Are citrus fruits acidifying?
Many people report that their dentist has warned them against consuming citrus fruits, those acidic fruits that could be a cause of enamel demineralization and, indirectly, dental cavities.
Let’s see what the situation is by studying some chemical characteristics of lemon juice, the most acidic of the citrus family. The pH of lemon juice is between 2 and 3 and its pKa (the acidity constant) is greater than 3. This means that the citric acid contained in lemon juice only releases its protons (the acidity) if it is in an environment where the pH is greater than 3. For this reason, it is said to be a weak acid. However, lemon juice is met by hydrochloric acid in the stomach, which has a pH between 0 and 1, and a pKa of -6, making it a strong acid.
Therefore, lemon juice does not release protons (the acidity) in the stomach and is thus not acidifying for the body. Moreover, citric acid is found as a metabolite in the Krebs cycle, a set of chemical reactions that allows cells to produce energy. The citric acid we consume through lemon juice is either used directly by the cells to produce energy or metabolized by the liver into non-acidic compounds and bicarbonate (which is alkaline). Ultimately, after consuming lemon juice, the body has fewer acids to expel than before and additionally benefits from the intake of alkaline minerals such as potassium, calcium, and magnesium. This is why citrus fruits are classified among foods with a negative acid load (Potential Renal Acid Load).
Citrate (the ionized form of citric acid) also inhibits the formation of certain types of kidney stones, particularly those based on calcium oxalate. Overall, it can be said that the weak acids from fruits contribute to the regulation of the body’s pH, especially if one has a diet that is too acidic.
The citric acid found in citrus fruits and some red fruits has other benefits:
- Promote digestion: Citric acid stimulates the production of gastric juices, which helps better digest food.
- Natural antioxidant: Citric acid helps neutralize free radicals, thus protecting cells against excess oxidative stress (in the right proportions, the oxidation process is normal and necessary).
- Improve mineral absorption: It can enhance the absorption of non-heme iron (from plant sources), especially when consumed with vitamin C.
- Natural preservative: It helps preserve food by slowing down oxidation and the proliferation of bacteria.
Do citrus fruits damage teeth?
Citrus fruits are therefore not acidifying, but can they still damage tooth enamel? As we have seen, they are weak acids and their transit time in the mouth in contact with teeth is short. On the other hand, when the body is acidified, the pH of saliva decreases and becomes a favorable environment for bacteria responsible for cavities (Streptococcus mutans) that feed on food residues stuck in the teeth and release acidic waste that can erode enamel. Since our teeth are bathed in saliva 24/7, the acidity of saliva is the number one cause of enamel demineralization.
Conclusion
Experience shows that the more acidified one is, the more one is attracted to acidic fruits which, once digested and metabolized, are alkalizing. This is why it is easy to misinterpret the true culprit of dental problems or, more generally, acidosis… Some still believe that we are not all capable of transforming the acidity of fruits into base when the liver or the Krebs cycle (which produces energy from nutrients) are defective. A rare scenario that only concerns physically inactive individuals with very low vitality. Moreover, an organism with a tired or congested liver will not be able to properly digest its food, whatever it may be, without producing acidic residues. Furthermore, under the principle of alliesthesia, it is unlikely that these individuals will be attracted to acidic fruits if the body does not have the resources to use them to its advantage, simply because the experience will be unpleasant.
Moral: Don’t deprive yourself of eating acidic fruits if you love them! But don’t force yourself either; the body knows exactly what it needs and in what quantity!
To go further:
Read these articles on “Dental hygiene” and “How to use instinct to choose the foods the body needs?”
