What You Need to Know First
If you are thinking about using dietary supplements such as
vitamins, herbs, or any product made from plants (botanicals) as part
of your cancer treatment, you need to consider your choice carefully.
Right now, few governmental standards are in place to control the
production and ensure the safety, effectiveness, and quality of dietary
supplements. Although the U.S. Food and Drug Administration (FDA) put
out new regulations in 2007 to help improve the safety and consistency
of supplements, some of these rules will not be fully in effect until
2010. Even then, there are concerns about what will not change under
the new rules. So it still falls to you, the consumer, to gather
truthful information about using these products safely.
Like drugs, dietary supplements have risks and side effects.
They can usually be used safely within certain dosage guidelines. But,
unlike drugs, dietary supplements are mostly "self-prescribed," with
little or no input from informed medical sources like doctors, nurses,
or pharmacists. There is a lot of wrong information out there. Often,
there is not enough reliable information about the safe use and
potential risks of dietary supplements.
As part of its activity to monitor supplement safety, the U.S.
FDA gathers reports of illness, injury, or reactions from supplements.
However, before December 2007, supplement makers were not required to
report serious harmful effects to the FDA, so most of these events were
not reported. Exposures to supplements (such as vitamins and herbs or
botanicals) accounted for nearly 24,000 calls to U.S. poison control
centers in 2005 alone. Of these calls, there were more than 212
moderate to severe outcomes, and 13 resulted in deaths. More than 350
of these cases were described as "adverse reactions." It is safe to
assume that most people who suffered unexpected side effects,
illnesses, or drug interactions from dietary supplements did not call a
poison control center. That means that these numbers are likely to be a
very low estimate of actual events.
This is not to say that used properly, certain dietary
supplements cannot reduce the risk of some diseases, relieve or reduce
discomfort caused by certain drugs or conditions, or simply improve
your quality of life. However, particularly in the case of people who
are getting treatment for cancer, taking dietary supplements can be
For example, some dietary supplements can cause skin
sensitivity and severe reactions when taken while receiving radiation
treatments. Patients having radiation treatment should talk to their
doctors before taking any supplement. Also, patients getting
chemotherapy may be at higher risk for drug interaction if they take
dietary supplements. Cancer experts often recommend that these patients
avoid dietary supplements altogether.
Keep in mind that most of what you hear or read about dietary
supplements is based on anecdotal evidence -- that is, evidence based
on people's (even doctors') personal experiences or opinions rather
than objective, controlled scientific studies.
Be skeptical of sources that make grand claims based on a few
people's testimonials or vague references to "scientific proof." The
rule "if it sounds too good to be true, it probably is" usually applies
to such claims. Remember also that the makers and sellers of
supplements have a vested interest in promoting their products. Look
for evidence or research on the supplement from objective, third-party
sources wherever possible.
Regardless of your treatment, it is always safest to talk with
your doctor about the exact amount of each supplement you plan to take
before starting on a supplement regimen.
Talking With Your Doctor
Many doctors are just starting to learn about the uses, risks,
and potential benefits of dietary supplements. In some cases, this can
widen the gap between patient and doctor when it comes to using
supplements along with a mainstream treatment. This situation should
improve as more studies are done and better information becomes
We encourage you to gather as much information as possible on
the dietary supplement you are thinking about. Then, approach your
doctor with the information you have, and ask for an open conversation.
Ask for his or her professional opinion as to whether the treatment is
safe and medically sound, and how it might be safely added to your
The American Cancer Society has compiled the following basic
information about choosing safe dietary supplements. If you are
thinking about taking a dietary supplement, you may find the following
information and suggestions helpful.
Common Misconceptions About
Megadosing: The "More Is Better"
Many people wonder why dietary supplements such as vitamins,
herbals, and botanicals are sold over the counter or without a
prescription from a doctor, while medications (or drugs) are more
closely regulated and controlled. People often make the mistake of
assuming that because supplements are sold over the counter, sometimes
with little or no direction on the label, they are completely safe to
take, even in high doses. In the 1990s there was a trend of
"megadosing" antioxidants such as vitamin C, beta carotene, and vitamin
E. Even though no scientific studies have ever proven that large doses
of vitamin C can prevent or cure colds, many people still think this is
true. You may have heard a number of claims about the benefits of
taking large doses of certain vitamins. But the practice of using large
doses of vitamins to fight disease in humans is not supported by the
available scientific evidence.
