Bowl of broth

Image Credit: Hans Braxmeier / Pixabay. This image has been modified.

How Much Lead Leaches Into Organic Chicken Bone Broth?

“Lead poisoning still occurs in the United States despite extensive prevention efforts and strict regulations.” Ayurvedic supplements specifically marketed to pregnant women, for example, exceeded safety levels by up to 4 million percent, making Ayurvedic medicine use and lead poisoning “a continued concern in the United States.” In fact, “heavy metals are added intentionally to several Ayurvedic medications,” though Ayurvedic practitioners claim that practice shouldn’t cause worry because the “process of detoxifying heavy metals…includes the use of…cow’s urine” among other substances.

We’ve known for about a half-century now that calcium supplements can be an additional source of lead contamination. Those made from bone may have the highest lead levels, but regular calcium supplements, including a number manufactured by national brands, were also found to be contaminated.

In terms of our diet, the greatest contributor to the lead intake of children and their parents may be dairy, but the most concentrated source may be wild game shot with lead-containing ammunition. Concerns have been raised by hunters, though, that lead-free bullets wouldn’t have the same “wounding capacity.” However, CT scans of kills show they inflict just as much damage, “demonstrat[ing] that lead-free bullets are equal to conventional hunting bullets in terms of killing effectiveness,” even against ballistic soap, which evidently has a similar density to vital organs.

Workers in battery plants, for instance, can be exposed to a lot of lead, but the number one nonoccupational exposure is from shooting firearms. It isn’t eating lead-laden meat—just taking target practice in indoor firing ranges. Indeed, 75 percent of target shooters have elevated lead levels in their blood, as you can see at 2:02 in my video How Much Lead Is in Organic Chicken Soup (Bone Broth)?. Even outdoors, airborne lead released by the friction of the bullet against the barrel or lead-containing primers can cause substantial lead exposure both in people and local wildlife, as well as contaminate the soil. Lead levels in the soil by a firing range were higher than those found next to an industrial lead factory. However, most lead in urban soil is from decades of use of leaded paint and gasoline, raising concerns about urban gardens. Though most of the lead in soil doesn’t get taken up by plants, it can stick to their leaves and roots. This is bad news since even crops from raised beds using clean soil may get contaminated in an urban environment, but, the good news is that, presumably, the lead can just be washed off. The health benefits of gardening and fresh produce “are likely to more than fully compensate risks at most sites.”

What about eggs from backyard chickens? They should be tested for lead because the lead gets inside the eggs and therefore can’t be washed off. As you can see at 3:22 in my video, most of the lead ends up in the birds’ skeletons, which raises the question: What happens when you try to make chicken soup?

There may be an upswing in people boiling bones, which is “encouraged by advocates of the paleolithic (or ‘paleo’) diet,” but the problem is that lead is a neurotoxin—but not just a neurotoxin. Lead also adversely affects the bone marrow, digestive tract, kidneys, circulatory system, hormones, and reproduction. Symptoms of too much lead exposure include impaired cognition, anemia, abdominal pain, kidney problems, high blood pressure, miscarriages, memory problems, constipation, impotence, depression, poor concentration, and more. What’s more, we know from human studies that lead is sequestered in bones. When there is a lot of bone turnover, for example, during menopause or pregnancy, lead levels in the blood can go up. This bump can be minimized during pregnancy by getting enough calcium and lowering sodium intake, though. When astronauts lose bone in space, the lead is released into their bloodstream. Ironically, since they’re no longer being exposed to all the lead on Earth, their overall lead levels may go down. Bones are so good at sucking up lead, they can be sprinkled on firing ranges to prevent lead from leeching further into the environment.

Researchers concerned that the boiling of farm animals’ bones might release lead into the broth made three types of organic chicken broth—one using the bones, a second using meat without the bones, and a third using the skin and cartilage without the bones. All three of the broths exceeded the maximum allowable dose level for lead—even the one made without bones. Surprisingly, the skin and cartilage broth was the worst, exceeding the safety level per one-cup serving by about 475 percent.


  • Leading poisoning is a concern in Ayurvedic medicine and calcium supplements, not only those made from bone.
  • Dairy may contribute most to our intake of lead dietarily, but wild game shot with lead-contaminating ammunition may be the most concentrated source.
  • Shooting firearms, including at target practice in indoor ranges, is the top nonoccupational exposure to lead.
  • Airborne lead released from shooting can expose people and wildlife, as well as contaminate the soil, and levels in the ground by a firing range have been found to be higher than those next to an industrial lead factory. 
  • In urban soil, most lead is from decades of use of leaded paint and gasoline.
  • Eggs from backyard chickens should be tested for lead as it may get inside the eggs and cannot be rinsed off.
  • Lead is sequestered in bones, and boiling the bones of farm animals may release lead into the broth. 
  • Lead exceeding the maximum allowable dose level was found in broths made from organic chicken bones, organic chicken meat without the bones, and organic chicken skin and cartilage without the bones.

Did you just experience a little déjà vu? About two years ago, I produced a video about this very same study. Then, while researching for my extensive series on lead last year, I ran across the paper again and created the video for this article. Once I realized I had double-dipped on the same study, I had fun going back to see how such a different video can be produced around the same science. You can check out the first video at Lead Contamination in Bone Broth.

I alluded to my videos California Children Are Contaminated and Filled Full of Lead. For even more on lead, see:

Interested in the paleo diet? Here’s the science I could find on it:

In health,
Michael Greger, M.D.

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Michael Greger M.D., FACLM

Michael Greger, M.D. FACLM, is a physician, New York Times bestselling author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous "meat defamation" trial.

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