What Is a Nutraceutical: Food, Medicine, or Both?

A nutraceutical sits in a gray zone between food and medicine, and that ambiguity is the point. The term was coined in 1989 by Dr. Stephen DeFelice, who blended “nutrition” and “pharmaceutical” to describe any food-derived substance that delivers a health benefit beyond basic nourishment.¹ In practice, it covers everything from fish oil capsules and turmeric extracts to probiotic yogurts and fortified cereals. Whether that makes a nutraceutical “food,” “medicine,” or both depends less on the substance itself and more on the regulatory framework of the country you happen to live in.

A Term Without a Legal Definition

Despite decades of use, “nutraceutical” has no internationally agreed-upon legal definition. Neither does “functional food,” “health food,” or most of the related labels consumers encounter on shelves. A 2017 analysis in the British Journal of Clinical Pharmacology argued that “nutraceuticals” and “functional foods” are vague, nondiscriminatory terms that should be abandoned in favor of more precise language.² The paper pointed out that “dietary supplement” is widely used to describe many of the same products, while terms like “food,” “nutrition,” and “medicinal product” already have clear, well-established meanings. The word “nutraceutical,” by contrast, tries to straddle both categories and ends up being legally recognized in neither.

This is not a trivial semantic gripe. The looseness of the term lets manufacturers market products using health-adjacent language without meeting the evidentiary bar required of actual pharmaceuticals. A prescription drug must go through years of clinical trials proving it works and cataloguing its risks before it can be sold. A nutraceutical, depending on its classification in a given country, may only need to demonstrate that it is not actively dangerous.

How Regulation Differs Around the World

The regulatory landscape for nutraceuticals varies dramatically by country, and understanding these differences matters if you care about what is actually in the bottle you are buying.

In the United States, most nutraceuticals are sold as dietary supplements under the Dietary Supplement Health and Education Act of 1994 (DSHEA). Under this law, manufacturers can make “structure/function claims” about their products, describing how an ingredient may affect the body’s structure or function. These claims were designed to give consumers useful information about supplements without requiring the same level of proof demanded for prescription drugs.³ That is why you see labels saying “supports heart health” rather than “lowers cholesterol by 15%.” The first is a structure/function claim; the second would be a drug claim requiring FDA approval. The practical consequence is that supplements reach the market without pre-approval. The FDA can pull a product after it causes harm, but it does not gate-check products before they are sold.

Europe takes a somewhat different approach. The European Union’s Nutrition and Health Claims Regulation, in effect since 2006, introduced a science-based standard for health claims on food products.⁴ Safety decisions are grounded in risk analysis, with scientific risk assessment performed by the European Food Safety Authority and risk management carried out by the European Commission and member states.⁵ In practice, this means that European regulators have rejected a large number of proposed health claims that lacked sufficient scientific backing, forcing manufacturers to either fund better research or drop the claims from their labels.

Japan was arguably ahead of both the U.S. and Europe. In 1991, the Japanese Ministry of Health, Labour, and Welfare established “Foods for Specified Health Use” (FOSHU), a system under which food products must be scientifically evaluated for both effectiveness and safety before they can carry health-related label statements. The system was broadened in 2001 to accept capsules and tablets alongside conventional food forms.⁶ Under FOSHU, a product has to earn its health claim through evidence, which is a fundamentally different philosophy from the U.S. model where the claim is permitted unless the FDA objects.

How Nutraceutical Compounds Actually Work

One reason nutraceuticals are hard to classify is that some of them do have genuine, measurable biological activity. Polyphenols, a broad family of compounds found in berries, tea, olive oil, red wine, and many other plant foods, offer a good example. Research has shown that polyphenols can activate the body’s own antioxidant defense systems by influencing a transcription factor called Nrf2.⁷ Rather than acting as direct antioxidants themselves (a common oversimplification in marketing), many polyphenols appear to trigger the cell’s own protective enzymes. Curcumin, the yellow compound in turmeric, and epigallocatechin gallate from green tea have both been shown in laboratory studies to activate this pathway in brain cells, boosting the production of a protective enzyme called heme-oxygenase-1.⁸