In fact, large doses of some vitamins or minerals can be
dangerous and toxic. For example, too much vitamin C can interfere with
the body's ability to absorb copper, a metal that is essential to our
body chemistry. Also, too much phosphorous can inhibit the body's
absorption of calcium. In addition, large doses of vitamins A, D, and K
are not eliminated quickly by the body and can easily reach toxic
levels when too much is taken. Talk with your doctor before taking
large doses of any vitamin, mineral, or other supplement. Your nurse or
pharmacist may also be able to give you more information on safe
dosages. Even when vitamin doses are not high enough to cause toxic
effects, the overall impact on health may be negative. For example,
several large studies found that, on average, people taking vitamin E
supplements lived no longer than those who didn't. Some even died
sooner, particularly of heart failure.
The "Natural Is Safe" or
"Natural Is Better" Myth
In today’s cultural climate, you will not find much support
for the idea that a man-made or refined substance is better or safer
than one sold in its unrefined, natural state. However, supplements
that claim to be "all natural" are not always better or safer for
people to take than refined or manufactured substances. Keep in mind
that some of the most toxic substances in the world occur naturally.
Poison mushrooms, for example, are completely natural but not safe or
helpful to humans. Many plants in nature are toxic, even deadly, if
Botanical supplements (such as garlic, ginger, ginkgo biloba,
echinacea, and others) are made of plant material, so many of them are
sold as "natural" products. However, plants are made up of many
chemicals. Some of these chemicals can be helpful while others are
poisonous or can cause allergies in humans. Botanicals that market
themselves as "all natural" are not always the most helpful ones, since
they re not refined to remove potentially harmful chemicals.
Botanicals can contain any or all parts of the plant,
including roots, stems, flowers, leaves, pollen, and juices. Different
parts of plants can have very different effects on humans. For example,
dandelion root is a laxative (causes bowel movements), while dandelion
leaves contain a diuretic (chemical that increases urination). If you
decide to use a botanical supplement, make sure you know what parts of
the plant were used in its production. If you are unsure, contact the
company and ask about how they make their supplement.
Also, remember that safety and dose are related. The leaves or
roots of some plants can be safely consumed in small amounts as an
herb. But concentrated extracts sold as liquids or pills may contain
the plant's chemicals in far greater amounts and may not be safe.
The "It's Been Used for
Thousands of Years, So It Must Be Good" Myth
Knowing that a botanical has been used in folk or traditional
medicine for thousands of years is helpful but is not convincing proof
of safety. If small amounts of a plant caused painful or
life-threatening side effects right away, its use is unlikely to have
persisted in folk medicine or traditional medical systems. However,
traditional medical systems of thousands or even hundreds of years ago
did not have the scientific methods to detect long term side effects.
So, if a plant seemed useful over the short term but actually increased
the risk of chronic disease (like cancer, heart failure, or kidney
failure) after years of use, those side effects would have not been
It is also important to find out whether a plant is being used
now like it was in its traditional use. For example, tea prepared from
a certain plant might have been safely used in traditional Chinese
medicine to treat occasional bouts of asthma when given by an
experienced practitioner. On the other hand, daily use of much higher
doses taken in a concentrated form with no professional supervision
might be quite unsafe.
The "It Can't Hurt to Take
Supplements With my Regular Medicines" Myth
Many people also assume that dietary supplements can safely be
taken along with any prescription drugs. This is also not true. For
example, certain botanicals can block or speed up the body's absorption
of some prescription drugs, causing the person to have too much or too
little of the prescribed drug in their bloodstream. Most drug companies
and producers of herbal supplements do not do research on possible drug
interactions, so the risks of taking supplements with many medications
Talk with your doctor about any herbal supplements you wish to
take. He or she can tell you of any known interactions with medicines
you may be taking. Unfortunately, there are always new drugs and
supplements for which interactions have not yet been found. Talk with
your doctor or pharmacist about the chance of interactions if you are
taking newer drugs or supplements.
FDA Regulation of Drugs Versus
All over-the-counter and prescription drugs are regulated in
the United States by the Food and Drug Administration (FDA). Because
dietary supplements (including all forms of botanicals and vitamins)
are not considered drugs, they are not put through the same strict
safety and effectiveness requirements that other drugs are.
