You might hear that berries, turmeric, or green tea are good for your health. Later, you see these same names on bottles in the supplement aisle, packed into capsules. Taking a capsule seems easier, and you don’t have to eat the food. But the study that convinced you may have tested the food, not the extract in your hand! Evidence from a food should not be assumed to apply to a supplement made from it.

U.S. consumers spent approximately $13.2 billion on herbal dietary supplements in 2024, the highest annual sales figure reported. Turmeric and other plant-based products now form a major portion of the market.

Much of the research behind plant-based supplements begins with whole foods. Berries are studied for anthocyanins, turmeric for curcuminoids, and onions and apples for quercetin. The question is whether evidence from the food still applies after that compound is extracted and reformulated. In whole foods, these compounds are consumed with fiber, fats, carbohydrates, proteins, organic acids, and other phytochemicals that can influence digestion, absorption, and metabolism.

Anthocyanins, the red and purple pigments in berries, are studied for possible heart health benefits and sold as concentrated supplements. A 2024 review comparing anthocyanin-rich whole foods with extracts found that evidence generally favored whole-food sources, although direct human comparisons remain limited. Turmeric shows a similar pattern. In a study, healthy men ate meals with 400 mg of curcumin as pure powder, turmeric powder, or fresh root. Both turmeric meals produced higher blood curcuminoid levels than curcumin powder. Even for a single extract, the form matters: in a 2025 research study, one curcuminoid formulation was absorbed 76% better from an oat-based drink and 40% better from a nutrition bar than from a capsule, though a fruit drink and gummies did no better. A 2025 analysis of 31 human studies found that adding fat or fiber nearly doubled how much quercetin the body could absorb.

Together, these studies show that the same compound can behave differently depending on the form in which it is consumed. That point is often lost when research reaches the public. News coverage names the food, not the form that was tested, and supplement labels reinforce the link by showing the fruit or plant on the bottle. As a result, consumers reasonably assume the extract offers the same benefit as the food. Even people trained in nutrition make this assumption. But a capsule is a different product from the food that was studied, and unless the capsule itself has been tested, its benefit remains unproven.

The FDA does not preapprove structure/function claims on dietary supplements. Manufacturers must have evidence that these claims are truthful and not misleading. However, a claim does not mean the specific product or formulation has been tested in a human clinical trial.

For consumers, the practical question is simple: What form was actually studied? If the evidence comes from a whole food, it should not be treated as evidence for every extract made from that food. Before buying a concentrated plant supplement, consumers should look for human studies using the same extract type, dose, and formulation.

Researchers need more direct human trials comparing whole foods with concentrated extracts. Supplement manufacturers should report the amount and form of active compounds in their products and clarify whether their claims are based on studies of the product itself or the original food. When formulation-specific evidence is lacking, a supplement should be evaluated as its own product rather than assumed to reproduce the effects of the food it came from.