Lead in the Diet

Where it Comes From and How to Avoid It

Sep 1, 2009 Alicia Richardson

No one intentionally adds lead to their food; but dietary sources of lead abound from sources which are more common than people know.

Lead (Pb) - "Plumbum" in Latin - is the most common toxic and widespread mineral in our environment. It is present in soil, air, water, homes, industrial facilities, and food. Our bodies contain about 125-200 mg of lead, which can tolerate about 1-2 mg of lead daily without ill effects.

Lead poisoning is a chronic disorder caused by the accumulation of lead in the blood. It impairs brain performance, kidney function, and the body's ability to manufacture red blood cells. In children, it undermines intellectual skills, causes irritability, decreased play activity, persistent vomiting, uncoordinated walking, seizures, confusion, sleepiness, and coma. In adults it triggers headaches, poor appetite, abdominal pain (Devon Colic), vomiting, and constipation.

Although dietary lead is poorly absorbed (less than 5%), children absorb higher levels of lead through the mouth and skin. Dietary calcium, magnesium, iron, copper, and zinc blocks its absorption. An empty stomach enhances its absorption. It is excreted in the feces; accumulated lead is stored in the central nervous system, brain, glands, liver, hair and bones. In the blood it stays for about 30 days; in the bones - about 10 years.

Dietary Sources of Lead

Drinking water (home and public places including fountains). Lead was used to produce pipes to carry water and solder iron to copper pipes. Older homes before 1950s were often built with lead plumbing; new homes (after 1990) may contain lead solder and leach until the pipes form a protective oxide layer. It is found in soft or acidic water. Water from drinking fountains may have higher levels of lead as water stands longer in the pipes.

Food Additives: Before the 1900s, lead was widely used as food preservative. Lead chromate was used in custard powders, candy, and milk, which were tinted "yellow" to prevent people from detecting blue-colored skimmed milk. Cayenne and curry powders contained lead oxide, butter contained lead carbonate or lead acetate which was once used by the Romans to sweeten wine.
Canned foods including infant formulas due to lead solder. Previously, lead solder was used to close seams in food cans. Today, most food manufacturers in North America use seamless cans. Other countries may still use lead soldered cans.
Alcoholic beverages (leaded foil wrappers, contaminated soil, water, air, lead-soldered pipes and vats). Today's producers use screw-top caps instead of cork, thereby eliminating the need for leaded-foil wrappers.
Allotment plot produce from reclaimed lands near industrial areas or highways. Lead accumulates at different concentrations in roots and aerial parts of the plants. Beet greens absorb more lead than beet roots; lettuce leaves absorb more lead (8%) than carrots (2%). A study conducted by Thomas and his team found that on average, fresh produce contained 0.01-3.85 parts per million (ppm) of lead. They took 231 samples. Their investigation was published in the May 2006 issue of the Journal of the Science of Food and Agriculture.
Lead Crystal: When crystal comes in contact with acidic beverages - wine, fruit juices, soft drinks,etc.- some lead dissolves into the liquid. The amount depends on the lead content of the crystal, type of beverage, and length of time they are in contact with each other.
Ceramic dishes or glassware. In North America, most ceramic and glasswares no longer contain lead, but other countries may still be using lead.

Reducing Your Risks

Let tapwater run for a few minutes before taking a drink.
If you're not sure about the food additives used in a product, ask/write the manufacturer for details.
If you do not know if solder has been used in your canned food (e.g. baby formula, etc.), write/call the manufacturer.
Do not serve or store food or beverages in lead crystal or ceramic containers.
Do not eat produce grown in allotment gardens unless you are certain that the soil is "safe" from lead. Wash all produce very carefully before using. Use clean running water.
Eat foods high in calcium, magnesium, iron, and zinc (milk and dairy products, and meats).

References

Payne Mark " Lead in Drinking Water" Can Med Assoc J July 29, 2009;179(3):253-254

"Effects of Lead on Human Health" It's Your Health Health Canada, Ottawa, Canada 2004

Thomas B et al. "Lead and Cadmium content of some vegetables foodstuffs" Journal of the Science of Food and Agriculture 9 May 2006; 23(12):1493-1498

Kirschman JD "Vitamins, Minerals, and Water" Nutrition Almanac Nutr Res Inc, 2006 pp:67-68

The copyright of the article Lead in the Diet in Nutrition is owned by Alicia Richardson. Permission to republish Lead in the Diet in print or online must be granted by the author in writing.