FDA Regulation of Drugs
Generally speaking, new drugs are considered by the FDA to be
unsafe until they are proven safe by clinical trials. Clinical trials
are tests done under well-controlled conditions on volunteer humans by
experts, even on drugs sold over the counter (without a prescription.)
The FDA must approve any new drug before it can be legally sold in the
United States. This approval process requires that the drug undergo a
series of several clinical trials. The clinical trials must show
"substantial evidence" that the drug is both safe and effective for
each of its intended uses.
Once the FDA approves the drug, it must be manufactured under
carefully monitored conditions and packaged with complete information
on the best dose, route, and schedule. The package information must
include a listing of known side effects, contraindications (special
conditions under which using the drug would cause too much risk), or
unsafe interactions with other drugs. Once the general public is using
a new drug, doctors are required to report to the FDA any ill effects
their patients may experience. This data ensures that any side effects
not seen in the clinical trials will eventually be found and kept track
of for the safety of other people.
FDA Regulation of Dietary
In 1994, the Dietary Supplement Health and Education Act
(DSHEA) defined dietary supplements as a category of food, and
therefore under different regulations than drugs. They are considered
safe until proven otherwise. Under the DSHEA, dietary supplements
cannot contain any ingredients that may have "a significant or
unreasonable risk of illness or injury" when the supplement is used as
directed on the label, or under normal conditions of use if there are
no directions on the label. If a dietary supplement contains a new
ingredient, the manufacturer must provide the FDA with "adequate proof"
that the ingredient is safe before the supplement is marketed to the
However, manufacturers are not required to test new
ingredients or supplements in clinical trials, which would help find
risks and potential interactions with drugs or other substances. The
DSHEA gives the FDA permission to stop a company from making a dietary
supplement, but only when the FDA proves that the product poses a
significant risk to the health of Americans. They are found unsafe only
cause harm. This approach is the reverse of the way over-the-counter
and prescription medicines are treated.
Because dietary supplements are usually self-prescribed, there
is no controlled system for reporting bad reactions. If a supplement
has unknown side effects or interactions with other drugs, foods, or
supplements, they are not likely to be discovered as quickly as those
of new drugs on the market.
What Kinds of Problems Have
There Been With Supplements and Herbs?
Since they became widely available in 1994, the FDA has found
problems with some dietary supplements. Products such as herbs were
sometimes contaminated with germs, pesticides, or toxic heavy metals.
Others did not contain what was listed on the label at all. Still
others contained more or less than the amount claimed on the label.
Vitamin supplements, for example, were sometimes found to contain much
less than the stated amounts on the labels. Some "herbal" supplements
have been found to contain prescription drugs that were not listed on
their labels. Some of these problems can cause serious health issues
for the consumer.
How to Report Serious Adverse
If you or someone in your family suffers serious harm or
illness as a result of supplement use, first call your doctor or other
health care provider. After you have been treated, you or your doctor
may report the adverse reaction to the FDA by calling 1-800-FDA-1088 or
by going to the FDA's MedWatch Web site. The FDA
considers an adverse event serious if it causes death, a
life-threatening situation, admission to a hospital or a
longer-than-expected hospital stay, permanent disability, a birth
defect, or if it requires medical or surgical care to prevent permanent
impairment or damage. When talking to the FDA, you will need to
- The name and telephone number of the person who got sick or
had the problem; if that person cannot be reached, the FDA will need
the name and number of another person who can give more information if
- A description of the problem and how it was
- The name (including the brand or manufacturer) of the
In addition to the above required information, you will be
asked about the age, weight, and sex of the person who had the problem.
The FDA staff will ask when and how much of the supplement was taken,
and for how long. They will want to know where and when the product was
purchased, lot number, and expiration date if available. This
information is generally not required, but if you can get it, it can
greatly help them follow up on the problem.
In addition to reporting to the FDA, you should notify the
manufacturer of the product (listed on the label) and the store,
seller, or Internet vendor where you bought the product.
Manufacturing Guidelines for
Currently, there are no guidelines in place for the production
of dietary supplements, although this should be improving over the next
few years. It is generally the manufacturer's responsibility to see
that the supplements they produce are standardized, quality products
that meet the specifications described on their label. Many
manufacturers follow careful, consistent production standards and
market only high-quality, correctly labeled supplements. However, some
less scrupulous manufacturers make supplements that contain little or
none of the products listed on the label. Some supplements contain a
larger dose than the label lists, possibly due to poor quality
controls. There have even been reported cases of toxic products.
