The Plant Rx

Your resource for a plant-based diet

Archive for the ‘Alzheimer’s Disease’ Category

How does a plant-based diet prevent disease? A short lesson

Posted by Jenn on January 31, 2011


There is an ever-growing mountain of evidence substantiating the numerous health benefits that a plant-based diet provides.

This colorized scanning electron micrograph (SEM) of red blood cells in an artery shows a layer of endothelial cells (beige) surrounded by muscle (pink). by: Steve Gschmeissner / Photo Researchers Inc.

Peer-reviewed medical paper after peer-reviewed medical paper published in the most well-respected of journals have shown that a plant-based diet free of meat and dairy products is the single most powerful tool we have at our disposal to prevent and fight disease.

Not only can heart disease and diabetes be prevented but the disease progression can be stopped and reversed. If that wasn’t enough there is a multitude of research showing how the consumption of a plant-based diet’s can prevent cancer, dramatically reduce cancer recurrence rates, reduce cognitive impairment as we age (Alzheimer’s Disease and Dementia) and reduce osteoporosis in addition to a myriad of others. This being the case, how exactly does something as seemingly simple and low-tech as one’s diet manage to do these things?

The short answer is this: via a gas called nitric oxide which is produced by our endothelial cells.  The problem with this very brief explanation is that most people have never heard of nitric oxide, much less endothelial cells. Consequently, that probably isn’t going to help most people understand how the very important the daily decision to eat a plant-based diet is able to accomplish such incredible feats.

What the heck are endothelial cells? and what the heck is Nitric Oxide (NO)? and how do they accomplish the mammoth task of keeping us healthy?

Endothelial cells are the thin single-layer of cells that line the interior surface of all blood vessels.  They are the cells that come in direct contact with blood flowing through our cardiovascular system.  A “healthy” endothelium can be best described as having like a Teflon coating on the vessels’ inner walls; this non-sticky quality enhancing the flow of blood.  An “unhealthy” endothelium, by contrast, acts like Velcro, grabbing white blood cells, platelets and cholesterol and packing them against the inner wall of the blood vessels narrowing them = causing the vessels to thicken over time, thereby inhibiting the flow of blood. This accumulation of “material” leads to the formation of  what are called atherosclerotic “plaques”.

healthy vs unhealthy endothelium

A healthy endothelium is not being covered by any plaque and therefore has the ability to release many beneficial substances into the blood stream.  An unhealthy endothelium  eventually narrows and thickens and resultantly loses flexibility.  The vessels can no longer expand as they should when the heart pumps blood through them. Pumping blood into stiff arteries containing plaque increases resistance to blood flow causing the heart to work harder. Your blood pressure must increase to pump the same volume of blood through these vessels.

That being said, what then determines the overall health of our endothelial cells that make up our endothelium? In other words what makes our endothelium non-stick or sticky?

That is where Nitric Oxide (NO) comes in. Remember, a healthy endothelium is able to release many beneficial substances into our blood stream.  (Note: we are born with a very healthy endothelium which means until we create an environment in which plaques are created, our vessels are healthy, slick and without plaque)  Nitric oxide is one of these substances.  Nitric oxide has a number of important functions.  One of its primary functions according to Dr. Louis J. Ignarro, the 1998 Nobel Prize winner in Medicine,

“…is to help keep the arteries and veins free of the plaque that causes stroke and to maintain normal blood pressure by relaxing arteries, thereby regulating the rate of blood flow and preventing coronaries (heart attacks)”.

He goes on to explain that,

“Nitric oxide is the body’s natural cardiovascular wonder drug”.

NO accomplishes this by controlling muscle tone of the blood vessels which directly impacts blood pressure control, inhibiting the aggregation of platelets and other particulate such as cholesterol and white blood cells.

Other functions worthy of note include: facilitation of proper kidney function, aiding in the transmission of messages between nerve cells, helping the immune system fight  viral, bacterial and parasitic infections as well as tumors, peristalsis, regulating inflammation, lowering of cholesterol levels and penile erection. Let’s discuss one of these functions in more detail to illustrate.

For example, erection of the penis during sexual excitation is mediated by NO release from the endothelial cells lining the blood vessels of the penis.  The NO release from the endothelial cells cause the blood to pool in the adjacent blood sinuses producing an erection.  Thus, if NO cannot be produced (or produced in sufficient amounts) as the result of a damaged endothelium, then an erection cannot occur. This is why difficulty getting or maintaining an erection is indicative of impending or active heart disease (= ample accumulation of plaque).  If you are currently experiencing impotence, it would be a very good idea to see your doctor such that he or she can discern the cause.

