Role of Mercury Toxicity in Hypertension, Cardiovascular Disease, and Stroke

Dr. Mark C. Houston is Associate Clinical Professor of Medicine at Vanderbilt University School of Medicine and Director of the Hypertension Institute at Saint Thomas Hospital in Nashville, TN. He has written an important review article on the cardiovascular consequences of mercury exposure in humans. The article discusses how mercury toxicity in humans is related to hypertension, generalized atherosclerosis, coronary heart disease (CHD), myocardial infarction (MI), cardiac arrhythmias, heart rate variability, sudden death, cerebrovascular accidents (CVA), carotid artery disease, renal dysfunction, and total mortality.

 

Mark C. Houston

Role of Mercury Toxicity in Hypertension, Cardiovascular Disease, and Stroke
J Clin Hypertens (Greenwich) 2011; 13 (8): 621-7

 

ABSTRACT

Mercury has a high affinity for sulfhydryl groups, inactivating numerous enzymatic reactions, amino acids, and sulfur-containing antioxidants (N-acetyl-L-cysteine, alpha-lipoic acid, L-glutathione), with subsequent decreased oxidant defense and increased oxidative stress. Mercury binds to metallothionein and substitute for zinc, copper, and other trace metals, reducing the effectiveness of metalloenzymes. Mercury induces mitochondrial dysfunction with reduction in adenosine triphosphate, depletion of glutathione, and increased lipid peroxidation. Increased oxidative stress and reduced oxidative defense are common. Selenium and fish containing omega-3 fatty acids antagonize mercury toxicity. The overall vascular effects of mercury include increased oxidative stress and inflammation, reduced oxidative defense, thrombosis, vascular smooth muscle dysfunction, endothelial dysfunction, dyslipidemia, and immune and mitochondrial dysfunction. The clinical consequences of mercury toxicity include hypertension, coronary heart disease, myocardial infarction, cardiac arrhythmias, reduced heart rate variability, increased carotid intima-media thickness and carotid artery obstruction, cerebrovascular accident, generalized atherosclerosis, and renal dysfunction, insufficiency, and proteinuria. Pathological, biochemical, and functional medicine correlations are significant and logical. Mercury diminishes the protective effect of fish and omega-3 fatty acids. Mercury inactivates catecholaminei-0-methyl transferase, which increases serum and urinary epinephrine, norepinephrine, and dopamine. This effect will increase blood pressure and may be a clinical clue to mercury-induced heavy metal toxicity. Mercury toxicity should be evaluated in any patient with hypertension, coronary heart disease, cerebral vascular disease, cerebrovascular accident, or other vascular disease. Specific testing for acute and chronic toxicity and total body burden using hair, toenail, urine, and serum should be performed.

 

Study Shows Soy Protein Reduced Progression Of Clogged Arteries In Women Within 5 Years Of Menopause

This large scale, first-of-a-kind study will be published in the November issue of Stroke

A new study published in the November 2011 issue of Stroke reveals some promising data on the positive effects of soy protein reducing the progression of clogged arteries in women who were within five years of menopause. This study was the largest and longest randomized controlled human study conducted to-date that directly investigated the efficacy of isolated soy protein consumption on the progression of atherosclerosis (lipid deposition in the artery walls).

“These results are consistent with what we have learned through research conducted over the past decade,” said Howard N. Hodis, MD, USC Keck School of Medicine and lead author of the study. “The literature demonstrates that there is a ‘window of opportunity’ of a potential beneficial effect on coronary heart disease for products that bind to the estrogen receptor including hormone-replacement therapy, soybean isoflavones or selective estrogen receptor modulators (SERMs) when initiated in women within 5-6 years of menopause.”

The progression rate of carotid artery intima-media thickness (CIMT) trended to be 16 percent lower on average in the isoflavone-containing soy protein group compared with the placebo group. However, in women who had experienced menopause within the past five years, isolated soy protein consumption was associated with a significant 68 percent reduction in CIMT progression compared to those consuming the placebo.

Excellent compliance was observed for this study as determined by package and bar count (86.5 percent for placebo and 91.0 percent for isolated soy protein). Compliance was confirmed by plasma and urine isoflavone measurements.

“The high compliance suggests that the clinical study products provided by Solae were very palatable and were not associated with any significant adverse effects as confirmed by the data,” said Elaine Krul, PhD, nutrition discovery lead, Solae.