The Department of Health and Human Services has put out a set
of standards (called Good Manufacturing Processes, or GMPs) for
producing dietary supplements. Until the new standards go into effect,
it may be hard to know whether the supplements contain what the label
says they do.
How Will the New FDA Rules
Affect Herbs and Supplements?
In June of 2007, the FDA announced plans for stronger
requirements for companies that make dietary supplements. The FDA will
require that dietary supplements follow standards called Good
Manufacturing Practices, or GMPs. This means that dietary supplements
- be produced in a quality manner
- not contain any contaminants or impurities
- be labeled with the actual ingredients in the product
The companies do not have to meet these requirements right
away. Large companies have until June 2008, medium-sized companies
until June 2009, and small companies have until June 2010 to comply
with the new rules.
The companies will still sell their products in much the same
manner as before. However, if companies are following the new rule, the
supplements will be more likely to contain what is listed on the label.
The new rule addresses the quality of manufacturing processes for
dietary supplements and the accurate listing of their ingredients on
the label. It is important to know what the new rule does not do.
- The new rule will not limit consumers' access to dietary
- The rule does not address the safety of their
- The rule does not address their effects on health as long
as proper manufacturing techniques are used.
Even so, the improvements in quality and label accuracy will
make supplements less likely to cause harm as long as these rules are
It is important to remember that, like all laws, the new
regulations will not stop manufacturers from selling supplements that
are falsely labeled. It will be up to the FDA and other law enforcement
groups to try and stop criminal manufacturers once they have been
discovered. As quickly as some of these groups have been surfacing,
that may be a challenge. See the ACS document Complementary
Methods for Cancer Management for more
quackery and fraud.
The USP Standard
The U.S. Pharmacopeia (USP) is an independent organization
dedicated to quality control for the strength, quality, and purity of
pharmaceuticals. In 1997, the USP began publishing standards for
dietary supplements. These standards focus on the strength, quality,
purity, packaging, and labeling of dietary supplements and are updated
yearly. The USP also does product testing and site visits for companies
who join their program.
Makers of dietary supplements are not required by law to
adhere to USP standards. Look for the USP notation indicating product
compliance with USP standards on the packaging of any supplement you
consider buying. The new FDA rule may not be as stringent as the USP
standards, so companies that have used these standards before may
continue to do so. You can still look for products that use USP
standards. The label may have the initials USP after the name of the
product, or note that it conforms to USP standards. Some companies have
the initials "NF" for National Formulary on their labels (The National
Formulary is allied with USP, and has standards that more specifically
relate to herbs and botanicals.) Some supplements even have both
Reading Dietary Supplement Labels
Before you buy a supplement, look at the label carefully. It
is easy to misread the claims that are being made about the product.
The manufacturers of dietary supplements are allowed to make 4 kinds of
claims on the labels of their products: nutritional claims, claims of
well being, health claims, and structure or function claims.
Nutritional claims: These are statements about the general
effects dietary supplements, vitamins, and minerals have on diseases
known to be caused by nutrient deficiency. For example, "vitamin C
prevents scurvy." These claims do not need to be approved by the FDA.
However, the label must also state how many cases of the disease occur
in the US. Consumers must weigh the risk of getting the disease in the
US against the potential risks of the supplement itself.
Claims of well being: These are just that-- statements such as
"makes you feel better." These claims also do not require pre-approval
by the FDA. (See the ACS document Complementary
Methods for Cancer Management
for more information on these kinds of effects.)
Health claims: These are statements about known health
benefits of certain compounds. For example, risk-reduction claims such
as "folate may reduce the chance of pregnant women delivering an infant
with neural tube defects" fall into this category. The FDA must
pre-approve all health claims and requires that they be supported by
evidence from scientific studies. Remember that risk-reduction claims
are not the same as prevention claims.