How a poor diet results in poor erections

Causes of endothelial damage  and resultant plaque formation:

  • Smoking – it decreases good cholesterol (HDL) and increases bad cholesterol (LDL) that damages your endothelial cells. Further, nicotine directly damages endothelial cells and the carbon monoxide from cigarette smoke damages the endothelium too.
  • A high fat, high cholesterol diet (particularly animal fat from meat and dairy products; plants do NOT have cholesterol) – LDL directly damages endothelial cells.
  • A diet low in fiber content (animal products do NOT contain any fiber) – High fiber foods absorb bile salts that your body uses in digestion.  Your liver manufactures bile from cholesterol.  Thus, high fiber foods are a natural way to reduce bad (LDL) cholesterol.
  • Diabetes – When blood sugars are beyond the normal range it causes oxidative stress to the endothelial cells resulting in damage to them.
  • Being overweight or obese – Fat cells store vitamin D and vitamin D inhibits vessel calcification (plaques eventually get harder as a result of calcification). Thus, losing weight or being at a healthy weight keeps the vitamin D in your system allowing for utilization thereby preventing plaque calcification. Read the rest of this entry »

Posted in Alzheimer's Disease, Cancer Prevention, Cholesterol, Dementia, Depression, Diabetes, Heart Disease, In the Media, Inflammation, Stroke, Women's Health | Tagged: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , | 3 Comments »

Study: Alzheimer’s May Have Same Cause As Heart Disease, Animal-Based Diet

Posted by Jenn on December 25, 2010


Drawing comparing how a brain of an Alzheimer ...

Image via Wikipedia

Blood vessel dysfunction linked to heart disease also impacts Alzheimer’s
American Heart Association Rapid Access Journal Report
Study Highlights:
  • A blood vessel dysfunction linked to cardiovascular disease seems to also play a role in Alzheimer’s disease.
  • The dysfunction may help account for the buildup of amyloid plaques in the brains of Alzheimer’s patients.

DALLAS, Dec. 2, 2010 — A dysfunction in the lining of blood vessels that is linked to cardiovascular illness also appears to play a role in the development of Alzheimer’s disease, according to a study published in Circulation Research: Journal of the American Heart Association.

Alzheimer’s disease is a progressive brain condition that typically affects people age 60 and older, depriving them of memory, reasoning and other cognitive skills. As many as 5 million Americans have Alzheimer’s, according to the National Institutes of Health.

Two distinct anomalies in the brain are hallmarks of Alzheimer’s: neurofibrillary tangles, twisted fibers composed primarily of a protein called tau that arise inside nerve cells, or neurons; and amyloid plaques, a buildup between neurons of protein fragments called amyloid beta peptides.

Previous research has found that people with multiple cardiovascular risk factors are also at greater risk for Alzheimer’s. A central feature of those cardiovascular risk factors is a nitric oxide deficiency in the endothelium, the layer of cells lining the blood vessels. Nitric oxide is crucial in vasodilation — the widening of blood vessels — which improves blood flow and the delivery of oxygen and nutrients to surrounding tissue.

“If you look at any risk factor for cardiovascular disease — the standard risk factors like high cholesterol, diabetes, hypertension, smoking, sedentary lifestyle, aging — all of these have been associated with loss of nitric oxide in the endothelium, a condition known as endothelial dysfunction,” said Zvonimir S. Katusic, M.D., Ph.D., senior author of the study and a professor of anesthesiology and pharmacology at the Mayo Clinic in Rochester, Minn.

In the study, the researchers tested whether endothelial dysfunction also plays a role in Alzheimer’s disease. Using endothelial cells from microscopic blood vessels in the human brain, the scientists chemically inhibited eNOS (endothelial nitric oxide synthase), an enzyme involved in nitric oxide production.

Inhibition of eNOS triggered a series of biochemical effects that led to an increase in the production of amyloid precursor protein (APP), the raw material for the amyloid plaques seen in the brains of Alzheimer’s patients.

The quantity and activity of BACE1 also increased. BACE1 is an enzyme that cleaves APP to create the amyloid beta peptides that make up the plaques.

“Once you lose that basal nitric oxide, you see the increases in APP and BACE1, and the increase in amyloid beta generation,” said Susan Austin, Ph.D., first author of the study and a postdoctoral research fellow at the Mayo Clinic.

The research team also studied tiny blood vessels in the brains of mice that had been genetically engineered to lack the eNOS enzyme. Those mice — which naturally have higher blood pressure and are prone to insulin resistance compared with normal mice — had about a 50 percent reduction in nitrates and nitrites which indirectly reflect nitric oxide production. The eNOS-deficient mice also showed higher levels of amyloid beta peptide in the brain, along with more APP and BACE1.

The study suggests that preserving a healthy blood vessel wall is important in preventing cognitive impairment and ultimately Alzheimer’s disease, Katusic said. “On the cardiovascular side we’ve known for some time that preservation of healthy endothelium is critical to prevent major cardiovascular events. Now it seems this may have important implications for cognitive impairment.”

The research could help explain, for instance, how exercise benefits cardiovascular health and the aging brain, Katusic said. Previous research has shown that exercise can delay or prevent cognitive impairment.

“There is a lot of literature showing that every time you exercise, you stimulate the endothelium to produce more nitric oxide,” Katusic said. “What we have identified in this paper may help explain the reported (cognitive) benefit of exercise.”

This study was funded by the National Institutes of Health, the Mayo Alzheimer’s Disease Research Center, an American Heart Association Scientist Development Grant, Clinical Pharmacology Training Grant and The Mayo Foundation.

Posted in Alzheimer's Disease, Heart Disease, In the Media | Tagged: , , , , , , , , , , | 1 Comment »