Are Toxic Chemicals Lowering Our IQ?

Written by Dr. Steve Chaney on . Posted in Environment and Health, Issues

Is Chemical Brain Drain A Pandemic?

 Author: Dr. Stephen Chaney

In a past issue of “Health Tips From the Professor” I examined the evidence suggesting that toxic chemicals in the home could cause childhood asthma. That is alarming because asthma can predispose individuals to other diseases and affects quality of life.

Confused ChildBut, what if that were only the tip of the iceberg? For example, a recent headline stated: “More Toxic Chemicals [In Our Environment] Are Damaging Children’s Brains”. If that headline is true, it’s downright scary.

The authors of this study suggested that toxic chemicals which are abundant in our environment can cause decreases in IQ and aggressive or hyperactive behavior in children – and that those changes may be permanent.

The Study Behind The Headlines

The paper that generated the headlines (Grandjean & Landrigan, The Lancet Neurology, 13: 330-338, 2014) was a review of the literature, not an actual clinical study.

Based on published clinical studies, the authors identified 12 chemicals commonly found in the environment as developmental neurotoxins (toxins that interfere with normal brain development) based. [If you would like to find out what those “Dirty Dozen” chemicals are and where they are found, click here.]

This finding compares with 6 developmental neurotoxins that they were able to identify in a similar study in 2006.

The authors were not claiming that the number or amount of toxic chemicals changed between 2006 and 2014. They were saying that science has advanced to the point where we can classify six more chemicals that have been in our environment for years as developmental neurotoxins.

Even more worrisome, the authors postulate that many more environmental neurotoxins remain undiscovered.

Are Toxic Chemicals Lowering Our IQ?

To answer that question, you need to look at some of the studies they cited in their review. For example:

  • Elevated blood lead levels in children are associated with as much as a 7 point decrease in IQ (Lamphear et al, Environmental Health Perspectives, 113: 894-899, 2005).
  • Elevated fluoride levels in drinking water are also associated with as much as a 7 point decrease in IQ (Choi et al, Environmental Health Perspectives, 120: 1362-1368, 2012).

The effects of many of the toxic chemicals on IQ were difficult to quantify, but the authors estimated that exposure of US children to just 3 of the chemicals (lead, methymercury and organophosphate pesticides) was sufficient to lower their average IQ by 1.6 points.

What Are The Potential Consequences?

The authors spoke of the environmental neurotoxins they identified as representing a “silent pandemic of a chemical brain drain” that could cost the US economy billions of dollars.

One of the blog posts I read on this topic summarized the consequences in a very graphic manner. It said:

If one child’s IQ is reduced by 5 points, it doesn’t appear to make a big difference.  For example, that child might be:

  • A little slower to learn
  • A little shorter of attention
  • A little less successful at tests and at work

That might result in $90,000 in lost lifetime earnings

However, if the average IQ of every child in the US were decreased by 5 points, the effect becomes significant:

  • Only half as many members of the next generation would be “intellectually gifted”.
  • Twice as many of the next generation would be “intellectually impaired”
  • Lost productivity could be in the billions

Of course, statements like that are a bit over the top. Drs. Grandjean and Landrigan did not claim that the net effect of the chemicals they identified was a 5 point drop in IQ. Nor did they claim that all US children were affected equally.

Still, it’s enough to make you think.

Are Toxic Chemicals Causing Behavior Problems?

Angry boy portraitThe authors cited numerous studies linking the chemical neurotoxins they identified to aggression and hyperactivity. But perhaps the most compelling reason to suspect that environmental chemicals may be affecting brain development is the spiraling incidence of developmental disorders such as autism and ADHD. For example:

  • Autism has increased by 78% since 2007 and now affects 1 of 88 eight year old children.
  • ADHD has increased by 43% since 2003 and now affects 11% of children age 4-17.

Some of this increase could be due to better diagnosis of these conditions, but nobody believes that all of it is due to improved diagnosis. The authors claim that much of this increase is likely due to environmental exposure to the kinds of developmental neurotoxins they identified.

