Acidifying Foods: Should You Avoid Them?
One theory suggests that modern diets cause excess acidity in the body, which, in turn, causes a variety of health problems and excess weight gain … This theory is based on the following hypothesis: Some “acidifying” foods cause an imbalance in one’s metabolism. The best way to counteract this acidity in the body would be to consume more “alkalizing” foods and less of those that are “acidifying”, in order to restore the body balance.
Is there any truth to all of this? Let’s explore it now…
The PRAL (Potential Renal Acid Load) index measures the capacity of a given food (in mEq) to lower the pH, in other words increase the acidity, of the urine. This index is used by those following an alkaline diet to determine which foods to prioritize. The goal is to reduce the acidity of the urine to preserve, among other things, one’s bones. Indeed, one of the regulating mechanisms of the body uses calcium which is found in the bones, and depletes its stores.
Which are the types of foods might increase the acidity in the body? Meat and poultry, grain products, refined sugars, dairy products, alcohol, caffeine, and processed and ultra-processed foods.
The types of food to prioritize are vegetables and fruits, as well as nuts, seeds and legumes. According to this theory, these foods might help maintain the normal pH of the body.
However, the pH of the urine does not reflect the blood pH, or even the pH of a particular organ. Urine serves, among other things, to eliminate the minerals that are in excess quantities in the body, resulting in some flexibility in its pH. The pH of other systems, on the other hand, is tightly regulated. In addition, some organs must have a different pH from others. For example, the stomach is very acidic (pH ~ 2) while the small intestine is more neutral (pH ~ 7).
It is, therefore, not correct to say that one must alkalize the whole body! In addition, no study has yet demonstrated that eating or avoiding a group of foods can influence one’s blood pH.
Alkaline foods against cancer?
Some in vitro studies have shown that cancer cells grow faster in a more acidic environment. On the other hand, the results cannot be extrapolated to the human body.
Interesting points to remember
Despite the fact that scientific evidence does not show a basis for this type of diet, some points are still interesting and are compatible with current nutritional recommendations:
- Increase your consumption of fruits and vegetables (for fiber, micronutrients and phytonutrients)
- Decrease your consumption of meat, refined sugars, alcohol and processed and ultra-processed foods
- Armidor, T. (January 2018). Keeping Up with Fad Diets – Alkaline Diet. Today’s Dietitian. Tiré de http://viewer.zmags.com/publication/4d490022#/4d490022/5
- Fenton, T. R., & Huang, T. (2016). Systematic review of the association between dietary acid load, alkaline water and cancer. BMJ open, 6(6), e010438. doi:10.1136/bmjopen-2015-010438
- Maurer, J. M., et al. (2015). Gastrointestinal pH and Transit Time Profiling in Healthy Volunteers Using the IntelliCap System Confirms Ileo-Colonic Release of ColoPulse Tablets. PloS one, 10(7), e0129076. doi:10.1371/journal.pone.0129076
- NHS. (March 2018). Healthy Weight – Top diets review. Tiré de https://www.nhs.uk/live-well/healthy-weight/top-diets-review/
- Schwalfenberg, G.K. (2011). The alkaline diet: is there evidence that an alkaline pH diet benefits health?. Journal of environmental and public health, 2012, 727630.