This is because non-heme iron is usually in an insoluble form, so it needs to be converted to a soluble form “and then go through the intestinal wall where it has to compete with other nutrients,” Donelan explains.
Fortunately, research shows vitamin C enables non-heme iron to change forms and thus dissolve easier.
To get the most bang for your buck, squeeze some lemon juice over sautéed Brussels sprouts, or fix a spinach salad with strawberries, oranges, or bell peppers. Putting plant-based iron and meat-based iron on the same plate may also increase your intake, research finds; try Tuscan fish with white beans for dinner.
Curcurmin and piperine
Polyphenols, a subclass of phytochemicals, also garner interest among nutritionists for their antioxidant properties. Turmeric contains one polyphenol whose benefits know no bounds: Its main active ingredient is curcumin, which is anti-inflammatory, antioxidant, and neuroprotective.
But curcumin doesn’t hang around long in the body when we eat it. “When the body takes up curcumin, it gets metabolized very fast,” Zingg explains. As a result, less curcumin is absorbed in the bloodstream.