Only very small amounts of sodium chloride are used in brewing. In moderation, sodium chloride can emphasise the caramel flavours found in malty beers.
If you intend to make a dark beer, add half a teaspoon to 5 gallons of water.
Adding 1 teaspoon of sodium chloride in 5 gallons of water increased the sodium level by about 130ppm and the chloride level by about 210ppm