Lead Still a Problem

IN THIS ARTICLE: (click to read)

Lead - How children get exposed

How lead affects learning

What makes lead poisoning worse

Lead - Alzheimer's risk?

Checklist - Prevent lead exposure

Testing for Lead

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Lead - How children get exposed

Millions of children are still exposed to lead everyday, putting them at risk of problems with learning and behavior that could last a lifetime. How do they get exposed?

• Eating strangely sweet, crisp bits of peeling paint, especially when they are hungry and malnourished (pica).
• Drinking tap water from lead pipes in an old home or building
• Inhaling the dust from the demolition of old painted walls during renovation
• Playing with toys made of lead or coated with lead paint, or consuming food or drink from lead-containing ceramics
• Playing on the floor or on the ground contaminated with lead dust
• Inhaling dust from work clothing of parent who works with lead.
  

According to environmental health expert Philip Landrigan MD MPH, children are more vulnerable to lead and other environmental toxins for several reasons: their small size in relation to food intake, relative closeness to the ground, tendency to put things in their mouths, and differences in metabolism.

How lead affects learning

For years researchers have known that lead exposure lowers IQ and learning abilities. New studies shed light on possible causes.

Lead may block new cell growth in the brain

Lead appears to affect the dentate gyrus, part of the hippocampus that helps form new brain cells. These new neurons are incorporated into the vast network of neurons that process and “hold” all that we learn - known as neural networks.

As we learn new information, our neural network grow and change - a quality of the brain known as   “plasticity”. 

Scientists suggest that in humans, lead impairs plasticity impacting the ability to learn.

Lead may block brain communication

One effect of lead appears to be its interference with an important function of calcium in the brain. Calcium helps to create a wave of electrical current along the surface of neurons that helps them to communicate.

When children do not get enough calcium in their diets, they are more vulnerable to lead accumulation in their bodies. Lead accumulates in bones, further displacing calcium.

This electrical wave is a necessary part of thinking and learning. Animal studies suggest that learning problems may be related to the effect of lead blocking calcium in brain communication.

Lead may interfere with memory links

Learning math, how to jump rope, to keep your socks, or anything else, requires linking of multiple signals to to form a memory.

For example chewing an ice cube for the first time, you notice it’s crunchy and cold. Maybe you get a headache from the intense cold sensation, or relief from a hot summer day.  All of these signals are processed together to form a memory of what it’s like to chew an ice cube.

One step is the linking of simultaneous aspects of an experience involves the NMDA receptor, a specialized structure on the surface of some neurons. The NMDA receptor is also involved in forming mental “maps” of the space around us, or the ability to discern relationships between objects in space, known as spatial memory.

Animal studies suggest that lead interferes with the function of the NMDA receptor, so that it is more difficult to form memory, especially spatial memory. Spatial memory is important not only in orienting ourselves but also in understanding abstract concepts in math and other subjects.

Lead may make it harder for learning to “stick”

Did you ever try to glue two pieces of paper together? You probably noticed that if you did not use enough glue the paper would not stick together.

Lead may impact the “sticking” process a gradual formation of a long-term connection between neurons called a synapse (the neurons are nearly touching). This process known as LTP (long-term potentiation) is a fundamental process in helping the brain form new memories.

Studies suggest that lead interferes with LTP, another potential cause of  impaired learning.

What makes lead poisoning worse

Malnutrition

A malnourished child will absorb more lead from eating lead paint chips, than a well-nourished child.

Many children eat no vegetables in a day, according to a national nutrition survey. A plant-based diet will provide essential nutrients that make it more difficult for lead to get absorbed into the body. In addition, these nutrients support brain health and learning.

Some key nutrients that support learning AND discourage lead absorption:

• Calcium (Dark leafy greens)

• Vitamin D (Sunlight, supplements)

• Iron (lentils, dark leafy greens)

• Vitamin C (broccoli, citrus)

• Zinc (Sesame tahini, almonds)

 Stress

Stress increases cortisol, which damages the same area as lead (dentate gyrus). This worsens the effect of lead in children under chronic stress.

Cortisol also interferes with  the dopamine system in brain, which is important in  learning and memory.

Alcohol

When children are exposed to alcohol prenatally, they may develop fetal alcohol syndrome, a cluster of developmental problems resulting from alcohol exposure to the developing brain and body.

The dentate gyrus, mentioned earlier as a source of sprouting neurons that help children to wire new information into their growing brains, is especially vulnerable to alcohol.

Thus, exposure to both alcohol and lead could result in more severe brain damage.

Poverty

In poverty, multiple risks converge on a developing brain.

Many children who are in poverty experience not only lead exposure, but chronic stress, exposure to alcohol and malnutrition.

At the same time, they are most likely to live in homes where they will be continually exposed to lead and have least access to medical care.

Lead - Alzheimer's risk?

The dentate gyrus continues to supply us with new neurons throughout life.

Damage to this area is indeed a loss that could impact the life path of each child exposed to lead.

New studies suggest that lead exposure early in life can impact the brain as it ages, causing changes that resemble early Alzheimer’s disease. 

Checklist - prevent lead exposure

• Check toys, paint, plumbing for lead.

• Feed children a a nutrient-rich diet to reduce absorption of lead, and provide antioxidants and folic acid to help the body get rid of lead.

• Increase sun exposure or supplementation to improve vitamin D levels, to improve calcium absorption

• Reduce lead dust exposure. Wash hands and toys regularly, and check to be sure toys do not contain lead. Wash floors and windowsills and make sure your child is not eating paint chips.

•  If you have lead pipes, filter your water. Avoid using unfiltered tap water, especially hot tap water, which may increase lead from plumbing.

• Do not allow children in areas of renovation if you have lead paint in your home.

• If you work with lead, try to change your clothing at work and do not bring home any clothing with lead dust.

Testing for lead

Your health provider can order a blood test to determine your child’s lead level. Depending on your child’s risk of exposure and overall health and academic history, other tests might be ordered.

If you have children in your life, make sure they have been tested for lead. If you are a teacher or provider let families know about local resources to help with lead testing and treatment and that it is worth every effort to identify and treat lead so that each child can learn and grow to their potential.

For more information go to the Environmental Protection Agency, or the American Academy of Pediatrics