What is acid-base balance and how to restore it?

Here are the different terms used when talking about acid-base balance:

• The concept of pH : THE ppotential ofHhydrogen is a measure of the activity of hydrogen H+ ions in a solution (often water). The enzymatic activity of all the body's biochemical reactions is dependent on this pH. The range is 0 to 14; 7 being a neutral pH. Below 7, the pH is acidic while it is basic if its value is greater than 7. Therefore, when we speak acid, we are talking about a donor of H+ (hydrogen) ions. Conversely, a base accepts H+ ions from acids by releasing an OH- (hydroxyl) ion in exchange. This is why we talk about a couple acid-base.

• The pH of the body : These differ depending on their location. For example, the pH of blood is slightly alkaline (between 7.35 and 7.45); the urinary pH is between 4.5 and 8 and the liver pH between 7.6 and 8.6. As for it, the pH of the stomach is particular, it is located during the fasting period between 5 and 7. However, the arrival of food during the prandial period leads to the secretion of hydrochloric acid reducing the pH of the stomach. less than 2! Thus, pH variations are recurrent and normal, but should not exceed the reference ranges. Indeed, if the blood pH varies outside of these ranges, we are talking about blood acidosis which requires emergency medical attention. Be careful not to confuse with l'tissue acidosis, which is a pathological condition created by the body's inability to compensate for excess H+. The latter has repercussions on the body at the enzymatic and cellular level. Furthermore, when we talk about an imbalance in the acid-base balance, it is tissue acidosis which is the cause.

• An acidifying food : It is a food that produces many acids during its breakdown by the body. It therefore lowers the pH between 0 and 7. For example, proteins generate multiple acids (hydrochloric, phosphoric, sulfuric, uric, etc.) during their metabolism. Thus, foods rich in protein such as cheeses and meats will be acidifying even though they do not have an acidic flavor.

• A basifying/alkalizing food : These terms are equivalent. These foods increase the pH between 7 and 14 as they break down. Therefore, after decomposition of this food, their alkalizing nutrients will form bicarbonates which will allow the H+ ions of the acids to be accepted, in order to return the pH to normal.

• An acidic food : It is a food with an acidic pH before entering the body. However, the body will neutralize the acids to release the bases. As a result, lemon has an acidic pH and an acidic flavor, but it is alkalizing.

• An alkaline food : In the same way as an acidic food, it is a food having an alkaline pH before its entry into the body. However, this does not mean that it is an alkalizing food once metabolized.

• PRAL index (Potential Renal Acid Load): This index was established by Thomas REMER and Friedrich MANZ and makes it possible to assign an acidifying or alkalizing status to a food once it is metabolized by the body. It is measured in mEq/100 g and evaluates the acid load of a food based on its protein and mineral content. Once evaluated, the food will receive a result that will determine whether it is acidifying, close to neutral, or alkalizing. The ranges are as follows: if the PRAL index is less than -3, the food will be alkalizing; between -3 and +3, the food will be considered neutral or close to neutral; if he is greater than +3, the food will be acidifying.

Acid-base imbalance is linked to excess intake or production of acids. Several factors such as stress, overwork, lack of sleep and modern diets, too rich in acid-forming foods, contribute to acidification. We speak of acidosis when the body is no longer able to compensate for excess acids. Indeed, the acids produced need a base to be balanced and so that they can be evacuated through the urine.

Let's take the example of a basifying nutrient like calcium. The body demineralizes the bones in order to recover calcium so that it accepts the H+ ion of an acid. After having given its negative OH- hydroxyl ion in exchange for this positive H+ hydrogen ion, calcium becomes a waste to be disposed of since it no longer has the same structure. In this way, the calcium used is transported to the liver where it will be recognized as waste. Following this, it is sent to the kidneys to be evacuated through urine.

The production and presence of acids in the body is a normal phenomenon. Indeed, normal metabolism produces H+ ions in the form of volatile (weak acids) or non-volatile (strong acids) acids and CO2. Cellular oxidation of nutrients produces large amounts of CO2. Hepatic catabolism of amino acids generates strong acids (sulfuric and phosphoric). These H+ ions are neutralized by three main regulatory systems:

• THE bone buffer systems : A buffer substance is a couple consisting of a weak acid and its conjugate base. Therefore, the bone response provides calcium carbonate and bicarbonate to neutralize the H+ ions of the acids. 

• THE respiratory system through the lungs : The lungs use bicarbonate (HCO3-) generated by the kidney to neutralize H+ ions in the form of CO2. The latter will be evacuated by ventilation.

