Wednesday, 5 December 2012

Acidifying Foods, Protein, Phosphorus & Bone Health

Are grains acidifying? Should we avoid them if they are?

PRAL (potential renal acid load)is a rating of how potentially acid or alkaline a food is, calculated on the major acid and alkaline substances.[1] 100 grams of brown rice has a PRAL of around 2. 100g of whole wheat bread has a PRAL of 1.1. This means they're slightly acidic. You could argue the acidifying effect could be less as the calculation is partly based on phosphorus content. Grains may have a lot of phosphorus, but a lot of it is in the form of phytate which isn't even absorbed.[2]

If you were to eat cooked brown rice all day, it would give you a PRAL of around 40, but if you ate almost a pound of raw spinach the same day, you would end up at around -6. There are more interesting ways of being net alkaline on a diet including acidifying foods of course.

PRALs of other foods per 100g

Chicken broilers, 17.3
Top sirloin steak, 15
Boiled egg, 8.7
Walnuts, 5.5
Almonds, 3
Kidney beans, -0.8
Orange, -3.6
Potato, -5
Banana, -6
Medjool dates, -13.6

The acidifying substances in the calculation are phosphorus and protein. There is still some debate as to whether high levels of these actually have significant effects on bone health.[3][4][5]

  1. http://www.ncbi.nlm.nih.gov/pubmed/12716680
  2. http://www.sciencedaily.com/releases/2010/12/101223171949.htm
  3. http://jn.nutrition.org/content/118/6/657.full.pdf
  4. http://lpi.oregonstate.edu/infocenter/minerals/phosphorus/
  5. http://www.ncbi.nlm.nih.gov/pubmed/11842948

No comments:

Post a Comment