nearly all adults by age of 60. Hopefully, this information provides incentive to support heart and brain health to those approaching 60 or who are already that age and older.
A weak or failing heart is thought to activate or worsen brain stress because of diminished blood flow to the brain. Changes in diastolic heart function may lead to fatigue, shortness of breath with activity and a night with lying down, fluid retention and an increased heart rate. These symptoms may be found with other disorders too.
Common causes of diastolic dysfunction and heart failure include aging, decreased blood flow to the heart or ischemia, high blood pressure, obesity, and stiffening and narrowing of the aorta. Even low diastolic blood pressure may be problematic.
Other things can trigger diastolic dysfunction including anemia, fever, infection, excess salt, and NSAIDs/non-steroidal anti-inflammatory drugs such as ibuprofen, Motrin, Aleve, etc. Considering how prevalent iron deficiency anemia is or how many millions of individuals use NSAIDs on a regular basis, this too should provoke desire to healthfully support the heart and brain. Quality of life in the senior years will depend significantly on what you do in the decades prior.
Take Away Points
Many times, it is easier to understand complex things when they are looked at from an isolated view. This is a classical Western medicine approach. However, your body is intimately connected with one part affecting another part. In this case, we see a small aspect of the heart-brain connection and what happens as a result of impaired blood flow either stemming from the heart or in the brain.
The heart and brain are both high energy organs. They require critical levels of oxygen, nutrients, and antioxidants to support daily function. Mitochondria are at the “heart” of support for the brain and heart. Mitochondria are directly involved with energy production and oxygen usage.
Physical activity and healthy blood sugar levels throughout life are imperative for brain and heart health. Now more than ever with today’s food supply, it is easy to indulge in more sugar and simple carbohydrates than we realize. These foods contribute to the stiffening of tissues. Modern diets are either void of nutrient dense foods or cause an increased need of critical minerals and vitamins necessary for brain and heart function. Extra fiber like oat bran fiber may be needed to assist healthy cholesterol metabolism and blood sugar regulation.
Cleaning up the brain from daily wear and tear depends on healthy glymphatics (glial cells + lymphatics). You may learn more about this in the article Glymphatics: Keeping the Brain’s Waste Removal System Healthy. Also note that when there is increased blood barrier permeability, it is also likely present in the intestinal tract. When it happens in the gut, it is known as leaky gut syndrome.
Alzheimer’s disease and heart disease concerns don’t happen overnight. They take years, decades to develop before the full-blown disease presentation occurs. What you do now to keep your circulation, brain, heart, blood pressure, and metabolism healthy is vital for aging well into the future. You may find these additional articles helpful.