~ Mainstream Doctors Still Confused About Homocysteine
By William Faloon
Two months ago, the New England Journal of Medicine published two studies showing that moderately lowering homocysteine blood levels did not reduce heart attack risk in those with existing cardiac or vascular disease.
The following statement was made in an editorial that accompanied these two articles:
“. . . the results lead to the unequivocal conclusion that there is no clinical benefit to the use of folic acid and vitamin B12 (with or without vitamin B6) in patients with established vascular disease.”1
The media then boldly proclaimed:
“Hope Abandoned for Benefit to Lowering Homocysteine” Contrary to these negative opinions, the two studies in the New England Journal of Medicine confirm what Life Extension long ago published about vascular disease and what steps are required to achieve optimal homocysteine control.
As a reader of Life Extension magazine, you have a front row seat to a raging debate that could very well affect how many Americans will develop heart disease, stroke, osteoporosis, Alzheimer’s disease, blindness, depression, and other disorders associated with excess homocysteine.
Homocysteine was first theorized to cause vascular disease when autopsy results of young people revealed atherosclerotic plaque in those with very high homocysteine levels. Over a 37-year period, doctors uncovered startling evidence linking elevated homocysteine to increased risks of heart attack,2-36 stroke,37-50 and other disorders in aging adults.
In addition to human epidemiological data, scientists have identified specific mechanisms by which homocysteine causes the most common age-related diseases. One of the New England Journal of Medicine authors summed up these toxic mechanisms by stating:
“ . . . homocysteine is an atherogenic determinate that promotes oxidant stress, inflammation, thrombosis, endothelial dysfunction, and cell proliferation.”1
Based on the description above, excess homocysteine would appear to be linked to virtually every human degenerative disease. If this is the case, then why did the same author state that reducing homocysteine had no effect in preventing heart attack?
Homocysteine May Not Have Been Reduced Enough
Scientific studies dating back to the early 1990s indicate that optimal homocysteine levels should not exceed 9-10 micromoles per liter (µmol/L),51 and ideally should be even lower than that, perhaps under 7 µmol/L for optimal risk reduction.52
One epidemiological study demonstrated that homocysteine levels above 10 µmol/L are associated with an increase in heart attack risk.22 Another study showed that homocysteine levels as low as 9 carry long-term danger, with cardiac risk escalating more sharply when homocysteine levels are at 15 or greater.17 Still another (Japanese) study showed that those with a homocysteine level below 7 were much less likely to suffer a stroke than patients with homocysteine levels higher than 11.51
The New England Journal of Medicine recently published two studies showing no benefit to lowering homocysteine in those with pre-existing vascular disease. In the first study, baseline homocysteine levels of 12.2 µmol/L were reduced to a mean of 9.7 over a two-year period. Study participants in the active group were given one daily supplement that consisted of 2.5 mg of folic acid, 1 mg of vitamin B12, and 50 mg of vitamin B6.53
In the second New England Journal of Medicine study, the baseline homocysteine level of 13 µmol/L was reduced to a mean of 9.6 after three years. One active group in this study received only 40 mg of vitamin B6, while other groups received 0.8 mg of folic acid and 0.4 mg of B12 with and without 40 mg of B6.54
Life Extension long ago advocated that members take aggressive steps to keep homocysteine levels below 7-8 µmol/L.55-57 The rationale was based on an extrapolation of the existing published studies relating to homocysteine blood levels and heart attack risk.
For instance, an earlier study17 in the New England Journal of Medicine looked at mortality in coronary artery disease patients and found the following: As the table above shows, homocysteine blood levels between 9 and 15 µmol/L doubled mortality rates compared to values less than 9, while homocysteine above 15 increased mortality by an astounding 6.47 times compared to levels below 9!
The two recent studies published in the New England Journal of Medicine failed to reduce homocysteine to the levels that the Life Extension Foundation long ago stated were needed to reduce heart attack risk. In fact, these two recent studies failed to reduce homocysteine to the less than 9 µmol/L level that had previously been shown in the same medical journal to confer benefit.
The question still begs, however, as to why moderate homocysteine reduction did not result in at least some reduction in heart attack risk. The answers become obvious as the study’s design methods are uncovered.
Unhealthy Study Subjects
To participate in the first study that used modest doses of nutrients to moderately reduce homocysteine levels, one had to have “a history of vascular disease (coronary, cerebrovascular, or peripheral vascular) or diabetes and additional risk factors for atherosclerosis.”
To qualify for the second study that used lower potencies of nutrients, participants had to first suffer “an acute myocardial infarction,” more commonly known as a heart attack, within seven days of enrollment in the study.
