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Bromeline "Diet Pills"
Stephen Barrett, M.D.
I have seen ads for diet pills whose special ingredient is said to be
bromelain from pineapples? Do they work?
Bromelain (also spelled bromelin) is a mixture of protein-digesting and
milk-clotting enzymes found in the juice and stem of the pineapple plant
Ananas comosus (Linné) Merr (Fam Bromeliancaea). A leading
textbook of pharmacognosy (plant medicine) states that bromelain is used
to make protein hydrolysates, to tenderize meat, and in the leather industry
. I know of no scientific evidence that bromelain digests fats or is
effective as part of a weight-reduction regimen.
In 1995, the Pennsylvania Attorney General obtained an injunction against
Ananas, Inc., a Canadian company that was marketing bromeline products in
Pennsylvania . The company's claims included:
- Users would lose up to 20 pounds in two weeks and never be hungry.
- No dietary changes or exercise would be necessary
- Ananas Bromeline was an astonishing discovery of German researchers
who found an enzyme that digests 900 times its own weight in fat.
- Six to eight Bromeline capsules per day will force your organism to
dissolve all of its excess fats.
- In a controlled medical tests three people lost their excess weight
while eating more than usual.
- After breing absorbed into your bloodstream, Bromeline attacks surplus
fat in your hips, thighs, stomach, buttocks, and calves, to uniformly reduce
- Bromeline will drain fatty accumulations out of your body.
The Attorney General charged that all of the above statements was fraudulent,
false, or misleading. The Complaint noted that the company had received
approximately 11,000 orders totaling $385,000. I served as a consultant
in the case. My report pointed out:
- No nonprescription product can produce weight reduction without reducing
caloric intake. Nor can most people lose weight without increasing the
amount of exercise they do.
- Weight loss is a matter of arithmetic. There are about 3500 calories
stored in a pound of fat. The solicitation claims that 98% of people using
the product lost an average of 1.8 pounds a day. That would require an
average deficit of 6,300 calories per day. This claim is absurd. Most people
who lead a moderately active life need about 15 calories per pound to maintain
their weight. Such a person with a steady weight of 200 pounds would consume
about 3,000 calories per day. Even fasting (which would be very dangerous
after a few days) would not result in loss of a pound of fat per day. (Starvation
will trigger loss of body fluid, but that is unsafe and does not contribute
to meaningful weight reduction.)
- Literature for the product claims that a controlled experiment demonstrated
weight loss among people in Brussels who took Bromeline capsules. But no
reference for this alleged study is cited.
- Bromelain is not absorbed into the bloodstream and transported throughout
the body. Bromelain is a protein. When eaten by humans, it is broken down
into its component amino acids and is not absorbed intact into the body.
Even if it were absorbed and could "attack surplus fat," the
breakdown products would be reassembled into fat and not "efficiently
eliminated by your body's natural functions."
- 1. Tyler VE, Brady LR, Robbers JE. Pharmacognosy, 9th edition. Philadelphia,
Lea & Febiger, 1988.
- 2. Commonwealth of Pennsylvania vs. Ananas, Inc, and Margaret Agnes
Lebovits. Civil action No. 95-165, Court of Common Please of Centre County.
Judicial order, Jan 24, 1995.
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This Article was posted on October 18, 1999.