Circulation

The swollen taproot of a cultivated Beta vulgaris, deep red from betalain pigments. It is among the richest dietary sources of…

Endothelial function: Several trials report improved flow-mediated dilation after beetroot juice, consistent with its blood-pressure effect. Trials are mostly short and small, and the longer-term significance is untested.

Small blue-purple berries of the Vaccinium genus, sold fresh, frozen and dried. Cultivated highbush varieties are larger and…

Endothelial function: Some trials report improved flow-mediated dilation in the hours after a blueberry drink, with smaller effects reported over several weeks of daily intake. Whether that translates into a difference in cardiovascular events has not been tested.

Oil pressed mechanically from olives without heat or solvents, retaining the phenolic fraction that refining removes. Phenolic…

Endothelial function: Some trials report improved flow-mediated dilation after high-phenolic olive oil compared with refined olive oil, indicating that the phenolics rather than the fat carry this particular effect.

The wrinkled kernel of the walnut tree, unusual among common nuts for being dominated by polyunsaturated rather than…

Endothelial function: Several trials report improved flow-mediated dilation after walnut-enriched diets, a measure of how well blood vessels relax. The trials are short and the clinical meaning of the change is not established.

A peppery salad leaf in the mustard family, eaten raw or briefly wilted. Its sharpness comes from isothiocyanates released when…

Endothelial function: Some trials of high-nitrate vegetables report improved flow-mediated dilation within hours. The number of trials using arugula rather than beetroot is very small.

The round nut of the hazel shrub, mostly grown in Turkey and Italy and largely destined for confectionery. The USDA reference…

Endothelial function: Evidence is limited. A few small trials report improved vascular measures after hazelnut-enriched diets, with short duration and few participants.

The sweet orange, a hybrid citrus grown commercially on every inhabited continent. Most of the world crop is pressed for juice…

Endothelial function: Evidence is limited for an effect on vascular function. A handful of trials report improved flow-mediated dilation after citrus flavanones, usually at doses higher than a single glass of juice supplies.

A thick-skinned fruit filled with hundreds of juice-filled arils, each containing a seed. Commercial juice is usually pressed…

Endothelial function: Some trials report improved flow-mediated dilation with pomegranate juice. The studies are small and heterogeneous, and results depend partly on whether participants produce urolithins at all.

The fruit of the common grapevine, eaten fresh, dried as raisins or fermented into wine. Red and black varieties carry…

Endothelial function: Some trials of grape products report improved flow-mediated dilation, most often using concentrated grape juice or grape seed extract rather than whole fruit. Results across trials are inconsistent.

The fruit of a nightshade plant, used culinarily as a vegetable. Its red colour comes from lycopene, which becomes considerably…

Endothelial function: Evidence is limited for an effect on vascular function. A handful of trials report improved flow-mediated dilation with tomato products or lycopene, mostly in people who already had cardiovascular risk factors.

A large cucurbit fruit that is over nine-tenths water by weight, with red flesh coloured by lycopene. The rind and the flesh both…

Endothelial function: Watermelon is often promoted for circulation on the strength of its citrulline. Trials measuring vascular function after eating the fruit are too few and too small to support a dependable conclusion.