Based on the enrollment criteria, the study subjects had to have significant pre-existing vascular impairment in order to participate. In this article, you will read why the use of these unhealthy subjects virtually guaranteed that this study would fail. Next, however, we need to emphasize that. . .
Homocysteine Level and Coronary Artery Disease Risk
Logistic regression is a statistical tool used to understand data. In the chart above, logistic regression assumes that an increase anywhere along the curve for homocysteine values will have the same effect, regardless of baseline value. Using an additive model for logistic regression, the risk of cardiovascular disease is greater with homocysteine values at the upper end of the "normal" range compared to values at the lower end of the “normal” range. This risk (comparing the upper end of the “normal” range such as 13-15 µmol/L vs. the lower end of the “normal” range such as 7-8 µmol/L) is 4 to 5 times greater.
The Study Period Was Too Short!
Based on the enrollment criteria, the study subjects had already suffered significant arterial damage over most of their lifetime. The study design expectation was that within two or three years, taking modest doses of only three nutrients would somehow protect the test subjects against future vascular events.
Please note the word “within” when describing the study period. While the first study lasted two years and the second study lasted a little over three years, any participant who encountered a vascular event even one day after the study’s commencement was considered a statistic.
In other words, if a study participant suffered any kind of vascular disease after they took even one dose of B vitamins, then that person was listed as a “failure,” meaning that he or she filled a statistical column showing no benefit to B vitamins as far as this study was concerned.
Remember that these were high-risk participants with pre-existing vascular disease. It is absurd to expect that moderately lowering homocysteine within a very short time period would result in a miraculous disease reduction in these unhealthy individuals.
As any enlightened person knows, atherosclerosis does not develop overnight. Initial arterial lesions are sometimes seen in teenagers. The process of inner arterial wall degradation leading to atherosclerosis lasts for many decades. When one has pre-existing vascular disease—as was the case for most of these study subjects—the arteries are severely damaged and the risk of future arterial-related diseases is high.
For people with pre-existing arterial disease, protecting against a future heart attack or stroke requires extraordinary effort. Swallowing one modest-dose daily supplement after you have developed significant vascular disease is not going to do it!
Baseline Homocysteine Levels May Not Have Been High Enough
We discussed before that the two studies failed to adequately reduce homocysteine levels to optimal safe ranges. While that is one significant flaw, another defect in these two studies was that the subjects’ homocysteine levels were not particularly high to begin with.
To clarify this point, while some studies show that homocysteine levels above 7-9 µmol/L increase vascular disease risk, the most lethal effect occurs when levels exceed 13-15. The subjects chosen for these two studies had baseline homocysteine levels of 12.2 and 13 on average, which were reduced to 9.7 and 9.6, respectively. Existing data indicate that there may not have been much of a statistical difference between the study subjects’ baseline levels and their homo-cysteine levels two and three years later.
The following chart using data from a study published by the American Heart Association helps explain why the baseline homocysteine levels in these two studies may not have been high enough.58
As one can see, cardiac risk increases incrementally with rising homocysteine. Generally speaking, when the odds ratio exceeds 2.0 or 2.5 in epidemiology studies, scientists become concerned that risk increases. In this chart, a homocysteine level of about 13 µmo/L corresponds to an odds ratio of about 2.0 to 2.5. From the chart, the risk associated with a homocysteine level of 13-15 is 4 to 5 times greater compared to the risk associated with a homocysteine level of 7-8.It should be noted that this chart uses logistic regression to describe heart attack risk in relationship to increasing homocysteine levels.
Heart disease remains the number-one killer in the Western world, but the leading cause of disability is stroke.59,60 The paralyzing effects of stroke are often far more feared than a heart attack, and stroke is the third leading cause of death in the United States.61
Studies examining stroke incidence indicate that elevated homocysteine is a greater risk factor for stroke than it is for cardiac disease. In other words, even a modest increase in homocysteine is more likely to damage one’s brain than one’s heart.
The following table is based on data from the stroke study mentioned earlier51 and helps elucidate these startling findings.
As the table above clearly shows, while homocysteine levels below 7 µmol/L are ideal, a sharp increase in stroke incidence occurs when homocysteine levels exceed 11.51 This study helps corroborate Life Extension’s longstanding position that optimal homocysteine levels should be under 7-8 µmol/L.62-64
Other Cardiac Risk Factors Ignored
The design of these studies took into account conventional risk factors for vascular disease such as cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL), triglycerides, glucose, body mass index, and blood pressure. For example, the average fasting glucose level at baseline was 128.8 mg/dL in one group receiving the B vitamins and 125.7 mg/dL in the placebo group. Both groups clearly had poor glucose control (pre-diabetic, at a minimum).
