What to Look For in Vitamins & Supplements

Reviewed by Dr. Jonathan Bonnet, MD, MPH, Judy Singer, RD and Heather Hodson, RD

Taking steps to improve your health can include a variety of self-guided strategies, including incorporating manageable and joyful movement and various stress management techniques into your daily routine.

Many adults are also drawn to the use of vitamins and supplements to boost their intake of specific minerals, botanicals, enzymes, and other ingredients.

But do these products really work to improve your health? And are there any instances in which taking a vitamin or dietary supplement can be harmful?

Here we dive into the evidence behind vitamins and supplements to help explain what they are, when they should be used, and how to source high-quality options when needed.

What are vitamins and supplements?

Vitamins and dietary supplements are products that can contain minerals, vitamins, herbs, botanicals, enzymes, amino acids, and many other ingredients. Some of these ingredients are derived from natural sources while others are created in a laboratory.

There are over 90,000 dietary supplements available on the market. Most are advertised as a tool to help support certain benefits, like a stronger immune system or healthier heart, but these claims are not necessarily supported by scientific evidence or tested by the Food and Drug Administration (FDA).

Nationally, vitamin and supplement use is on the rise. Research shows that more than half of adults in the US use dietary supplements, contributing to the annual sales of these supplements surpassing $11 billion. But data also shows that only 23% of the products being used are based on the recommendations of a healthcare provider.

According to survey data from 2013, the most common uses for dietary supplements include:

  1. Improving or maintaining overall health

  2. Supporting bone health in women

  3. Supporting heart health in men

However, concerns about the safety and effectiveness of many of these supplements exist.

How do I know if I need vitamins and supplements?

The reality is, most people in the US (and other developed countries) do not need to take vitamins or supplements. This is because most of us are able to get all the vitamins and nutrients we need from a balanced diet of whole foods.

What’s more, evidence shows that people who eat a balanced diet reap positive health benefits that cannot be obtained through supplement use alone.

However, there are some instances in which a provider may recommend taking a dietary supplement:

  • If you’re pregnant or planning to become pregnant

  • If you follow a very specific or narrow diet (i.e. vitamin B12 deficiency among vegans)

  • If you are at risk for being deficient or have been deficient in any nutrient previously (i.e. low vitamin D levels or don’t get much sun exposure)

  • If you’re an elite athlete your provider may recommend caffeine, creatine, sodium bicarbonate, carbohydrates, protein, or beta-alanine supplements, depending on the sport

  • If you have certain medical conditions such as:

    • Osteoporosis. In this case your provider may recommend a supplement to boost your vitamin D or calcium intake

    • Certain gastrointestinal conditions. Depending on the issue, different vitamins and minerals may need to be supplemented

    • If you’ve had bariatric surgery, you’ll generally need lifelong supplementation to prevent multiple nutrient deficiencies

Lab tests have been developed to check levels of most micronutrients. If there is a concern about having low levels or if you are having symptoms that might be related to a nutrient deficiency, lab tests can help figure out if you’re low or would benefit from supplementation.

When in doubt, ask your provider about whether your micronutrient levels should get checked and whether or not you should be taking a vitamin or dietary supplement.

Are vitamins and supplements safe?

Though the FDA oversees the vitamin and dietary supplement industry, they do not test the products to confirm safety or efficacy (like they would with a new drug or treatment brought to market).

For this reason, regulation of these products is impossible—meaning that among the wide variety of products available, some may be unsafe to use.

Here are some of the risks to consider when shopping for vitamins and dietary supplements:

  • Some supplements are contaminated with or have unreported ingredients that can be dangerous: Evidence shows that some of the ingredients in dietary supplements and vitamins can be toxic or pose certain risks.

  • Some ingredients in high doses can be dangerous: Research shows that there can be “too much of a good thing” when it comes to supplements. One landmark study used beta-carotene supplementation thinking that it would decrease cancer risk in smokers, however, the data showed that supplementation actually ended up increasing the risk of lung cancer.

  • Some products may cause harmful interactions when taken with certain medications: Certain vitamins and dietary supplements can cause adverse reactions when mixed with medication. For example, vitamin K can reduce the effectiveness of the blood thinning medication warfarin, St. John’s wort can reduce the effectiveness of some birth control medications, heart medications, anti-HIV medications, and transplant drugs, and vitamins C and E may reduce the effectiveness of some types of cancer chemotherapy.

  • Other side effects are possible: The active ingredients in vitamins and dietary supplements can cause strong reactions in some people. Be sure to keep your provider informed if you experience any unwanted side effects, like vomiting, nausea, diarrhea, headaches, and more.

  • Some supplements can increase the risk of bleeding or change your response to anesthesia: If you take blood thinners or are planning upcoming surgery, talk to your provider about all of the supplements or vitamins you’re currently taking or planning to take.

What to look for when buying vitamins and supplements

Before shopping for vitamins or supplements, speak with a provider to determine if you need to take these products and, if so, how to source high quality options.

In addition to your provider’s recommendations, there are a few third-party groups who work to test and certify some supplements. Since the FDA does not regulate these products or what’s inside them, these groups help to keep an eye out for unwanted ingredients, including heavy metals, bacteria, and pesticides.

Finding a product with a certification from one or more of these agencies can help you determine a higher quality product:

  • The National Science Foundation (NSF)

  • U.S. Pharmacopeia (USP)

  • Consumer Lab (CL)

Additionally, you may wonder about the bioavailability of a supplement when shopping for options. Bioavailability (the amount of a substance that is able to have an active effect on the body) is specific to the supplement in question and can vary depending on the formulation of the supplement, how the supplement is metabolized as well as on the administration route (oral pills, sublingual tablets, etc.) If you’re concerned about receiving a steady dose of a specific supplement, be sure to follow the recommended dosing instructions. Some will require repeat dosing while others may have formulations that are marketed as “sustained release.” You can always reach out to your provider for their recommendations.

It’s also good to keep in mind that while combining supplements can sometimes provide additional benefits, it can also counteract their use. If you’re unsure about whether or not to combine multiple supplements, reach out to your provider first.

The bottom line

After the last two years, taking control of your health is more important than ever. But not every “health and wellness” product on the market will lead to living a better quality life. In fact, some of these products may even pose a risk to your health.

In general, it’s important to keep in mind that maintaining a balanced diet rich in whole foods is the best foundation for meeting your daily micronutrient requirements.

This is why it’s vital to find a flexible and reliable provider you trust to help you identify your personal health risks and needs.

With Forfend, we can help you get the right labs and tests done to understand your individual health risks and create a customized care plan for you.


Adverse Effects of Nutraceuticals and Dietary Supplements. (2018).

Effects of Beta-Alanine Supplementation on Physical Performance in Aerobic-Anaerobic Transition Zones: A Systematic Review and Meta-Analysis. (2020).

Ergogenic Aids: Counseling the Athlete. (2001).

How to Choose Supplements Wisely. (2019).

Liver Injury from Herbal and Dietary Supplements. (2017).

Strengthening Knowledge and Understanding of Dietary Supplements. (2020).

The effect of vitamin E and beta baritone on the incidence of lung cancer and other cancers in male smokers. (1994).

Vitamin and Mineral Supplements: Do We Really Need Them? (2012).

Vitamins and Nutritional Supplements: What Do I Need to Know? (2019). Why US Adults Use Dietary Supplements. (2013).

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