Considerations When Choosing Supplements

By Maya Shetty, BS

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Key Takeaways: 

  • The supplement industry operates with minimal external oversight. Thus, it is critical for consumers to rigorously assess the actual need and proven efficacy of a supplement prior to its use.
  • Most supplement claims lack scientific evidence. Consumers should only consider supplements with solid scientific backing.
  • Opt for brands verified for purity and bioavailability by third-party organizations.
  • Supplements should supplement—not replace—a healthy diet and lifestyle. Emphasize whole foods, physical activity, and balanced health practices over seeking quick fixes.

In an era where every shelf in the wellness aisle promises a solution to your health concerns, supplements stand out as both suspects and saviors. The market is flooded with options: B12 promises to energize you, omega-3 asserts it will curb inflammation, vitamin C and zinc vow to enhance your immunity, and greens powders claim to do everything in between. With so many claims, it’s important to learn how to navigate the supplement world with a critical eye and an informed mind. Stanford Lifestyle Medicine Registered Dietician Marily Oppezzo, PhD, MS, RDN, DipACLM explains how to approach the supplement market and make informed choices for your health.

What is a Dietary Supplement?

Dietary supplements are ingestible products that contain “dietary ingredients” intended to supplement the diet, including vitamins, minerals, herbs, amino acids, fatty acids, live microbials, and protein powders, among many others. Navigating this expansive world requires an understanding of their nature and regulation—or lack thereof. Though many claim to be from natural sources, supplements are essentially laboratory-created entities designed to alter our physiology, underscoring the importance of approaching them with the same level of scrutiny as any medication.

“Just because a supplement is labeled as ‘natural’ or derived from natural sources doesn’t make it healthy, or even safe,” states Dr. Oppezzo. “This is particularly relevant when considering the unnaturally high concentrations [of the nutrient] often found in supplements.”

Despite their widespread use for health-related purposes, dietary supplements are in a regulatory gray area. When it comes to most supplements, the Federal Drug Administration (FDA) is not responsible for ensuring safety, efficacy, purity, or potency. These aspects are managed by the supplement manufacturers themselves (per the Dietary Supplement Health and Education Act of 1994). This means that supplements are exempt from the rigorous testing and validation process mandated for pharmaceuticals, with the FDA stepping in only if enough post-market reports indicate adverse effects. This regulatory gap makes it challenging for consumers to navigate the supplement aisle, emphasizing the importance of thorough evaluation when considering the necessity of a supplement.

Evaluating the Need for a Supplement

While many individuals view supplements as a way to meet their basic nutritional requirements or as a convenient method to optimize health, the reality is that there are relatively few situations where supplements have proven beneficial.

Before taking any supplement, Dr. Oppezzo recommends pausing to consider several key questions: 

  • What is my reason for believing I have a nutritional deficiency or need to take this supplement? Have I spoken to my doctor or taken a blood test to confirm this deficiency? Is there even a test to confirm this?
  • Has a credible source such as a Registered Dietitian or Doctor recommended this to me, or am I influenced by persuasive advertising?
  • What benefits do I expect to gain from taking this supplement? Is there any scientific evidence that this supplement will help me?

Of course, there are circumstances where supplementation can be beneficial. Age, certain medical conditions, and specific lifestyle choices can impact our body’s ability to absorb or synthesize vital nutrients. For instance, older adults might struggle to produce enough vitamin D or B-12 naturally. Athletes engaging in intense training may require additional iron or protein or calories to support their performance levels, while those following vegan or vegetarian diets might need nutrients less common in plant-based foods, such as B-12, omega-3 fatty acids, calcium, and vitamin D.

The most reliable way to determine your nutritional needs is through a professional consultation with a dietitian. This approach allows for a tailored assessment for needs, evaluation of evidence behind supplements you are interested in, and ongoing monitoring to adjust as necessary. 

Assessing Supplement Claims

A significant portion of supplement usage is driven by misconceptions and marketing rather than genuine need. “The wellness industry often races ahead of scientific validation, promoting products with claims that outpace the available evidence,” states Dr. Oppezzo. “They aren’t cutting edge, they are flying out way past the cliff of evidence.”

Addressing this challenge, Dr. Oppezzo encourages consumers to first look for any peer-reviewed studies backing the “need” or the claim of a supplement. Ideally, ask an expert to do this for you. 

While certain supplements, such as vitamin B12, are actually essential nutrients, supported by extensive research, others, like various greens powders and phytochemical blends, lack robust evidence demonstrating their effectiveness throughout the body. The absence of any regulation allows many products to make exaggerated claims without solid proof. As such, many supplement labels contain a hodgepodge of wellness buzzwords, such as “immune booster,” “supports gut health,” and “promotes health aging,” without any science to back up the claims.

Secondly, Dr. Oppezzo urges us to think about its bioavailability—the extent to which it can be absorbed and utilized by the body. Imagine being in the shoes of a supplement itself, considering all the gauntlets it has to pass to do the thing you think it will do and deliver the marketed effects.

