Dietary Supplements Can Cause Liver Damage
More Research and Regulation Is Needed
Medical Author:
Tse-Ling Fong, MD
Medical Editor:
Leslie J. Schoenfield, MD, PhD
Medical Reviewing Editor:
Dennis Lee, MD
Dietary supplements, which are also referred to as health supplements,
include herbal products, vitamins, minerals, and any product that is not being
marketed as a food or drug (medication). People take dietary supplements with
the idea of maintaining or improving their health. Recently, however, my
colleagues and I reported in a medical journal a series of seven patients who
were referred to us with severe liver injury. They developed the liver damage
after taking a health supplement called Lipokinetix® to lose weight. This
supplement is a mixture of chemicals that includes an extract from a particular
tea. It is said to reduce weight by working to mimic exercise and increase
metabolism.
How and why can dietary supplements damage the liver? Within three months of
starting Lipokinetix, these seven patients developed symptoms of acute
hepatitis, including tiredness, loss of appetite, and abdominal pain. They
sought medical attention and their blood tests revealed severe liver damage. One
of the patients actually developed acute (rapid) liver failure and almost
required a liver transplant to save her life. After being in a coma for three
days, she miraculously recovered and was able to leave the hospital. Indeed, in
all seven patients, the symptoms disappeared and the liver tests returned to
normal within several months after discontinuing Lipokinetix. That said, I have
since been informed of another individual who took this same supplement,
developed acute liver failure, and did require a liver transplant. She is doing
well now. However, so that her body can continue to accept the new (foreign)
liver, she will be taking powerful anti-rejection medications for the rest of
her life.
But that's not all! Numerous instances have been reported in the medical
literature of dietary supplements, especially herbal products, causing liver
damage. These supplements include kava (which has received much recent coverage
in the press), Jin Bu Huan, germander, chaparral, shark cartilage, and
mistletoe, to name a few. Dietary supplements can cause liver injury in a number
of different ways. In some instances, for example with kava, liver injury is
dose-related. That is, the higher the dose, the more often liver damage occurs.
In many instances, however, liver injury is an unpredictable peculiarity in an
individual (an idiosyncratic reaction).
It is well known that people often take combinations of herbal and/or other
dietary supplements. In this circumstance, if a person develops severe liver
injury, identifying which supplement is the specific culprit is very difficult.
What's more, as the dietary supplement market becomes more competitive, the
manufacturers of supplements are mixing and matching their products and doing so
in proportions that have never before been tried. A case in point is the
above-mentioned Lipokinetix, which contains among its ingredients an
ephedrine-like stimulant, a type of thyroid hormone, and the tea extract.
The main problem is that the Food and Drug Administration (FDA) does not
regulate the manufacturing process for dietary supplements, as it does for
conventional drugs. You see, the FDA cannot consider a dietary supplement to be
a food or a drug. Thus, the purity of dietary supplements is determined and
reported to the public by the manufacturer only. Moreover, the dosage of these
supplements is determined by the manufacturer and is often without scientific
support or data that is published in peer reviewed scientific journals.
Furthermore, the FDA requires no pre-marketing animal or clinical testing of
dietary supplements, as it does for conventional drugs. Additionally, physicians
report adverse events only voluntarily when they happen to encounter them.
Therefore, as long as the manufacturer does not make an outrageous claim
about their product, and does not market the product as a food or a drug, these
supplements end up on the store shelves without much, if any, scrutiny by the
FDA. It turns out that designating a health product as a dietary supplement is a
loophole created by the 1994 Dietary Supplements Health and Education Act. (The
term "dietary supplement" implies an addition to the diet of something
that is already present in the food we eat.) This loophole enables the producers
of dietary supplements to avoid FDA regulation of the manufacturing of these
products. Well, this situation regarding the rather loose regulation of dietary
supplements makes me nervous. I am concerned, especially when considering that
conventional drugs (medications) are subjected to a fairly rigorous review
process.
What is the review process for conventional drugs? For a drug to be released
on the market in the U.S., it must go through many steps, including extensive
testing in animals and three phases of clinical testing in people. In the first
phase, the drug is given to healthy subjects to determine the potential for
adverse effects (toxicity). In doing this, different doses of the drug are
tested to ensure that even a dose that is several times greater than the
intended dose is safe in humans.
In the second phase, the drug is given to patients who actually have the
condition that the drug is intended to treat. This phase usually involves up to
fifty to one hundred patients. Once again, several different doses are tried to
determine the effectiveness and toxicity of the various doses. The goal is to
find the dose that achieves maximal efficacy with minimal (tolerable) side
effects (toxicity).
The third phase usually involves a randomized controlled trial (RCT). In an
RCT, each of usually two groups of several hundred patients with the specific
condition is randomly assigned to receive one of two treatments. One treatment
is the drug that is being evaluated and the other (the control) treatment is
either a placebo (an inactive, so-called sugar pill) or the standard (effective)
treatment for the specific condition. RCTs are usually carried out in a double
blind (masked) fashion. This means that neither the patients nor the physicians
caring for and evaluating them know which treatments the individual patients are
receiving until the study is completed. A drug safety monitoring board
consisting of independent experts that are unrelated to the manufacturer and
researchers is usually appointed to oversee the study.
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