Estimating sodium from bouillon (stock) cubes

The whole bouillon cube
>>  The whole cube contains 900 mg of sodium

Two-fifths of the bouillon cube
>>  A two-fifths serving gives 360 mg of sodium

One-third of the bouillon cube
>>  One-third (33%) gives 300 mg of sodium
>>  For ease of calculation, this case study uses the one-third measure

You can base your calculations on the spaghetti Bolognese recipe provided in the last consultation (six months ago), where Mr Robertson’s serving is two-fifths of the recipe; or you can follow the diet history and estimate his share of the bouillon cube at a one third. The difference is 60 mg.

Clinical significance 
There are times when accuracy is important: such as when you have sodium restrictions in place. There are other times when 
a small variation such as this is of no clinical significance. Your decision is based on clinical judgment. 

1 mmol of sodium = 23 mg of sodium; in practice the rounded figure of 20 mg is often used 
1 mmol of potassium = 39 mg of potassium; in practice the rounded figure of 40 mg is often used