Hormones are small molecules which regulate all the biological
reactions in living organisms. They are:
- produced in specialized cells,
- released into the bloodstream when needed, and
- carried to distant target sites where they function.
For example, insulin is necessary to transport glucose molecules
into cells and maintain a steady level of glucose in the bloodstream for normal
functioning. Another example is growth hormone, which initiates growth in children.
Hormones are used in livestock for several reasons, such
- control the growth and metabolism of livestock for food,
- produce larger, leaner animals,
- increase milk production, and
- lower producer cost, thus lowering the cost of the food
product to the consumer.
BST: Bovine Somatotropin
The hormones-in-meat controversy is currently being overshadowed by the BST
controversy in milk. BST is a hormone that is produced naturally in cows; it
stimulates milk production. Dairy cows injected with BST increase milk production
by 10 to 25%.
However, the practice of using BST may not be without risks.
Consumers are concerned whether:
- hormones carry over into the food;
- the trace amounts of hormones in the food affects humans,
- the hormones produced by biotechnology are different
from the natural hormone and that these small differences may
lead to any associated human health risk. In addition, some opponents question
the safety of BST from another point of view. Will there be more stressed
and sick animals, due to higher milk production capabilities? Could this lead,
in turn, to more drug use and a greater likelihood of drug residues in milk?
Proponents point out the facts in the BST issue:
- Residual levels of BST in milk are no higher than milk
from untreated cows.
- Residues in milk (or meat) are destroyed by the heat
of pasteurization (or cooking) or they will be digested by the body.
- Milk from BST-treated cows is identical to milk from
- Even if BST could survive intact in the human bloodstream,
it could not function because hormones are species specific; BST, functions
in cows only, not humans.
PST: Porcine Somatotropin
A growth hormone that helps produce lower-fat pork called porcine somatotropin,
or PST, may be the next controversial issue. Like BST, it is a result of biotechnology
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