→ ZeroG science lab

A balanced diet: the potential renal acid load

Research has shown that a more acidic diet seems to decrease the mineral content of your bones. This is in particular of interest for people who are inactive and have a lower mineral bone density. This is also of importance for astronauts during their missions since astronaut bones already have less loading in space so they suffer from reduced bone mineral density.

One might think that the potential renal acid load derives from the acids in the food we eat. The main nutrients affecting the acid load of a diet are protein, calcium, potassium, phosphorus and magnesium. An algorithm to calculate the potential renal acid load (PRAL)  was developed by Remer & Manz (J Am Diet Assoc 1995). They took into account the absorption rates of nutrients in the gastrointestinal tract as well as the metabolic processes in the body

PRAL (mEq/d) = 0.49   * protein (g/d)

+ 0.037 * phosphorus (mg/d)

– 0.021  * potassium (mg/d)

– 0.026  * magnesium (mg/d)

– 0.013  * calcium (mg/d)


The information needed to calculate a PRAL  is often found on food packaging. Another way is to take information from tables of nutritional values. Precalculated PRALs are available such as www.saeure-basen-forum.de/pdf/IPEV-Food_table.pdf. To calculate the total PRAL of a meal you just add the food items together.

Food that is high in protein content, such as meat, fish, milk or cereals are acidic while vegetables and fruits are generally more alkaline because of their high potassium content. Meat lovers are highly recommended to combine meat with large portions of vegetables or fruits to compensate for the acidity from meat’s high protein content.

Martina Heer

Protein and muscles | ZeroG science lab