8 Reasons You May Need a Dietary Supplement, According to an Expert

Various pills and capsules, vitamins and dietary supplements in petri dishes on a beige background

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It seems as if everyone is taking one supplement or another. In fact, dietary supplements are a more then $60 billion industry in the United States.

Regardless of whether you want to get stronger, boost your immunity, or correct a deficiency, a supplement may be right for you. While nothing replaces nutrients coming directly from food, supplements may play a necessary role in your diet.

But choosing a dietary supplement can be tricky, which is why its important to turn to healthcare experts for evidenced-based recommendations. Supplements range anywhere from vitamins and minerals to omega-3 fatty acids and branch chain amino acids.

And while they may not always be medically indicated, there are some instances where they may be helpful. Here are some potential reasons you may need a dietary supplement.

You Have an Identified Deficiency

If you are concerned about a nutrient deficiency, it is always a good idea to have bloodwork done to obtain the data first. Then, if you have evidence of a deficiency, talk with a healthcare provider about supplements you may need to correct it.

The most common deficiencies in the U.S. are vitamin B6, iron, and vitamin D. If your bloodwork indicates a deficiency in any of these nutrients, a supplement may be warranted.

Vitamin B6 is a water-soluble vitamin is that is naturally present in many foods. It is responsible for a number of important functions in the body, including protein, carbohydrate, and fat metabolism. Vitamin B6 also plays a role in cognitive development, immune function, and hemoglobin formation.

Vitamin B6

A deficiency in vitamin B6 is associated with microcytic anemia, cognitive abnormalities, dermatitis with cheilosis (cracks at the corners of the mouth), glossitis, depression, confusion, and weakened immune function. B6 deficiency can also result from diseases that cause malabsorption, such as celiac disease, Crohn's disease, or ulcerative colitis.

Vitamin B6 is commonly found in multivitamins or as a stand-alone supplement. Taking a supplement if recommended by your healthcare provider can help alleviate symptoms of deficiency.


Another common deficiency, particularly in women, is iron. Its primary role is to support erythropoiesis, or the formation of red blood cells. Every cell and organ system requires iron for proper development and metabolic function.

Iron-deficiency anemia occurs when you do not have enough iron in your blood, and therefore, a decreased level of hemoglobin in your red blood cells, causing a deficiency in the oxygen delivered to your tissues. Common causes of iron-deficiency include loss of blood to heavy menstruation or pregnancy, a poor diet, or intestinal diseases that affect how iron is absorbed.

Symptoms of iron deficiency include fatigue, weakness, pale skin, shortness of breath, dizziness, and cold hands and feet. Taking iron supplements can help restore iron levels in your body and solve issues related to anemia.

Vitamin D

The best source of vitamin D is from sunlight and because many parts of the country do not get adequate sunlight all year round, vitamin D deficiency is common. Vitamin D is important for immune health and it is critical to bone health.

It also may help protect against cancer, depression, type 2 diabetes, heart disease, and multiple sclerosis. Symptoms of vitamin D deficiency include frequent illness or infections, fatigue, bone and back pain, depression, impaired wound healing, bone loss, and muscle pain.

Oral supplements are a go-to treatment for vitamin D deficiency. Ask a healthcare provider for the recommended dosage based on your unique situation.

You Are at Risk for a Specific Deficiency

Certain conditions may put you at risk for a specific deficiency. If this is the case, your healthcare provider will likely have you obtain regular bloodwork to monitor your nutritional status.

For instance, if you have a gastrointestinal disorder such as celiac disease, Crohn's disease, or ulcerative colitis, you have an increased risk of calcium, magnesium, zinc, iron, vitamin B12, folate, and vitamin D deficiencies. Additionally, if you have gastric surgery such as a bowel resection or bariatric surgery, you are at risk for the same deficiencies and supplements are likely needed.

A number of prescription medications may cause depletion of certain nutrients as well. For instance, some cancer drugs cause folate deficiencies. Meanwhile, angiotension-converting enzyme inhibitors—a blood pressure medication—competes with binding sites for zinc.

About 6% to 30% of individuals who take metformin for diabetes management show vitamin B12 deficiencies. The severity of the deficiency depends on the dose and duration of treatment. A B12 supplement may be needed to correct for this deficiency.

You Follow a Vegan Diet

If you follow any diet that removes certain food groups, you may be at risk for a deficiency. There are a number of nutrients that are either most available or only available in animal products. Vegans are at risk for deficiencies of these nutrients that are not as prevalent in plant-based foods.

These nutrients include calcium, iron, zinc, vitamin B12, vitamin D, protein, and omega-3 fatty acids. One study assessed the nutrition status of vegans who took supplements and non-vegans. The study found very little difference between the groups, which was attributed to the high rate of supplementation.

You Don't Get Enough Protein

If you follow a vegetarian or vegan diet or you have a preference for foods lower in protein, you might be at risk of not getting enough protein. Not eating enough protein can result in poor growth, anemia, physical weakness, edema, vascular dysfunction, and impaired immunity.

Using protein powder to supplement your protein intake can be a convenient way to increase your protein intake. Add protein powder to smoothies, soups, baked goods, and oatmeal.

