Heavy Metal Toxicity In Human Diet And Effect On Human Health

by John

What Are Heavy Metals?

You may remember this from your chemistry classes in school. Heavy metals are those chemical elements which have a high relative atomic mass. They have a specific gravity greater than 5.0 and are considered to be poisonous to many living organisms like humans.

The most common heavy metals that are present in our diet are Arsenic, Cadmium, Lead and  Mercury. Lets take a look at each of them to see how they enter our bodies and the bad effects they have on our health.

1. Arsenic – Source, Toxicity And Exposure

Arsenic comes in two forms – Organic and Inorganic. Inorganic Arsenic is known to cause cancers and is a common carcinogen.

Sources of Arsenic

  • Chicken can carry arsenic if the chicken were fed a diet that contained arsenic.
  • Wines can be a source of arsenic if the grapes, that they were made from, were sprayed with pesticides containing inorganic arsenic.
  • Sea food like fish sometime contain inorganic arsenic. Fishes can absorb arsenic directly into their bodies from the water they live in.

Health Effects Of Arsenic

Arsenic exposure can have severe health effects.  Here are some known problems associated with exposure to inorganic arsenic.

  • Irritation of the intestines, lungs and stomach.
  • Increased risk of lung cancer, lymphatic cancer, liver and skin cancer.
  • Infertility and miscarriages.
  • Brain damage.
  • Reduced productions of RBC (Red Blood Cells) & WBC (White Blood Cells).
  • DNA damage.
  • Exposure to high levels of Arsenic can lead to death.

2. Mercury – Source, Toxicity and Effects

Unlike Arsenic, the organic form of mercury is more hazardous. The Environmental Protection Agency (EPA) has classified mercury chloride and methyl mercury as possible human carcinogens.

Source of mercury in the human diet

  • The main dietary source of mercury is from fish. Methyl mercury in the sea binds to the proteins in fish tissue.
  • Dental amalgam fillings.
  • Commonly used brand name food products that use high fructose corn syrup like products made by Quaker, Hershey’s, Kraft  and Smuckers. This press release from the institute of Agriculture and Trade policy talks about a study which confirms this.

Health Effects Of Mercury

  • Exposure to high level of Methyl mercury can lead to permanent brain and kidney damage.
  • Can cause personality changes, deafness and muscle incoordination.
  • Damage to stomach and intestines.

To read in detail about possible health effects of mercury, read this public health statement on Mercury from the Agency of Toxic Substances and Diseases Registry.

3. Cadmium – Source, Toxicity And Effects

Sources of Cadmium in the human diet

  • Drinking water in some countries in known to have low concentrations of Cadmium.
  • Internal organs like kidneys and livers of certain species of oysters, scallops and mussels.
  • Crops that were grown on cadmium polluted soils and fertilized with rock phosphate derivatives and sewage sludge.
  • Cigarettes can contain different amounts of cadmium depending upon the brand. It depends on where the cigarette manufacturers are sourcing their tobacco. Now is a good time to kick the nasty habit smoking.
  • Fish and shellfish.
  • Food containers that are colored with cadmium pigment and can leech into the food that is stored in the container.

Health effects of Cadmium exposure

  • Severe irritation of the stomach leading to vomiting and diarrhea can sometime result in death.
  • Kidney damage.
  • Long term exposure to cadmium causes fragile bones and decreased bone strength.

4. Lead – Source, Toxicity and Effects

Lead is probably the more common metal that is associated with heavy metal poisoning and toxicity. All the recent news about the presence of lead in kids’ toys have helped create public awareness about the dangerous effects of lead.

Sources of Lead in the human diet

  • Even though the US has banned the use of lead solder, canned foods made in some other countries can still have lead solder along the seams.
  • If you love Mexican food then you need to watch out for prepackaged foods imported from Mexico. Tamarind, Chili and Candies from Mexico have been known to contain some lead.
  • High acid foods that are stored in containers that use ceramic to hold the fold inside. This ceramic could contain glazes with lead. This lead can easily leech into high acid foods.
  • Drinking water in houses with lead pipes – It is best to let water run for a while before drinking from the tap. This will ensure that any lead from the pipes that may have seeped into the drinking water is gotten rid of.
  • Cigarette smoke can contain small traces of lead.

Health effects of Lead exposure

  • Long term exposure to Lead can affect the nervous system.
  • Lead can lead to Anemia.
  • Brain and kidney damage.
  • Pregnant women may have miscarriages
  • Affects sperm production in men.

How Can you protect yourself from heavy metal toxins like Arsenic, Mercury, Cadmium & Lead

Given the fact that these heavy metals enter our bodies through some very commonly used foods, you cannot completely avoid exposure to them. You can and should try your best to keep your exposure to a minimum.

This is the ideal time to eat more fresh and organic food. The popularity of Organic food and buying locally produced food has increased recently. As the general population continues to learn the ill effects of dangerous chemicals that are used in products that we use everyday, the importance of Organic and chemical free produce will only grow. Organic crops and vegetables are grown in healthy soil and no chemical fertilizers and pesticides are used. So there is very minimal chance of heavy metals entering the plants through the soil. There is virtually no extensive post harvest processing in producing organic food, so you can be sure that they have not been exposed to any chemicals. Your organic fruits are not waxed to make them look brighter and more attractive.

You need to be very careful while consuming seafood. Wild caught fish like salmon, cod, pollock and tilapia will be low in mercury than their counterparts raised in a farm. Also, avoiding predator fishes like shark is a good idea. The predator fishes have way more mercury in them than the smaller fish.

If you are a smoker, it is never too late to quit. This will greatly reduce exposure to some heavy metals.

Creative Commons License photo credit: Horia Varlan


Related Blogs

Leave a Comment

Previous post:

Next post: