Dill.

Dill leaf carries flavonol glycosides and organic acids that bind non-heme iron in the gut lumen and hold it in a poorly absorbed form. Taking a plant-source iron supplement alongside a concentrated dill extract lowers the fraction that gets across. Spacing the two by a couple of hours removes the issue. This is standard lumen chemistry for any polyphenol-rich green herb.

Ascorbate keeps iron in the ferrous state and competes with plant polyphenols for the metal, which recovers part of the iron a herb-rich meal would otherwise lock up. Dill leaf also contributes some ascorbate of its own as a fresh green. The effect is on absorption at the point of contact, nothing further downstream. It is the reason citrus and greens are a sensible combination at the same meal.

Fresh dill weed is a leafy green and carries phylloquinone like other leafy greens do. For anyone on a vitamin K antagonist, the practical rule is consistency of intake rather than avoidance, and a concentrated dill product changes that intake. Dried and extracted forms carry far less than the fresh herb. The point is worth raising with a prescriber rather than solved by guesswork.

Dill contains quercetin and kaempferol glycosides among its main flavonoids, so a dill extract and a quercetin supplement are supplying overlapping chemistry. Combining them stacks the same class rather than adding a distinct one. That matters for anyone tallying total polyphenol intake. It is a composition point, not a claim about effect.

Both botanicals appear in products aimed at adults with high blood sugar, and human trial data for each are mixed rather than settled. Stacking two agents that each nudge glucose handling is a reason for anyone using glucose-lowering medication to monitor more closely, not less. The additive effect here is a caution as much as a benefit. Neither ingredient has combination trial data behind it.

Berberine has a considerably stronger and better documented effect on glucose handling than dill does, so the combination is really berberine plus a modest botanical. Anyone on glucose-lowering medication stacking both should be watching their readings. Flagging the direction is the useful part. There is no combination evidence for the pair.

The published dill work concentrates on lipid measures, and marine omega-3 acts on the triglyceride side through a different route. The two act on different fractions of the lipid panel rather than reinforcing one. Combining them covers more ground than either alone in principle. In practice no trial has tested the pairing.

Ginger and dill appear together in digestive formulas across several herbal traditions, both used after meals. Ginger has the stronger evidence base of the two for nausea. Presenting the pair as complementary is fair, presenting it as validated is not. Read it as tradition.

Applying selenium to growing dill raises the selenium concentration of the harvested herb, which is an agronomy finding about biofortification rather than a supplement interaction. It means a selenium-enriched crop is a different raw material from a standard one. Anyone sourcing dill for a mineral claim needs the assay on the batch. This row describes the crop, not the consumer.