Is The Science Solid?

This is a difficult area of research. You can’t do the gold standard double-blind, placebo-controlled clinical trial. Nobody in their right mind would give one group of children toxic chemicals and the other group a placebo.

The studies cited in this paper were mostly population studies. Basically this means that they compared children with exposure to certain toxic chemicals to a control group that was as similar as possible to the first group except that their exposure to the toxic chemicals was less.

The limitation of this kind of study is obvious. We are usually comparing children from different locations or of different backgrounds. We almost never know if we have controlled for all possible variables so that the groups are truly identical.

As a consequence it becomes important to ask how many studies come to the same conclusion. For some of the toxic chemicals, such as lead, methymercury and organophosphate pesticides, the weight of evidence is very strong. For some of the newer additions to their list of developmental neurotoxins, it is pretty clear that the chemicals have neurotoxic properties, but the significance of those effects on the developing human brain are hard to quantify at this point.

The Bottom Line:

1)     A recent review claims that there is a good scientific basis for classifying at least 12 environmental chemicals as developmental neurotoxins that are likely to reduce IQ and contribute to behavioral problems in US children. [If you would like to find out what those “Dirty Dozen” chemicals are and where they are found, click here.]

2)     The science behind the claims in this review is solid, but not iron-clad.

3)     However, there are times when we need to simply ask ourselves: “What if it were true?” The consequences of lowered IQ and developmental behavioral problems are so significant that it may not make sense to wait until we have unassailable scientific evidence before we act.

4)     We all need to be guardians of our personal environment. But, it is not easy. The “Dirty Dozen” chemicals identified in this study come from many sources:

  • Some are industrial pollutants. For those, we need lobby for better environmental regulation.
  • Some are persistent groundwater contaminants. For those we need to drink purified water whenever possible.
  • Some are insecticides and herbicides used in agriculture. For those we need to buy organic, locally grown produce when feasible.
  • Some are found in common household products and furnishings. For those we need to become educated label readers and use non-toxic products in our home whenever possible.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

Tags: , , , , , , , ,

Trackback from your site.

Leave a comment

Recent Videos From Dr. Steve Chaney

READ THE ARTICLE
READ THE ARTICLE

Latest Article

Do Omega-3s Lower Blood Pressure in Young, Healthy Adults?

Posted August 14, 2018 by Dr. Steve Chaney

What Is The Omega-3 Index And Why Is It Important?

Author: Dr. Stephen Chaney

 

Do omega-3s lower blood pressure in healthy adults?

omega-3s lower blood pressure young adultsThe literature on the potential health benefits of omega-3s is very confusing. That’s because a lot of bad studies have been published. Many of them never determined the omega-3 status of their subjects prior to omega-3 supplementation. Others relied on dietary recalls of fish consumption, which can be inaccurate.

Fortunately, a much more accurate measure of omega-3 status has been developed and validated in recent years. It’s called the Omega-3 Index. Simply put, the Omega-3 Index is the percentage of EPA and DHA compared to 26 other fatty acids found in cellular membranes. Using modern technology, it can be determined from a single finger prick blood sample. It is a very accurate reflection of omega-3 intake relative to other fats in the diet over the past few months. More importantly, it is a measure of the omega-3 content of your cell membranes, which is a direct measure of your omega-3 nutritional status.

A recent extension of the Framingham Heart Study reported that participants with an Omega-3 Index >6.8% had a 39% lower risk of cardiovascular disease than those with an Omega-3 Index <4.2% (WS Harris et al, Journal of Clinical Lipidology, 12: 718-724, 2018 ). Although more work needs to be done, an Omega-3 Index of 4% or less is generally considered indicative of high cardiovascular risk, while 8% or better is considered indicative of low cardiovascular risk. For reference, the average American has an Omega-3 Index in the 4-5% range. In Japan, where fish consumption is much higher and cardiovascular risk much lower, the Omega-3 Index is in the 9-11% range.

