Dietary Supplements: The Basics
encontrar mi
Many people take one or more dietary supplements without thinking about the safety of the products. The products might be promoted as natural, which can be misleading. These products may come from natural sources, but that does not mean they are always safe.
What is a dietary supplement?
Dietary supplements (DS) are things that are added to your diet, like vitamins, minerals, amino acids, herbals, and other botanicals. DS also includes hormone products such as melatonin and other supplement products like glucosamine, chondroitin, probiotics, fish oil, and SAMe. You can tell that an item falls under the DS category because the ingredient label will say "Supplement Facts." You may want to use a supplement if you aren’t getting all your nutrients from food.
Dietary supplements can come in many forms, including tablets/capsules, powders, oils, drinks, or edible items like chews, gummies, or bars.
Are dietary supplements helpful?
Your body best absorbs (takes in) nutrients from their natural source, which is your food. There are many beneficial nutrients in foods. For example, fruits and vegetables contain vitamins, minerals, fiber, and water. It can help you to use a supplement depending on your cancer treatment or if you have a known deficiency (low level). Ask your provider if a supplement would be helpful to you.
A DS is meant to supplement your diet, not to treat, prevent, or cure diseases. The manufacturer (company making the DS) should not make any claims on their labels or marketing to suggest that they do.
Does the FDA regulate dietary supplements?
Dietary supplements are less tightly regulated than prescription or over-the-counter medications, food additives, and even the food we buy. The FDA does not review DS products for safety or effectiveness before they are sold.
The manufacturer needs to be sure the products are safe. The manufacturer must do these things:
- Be sure that any claims made about the supplement are not false or misleading.
- Make its own manufacturing guidelines using clean and consistent practices.
- Ensure that what is on the label is what is actually in the product. This means they do not have any contaminants or impurities, and it has the amount the label says it has.
What are the risks of taking dietary supplements?
While many DS compounds are “natural,” this does not mean they are safe. These compounds can have strong effects on the body and can interfere with your medications. For example:
- Some supplements can affect how well the blood thinner Coumadin works.
- St. John’s wort can reduce how well many medications work because it causes them to break down faster in the body – this includes many oral chemotherapy medicines.
What are some concerns for people who are getting cancer treatment and taking dietary supplements?
Dietary supplements can cause problems while receiving cancer treatments. Antioxidants (Vitamins A, C, E, beta-carotene, selenium and others) may interfere with how chemotherapy and radiation kill cancer cells. Supplements can interact with cancer treatments and other medications, causing them to be absorbed differently. This can either make blood levels higher, leading to more side effects, or lower, causing the medication or treatment to be less effective. Some can raise the risk of bleeding. This is a concern if you have cancer and are at a higher risk of bleeding due to having a low platelet count.
Most providers recommend not taking dietary supplements during treatments. If you choose to take them, make sure your care team knows what you are taking so they can screen for possible interactions and side effects. If you are taking a DS product, be sure it is on your medication list.
Surveys have shown that many patients don’t tell their healthcare teams about supplement use. They may not think it is important or may think that their providers will not understand. Talk with your provider about possible interactions with medications or foods.
How can I choose a quality dietary supplement product?
Start by buying products from reputable retailers and manufacturers.
There are some organizations that check products to make sure they are made correctly and that what is on the label is what is actually in the product. If a company’s product passes their testing, they are given a seal of approval from the organization. These organizations include:
If you have a side effect or reaction to a DS, you should report it to the manufacturer and to the U.S. FDA.
If you have read something about what you are taking, bring it to your appointment for your provider to see. Tell them why you are taking it and talk about possible effects on your other medications and treatments. Some types of DS have false information and prey on cancer patients. Look to reliable resources for information about possible interactions and side effects (see resources below).
Your provider can help you make an educated decision about which supplements you may need or want to use.
Resources for more information
National Center for Complementary and Alternative Medicine
The U.S. Federal Government's lead agency for scientific research on complementary and alternative medicine. Part of the National Institutes of Health.
National Center for Complementary and Integrative Health – How Safe Is This Product or Practice? https://nccih.nih.gov/health/safety/topics.htm
National Center for Complementary and Integrative Health – Alerts and Advisories page https://nccih.nih.gov/news/alerts
National Institutes of Health – Office of Dietary Supplements
An informative website that provides information on vitamins, minerals, and other dietary supplements https://ods.od.nih.gov/