The independent vascular disease risk factors that were ignored include C-reactive protein, fibrinogen, fasting insulin, hemoglobin A1C, and free testosterone. Imbalances of any one of these “other” risk factors would have almost certainly negated the benefit that would be expected from a modest reduction in homocysteine.
The evidence linking C-reactive protein to vascular disease risk is overwhelming.65-82 In one scientific study after another, elevated levels of C-reactive protein are shown to be strong independent markers for determining who is likely to suffer a heart attack or stroke. Without factoring in proven risk factors such as C-reactive protein (along with fibrinogen,83-93 free testosterone,94-97 and others), it is difficult to know whether more subjects in the B-vitamin group required additional therapies beyond modest homocysteine reduction.
Other than the most basic conventional medical interventions, study subjects continued following the unhealthy lifestyles that may have induced their vascular disease, including cigarette smoking and poor eating habits. It is quite a leap of faith for the designers of these studies to have expected that modest homocysteine reduction would overcome dangerous lifestyles that are proven to cause cardiovascular diseases.
10 Daggers of Arterial Disease
The 10 Daggers: Elevated C-reactive Protein, Excess LDL, Excess Insulin, Low HDL, High Glucose, Excess Triglycerides, Low Free Testosterone, Excess Fibrinogen, Excess Homocysteine, Hypertension.
Because unhealthy lifestyle choices and normal aging can damage arteries, the arterial system serves as an Achilles heel of health for millions of adults in modern Western societies.
In rare cases, arterial disease may have just one cause. An example is the severe atherosclerosis observed in children who suffer from a genetic defect that causes severe hyperhomocysteinemia. In these children, blood homocysteine levels can exceed 100 µmol/L, and they can die in early life from advanced systemic atherosclerosis.
For typical heart attack victims, however, multiple factors cause arterial disease. To elucidate this point, the image above depicts daggers aimed at a healthy heart. Any one of these daggers would kill if thrust deep into the heart. In the real world, however, aging humans suffer small pricks from the point of many of these daggers over a lifetime. Although none of the pricks by itself is enough to cause a heart attack, the cumulative effect of these dagger pricks (risk factors) is arterial occlusion and, far too often, angina or acute heart attack.
This Study Has Nothing to Do with Healthy People
Despite the media proclaiming that the homocysteine theory of vascular disease has been discredited, the fact is that the authors of the studies themselves state that the findings pertain only to those with existing vascular disease.
Nowhere in the studies do they suggest that healthy people seeking to prevent atherosclerosis may not benefit from reducing their homocysteine levels. The authors of all of the studies went to great length in explaining why homocysteine is such a dangerous amino acid.
In today’s world of sound bites, the message from a study of people with serious disease somehow is distorted into a news story that is supposed to pertain to those who do not even have the disease. For instance, we know that selenium does not cure cancer, but it certainly appears that it prevents certain cancers.98 The fact that selenium is not an effective cancer treatment does not mean that those seeking to prevent cancer should not take it.
These two studies showed that modest homocysteine reduction by itself did not prevent cardiac events in those with pre-existing disease. This has no relevance for those seeking to maintain healthy arterial function by keeping their homocysteine in the lower ranges before they develop severe arterial disease.
In fact, one of these same groups of researchers is initiating a five-year study of healthy individuals to ascertain whether modest homocysteine reduction lowers vascular disease risk. The headline-hungry media ignored the fact that homocysteine-lowering therapies are still being researched when proclaiming the homocysteine theory of arterial disease to be “dead.”
Cross-section of an artery demonstrating plaque.
Lethal Misconceptions About Atherosclerosis
The hottest buzzword in cardiovascular research today is endothelial dysfunction, a term that describes the structural and functional damage to the inner arterial wall that so often results in atherosclerosis.
Atherosclerosis is the cause of most heart attacks and strokes, yet many doctors still do not understand that this artery-blocking process is both initiated and accelerated via the destructive endothelial dysfunction process.
The inner lining of the arterial wall is made up of a thin layer of cells called the endothelium. The endothelium protects the smooth muscle in the middle wall of the artery from direct contact with the blood. The endothelial barrier is important to arterial health because many blood components are highly toxic to the artery’s smooth muscle (that lies directly beneath the endothelium). When these damaging blood components attack the artery’s smooth muscle, the process of atherosclerosis is initiated.
Among the blood components that are damaging to the inner lining of arteries are glucose,99,100 homocysteine,101-122 low-density lipoprotein (LDL),123-131 free radicals,109,132-136 and pro-inflammatory cytokines.4,137-147
To protect the artery’s elastic smooth muscle against these damaging agents, it is critical to maintain an intact and properly functioning endothelium.
