Doses in lab animals many times higher than normally encountered in food. In evaluating the potential real- world effects here, note that the preceding discussion and tables concern lab results that utilized extremely high doses to produce easily measurable effects. In fact, by itself, the ingested daily amount of heterocyclic amines is very probably too small to explain the development of human cancers, and the same is true for numerous other carcinogens.
Epidemiological studies done so far remain inconclusive.
Hensch et al. Ward et al. Cancer risk calculations were based on previous laboratory analyses of HCA concentrations observed under given cooking conditions, and on an extensive food- frequency questionnaire including 188 food items, asking for the type of meat and fish ingested, frequency of consumption, portion size, cooking methods, and degree of surface browning. Overall impact, if any, appears to be small. Again, each of the HCAs was found to slightly decrease the risk for some cancers, and slightly increase the risk for others.