Your Goal Is to Gain Muscle

In addition to strength training and eating enough overall calories, if your goal is to gain muscle, you may need additional protein and supplements. According to the American College of Sports Medicine, to increase muscle mass it is recommended that a person who lifts weights regularly eat between 1.2 to 1.7 grams of protein per kilogram of body weight per day.

While it is always good to get your protein through food, protein powder can be added to meals and snacks for an extra boost to make sure you are meeting your needs. Studies show that creatine can also help to increase muscle mass, strength, and exercise performance. On a molecular level, creatine shares similarities with amino acids, the building blocks of protein.

Your body produces creatine from the amino acids glycine and arginine. Research shows that taking creatine can alter several cellular processes that lead to increased muscle mass, strength, and recovery.

Another important supplement you may need for muscle gain are branched-chain amino acids (BCAAs). They are a group of three essential amino acids, leucine, isoleucine, and valine, that cannot be produced by the body. They must be consumed through food or supplements. While many people eat enough protein foods that contain these amino acids, there is evidence that taking a BCAA supplement can help increase muscle growth and maintenance.

You're Pregnant (or Looking to Become Pregnant)

Your body has increased nutritional needs during pregnancy and you may want to get your body ready for pregnancy from a nutritional standpoint as well. For all pregnant people, it is recommended to take a prenatal vitamin.

You'll want to look for a prenatal vitamin that includes enough calcium, folate, choline, iron, and omega-3 fatty acids that are essential during pregnancy. Your healthcare provider or prenatal dietitian can advise you on what vitamin or combination of vitamins are best for you based on your individual diet and needs.

You Want to Boost Your Immunity

Good nutrition and getting enough macronutrients and micronutrients are important for a strong immune system. There are many products on the market that may claim to boost your immunity, but be wary of these claims and only use products that are proven.

Research has shown that taking supplements of certain vitamins, minerals, and herbs may help improve your immune response and protect against illness. Vitamin D is important for the health of your immune system. Deficiency in vitamin D is associated with increased risk of upper respiratory tract infections. Studies show that supplementing with vitamin D may help improve the immune response.

Zinc is also a mineral essential to healthy immune function. Zinc is needed for immune cell development and plays a role in the inflammatory response. Research shows that 16% of deep respiratory infections have been found to be due to zinc deficiency.

Perhaps the most commonly taken supplement for the immune system is vitamin C. Vitamin C plays an important role in supporting the function of immune cells and enhances their ability to protect against infection. Research shows that supplementing with vitamin C has been shown to decrease the severity and duration of upper respiratory tract infections.

Black elderberry has been used for many years to treat infections and is now being researched for its use as a supplement for immune health. Elderberry extract contains potent antibacterial and antiviral potential against bacterial pathogens. It is also shown to enhance the immune response and shorten the duration of viral infections.

You're an Older Adult

Not only do certain vitamin and mineral needs increase as you age, but reduced appetite may pose a challenge to getting enough nutrition for older adults. While it best to get your nutrients through food, talk with a healthcare provider to determine if a supplement is right for you.

As you age, there is a decrease in the efficiency by which the skin absorbs vitamin D. Additionally, older adults may get less sunlight. A vitamin D supplement may needed to protect immune and bone health.


Most people can get nutrients they need from a balanced and varied diet. It is also a good idea to take a look at the quality of your diet and see how you can improve it before turning to a supplement.

Not everyone needs a dietary supplement and taking more than you need isn't necessarily better. Always test your blood levels for necessity. And, don't guess when making the decision to take a supplement.

A Word From Verywell

Dietary supplements can certainly serve an important purpose in an individual's diet depending on their needs and nutrition goals. Always consult with a healthcare provider and a registered dietitian before starting a supplement.

A registered dietitian can give you specific recommendations for your individual nutrition needs and goals. Seek guidance if you are feeling any physical symptoms and ask for a blood test that indicates a deficiency—especially if you are pregnant, have medical condition that may put you at risk for deficiencies, or you feel you have any nutritional gaps in your diet.

Frequently Asked Questions

  • What are a few benefits of dietary supplements?

    Supplements can provide extra nutrients when your diet is lacking or you have certain health conditions that may put you at risk for a deficiency. Benefits of supplements include maintaining general health, gaining muscle mass and improving bone mass, and providing immune support.

  • What are the pros and cons of taking dietary supplements?

    The pros of taking a dietary supplement include ensuring you are receiving all micronutrients your body needs. Supplements also can treat a deficiency, and they can promote muscle gain.

    The cons of taking supplements include that they are not regulated by the Food and Drug Administration (FDA) and manufacturers do not have to prove that they are safe or effective. It is important to look for third-party tested supplements. Supplements also can be expensive and may not be necessary to take. Keep in mind, too, that taking too much of certain supplements can have adverse side effects.

  • When should I take dietary supplements?

    You should take a dietary supplement if you have a known deficiency, you are vegan (and are unable to meet your nutrient needs via diet alone), or if you have a medical condition that may put you at risk for a deficiency, such as Crohn's disease or celiac disease. You also want to take a supplement, like a prenatal vitamin, if you are pregnant or looking to become pregnant.

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Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Rebecca Jaspan, MPH, RD, CDN, CDCES
Rebecca Jaspan is a registered dietitian specializing in anorexia, binge eating disorder, and bulimia, as well as disordered eating and orthorexia.