Lead and mercury are toxic heavy metals that should be avoided.
LEAD
The chemical symbol for lead, Pb, comes from the Latin root word for plumbing. Lead is similar to some other ions with two positive charges such as calcium (Ca++) and iron (Fe++). Lead can take the place of iron or calcium, but lead cannot perform the functions that iron or calcium can perform. For instance, lead can take the place of iron in heme in hemoglobin, but this hemoglobin can no longer carry oxygen.
Lead can take the place of calcium in brain cells, but the brain cells are no longer capable of processing messages from nerve cells. Children who are exposed to lead are more likely to have lower intelligence quotients and to develop learning disabilities and behavioral problems than normal children. If women are exposed to lead during pregnancy, especially if they are calcium-deficient, their children may have abnormal neurological development.
Lead exposure in adults can increase the risk of kidney damage and high blood pressure. Lead can also be incorporated into bones. This lead can remain in the bones for decades. During pregnancy, if insufficient dietary calcium is taken, calcium and lead may be removed from bones and put into the blood circulation with damaging effects on the fetus. Lead can easily pass through the placenta and damage the vulnerable nervous system of the growing fetus. This is one reason for mothers to have sufficient daily intake of calcium, which makes the removal of calcium (and possibly lead) from bones unnecessary. During postmenopausal years, women can reduce their lead levels by taking in sufficient calcium so that bone demineralization does not occur.
Three Ways to Lower Blood Lead Levels
Adequate dietary calcium
Adequate dietary iron
Supplementary vitamin C
Sufficient dietary calcium can reduce the absorption of lead in the intestines. Another way to reduce lead levels is to have adequate dietary iron. Iron deficiency can increase the blood levels of lead in children. A third way to reduce levels of lead in blood is to take in higher levels of vitamin C. Vitamin C intakes of 100 mg to 1000 mg daily have been associated with lower blood levels of lead. These protective levels of vitamin C are difficult to obtain from diet alone.
Lead has many ill effects on the body. Lead can make red blood cells leaky and fragile. Lead impairs the immune system in two ways. Lead interferes with the ability of white blood cells to fight infection. Lead can also bind to antibodies and impair their effectiveness. Lead can interfere with growth and tooth development.
Lead exposure should be minimized, especially in children, because of its many harmful effects.
MERCURY
Mercury is a toxic heavy metal. The chemical symbol for mercury is Hg, which comes from the Greek word for quicksilver. Mercury exposure is most damaging to developing fetuses and nursing babies, where it can cause severe problems with nerve development. Mercury consumption is also damaging to children and adults. Mercury damages the central nervous system, endocrine system, kidneys, and adversely affects the mouth, gums, and teeth. Most of the exposure to mercury in America is from eating fish and shellfish. Fish and shellfish accumulate a highly toxic organic form of mercury called methylmercury.
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