Like any ingested substance, supplements are first broken down by the stomach, absorbed in the gut, processed in the liver, incorporated into the bloodstream, and then transported to organs and cells throughout the body. The critical question is whether the supplement can survive this journey in a form that retains its intended benefit and reaches the organ or cell where you think it will do its purported job.

“Let’s put essential vitamins and minerals aside for a moment. Even if there is evidence some supplement or chemical will do something if you dropped it on your cells in a test tube, you don’t know that this translates to your real live body. Further, you don’t even know if the supplement will even succeed at getting inside your body in the first place, let alone maintaining its original ‘active’ structure after it gets inside,” states Dr. Oppezzo.

It’s important to approach supplements with a healthy dose of skepticism and informed judgment. Not all supplements are inherently harmful; some can offer significant benefits when used appropriately. Yet, the decision to incorporate them into your health regimen should be made with careful consideration, guided by credible evidence and, when possible, professional advice. Once identifying the need for a supplement, Dr. Oppezzo recommends the following framework to decide the appropriate brand, dosage, and context for its consumption.

Framework for Choosing a Supplement

1. Assess the Safety and Efficacy

When it comes to supplements, third-party testing is a gold standard for ensuring product safety and efficacy. Organizations like ConsumerLab, US Pharmacopeia, and NSF International offer unbiased supplement evaluations, checking for purity, potency, and safety. Consumers can either check these websites to find a trustworthy supplement brand or look for products that bear their certifications. While some manufacturers conduct their own testing, third-party validation is preferable for an impartial review. Also, the supplement landscape is ever-changing, so checking for updates regularly is wise. 

However, it’s important to understand that these organizations do not directly test the efficacy and safety of supplements. This information can only be provided through clinical trials. According to Dr. Oppezzo, these organizations primarily verify the product has the amount that it claims on the bottle, has the supplement in at least a bioavailable form that can get absorbed into your body, and that it is free from high levels of known contaminants. 

2. Dosage Matters

The saying “more is better” is not necessarily true for supplements – or even essential nutrients. Both inadequate and excessive consumption of nutrients can have detrimental effects on health. Although the body is capable of excreting surplus nutrients, fat-soluble vitamins can accumulate in the body to toxic levels if consistently consumed in large amounts. On the other hand, overconsumption of water-soluble vitamins usually leads them to be excreted through urine, which is inefficient, costly, and known as “expensive urine.”

Therefore, it is crucial to adhere to recommended dietary allowances (RDAs) as a starting point and tailor intake based on individual responses. Importantly, consistently exceeding 100 percent of the RDA can result in nutrient imbalances. One example is selenium, a nutrient where both insufficient and excessive intake have been associated with hair loss. Ironically, many products marketed as “hair vitamins” contain selenium levels surpassing the RDA, potentially worsening the very issue they aim to remedy. 

3. Consider the Chemistry

The effectiveness of a supplement can also depend on its chemical form. For example, vitamins that are fat-soluble achieve maximum absorption when consumed simultaneously with a source of fat, such as a small portion of nuts. Additionally, the interaction between nutrients is important; for instance, copper and zinc compete for absorption, and an excess of one can lead to a deficiency in the other. Supplements can also have harmful interactions with certain pharmaceutical medications, so it is important to consult with healthcare providers before starting a new supplement. 

Another important consideration is the degradation of these compounds. For example, there is an oxidation potential of omega-3 and other fatty acid supplements. This means they have the potential to go “rancid” and lose their efficacy, especially when exposed to heat or open air. This vulnerability stems from the unsaturated nature of these fats, which contains double bonds in their molecular structure that are more reactive with oxygen. 

Indications of rancidity include a strong, fishy odor or an unpleasant taste in fatty acid supplements. Additionally, you can look for information on the peroxide value (PV), a common measure of its oxidation potential. This can be found on some supplement labels, as well third-party testing reports, such as NutraSource. Dr. Oppezzo recommends supplements with PV levels less than 8 mEq/kg.

Supplements Are Not Substitutes for a Healthy Diet

Regardless of whether supplements are part of your daily routine, it is important to remember supplements should be seen as supplemental and not taken at the cost of eating whole foods. While they can sometimes fill nutritional gaps, supplements should be distinct from other health behaviors, such as eating well and moving often.

Moreover, focusing on single ingredients or specific nutrients without considering the holistic picture can lead to misconceptions about what supplements can achieve. Just taking vitamin D, for instance, won’t fully address bone health if it’s not combined  with strength training and a calcium-rich diet.  Good health is about the synergy between multiple  health practices and how they complement each other.

“The allure of a quick fix or ‘magic pill’ is an enticing narrative in our fast-paced world, yet it’s important to remember that there is no replacement for a good diet and regular exercise,” states Dr. Oppezzo. “The foundation of healthy aging always has and always will be a direct result of the choices we make on a daily basis, which is what lifestyle medicine is all about.”