There are about 2.5 million tons of meat and bonemeal produced every year in the US as slaughterhouse by-products. These by-products are then taken and feed to farm animals, especially chickens. Thankfully most of the lead that comes in the bonemeal passes out of the animals through their manure. We then take the manure from animals like pigs, cows, and chickens and feed it back to the animals again. Because of this, levels of contaminants in their bodies can build up.
You might think that you would be able to lower your lead intake by eating a vegetarian diet. When studies have been done though, it was found that half of our lead intake comes from plants. Studies in Europe suggest that vegetarians have about the same dietary exposure to lead as the general population does. But it is not so important what you eat as what you absorb. Studies have shown that the absorption of harmful heavy metals from eating animal products may be higher than from plant products.
Here is what one study found after a year with a move towards a diet with large amounts of raw vegetables, fruits, and unrefined foods, whole grains, while eliminating meat, poultry, fish, and eggs. Clippings of hair where taken before and after the change. Their hair showed significant reductions in heavy metals, including reducing their lead levels nearly in half. Within three months after making the change, their toxic heavy metal levels went down, and stayed down. A few years later after the study was over, the levels of heavy metals in their bodies went back up to where they were before the study because they went back to their regular diet. The same thing happened with another study done for two years.
Lead is a non-biodegradable, toxic metal. It remains in the soil indefinitely unless extracted by plants and hauled off. Children are one of the groups at highest risk from lead exposure. Scientific research in Australia and overseas shows overwhelmingly that even low exposure to lead can result in serious and irreversible health and behavioural problems, especially for small children. Even low levels of lead exposure can harm intellectual development.
When looking at the nutritional aspect of lead absorption, the amount of other nutrients taken at the same time is important. People are more susceptible to the effects of lead when ingested with zinc, high fat intake, vitamin D, phosphorus, various vitamins (e.g. ascorbic acid, E, niacin, B6, B12), selenium, and protein. This list correlates with a high consumption of animal products.
Iron deficiency and lead poisoning are often found together. They both adversely effect neurocognitive development. Evidence suggests that the harmful results of lead are enhanced when a person is deficient in iron. Iron deficiency in children itself can damage early mental development so it is not clear if they enhance each other or there is simply a combined affect.
Ferritin is a protein in your cells that stores iron and releases it in a controlled manner. In humans, ferritin acts as a buffer against iron deficiency and iron overload. Children with low ferritin levels have greater lead levels than children with normal ferritin levels. In a study done by Bradman et al., the iron deficient children averaged 1-2 μg/dl higher blood lead than children with adequate iron levels. These results suggest that low iron levels can amplify lead absorption and possibly retention of lead in the body but the results are not conclusive.Written by Daniel Baldwin, B.S.
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