Previous studies have suggested that omega-3 fatty acids lower blood pressure to a modest extent. Thus, it is not surprising that more recent studies have shown an inverse correlation between Omega-3 Index and blood pressure. However, those studies have been done with older populations, many of whom had already developed high blood pressure.

From a public health point of view, it is much more interesting to investigate whether it might be possible to prevent high blood pressure in older adults by optimizing omega-3 intake in a young, healthy population, most of whom had not yet developed high blood pressure. Unfortunately, there were no studies looking at that population. The current study was designed to fill that gap.

 

How Was The Study Done?

omega-3s lower blood pressure young healthy adultsThe current study (M.G. Filipovic et al, Journal of Hypertension, 36: 1548-1554, 2018 ) was based on data collected from 2036 healthy adults, aged 25-41, from Liechtenstein. They were participants in the GAPP (Genetic and Phenotypic Determinants of Blood Pressure) study. Participants were excluded from the study if they had been diagnosed with high blood pressure and were taking medication to lower their blood pressure. They were also excluded if they had heart disease, chronic kidney disease, other severe illnesses, obesity, sleep apnea, or daily use of non-steroidal anti-inflammatory medications.

Blood samples were collected at the time of their enrollment in the study and frozen for subsequent determination of Omega-3 Index. Blood pressure was also measured at their time of enrollment in two different ways. The first was a standard blood pressure measurement in a doctor’s office.

For the second measurement they were given a wearable blood pressure monitor that recorded their blood pressure over 24 hours every 15 minutes during the day and every 30 minutes while they were sleeping. This is considered more accurate than a resting blood pressure measurement in a doctor’s office because it records the variation in blood pressure, while you are sleeping, while you are exercising, and while you go about your everyday activities.

 

Do Omega-3s Lower Blood Pressure In Young, Healthy Adults?

omega-3s lower blood pressure young adults equipmentNone of the participants in the study had significantly elevated blood pressure. The mean systolic and diastolic office blood pressures were 120±13 and 78±9 respectively. The average Omega-3 Index in this population was 4.6%, which is similar to the average Omega-3 Index in the United States.

When they compared the group with the highest Omega-3 Index (average = 5.8%) with the group with the lowest Omega-3 Index (average = 4.6%):

  • The office measurement of systolic and diastolic blood pressure was decreased by 3.3% and 2.6% respectively
  • While those numbers appear small, the differences were highly significant.
  • The 24-hour blood pressure measurements showed a similar decrease.
  • Blood pressure measurements decreased linearly with increasing Omega-3 Index. [In studies of this kind, a linear dose-response is considered an internal validation of the differences observed between the group with the highest Omega-3 Index and the group with the lowest Omega-3 Index.]

The authors concluded: “A higher Omega-3 Index is associated with statistically significant, clinically relevant, lower systolic and diastolic blood pressure in normotensive, young and healthy individuals. Diets rich omega-3 fatty acids may be a strategy for primary prevention of hypertension.”

 

What Does This Mean For You?

omega-3s lower blood pressure young adults questionPerhaps I should first comment on the significance of the relatively small decrease in blood pressure observed in this study.

  • These were young adults, all of whom had normal or near normal blood pressure.
  • The difference in Omega-3 Index was rather small (5.8% to 4.6%). None of the participants in the study were at the 8% or above that is considered optimal.
  • Liechtenstein is a small country located between Switzerland and Spain. Fish consumption is low and omega-3 supplement consumption is rare.

Under these conditions, even a small, but statistically significant, decrease in blood pressure is remarkable.

We should think of this study as the start of the investigation of the relationship between omega-3 status and blood pressure. Its weakness is that it only shows an association between high Omega-3 Index and low blood pressure. It does not prove cause and effect.

Its strength is that it is consistent with many other studies showing omega-3 fatty acids lower blood pressure. Furthermore, it suggests that the effect of omega-3s on blood pressure may also be seen in young, healthy adults who have not yet developed high blood pressure.