Structure or function claims: These are the most hotly debated
and confusing to consumers. They are claims about the effect of the
dietary supplement on the structure or function of the body. The FDA
published a ruling in January 2000 that explained exactly what kinds of
structure or function claims would be acceptable for dietary
supplements. Dietary supplements may not make any claims regarding the
treatment of disease. However, the following product descriptions are
acceptable as structure or function claims for dietary supplements:
- The product's mechanism of action ("works as an
- The product's effects on cellular structure ("helps
- The product's effects on the body's physiology ("promotes
- The product's effects on chemical or laboratory parameters
normal blood glucose")
- Claims of maintenance ("helps maintain a healthy
- Other non-disease claims ("helps you relax")
- Claims for common conditions and symptoms related to life
("reduces irritability, bloating, and cramping associated with
Structure or function claims are not reviewed by the FDA. In
fact, labels that carry them must also include the disclaimer "This
statement has not been evaluated by the Food and Drug Administration.
This product is not intended to diagnose, treat, cure, or prevent any
The FDA requires this disclaimer on supplement labels because
it is easy for consumers to misunderstand structure or function claims.
For example, many consumers believe that a statement such as "helps
maintain vision acuity" means the product has been proven to prevent
vision loss, or that a statement such as "helps maintain a healthy
prostate gland" means the product has been proven to prevent or remove
diseases such as prostate cancer. Do not assume that because a product
claims to support or promote healthy body function that it prevents or
reduces the risk of any disease, including cancer. Products that are
proven to have a significant effect on any disease are considered drugs
by the FDA and are strictly regulated as such.
Guidelines for Choosing Safe
Dietary Supplement Products
- First, speak with your doctor or other health care provider
about any supplement you might consider taking. He or she can probably
tell you if the supplement has any risks to your health and if the
supplement is safe to take with other medications you may be
- Find information on the product written by recognized
or government agencies. Bring this information to your doctor's
attention. You can start on the Web by visiting the National Institutes
of Health’s Office of Dietary Supplements at
http://dietary-supplements.info.nih.gov/ and clicking on "Health
- When you shop for supplements, look for USP or NF on the
- If you are shopping for a botanical, make sure to find a
uses only the effective part of the plant. Avoid botanicals that have
been made using the entire plant, unless the entire plant is
- Remember that a product described as "natural" is not
safer or more effective.
- Consider the name and reputation of the manufacturer or
Is it a nationally known name? Large companies with a reputation to
uphold are more likely to manufacture their products under strict,
- Does the label provide a way to
contact the company if you have questions or concerns about their
product? Reputable manufacturers will provide contact information on
the label or packaging of their products.
- Contact the manufacturer
and ask about their quality control procedures and manufacturing
- Try to avoid mixtures of many different supplements. The
ingredients, the greater the chances of harmful effects.
supplements priced significantly lower than similar products; they are
likely to be of lower quality.
- Avoid products that claim to be "miracle cures,"
"new discoveries," to have benefits but no side effects, or to be based
on a "secret ingredient" or method. Such claims are almost always
fraudulent, and the product may contain potentially harmful substances
- Avoid products that claim to be effective treatment for a
variety of unrelated illnesses. If a supplement claims that it can
diagnose, treat, cure, or prevent disease, such as "cures cancer," the
product is being sold illegally as a drug.
- Avoid products that claim
to be safe or effective based solely on testimonials.
More Information from Your
American Cancer Society
We have selected some related information that may also be
helpful to you. These materials may be ordered from our toll-free
Methods for Cancer Management
for Using Complementary and Alternative Methods
American Cancer Society Operational Statement on Complementary and
Alternative Methods of Cancer Management
National Organizations and Web
In addition to the American Cancer Society, other sources of
patient information and support include:
National Institutes of Health
Office of Dietary Supplements
Telephone: (301) 435-2920
Internet Address: http://ods.od.nih.gov/
U.S. Department of Health and Human Services
Internet Address: http://www.hhs.gov (click on "Drug & Food Information")
U.S. Pharmacopeia (USP)
Internet Address: www.usp.org
U.S. Food and Drug Administration
Telephone: 1-888-INFO-FDA (1-888-463-6332)
Internet Address: www.fda.gov
Center for Food Safety and Applied Nutrition (CFSAN)
Telephone: 1-888-SAFEFOOD (1-888-723-3366)
Internet Address: www.cfsan.fda.gov
Telephone: 1-800-FDA-1088 (1-800-332-1088)
Internet Address: www.fda.gov/medwatch
*Inclusion on this list does not imply endorsement by the
American Cancer Society
No matter who you are, we can help. Contact us anytime, day or
for information and support. Call us at 1-800-ACS-2345 or visit
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