Subjects in this study were ‘healthy’ with no previous signs of cardiovascular disease which may explain the lack of significant reduction in plasma lipids that is seen in persons with higher plasma lipid levels.

“This study also showed a significant increase in HDL (“the good”) cholesterol in participants consuming isolated soy protein,” said Krul. “The results of this study reinforce that soy protein can provide health benefits for the healthy aging market segment.”

 

Reference

Hodis HN, Mack WJ, Kono N, Azen SP, Shoupe D, Hwang-Levine J et al; for the Women’s Isoflavone Soy Health Research Group. Isoflavone Soy Protein Supplementation and Atherosclerosis Progression in Healthy Postmenopausal Women: A Randomized Controlled Trial. Stroke 2011 Sep 8. [Epub ahead of print]

 

Forks Over Knives

What has happened to us? Despite the most advanced medical technology in the world, we are sicker than ever by nearly every measure. Cases of diabetes are exploding, especially amongst our younger population. About half of us are taking at least one prescription drug and major medical operations have become routine.  Heart disease, cancer and stroke are the three leading causes of death in the USA, even though billions are spent each year to “battle” these very conditions.  Millions suffer from a host of other degenerative diseases.

Could it be there’s a single solution to all of these problems? A solution so comprehensive but so straightforward, that it’s mind-boggling that more of us haven’t taken it seriously?

Forks Over Knives (2010) examines the profound claim that most, if not all, of the socalled “diseases of affluence” that afflict us can be controlled, or even reversed, by rejecting our present menu of animal-based and processed foods.  The major storyline in the film traces the personal journeys of Dr. T. Colin Campbell, a nutritional scientist from Cornell University, and Dr. Caldwell Esselstyn, a former top surgeon at the world renowned Cleveland Clinic.

Inspired by remarkable discoveries in their young careers, these men conducted several groundbreaking studies, one of which took place in China and is considered among the most comprehensive health-related investigations ever undertaken.  Their separate research led them to the same startling conclusion: degenerative diseases like heart disease, type 2 diabetes, and even several forms of cancer, could almost always be prevented—and in many cases reversed—by adopting a whole foods, plant-based diet. Despite the profound implications of their findings, their work has remained relatively unknown to the public.

In addition, cameras follow “reality patients” who have chronic conditions from heart disease to diabetes.  Doctors teach these patients how to adopt a whole foods plantbased diet as the primary approach to treat their ailments—while the challenges and triumphs of their journeys are revealed.

The film features leading experts on health and tackles the issue of diet and disease in a way that will have people talking for years. Read More

 

Watch the full documentary

Beyond Pills: Cardiologists Examine Alternatives To Halt High Blood Pressure

Mistletoe

More and more, patients show up to appointments with hypertension expert John Bisognano, M.D., Ph.D. carrying bags full of “natural” products that they hope will help lower their blood pressure. And like most physicians, Bisognano doesn’t always know if these products will do any good, or if they will cause any harm.

“Right now we’re seeing a cultural shift where an increasing number of people want to avoid standard pharmaceuticals,” said Bisognano, professor of Medicine and director of Outpatient Cardiology at the University of Rochester Medical Center. “We’re also seeing a growing number of patients who require a large number of drugs to control their blood pressure and are looking for something else to help manage it.”

In an effort to better educate health care professionals and patients, Bisognano and Kevin Woolf, M.D., a cardiology fellow at the Medical Center, conducted the most comprehensive review to date of the evidence behind a wide range of non-drug interventions for the treatment of high blood pressure. The review is featured in the September 2011 issue of the Journal of Clinical Hypertension.

Kevin Woolf, M.D.

Woolf said there is not enough data to recommend any of these alternative options on a routine basis, but on an individual basis he thinks they are useful. “Patients have different backgrounds and different approaches to living their lives,” said Woolf. “This is where the art of medicine comes in; getting to know patients and what they will and will not embrace can help physicians identify different therapies that suit their patients’ habits and that will hopefully make a difference for them.”

Woolf and Bisognano, who is a member of the editorial board of the Journal of Clinical Hypertension, emphasize that all patients with hypertension should adhere to the low-salt DASH diet, which is high in fiber, low in fats and incorporates lots of fruits and vegetables, and follow an exercise and weight loss regimen – lifestyle modifications recommended by the American Heart Association. Any alternative options should be considered for use in addition to these lifestyle changes.