The endothelium can be disrupted at an early age because of poor health habits such as cigarette smoking, poor diet, and nutrient deficiencies. The aging process itself results in endothelial dysfunction that can be caused by a number of known risk factors.
The inner wall of diseased arteries is a battleground where multiple pathological reactions take place. Endothelial dysfunction occurring in damaged arteries provides fertile soil for the seeds of atherosclerosis. To expect a modest reduction of homocysteine to reverse this devastating process—especially after cardiac disease has already manifested—flies in the face of all that has been learned about the underlying causes of heart attack, stroke, and other vascular diseases.
What Causes Endothelial Dysfunction?
High blood pressure,148-153 elevated LDL,123-31 low HDL,154-156 cigarette smoking,157-163 diabetes,164-169 obesity,170-172 and lack of exercise173-175 all contribute to endothelial dysfunction and the subsequent development of atherosclerosis.
Additional endothelial-damaging factors include excess glucose,99,100 insulin,176 iron,177-179 homocysteine,103-122 fibrinogen,85-93 and C-reactive protein,65-82 as well as low free testosterone (in men).94-97
Homocysteine is dangerous because it can induce initial injury to the endothelium, then facilitate the oxidation of the fat/LDL that accumulates beneath the damaged endothelium, and finally contribute to the abnormal accumulation of blood components around the atherosclerotic lesion.
Fibrinogen is a clotting factor that accumulates at the site of the endothelial lesion, contributing to plaque buildup or participating in the blockage of an artery by a blood clot after an unstable atherosclerotic plaque ruptures.
Glucose at even high-normal levels may accelerate the glycation process that causes arterial stiffening, while high-normal fasting insulin inflicts direct damage to the endothelium.
High levels of iron promote LDL oxidation in the damaged endothelium, while low levels of testosterone appear to interfere with normal endothelial function.
C-reactive protein not only is an inflammatory marker, but also directly damages the endothelium. Chronic inflammation, as evidenced by persistent high levels of C-reactive protein, causes initial injuries to the endothelium and also accelerates the progression of existing atherosclerotic lesions.
Clearly, then, the degenerative process of endothelial dysfunction has multiple underlying causes. A modest reduction of homocysteine alone is not going to overcome all of the other risk factors involved in arterial degeneration. Nor is modest homocysteine reduction going to reverse a lifetime of cumulative damage to the arterial wall. Yet that is what these two recent studies were designed to demonstrate.
How Atherosclerosis Develops
Atherosclerosis begins with changes in endothelial cell function that cause white blood cells moving through the blood to stick to the endothelium instead of flowing by it normally. This weakens the endothelium, which allows blood cells and toxic substances circulating in the blood to pass through the endothelium and enter the sub-endothelial compartment. Lipid or fat-cell-like substances such as LDL, cholesterol, and triglycerides in the blood then accumulate in this sub-endothelial compartment that separates the endothelium from the smooth muscle middle arterial wall.
The lipids that accumulate in the broken endothelium become oxidized. This causes them to signal the endothelial cells, which then alert smooth muscle cells to begin a “repair” process that eventually results in an atherosclerotic lesion. Depending on an individual’s risk factors (poor diet, lack of exercise, smoking, high blood pressure, and the aging process itself), fat accumulation continues and the atherosclerotic process accelerates.
White blood cells called macrophages then invade the area to digest the fat. Smooth muscle cells that have migrated to the area have already changed their nature to also scavenge fat. These fat-laden white blood cells and smooth muscle cells are called “foam cells.”
Foam cells induce chronic inflammatory attack by various immune components. Smooth muscle cells try to curtail the injury to the endothelium by producing collagen, which forms a cap over the injury site. Then calcium accumulates and forms a material resembling bone. This is why atherosclerosis used to be called “hardening of the arteries.”
This complex array of foam cells, calcification, and lipid accumulation is called an atherosclerotic plaque. As the plaque grows, it often becomes unstable and vulnerable to acute rupture that exposes the contents of the plaque to the blood. Platelets can then rapidly accumulate around this ruptured plaque, resulting in a blockade (or blood clot) on the inner surface of the blood vessel wall. This clot can become very large and occlude the vessel. Even small plaques, if they rupture, can interfere with blood flow and cause an acute heart attack. Alternatively, atherosclerotic plaques can enlarge to such a degree as to completely block blood flow.
When reviewing the complex interplay involved in the development and progression of atherosclerosis, it defies scientific principle to take patients with pre-existing endothelial dysfunction and try to prevent future cardiac disease by only modestly reducing homocysteine levels.
