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Nutrient Interactions

Research is mounting about interactions between various vitamins, minerals and other nutrients. Some of such interactions have been known for centuries, such as the knowledge that it is not good to consume milk with meat (calcium from milk inhibits absorption of iron from meat). Other research data is much more recent and not as well known.

Linus Pauling Institute lists nutrient interactions for many vitamins and minerals.

In addition, below you will find a selection of articles on this topic.


J Trace Elem Med Biol. 2009;23(2):75-83. Epub 2009 Mar 24.
Influence of exogenous iron, calcium, protein and common salt on the bioaccessibility of zinc from cereals and legumes.
“… observed negative influence of supplemental iron and calcium on zinc bioaccessibility…”


Am J Clin Nutr. 1983 Mar;37(3):416-20.
Inhibition of food iron absorption by coffee.
“A cup of coffee reduced iron absorption from a hamburger meal by 39% as compared to a 64% decrease with tea, which is known to be a potent inhibitor of iron absorption.”


Am J Clin Nutr. 2001 Jan;73(1):93-8.
Effect of ascorbic acid intake on nonheme-iron absorption from a complete diet.
“…iron absorption correlated negatively with dietary phosphate (P = 0.0005) and positively with ascorbic acid (P = 0.0069) and animal tissue (P = 0.0285).” Vitamin C consume at the same meal with iron increased iron absorption.


Crit Rev Food Sci Nutr. 2000 Sep;40(5):371-98.
Effect of tea and other dietary factors on iron absorption.
“Recommendations with respect to tea consumption … include: consume tea between meals instead of during the meal; simultaneously consume ascorbic acid and/or meat, fish and poultry.”


Linus Pauling Institute – Micronutrient Information Center – Chromium.
“Chromium competes for one of the binding sites on the iron transport protein, transferrin. ”
“Chromium uptake is enhanced in animals when given at the same time as vitamin C (3). In a study of three women, administration of 100 mg of vitamin C together with 1 mg of chromium resulted in higher plasma levels of chromium than 1 mg of chromium without vitamin C (1). ”


Linus Pauling Institute – Micronutrient Information Center – Biotin.
“Large doses of pantothenic acid (vitamin B5) have the potential to compete with biotin for intestinal and cellular uptake due to their similar structures (37).”


Linus Pauling Institute – Micronutrient Information Center – Flavonoids.
“Flavonoids can bind nonheme iron, inhibiting its intestinal absorption. Nonheme iron is the principal form of iron in plant foods, dairy products, and iron supplements. The consumption of one cup of tea or cocoa with a meal has been found to decrease the absorption of nonheme iron in that meal by about 70% (126, 127). To maximize iron absorption from a meal or iron supplements, flavonoid-rich beverages or flavonoid supplements should not be taken at the same time. ”


Am J Clin Nutr. 2005 Sep;82(3):589-97.
Inhibitory effects of dietary calcium on the initial uptake and subsequent retention of heme and nonheme iron in humans: comparisons using an intestinal lavage method.
“Calcium supplementation reduced heme and total iron without significantly affecting nonheme-iron absorption, regardless of meal bioavailability. Calcium inhibited the initial mucosal uptake rather than the serosal transfer of heme iron.”


Am J Clin Nutr. 1997 Jun;65(6):1803-9.
High dietary calcium intakes reduce zinc absorption and balance in humans.
“600 mg of calcium consumed with a meal decreased the absorption of zinc from that meal by 50%.”
“Zinc absorption was reduced significantly by 50% when the calcium supplement was given with the meal. Inclusion of an extra 119.3 mumol (7.8 mg) Zn as part of a calcium supplement offset the detrimental effect of calcium on zinc absorption. Our findings suggest that high- calcium diets can reduce net zinc absorption and balance and may increase the zinc requirement in adult humans.”


J Nutr. 1981 Jan;111(1):68-75.
Effect of iron, vitamin B-6 and picolinic acid on zinc absorption in the rat.
“The results suggest that high levels of dietary iron inhibit zinc absorption via competition for binding with endogenous picolinic acid. The results provide further evidence to support the hypothesis that picolinic acid facilitates absorption of dietary zinc.”


Plant Physiol. 1969 Jun;44(6):796-800.
Influence of Calcium and Magnesium on Manganese Absorption.
“Calcium appeared to enhance the rate of Mn absorption; whereas, Mg had a highly depressive effect. The combination of both Ca and Mg was even more inhibitory to Mn absorption than Mg alone. Manganese had no effect on the usual negligible Ca absorption by this tissue, but effectively inhibited the absorption of Mg. ”


University of Maryland Medical Center – Magnesium.
“It is a good idea to take a B vitamin complex, or a multivitamin containing B vitamins, because the level of vitamin B6 in the body determines how much magnesium will be absorbed into the cells.”