There are so many of us who take multivitamins every single day trying to to supplement our diet with vitamins, dietary minerals and other nutritional elements. It is awailable in the form of tablets, capsules, pastilles, powders, liquids and injectable formulations. But have you ever thought that all those micronutrients can possibly interact with each other once they have been swallowed.
Chemical Interactions – some of which may also take place before consumption, during the manufacture of the nutritional supplements.
Copper, in the presence of inorganic sulphate at high concentrations, may reduce the amount of molybdenum that is absorbed and retained in the body.
Phosphorus can consequently decrease the absorption of magnesium.
Zinc may form insoluble complexes with folic acid, particularly at low pH.
Vitamin B2 (riboflavin) forms an advantageous complex with zinc, resulting in its increased absorption.
Folic acid (B9) can decrease absorption of zinc oxide.
Vitamin C (ascorbic acid) is able to reduce selenite to elemental selenium, which is biologically inert, if no other nutrients are present.
Vitamin B12 is destroyed if it is administered orally as a drug with ascorbic acid.
Biochemical Interactions – in which there may be competition between micronutrients for a common site of absorption and/or transport.
The B vitamins are essential co-factors in many metabolic reactions and consequently relate indirectly one to another.
Calcium has an inhibitory effect on absorption of iron provided that the two elements are consumed at the same time.
Calcium also depresses the absorption of zinc.
Chromium interacts with iron in binding to transferrin and consequently can impair iron metabolism and storage.
Iron and zinc have been reported to interfere with the absorption of each other.
Iron in the presence of ascorbic acid (vitamin C) and in relatively high amounts depresses the absorption of copper.
Manganese can depress the absorption of iron by as much as 40%.
Riboflavin (B2) is necessary for the absorption of iron, which is depressed when dietary riboflavin is deficient.
Vitamin C appears to have a direct interaction with iron, resulting in its increased absorption.
Vitamin A may indirectly aid the absorption of iron. Vitamin A can, when present in large amounts, interfere with the absorption of vitamin K.
Vitamin D regulates the absorption of calcium and this may be the result of the action of the vitamin on the transport of calcium from the lumen of the gut.
It has been concluded from animal studies that vitamins A and D may lessen the toxic effect of each other.
Vitamin E when consumed with vitamin A in relatively large amounts can increase the absorption of vitamin A and may also reduce its toxicity.
Physiological Interactions – which may result in either increasedor decreased utilisation.
Vitamin B (thiamin) has been shown to increase the utilisation of pantothenic acid.
Vitamin B2 (riboflavin) has also been shown in the same trial to increase the utilisation of pantothenic acid, but to a lesser degree than vitamin B.
Vitamin A directly affects the transport of iron and the production of red cells. It is also possible that when vitamin A is deficient, the mobilisation of iron from body stores is also impeded.
Vitamin C influences the storage and transport of iron.
Vitamin D regulates calcium and phosphate metabolism and the efficiency of their utilisation. Vitamin D is active in many tissues, the main ones being the intestine, bone and kidney where reabsorption of calcium is an important contribution to the overall economy of calcium.
Vitamin K is involved in the utilisation of calcium in the early stages of the formation of bone tissues.