Sodium chloride, an essential constituent of the body and present in many foods, exhibits acute and chronic toxic effects when ingested in excessive amounts. Excess sodium chloride may induce hypertension in rats. There is a strong genetic component in the hypertensive response, and by selective breeding, strains of "spontaneusly" hypertensive rats have been developed. Hypertension has been evoked by excess sodium chloride in the food or drinking water of dogs but the effects were reversible and related to osmotic factors. Salt appetite is an important expression of personal preference in relation to diet, and salt contributes to palatabiity of foods. For some, salt-containing foods have important cultural values. Foods in which salt is important for preparation or preservation are a prominent component of many diets. The causes of hypertension in man are related to genetic and environmental factors: race, family history, variations in endocrine and kidney function, degree of obesity, and life-style. Although the findings of epidemiological studies suggest a relationship between salt intake and onset of hypertension, the evidence that salt consumption is a major factor in causing hypertension is not conclusive. However, available data suggest that 10 to 30 percent of the U.S. population is genetically predisposed to hypertension and is exposed to a higher risk by ingestion of sodium at current levels. The Select Committee believes that a reduction of sodium chloride consumption by the population will reduce the requency of hypertension. For man, the daily requirement of sodium chloride is less than 1 g (17 mg per kg), an amount exceeded by that present as a naturally-occurring ingredient of most diets. The daily requirement is subject to considerable fluctuation from such conditions as excessive sweating and diarrhea. It is not possible, on the basis of currently available data, to recommend a level of intake of sodium chloride that could be considered optimal for health. Other dietary sources of sodium, the level of potassium, and the sodium to potassium ration in the diet need to be considered. Because of increasing use of processed foods in the diet, individuals who prefer to restrict salt intake find it difficult. The amount of sodium chloride consumed as a result of commercial food processing is about 70 to 100 mg per kg per day. The average daily intake of sodium expressed as sodium chloride from all sources is about 180 mg per kg for an adult (10 to 12 g per day). Such an intake exceeds estimates of the amount (range 2 to 10 g per day) that may elicit hypertension in susceptible individuals. A lower daily consumption of sodium chloride promises health benefits for the proportion of the population susceptible to hypertension. It is the prevalent judgment of the scientific community that the consumption of sodium chloride in the aggregate should be lowered in the United States. The Select Committee agrees and favors development of guidelines for restricting the amount of salt in processed foods, a major contributor of dietary sodium. Adequate labeling of the sodium content of foods would help meet these objectives. Based on these considerations, the Select Committee concludes that: The evidence on sodium chloride is insufficient to determine that the adverse effects reported are not deleterious to the health of a significant proportion of the public when it is used at levels that are now current and in a manner now practiced.
There is no evidence in the available information on sodium chloride that demonstrates, or suggests reasonable grounds to suspect, a hazard to the public when it is used as an ingredient of cotton and cotton fabrics used in dry food packaging and as an ingredient of paper and paper board products used in food packaging in the manner now practiced or that might reasonably be expected in the future.