Your gut bacteria play a surprisingly large role in determining whether a nutraceutical compound does anything useful. Most polyphenols are poorly absorbed in the small intestine, which means the majority travel intact to the colon, where resident bacteria break them down into smaller metabolites.⁹ These bacterial metabolites may be the actual bioactive players, not the original compound you swallowed. The catch is that this conversion depends on which bacteria live in your gut, and that varies enormously from person to person. For most polyphenols, the human body on its own is limited to relatively basic processing; it is the gut microbiome’s enzymatic capacity that determines how much of the compound gets converted into something the body can actually use.¹⁰

The Bioavailability Problem

Even when a nutraceutical compound has strong activity in a petri dish, getting it to work inside a living human body is a different challenge. Curcumin is the poster child for this problem. It has been studied extensively for anti-inflammatory and antioxidant properties, but it is notoriously difficult to deliver effectively. Poor absorption, rapid metabolism, and fast clearance from the bloodstream all contribute to very low levels of curcumin reaching tissues after oral consumption.¹¹ Clinical trials testing various delivery formulations have found that when bioavailability improves, so does therapeutic effect, which suggests the compound itself is active but the delivery is the bottleneck.¹²

This is a general issue across many nutraceuticals, not just curcumin. When compounds are isolated from their natural food matrix and packaged into supplements, they often lose the co-factors that helped with absorption in the original food. Researchers have explored two main strategies for fixing this. One involves specially designed delivery systems, like colloidal carriers, that improve how well the compound disperses, stays stable, and gets absorbed. The other takes the opposite approach: rather than engineering the supplement, you engineer the meal. “Excipient foods” are foods specifically designed to be eaten alongside nutraceuticals to boost absorption, essentially re-creating the food-matrix advantages that pills lost.¹³

Genetics adds another layer. Candidate gene studies and genome-wide association research have identified genetic variants that affect how people absorb, transport, and metabolize vitamins and other nutrients. Differences in enzymes, carrier proteins, and cell membrane channels mean that two people eating the same food or taking the same supplement can end up with very different levels of the nutrient in their blood.¹⁴ This is one reason blanket dosing recommendations for supplements can miss the mark for many individuals.

Where the Evidence Is Strong and Where It Falls Apart

Not all nutraceuticals are created equal in terms of clinical evidence, and the range is enormous. On the strong end, prescription-grade omega-3 fatty acids have solid data behind them. When used at high doses in patients with very high triglyceride levels, omega-3 formulations can reduce triglycerides by roughly 26 to 45%, depending on the dose and formulation.^{15 16} The REDUCE-IT trial found a 25% reduction in major cardiovascular events in high-risk patients treated with a statin and a high-dose EPA-only formulation.¹⁷ These are the kinds of results that move a compound from the nutraceutical shelf into the territory of legitimate medicine, and indeed prescription omega-3 products are now FDA-approved drugs.

But that level of evidence is the exception, not the rule. A key challenge for nutraceutical research is that response rates vary wildly between individuals. One analysis of nutraceutical clinical trials found that only about 25% of participants showed a positive blood pressure response, and roughly a third responded for insulin sensitivity. That means roughly two-thirds to three-quarters of participants saw no benefit at all.¹⁸ In a traditional drug trial, this would be a failing grade. But the finding is more nuanced than that: the intervention clearly worked for a subset of people, just not for most. The problem is that researchers could not identify in advance who would respond and who would not. This has led to growing interest in personalized or “N-of-1” trial designs, where each individual serves as their own control, rather than relying on group averages that may obscure real effects in a minority of participants.

Safety Is Not Guaranteed by “Natural”

Perhaps the most dangerous misconception about nutraceuticals is the assumption that natural origin equals safety. Several distinct problems undermine the safety of the supplement market.

Adulteration and contamination are widespread. Analytical studies of dietary supplement products have found that anywhere from 14 to 50% of samples tested positive for prohibited substances such as anabolic agents.¹⁹ This is not limited to fringe bodybuilding supplements. A study of turmeric products found that only four out of fourteen samples supported their label claims.²⁰ Another investigation of regulated herbal medicines and supplements found contamination in nearly half the products tested, including undeclared pharmaceutical drugs, stimulants like caffeine and ephedrine, undisclosed allergens, and even animal DNA from species not listed on the label.²¹

