Supplements provide essential nutrients like vitamins, minerals, fiber, and probiotics. They can help fill gaps in your diet and support your overall health.
How Can Supplements Fit Into Your Diet?
Dietary supplements are primarily used as a way to supplement—add to—your diet. Some people take supplements to ensure they get enough of a particular nutrient each day.
Someone who follows a vegetarian, vegan, paleo, or ketogenic (keto) diet may not consume the daily recommended amounts of certain nutrients, like B vitamins.1 They may take supplements to bridge this gap. Others might use supplements to address a known vitamin deficiency.
Many adults in the United States take supplements to boost their daily consumption of key nutrients like:2
Calcium
Iron
Vitamin D
Potassium
Magnesium
Vitamin B12
Vitamin C
Vitamin A
Folic acid
Fiber
Some people also take supplements to relieve the symptoms of a diagnosed health condition, prevent health problems, or provide certain health benefits.
A few common examples include:3
Using melatonin to treat insomnia
Taking fiber supplements to regulate bowel movements
Taking vitamin D or calcium to prevent bone loss
What Are the Different Types of Supplements?
There are many different kinds of dietary supplements. Common types of supplements include:3
Multivitamins: These supplements contain a mix of several vitamins and minerals in the recommended amounts. Often, they are once-daily pills for general health. Some may be marketed as having a specific benefit, such as increased immunity or energy, and can include additional ingredients.4
Individual vitamins: Supplements can be one vitamin, such as vitamin C or vitamin D, and may be used to target a specific deficiency.
Minerals: Supplement forms of a particular mineral, such as potassium and calcium, can be used to manage a deficiency.
Botanicals: Herbs and botanical compounds, such as ginger and caffeine, are often used for their purported health benefits, such as decreasing inflammation or increasing energy.5
Probiotics: Probiotic supplements are meant to support the growth of beneficial bacteria in your gastrointestinal tract.6
Amino acids. These supplements can contain any of the nine essential amino acids or other non-essential amino acids. As the building blocks of protein, amino acids may offer several benefits. For instance, supplements to support athletic performance and recovery may contain amino acids.7
What Benefits Can They Offer?
Vitamins and minerals are involved in many of your body's most essential functions, and offer a wide variety of potential health benefits.2
Here are some of the purported benefits associated with some popular dietary supplements:
Calcium: Increases bone density, prevents fractures among older adults (especially women who have gone through menopause), and prevents preeclampsia during pregnancy8
Vitamin D: Improves the body's ability to absorb calcium and preventing osteoporosis9
Magnesium: Decreases blood pressure and migraine frequency10
Folate/folic acid: Lowers the risk of certain birth defects when taken during pregnancy, makes antidepressants more effective, and lowers the risk of stroke (when taken alongside B vitamins)11
Iron: Prevents iron deficiency anemia and lowers the risk of premature birth and low birth weight during pregnancy12
Can They Really Make a Difference?
The available clinical evidence about whether or not dietary supplements work is mixed. Studies suggest some dietary supplements do what their manufacturers claim, while others indicate they don't work as advertised.
For example, there's no evidence the herbal supplement gingko biloba works to prevent the effects of cognitive decline, despite its popular use for this benefit.13
The U.S. Food and Drug Administration (FDA) regulates dietary supplements. It does not require manufacturers to demonstrate their products' effectiveness and safety before putting them on the market.
This means the health claims on a supplement label don't have to be verified or vetted before they're sold for human consumption.13 However, some research about the health benefits of dietary supplements is promising.
Here are a few study findings about the efficacy of select supplements:
Daily iron supplementation has been shown to lower the risk of anemia in pregnant people.14
Taking folate (folic acid) lowers the risk of some neural tube defects, such as spina bifida, in infants.15
Fiber supplements have been shown to relieve chronic constipation and lower cholesterol.16
Risks To Watch Out For
For most people, taking common dietary supplements (such as multivitamins) is safe and doesn't pose serious health risks.
However, anyone can have an adverse reaction to a supplement—particularly if you take a large dose or not as directed. The side effects of taking too much of a given supplement vary widely.
Possible complications include, but are not limited to, liver damage, excessive bleeding, and stroke.1713
Signs of a serious adverse reaction to a supplement may include:17
Stomach pain
Nausea or vomiting
Lightheadedness or fatigue
Chest pain
Difficulty breathing
Rapid heart rate
Difficulty urinating or dark urine
Diarrhea or bloody stool
Loss of appetite
Unintended weight loss
If you are allergic to a supplement or supplement ingredient, you may experience an allergic reaction. This can present as a rash or hives, itching, and swelling in your throat, tongue, or lips.17
Seek emergency medical help if you experience any of the above symptoms or reactions.
Drug Interactions
Certain supplements may also have harmful interactions with medications and other supplements. Taking multiple supplements or combining supplements with prescribed medications may increase the risk of side effects or make your medication less effective.18
The herbal supplement St. John's wort can make antidepressants and birth control pills less effective. Certain antioxidant supplements like vitamin C and vitamin E can decrease the impact of chemotherapy treatments.18
Several supplements also interact negatively with blood-thinning medications, either increasing or decreasing their effectiveness. Vitamin K may lower the effectiveness of the blood-thinner Warfarin (Coumadin).18
Tips for Safe Supplement Use
There are steps you can take to make sure you are using supplements safely and appropriately.
If you are taking a supplement or thinking about starting a supplement, try to follow these guidelines:13
Talk to a doctor before taking any supplements. Let them know about any other supplements and medications you're taking.
Take supplements exactly as directed on the product label.
If you experience any side effects from a supplement, stop taking it immediately and seek medical help.
Contact a doctor before starting (or continuing to take) any supplements if you are pregnant or breastfeeding. Many dietary supplements on the market have not been tested for safety in people who are pregnant or breastfeeding.
If you're scheduled for surgery, let a doctor know about any supplements you're taking. Some can interfere with the effectiveness of anesthesia and increase your chance of abnormal post-operative bleeding.
Important Things To Keep in Mind
Most experts do not recommend using supplements as a substitute for food sources to meet your daily intake of certain essential nutrients.
There is also not enough research to support the benefit of taking an excess of certain nutrients through supplements. Some nutrients can be harmful in very high doses. When possible, it's often better to get the nutrients your body needs through food rather than supplements.19
Supplements also cannot replace the medications you've been prescribed to treat any particular health condition. If you are interested in the potential benefits of supplements, make sure to discuss the uses and risks of the supplement with a doctor.