Why These Two Studies Were Doomed to Fail
Homocysteine is one of many causes of endothelial dysfunction. Endothelial dysfunction is known to occur in otherwise healthy people with elevations in fasting homocysteine ranging from 15 to 35 µmol/L.180 Furthermore, in otherwise healthy people, impaired endothelial function is seen with small increases in plasma homocysteine (2-3 µmol/L), even when blood homocysteine does not rise above the upper limit of “normal” (15 µmol/L).181 This means that even relatively low circulating levels of homocysteine can damage the arterial wall!
Despite the documented evidence of homocysteine’s adverse effects on normal endothelial function, expecting a significant drop in cardiovascular risk in a group of patients with severe pre-existing endothelial dysfunction with a modest dose of B vitamins is quite a stretch. Yet, that was exactly the assumption made in the two recent studies.
For example, in one of the homocysteine-lowering trials, patients had to have suffered a heart attack within seven days of enrolling in the study. These patients would have already had significant endothelial impairment, and it is well known that the risk of sudden death is greatly increased during the time after a heart attack. For example, a study published in the New England Journal of Medicine evaluated 14,609 patients who suffered heart attacks. The risk of dying was highest in the first 30 days after a heart attack. In fact, 83% of all patients who died suddenly did so in the first 30 days after hospital discharge, and risk persisted for up to two years.182 Clearly, these patients had a high degree of endothelial dysfunction to begin with, and were a very sick group of patients. Assuming that B vitamins alone would have a major impact in this very sick patient population—with severe, pre-existing endothelial dysfunction and at high risk of sudden death—is a major design flaw.
When one steps back and looks at what was done in these studies, it should be no surprise that cardiac risks were not lowered in the B-vitamin groups. Based on everything we know about arterial disease, it would have been impossible to reverse the severe arterial damage in these patients merely by reducing homocysteine levels a few points within the normal mid-range.
The study subjects’ baseline homocysteine levels were not severely high. This means it is likely that their arterial disease was caused by some of the other known risk factors. For instance, compared to the placebo arm, a statistically significantly higher number of people in the B-vitamin group of one study were treated with warfarin (Coumadin®). Could this point to some unknown factor at baseline that increased cardiac risk in the B-vitamin group?
A Windfall for Drug Companies
Pharmaceutical companies profit more from sales of cardiac drugs than from any other class of medication.
With all the media hype about homocysteine not being a cardiac risk factor, many doctors will advise their patients to discontinue their B-vitamin supplements. This is particularly unfortunate for the coronary artery disease patients with homocysteine readings of 15 µmol/L and above. While these two studies do not relate to cardiac patients with these higher homocysteine readings, hurried doctors (who neglected to read the actual studies) may uniformly advise all their cardiac patients to discontinue B-vitamin supplements.
Uninformed consumers will reduce their B-vitamin consumption based on media reports that homocysteine is no longer considered a cardiac risk factor.
All of this adds up to a financial windfall for drug companies, which stand to sell their expensive cardiac drugs to millions of new heart attack patients who become victims of homocysteine-induced atherosclerosis.
Excess homocysteine causes more than just heart attacks. Osteoporosis,183-185 depression,186-189 and Alz-heimer’s disease,190-200 as well as sharply increased risks of stroke,37-50 are linked with elevated homocysteine. If even a small percentage of the American public discontinues its B-vitamin supplements, the demand for prescription antidepressants, anti-Alzheimer’s drugs (acetylcholinesterase inhibitors), and bone-building prescription medications such as the bisphosphonates is likely to skyrocket.
Discrediting low-cost nutrients that have been shown to reduce disease risk is great news for companies that sell drugs to those who fall ill. In a forthcoming issue, we will follow up with a feature article by Dr. William Davis discussing novel nutritional strategies that you can use to lower high homocysteine levels and gain truly effective control of this potentially lethal compound.
Protect Yourself Against the Epidemic of Vascular Disease
The number-one killer in the United States is atherosclerosis, which causes most heart attacks and strokes.59 Doctors remain confused as to how this artery-blocking process occurs and overlook the numerous independent factors that can inflict severe damage to the arterial wall.
Many of the underlying causes of atherosclerosis are readily detectable with annual blood tests. Once the risk factors that predispose one to a heart attack or stroke are identified, corrective actions can be initiated.
What follows are the 10 most important blood tests one should have at least once a year to evaluate cardiac health:
- C-reactive protein
- Free Testosterone
- Hemoglobin A1C
- Total Cholesterol
- Fasting Glucose
References . . .
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