Final answer:
True, various factors including calcium, antacids, coffee, and fiber can inhibit iron absorption by forming insoluble complexes or by altering the gastrointestinal pH, which affects iron solubility and uptake.
Step-by-step explanation:
Factors that inhibit iron absorption include not only calcium, antacids, coffee, and fiber, but also other dietary components like phosphate, phytic acid, and oxalic acid as these form insoluble complexes with iron. Phosphorus also plays a role, as high levels of iron can disrupt the calcium to phosphorus ratio by forming insoluble ferric phosphate. Conversely, conditions that enhance iron absorption include acidic gastrointestinal pH and the presence of substances like ascorbic acid that reduce ferric iron to the more soluble ferrous state. Alcohol can also favor iron absorption. Overall, the statement that calcium, antacids, coffee, and fiber inhibit iron absorption is true.