Calcium performs many vital functions in the body. The majority of calcium can be found in your bones and teeth making them strong, but calcium also carries messages between the nerves and the brain, helps muscles move, aids in the flow of blood and releases hormones and enzymes. Although a vitamin vital to sustaining life, calcium can interfere with the absorption of other minerals and therefore they should not be taken together. In addition, many substances interfere with the concentration of calcium in the body and should not be mixed with high calcium foods and calcium supplements.
Iron is an essential mineral necessary for the production of many proteins, including hemoglobin – the protein in red blood cells responsible for carrying oxygen. Iron exists in two different forms – heme iron found in animal products and non-heme iron found in plant-based products. Foods such as red meat, fish and poultry contain heme iron, the form the body absorbs more effectively. Vegetables including lentils and beans provide non-heme iron. The Food and Nutrition Board of the Institutes of Medicine recommends that adult men and post-menopausal women consume 8 mg of iron per day. Due to the loss of blood and therefore iron that occurs during menstruation, pre-menopausal women should consume 18 mg of iron each day. Calcium can interfere with the absorption of both heme and non-heme iron, according to a 1998 editorial in the "American Journal of Clinical Nutrition." Since the majority of iron comes from food, if you have high iron requirements you should restrict your intake of calcium during the meal at which most of your iron is consumed. If taking calcium supplements, the researchers recommend taking them at bedtime to avoid interference with iron absorption.
Zinc, another essential mineral, supports a healthy immune system and promotes the activity of hundreds of enzymes. Zinc is important for normal growth and development and for a proper sense of taste and smell. Oysters serve as the highest source of zinc, but other foods -- including red meat and poultry -- ovide the majority of your daily zinc intake. The National Institutes of Health Office of Dietary Supplements reports that adults should consume between 8 and 11 mg of zinc per day. A high-calcium diet can interfere with zinc absorption and result in a negative zinc balance, suggests research conducted by Wood and Zheng in the “American Journal of Clinical Nutrition.” Although the mechanism of action remains poorly understood, to avoid zinc deficiency reduce your calcium intake during mealtime.
Sodium chloride, commonly called salt, functions as an electrolyte in the body, meaning it helps balance the amount of water in your body and transmits nerve signals. The kidneys balance the amount of minerals, including sodium and calcium, in the blood. Excessive sodium intake can increase the amount of calcium lost in urine due to the competition between sodium and calcium to get reabsorbed into the blood, describes the Linus Pauling Institute. Caffeine, a substance found in coffee, tea and other foods and beverages, also increases the amount of calcium lost through urine. Phosphorus, another essential mineral, decreases the amount of calcium lost in urine, but can increase the amount of calcium lost in the feces, therefore affecting the total amount of calcium in the body.
- National Institutes of Medicine: Food and Nutrition Board: Dietary Reference Intakes
- National Institutes of Health Office of Dietary Supplements: Iron
- “The American Journal of Clinical Nutrition”: Does Calcium Interfere With Iron Absorption?
- “The American Journal of Clinical Nutrition”: High Dietary Calcium Intakes Reduce Zinc Absorption; Wood and Zheng; 1997
- National Institutes of Health Office of Dietary Supplements: Zinc
- Linus Pauling Institute: Calcium