wise, systems to monitor and evaluate the impact of such programs closely over time help to track the possibility of such consequences and identify those that emerge in unexpected ways. The section identifies four unintended consequences that are potentially associated with the implementation of strategies to reduce sodium intake. Awareness of such consequences among the medical and public health communities will be essential for ensuring that any such adverse events are quickly identified and mitigated.

Concerns have been raised that low sodium intake adversely affects plasma renin activity, sympathetic nervous system activity, blood lipids, and insulin resistance. The suggestion is that attempts to achieve the levels recommended in the Dietary Guidelines for Americans on a population basis would place some persons at risk.

When sodium intake is reduced, there is a physiological stimulation of counter regulatory hormone systems, specifically the renin-angiotensin system and the sympathetic nervous system (IOM, 2005). These compensatory responses are much greater with abrupt large changes in sodium intake than with gradual reductions (Sagnella et al., 1990) as currently recommended. Furthermore, in contrast to the well-accepted benefits of blood pressure reduction, the clinical relevance of modest rises in plasma renin activity as a result of sodium reduction is uncertain.

Other studies have examined the effects of changing sodium intake on lipids, glucose tolerance, and insulin sensitivity. Adverse changes have been noted in some studies, but these studies often involved a very large change in sodium intake for only a few days. In the largest and longest controlled trial that addressed the effects of sodium reduction on blood lipids, there was no significant effect of sodium levels within the recommended range of intake (Harsha et al., 2004). Accordingly, the IOM, as part of its Dietary Reference Intake development process for nutrients including sodium, concluded that at the level of intake consistent with the reference value, the preponderance of evidence does not support the contention that the recommended intake would adversely affect any of these measures (IOM, 2005).

Because salt and other sodium-containing compounds function as food preservatives, efforts to reduce their presence have the potential to impact the safety of the food supply.

Past efforts to reformulate foods to improve their nutrient composition have occasionally resulted in foodborne illness. A well-known example is an effort to make sugar-free hazelnut conserve for use in reduced-calorie