Acupuncture

When it comes to safety, Bisognano adds, “These alternative options are usually harmless, except when they keep patients from taking medications they need to take. If a patient is taking a supplement instead of something that we know is useful, that could be a problem.”

Dietary Supplements

The shining star among supplements is coenzyme Q10, an enzyme involved in energy production that also acts as an antioxidant. Patients with hypertension tend to have lower levels of the enzyme, and a meta-analysis – an overarching analysis of past studies – found that treatment with coenzyme Q10 supplements significantly reduced blood pressure.

John Bisognano, M.D., Ph.D.

Woolf noted that “Coenzyme Q10 has a pretty profound effect on blood pressure, but whenever research is based on a collection of other data you have to have some skepticism.” Woolf said he still thinks the compound is promising.

Woolf also found that potassium helps lower blood pressure, and there is evidence that increasing the amount of potassium we get through the foods we eat could carry some of the same mild benefits as taking supplements.

Herbal Remedies

The potential herbal remedies Woolf identified include mistletoe extract, used in traditional Chinese medicine to treat hypertension. Mistletoe extract reduced blood pressure in animal studies, but Woolf cautions that it may be toxic at high doses. The extract from Hawthorn, a type of tree, is also used, but provides only a slight reduction in blood pressure. Conversely, Woolf uncovered a handful of herbal remedies – St. John’s wort, ephedra/ma huang, yohimbine and licorice – that may increase blood pressure.

Woolf and Bisognano stress that the Food and Drug Administration does not regulate dietary and herbal supplements the way they regulate traditional pharmaceuticals. They say health care providers and patients need to be aware that the safety of these products is not always rigorously established and that formulations can vary.

Acupuncture/Meditation

Research on both practices is mixed – the types of patients included, the methods used, and the results, which vary from study to study. While there is no conclusive evidence that either lowers blood pressure, researchers found that acupuncture reduces blood pressure compared to placebo in patients also taking anti-hypertensive medications, while in a meta-analysis, transcendental meditation appeared to lower blood pressure. Other techniques that may provide some benefit include Zen Buddhist meditation and Qi Gong.

Devices

Some devices developed in recent years involve a medical procedure, while others use technology that requires patients to participate in various exercises.

Those that involve a procedure include the implantable Rheos® device, which regulates blood pressure much like a pacemaker regulates heart rhythm, and the Symplicity® catheter system, which ablates or destroys nerves around the kidneys that send inappropriate signals to the brain to increase blood pressure. Both are designed for patients with difficult-to-treat hypertension and led to significant drops in blood pressure in clinical trials. They are only available to research participants at this time.

Two devices that patients can use in the comfort of their own homes are the RESPeRATE breathing device and the Zona Plus hand drip device. The RESPeRATE system uses a breath sensor and gives patients feedback through headphones to help them slow their breathing, which research suggests benefits blood pressure. If used 15 minutes a day, studies show RESPeRATE leads to a modest decrease in hypertension.

The Zona Plus is a device that patients grip in either hand and perform multiple sets of squeezing at different levels in response to electronic cues. Bisognano says there is no good explanation as to why this works, but studies found the device decreased hypertension in patients using it three days a week for at least eight weeks. Patients can buy both devices for between $300 and $400, and Bisognano suggests them to interested patients.

 

It’s Official — Chocolate Linked To Heart Health

Chocolate consumption and cardiometabolic disorders: systematic review and meta-analysis.

High levels of chocolate consumption might be associated with a one third reduction in the risk of developing heart disease, finds a study published on bmj.com.

The findings confirm results of existing studies that generally agree on a potential beneficial link between chocolate consumption and heart health. However, the authors stress that further studies are now needed to test whether chocolate actually causes this reduction or if it can be explained by some other unmeasured (confounding) factor.

The World Health Organisation predicts that by 2030, nearly 23.6 million people will die from heart disease. However, lifestyle and diet are key factors in preventing heart disease, says the paper.

A number of recent studies have shown that eating chocolate has a positive influence on human health due to its antioxidant and anti-inflammatory properties. This includes reducing blood pressure and improving insulin sensitivity (a stage in the development of diabetes).

