We eat for our health and to feed our our bones, blood, and bowels, but some nutrients just don't play well with others. Take calcium and iron for instance. Calcium can reduce your ability to absorb iron by as much as 50 percent. However, calcium only interferes with non-heme iron, which comes from plant-based foods, not with heme iron, found in meat. This interplay between calcium and iron is really only important if you suffer from anemia, because although short-term iron absorption is reduced by calcium, studies have found that iron stored in the blood is not.
When it comes to calcium, fiber binds to the mineral, reducing its absorption. Studies have found that wheat fiber reduces calcium absorption by about half. If you're like most folks and you aim to get a jump-start on fulfilling your recommended daily intake of fiber and calcium with your bowl of breakfast cereal, choose cereals that feature oats or other grains since they don't seem to block the calcium.
Ultimately, if you eat a well balanced diet and aim to eat your nutrients rather than find them in supplements, you're probably getting all the vitamins, minerals, and fiber you need. Just think of this post as a little food for thought.