Health effects antagonism

Because there is rarely actual data on the mixture of concern, an additivity approach (adding all the toxic effects of the individual components) is sometimes used. This approach involves a number of assumptions and has certain limitations due to the lack of consideration for potential synergism or antagonism between individual chemical compounds. Further research is needed on human health effects from chemical mixtures to more accurately predict the risks involved in these common environmental situations. 

Environmental/Health/Safety Constraints Combination effects include both synergism and antagonism. These constraints combine the following activities ... 

The determination of a permissible exposure to a toxic substance requires evaluation of qualitative and quantitative factors including the identification and health significance of the adverse effect the sensitive members of and the size of the exposed population, biological absorption, distribution, metabolism, and excretion and the possible additivity, synergism, or antagonism with coexposed substances. 

Vitamin K is required for y-carboxylation of osteocalcin before incorporation into bone matrix. Low-vitamin-K diets are associated with high amounts of uncarboxylated osteocalcin, lower BMD, and higher hip fracture rates. Early research suggests added vitamin K, especially when combined with other antiresorptive agents, has a positive effect on bone health. Currently, however, supplements are not recommended. Although warfarin decreases clotting factor production by antagonizing vitamin K, it alone probably does not cause bone loss. 

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