Even when a supplement contains exactly what it says, dosing can be a problem. An analysis of food supplements containing fat-soluble vitamins found that the majority of labels recommended daily doses above the recommended dietary allowance, with some exceeding the tolerable upper intake level.²² Unlike water-soluble vitamins, fat-soluble vitamins accumulate in the liver and fat tissue and are eliminated slowly. Chronic overuse can lead to real toxicity, including vision problems, bone disorders, kidney damage, cardiovascular issues, and coagulation disturbances.²³

Drug Interactions That Catch People Off Guard

One of the most clinically significant risks of nutraceuticals is their ability to interfere with prescription medications, and St. John’s wort is the textbook case. Hyperforin, the compound in St. John’s wort responsible for its antidepressant activity, turns out to be a potent activator of a nuclear receptor that controls the expression of a key liver enzyme involved in breaking down more than half of all prescription drugs.²⁴ When that enzyme gets ramped up, medications are cleared from the body faster than intended, making them less effective.

This is not a theoretical concern. Studies in healthy volunteers showed that two weeks of St. John’s wort dramatically reduced the blood levels of omeprazole, a common stomach acid drug, by inducing the liver enzymes that metabolize it.²⁵ Separately, St. John’s wort was found to increase expression of an intestinal transport protein that pumps drugs back out of cells before they can be absorbed. In one study, this led to an 18% decrease in digoxin exposure, a heart medication where even small changes in blood levels can be dangerous.²⁶ The list of drugs that St. John’s wort can interact with is long and includes blood thinners, HIV medications, oral contraceptives, immunosuppressants, and antidepressants.

The broader lesson is that “herbal” and “natural” do not mean pharmacologically inert. Many nutraceutical compounds are biologically active precisely because they engage the same metabolic pathways that process drugs. If you are taking any prescription medication, treating a supplement as automatically safe because it came from a plant is a real mistake.

Why “Natural” Feels Safer Than It Is

Consumer psychology helps explain why nutraceuticals continue to sell well despite the evidence gaps and safety concerns. Research into food choice shows that people have a deep-seated preference for products they perceive as natural, and that this preference is driven partly by a mental shortcut: if something resembles a prototype of what a “natural” food looks like, it feels trustworthy and beneficial.²⁷ This means a supplement packaged in an earthy brown bottle with botanical illustrations triggers a different instinct than the same compound in pharmaceutical blister packs, even if the contents are chemically identical.

The market has responded accordingly. The global nutraceutical market reached an estimated $500 billion in 2024, with projections putting it near $878 billion by 2033.²⁸ That growth is being driven by aging populations, rising awareness of the link between diet and chronic disease, and a consumer class that increasingly prefers perceived self-care over physician-directed pharmaceutical interventions. Asia Pacific currently leads in market share, while North America remains a center for innovation and regulatory development.

Nanoencapsulation and the Future of Delivery

The bioavailability problem has pushed researchers toward increasingly sophisticated delivery technologies. Nanoencapsulation, which involves packaging active compounds inside nanoscale carriers, has emerged as a leading approach. These tiny carriers can protect sensitive nutrients from being degraded by light, heat, stomach acid, and oxygen. They also improve absorption through several mechanisms: boosting solubility, allowing controlled release in the gut, sticking to intestinal walls long enough for uptake to occur, and even routing compounds through the lymphatic system to bypass the liver’s first-pass metabolism, which would otherwise break them down before they reached the bloodstream.²⁹

Liposomal delivery, one of the earliest forms of nanoencapsulation, uses tiny fat-based bubbles that can carry both water-soluble and fat-soluble compounds. These systems have been widely adopted in the food industry for nutrient enrichment and supplement production, offering higher surface area and better targeting of the encapsulated material compared to older microencapsulation methods.³⁰ You may have already seen “liposomal vitamin C” or “liposomal curcumin” products on shelves. The technology is real, but the quality and effectiveness of commercial products vary widely, and claims often outpace the evidence for any specific formulation.

Looking further ahead, the convergence of modern extraction techniques, computational drug screening, DNA barcoding for raw material authentication, and nano-formulation technologies is gradually transforming how nutraceuticals are developed and standardized.³¹ The direction of travel is clear: the nutraceutical industry is borrowing tools from pharmaceutical science to close the gap between food and medicine. Whether regulators will update their frameworks to match that convergence remains an open question. For now, nutraceuticals live in a space that is neither fully food nor fully medicine, and the consumer is the one who has to navigate the ambiguity.