The role of salt has been an important topic in the field of public health with the increase of fast-food culture.

Excess salt intake is believed to be a human health risk; however, recent studies drew attention to the role of fetuses in growth of babies and development of diseases in adulthood.

It has been suggested that salt restriction during pregnancy has a critical influence on the fetus growth and the development of organs of fetuses, probably switching the important factors of adult-type diseases through hormonal control which involves gene modification. Salt restriction during pregnancy is connected to low birth weight, organ underdevelopment and dysfunction in adulthood.

In the field of research, a salt intake of 6g per day (equivalent to 2.4g sodium) has been recommended to a normal individual. However, the average salt intake worldwide is estimated to be approximately 9.87g per day, according to the Global Burden of Diseases Nutrition and Chronic Disease Expert Group.

While a high-salt intake diet would be linked with cardiovascular diseases such a heart attack, a low-salt intake diet is associated with low birth and survival rates. In an animal study with rats, intake of low-salt food (0.3g) during mating and growth is related with low birth and survival rates of rat pups, compared with pups from mothers who were fed with a high-salt diet (4g).

In humans, the direct evidence of salt restriction and impaired growth of infants is limited. Originally, it was reported that severe morning sickness is often associated with low birth weight or premature labor. The loss of salt resulting from vomiting is believed to be responsible for both the low birth rate and low birth weight. The sensitivity to salt intake may differ according to growth stage, i.e., intrauterine, lactation and after weaning.

Unfortunately, there have been few studies thus far that explain the effects of salt in the respective life stage. In this sense, doctors will have to wait to determine the exact relationship between salt intake and effects in adulthood. Despite limitations, it has been revealed that salt restriction in pregnant mothers or chronic salt restriction in both animals and humans is associated with decreased glucose uptake and insulin sensitivity.