However, the evidence about how eating chocolate affects your heart still remains unclear. So, Dr Oscar Franco and colleagues from the University of Cambridge carried out a large scale review of the existing evidence to evaluate the effects of eating chocolate on cardiovascular events like heart attack and stroke.

They analysed the results of seven studies, involving over 100,000 participants with and without existing heart disease. For each study, they compared the group with the highest chocolate consumption against the group with the lowest consumption. Differences in study design and quality were also taken into account to minimise bias.

Five studies reported a beneficial link between higher levels of chocolate consumption and the risk of cardiovascular events and they found that the “highest levels of chocolate consumption were associated with a 37% reduction in cardiovascular disease and a 29% reduction in stroke compared with lowest levels.” No significant reduction was found in relation to heart failure.

The studies did not differentiate between dark or milk chocolate and included consumption of chocolate bars, drinks, biscuits and desserts.

The authors say the findings need to be interpreted with caution, in particular because commercially available chocolate is very calorific (around 500 calories for every 100 grams) and eating too much of it could in itself lead to weight gain, risk of diabetes and heart disease.

However, they conclude that, given the health benefits of eating chocolate, initiatives to reduce the current fat and sugar content in most chocolate products should be explored.

 

Reference

Buitrago-Lopez A, Sanderson J, Johnson L, Warnakula S, Wood A, Di Angelantonio E, Franco OH. Chocolate consumption and cardiometabolic disorders: systematic review and meta-analysis. BMJ 2011; 343: d4488.

 

Fructose Consumption Increases Risk Factors for Heart Disease

Study suggests U.S. Dietary Guideline for Upper Limit of Sugar Consumption is too High:

A recent study accepted for publication in The Endocrine Society’s Journal of Clinical Endocrinology & Metabolism (JCEM) found that adults who consumed high fructose corn syrup for two weeks as 25 percent of their daily calorie requirement had increased blood levels of cholesterol and triglycerides, which have been shown to be indicators of increased risk for heart disease.

The American Heart Association recommends that people consume only five percent of calories as added sugar. The Dietary Guidelines for Americans 2010 suggest an upper limit of 25 percent or less of daily calories consumed as added sugar. To address this discrepancy in recommended consumption levels, researchers examined what happened when young overweight and normal weight adults consumed fructose, high fructose corn syrup or glucose at the 25 percent upper limit.

“While there is evidence that people who consume sugar are more likely to have heart disease or diabetes, it is controversial as to whether high sugar diets may actually promote these diseases, and dietary guidelines are conflicting,” said the study’s senior author, Kimber Stanhope, PhD, of the University of California, Davis. “Our findings demonstrate that several factors associated with an elevated risk for cardiovascular disease were increased in individuals consuming 25 percent of their calories as fructose or high fructose corn syrup, but consumption of glucose did not have this effect.”

In this study, researchers examined 48 adults between the ages of 18 and 40 years and compared the effects of consuming 25 percent of one’s daily calorie requirement as glucose, fructose or high fructose corn syrup on risk factors for cardiovascular disease. They found that within two weeks, study participants consuming fructose or high fructose corn syrup, but not glucose, exhibited increased concentrations of LDL cholesterol, triglycerides and apolipoprotein-B (a protein which can lead to plaques that cause vascular disease).

“These results suggest that consumption of sugar may promote heart disease,” said Stanhope. “Additionally our findings provide evidence that the upper limit of 25 percent of daily calories consumed as added sugar as suggested by The Dietary Guidelines for American 2010 may need to be re-evaluated.”

Also working on the study were: Andrew Bremer, Guoxia Chen, Tak Hou Fong, Vivien Lee, Roseanne Menorca, Valentia Medici, Peter Havel and Nancy Keim of the University of California, Davis; Katsuyuki Nakajima and Takamitsu Nakano of Otsuka Pharmaceutical Co. in Tokyo, Japan; and Yasuki Ito of Denka Seiken Co. in Tokyo, Japan.

The article, “Consumption of fructose and high fructose corn syrup increase postprandial triglycerides, LDL-cholesterol, and apolipoprotein-B in young men and women,” appears in the October 2011 issue of JCEM.

 

Indoor Air Pollution Linked To Cardiovascular Risk

An estimated two billion people in the developing world heat and cook with a biomass fuel such as wood, but the practice exposes people — especially women — to large doses of small-particle air pollution, which can cause premature death and lung disease.

Read More