|"Despite overwhelming evidence linking increased salt intake to hypertension, the relation is still disputed in some circles. Viewing the introduction of salt to human diet on an evolutionary time scale would help us better understand the role of salt in hypertension. Humans and related species evolved in a salt-free environment over millions of years with intense evolutionary pressure for the selection of salt conserving genes. The recorded history confirms how rare and inaccessible salt has been until recently. Thrusting the species that has exquisitely adapted to very low salt intake into salt surfeit conditions represents evolutionary mismatch with catastrophic health consequences. More than a quarter of human populations suffer from hypertension. World Health Organization (WHO) and many governments have now taken action to reduce dietary intake of salt in an effort to reduce the incidence of hypertension and the associated cardiovascular morbidity and mortality."
The impact factor of journal provides quantitative assessment tool for grading, evaluating, sorting and comparing journals of similar kind. It reflects the average number of citations to recent articles published in science and social science journals in a particular year or period, and is frequently used as a proxy for the relative importance of a journal within its field. It is first devised by Eugene Garfield, the founder of the Institute for Scientific Information. The impact factor of a journal is evaluated by dividing the number of current year citations to the source items published in that journal during the previous two years.