The study looked at the effect of various juices red grape, white grape, prune, pear, orange, apple and grapefruit on the ability of intestinal cells to absorb iron.
Using a novel laboratory model comprised of human intestinal cells, the researchers simulated conditions of digestion (including digestive enzymes and acidity) to compare the juices.
Dark grape juice reduced iron availability by 67 percent, while prune juice produced a 31 percent reduction. Light-colored juices, on the other hand, actually had the opposite effect; they increased iron uptake. Pear juice produced the highest uptake levels, followed by apple, orange, grapefruit and white grape juices.
Getting proper amounts of iron is particularly important for infants and children, as the mineral is essential for normal physical and mental development, whereas adult males and post-menopausal women generally get sufficient amounts of iron. Insufficient amounts of dietary iron, the number one nutritional disorder in the world, can lead to iron-deficiency anemia. This condition is characterized by excessive tiredness, decreased work and school performance, and decreased immune function, among others.
Iron metabolism differs among individuals. For the best advice on addressing the specific nutritional needs of children and adults, see a doctor or nutritionist.