Finally, the authors suggested that a diet rich in omega-3s might reduce the incidence of high blood pressure by slowing the age-related increase in blood pressure that most Americans experience. This idea is logical, but speculative at present.

However, the GAPP study is designed to provide the answer to that question. It is a long-term study with follow-up examinations scheduled every 3-5 years. It will be interesting to see whether the author’s prediction holds true, and a higher Omega-3 Index is associated with a slower increase in blood pressure as the participants age.

 

Why Is The Omega-3 Index Important?

 

The authors of this study said: “The Omega-3 Index is very robust to short-term intake of omega-3 fatty acids and reliably reflects an individual’s long-term omega-3 status and tissue omega-3 content. Therefore, the Omega-3 Index has the potential to become a cardiovascular risk factor as much as the HbA1c is for people with diabetes…” That is a bit of an overstatement. HbA1c is a measure of disease progression for diabetes because it is a direct measure of blood sugar control.

In contrast, Omega-3 Index is merely a risk factor for cardiovascular disease. However, if it is further validated by future studies, it is likely to be as important for predicting cardiovascular risk as are cholesterol levels and markers of inflammation.

However, to me the most important role of Omega-3 Index is in the design of future clinical studies. If anyone really wants to determine whether omega-3 supplementation reduces cardiovascular risk, high blood pressure, diabetes or any other health outcome they should:

  • Start with a population group with an Omega-3 Index in the deficient (4-5%) range.
  • Supplement with omega-3 fatty acids in a double blind, placebo-controlled manner.
  • Show that supplementation brought participants up to an optimal Omega-3 Index of 8% or greater.
  • Look at health outcomes such as heart attacks, cardiovascular deaths, hypertension, stroke, or depression.
  • Continue the study long enough for the beneficial effects of omega-3 supplementation to be measurable. For cardiovascular outcomes the American Heart Association has stated that at least two years are required to obtain meaningful results.

These are the kind of experiments that will be required to give definitive, reproducible results and resolve the confusion about the health effects of omega-3 fatty acids.

 

The Bottom Line

 

An accurate measure of omega-3 status has been developed and validated in recent years. It’s called the Omega-3 Index. Simply put, the Omega-3 Index is the percentage of EPA and DHA compared to 26 other fatty acids found in cellular membranes.

Although more work needs to be done, an Omega-3 Index of 4% or less is generally considered indicative of high cardiovascular risk while 8% or better is considered indicative of low cardiovascular risk.

Previous studies have shown an inverse correlation between Omega-3 Index and blood pressure. However, these studies have been done with older populations, many of whom had already developed high blood pressure.

From a public health point of view, it is much more interesting to investigate whether it might be possible to prevent high blood pressure in older adults by optimizing omega-3 intake in a young, healthy population, most of whom had not yet developed high blood pressure. Until now, there have been no studies looking at that population.

The study described in this article was designed to fill that gap. The participants in this study were ages 25-41, were healthy, and none of them had elevated blood pressure.

When the group with the highest Omega-3 Index (average = 5.8%) was compared with the group with the lowest Omega-3 Index (average = 4.6%):

  • Both systolic and diastolic blood pressure were decreased
  • Blood pressure measurements decreased linearly with increasing Omega-3 Index.

The authors concluded: “A higher Omega-3 Index is associated with statistically significant, clinically relevant, lower systolic and diastolic blood pressure in normotensive, young and healthy individuals. Diets rich omega-3 fatty acids may be a strategy for primary prevention of hypertension.”

Let me translate that last sentence into plain English for you. The authors were saying that optimizing omega-3 intake in young adults may slow the age-related increase in blood pressure and reduce the risk of them developing high blood pressure as they age. This may begin to answer the question “Do omega-3s lower blood pressure in young, healthy adults?”

Or even more simply put: Aging is inevitable. Becoming unhealthy is not.

For more details, read the article above.

 

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

UA-43257393-1