• THE renal system through the kidneys : The renal response of net excretion of acids via urine occurs after several days. 

Current lifestyle and diet are the source of excess intake of acidifying foods. As a result, the regulation systems can unfortunately to be overwhelmed by this excess and this leads to an accumulation of acids in the blood and CO2 in the respiratory circulation. It is when these systems are overwhelmed that the body can find itself out of balance. This accumulation will result in metabolic acidosis. Be careful not to confuse “acidity” and “metabolic acidosis”. Acidity is linked to the concept of pH and the different pH levels of the body, while metabolic acidosis is linked to the excessive production of acids and the overflow of buffer systems. Following this accumulation, the acids neutralized by the bases will be deposited in fragile areas, causing a "cell fouling".

Metabolic acidosis leads to an inflammatory environment leading to high risks of inflammation, which affects all organs, tissues, cells and enzymatic systems. Be careful not to confuse it with the signs of blood acidosis, because there are not necessarily specific symptoms of acidosis. She evolves at low noise without being visible or measured by routine analyses. These include, for example, morning weakness, sleep problems, constipation, muscular pain in the neck and shoulders, migraines or loss of enthusiasm. Indeed, tissue acidosis disrupts the functioning of the body at several levels:

• Enzymatic.

• Fabric : it attacks tissues, promotes inflammation and facilitates viral or microbial infections.

• Bony and articular : it demineralizes tissues by mobilizing minerals in order to neutralize acids. This demineralization leads to osteoporosis (what to eat in case of osteoporosis?) and joint pain, or even osteoarthritis (what to eat in case of osteoarthritis?).

• Muscular : the attack on the tissues causes muscle weakness, frequent muscle pain, aches, but also tendinitis (what to eat in case of tendinitis?).

• Immune : it weakens the body's defenses. Indeed, the actors of the immune system are affected by acid aggression and demineralization.

• Vascular : deposits in fragile areas cause sclerosis and facilitate the appearance of urinary and gallstones, as well as hypertension.

Low-grade metabolic acidosis is a reality and diet is crucial to prevent it. It directly affects oxygen transport, cell nutrition and leads to a weakening of enzymatic activity. In the long term and with age, metabolic acidosis can be the cause of many diseases such as osteoarthritis and osteoporosis, but also of metabolic and cardiac disorders (overweight, cholesterol, hypertension, diabetes, thyroid disorders). ).

Diet plays a preventive role in acid-base balance. Indeed, the modern diet is too rich in acidifying foods and not rich enough in alkalizing foods. According to some studies, everyone's diet should contain on average 30% acidifying foods and 70% alkalizing foods in order to restore an acid-base balance. Indeed, diet helps prevent the body's regulatory systems from being overwhelmed by excess intake or production of acids. In addition, it allows at the same time to reduce the inflammatory area induced by the acidity of the body, thanks to the reduction of acidic foods or the moderation of their impact by the increase of alkalizing foods. To do this, you must refer to the PRAL index (Potential Renal Acid Load). It allows foods to be classified according to their acidifying or alkalizing effect once metabolized by the body.

• Acid-forming nutrients via the production of organic acids: proteins (sulphur-containing amino acids induce production of sulfuric acids), the chlorine (hydrochloric acid), sulfur (sulphuric acid) and phosphorus (Phosphoric acid).

• Basifying nutrients via the production of bicarbonate ions (HCO3-): the potassium (K+), the calcium (Ca2+) and the magnesium (Mg2+).

Sport is an activity that increases the production of organic acids and particularly lactic acid (via the combustion of carbohydrates and lactates). Therefore, it is recommended to ensure a very alkalizing meal after a sporting activity. It will therefore be necessary to move towards starchy foods such as potatoes and chestnuts, as well as vegetables and fruits. The presence of food sources of protein will still be wise since amino acids are essential in the muscle and tissue recovery processes. It is therefore recommended to consume eggs and dairy products (natural yogurt in particular) which will be best tolerated. This specific case is a good example of the benefit of judiciously combining acidifying foods and alkalizing foods to tend towards balance, without risking lacking essential nutrients such as amino acids.

Foods are classified according to their PRAL index to determine their acidifying or alkalizing effect once metabolized by the body. For a simple visual rendering, we have classified certain foods into 4 categories: very acidifying, slightly acidifying, slightly alkalizing and very alkalizing. Furthermore, only water and oils have a neutral PRAL index of 0.

The diet allows you to tend towards a balance between acidifying and alkalizing foods over 24 to 48 hours. Therefore, you should not worry if during a meal the food is too acidic. However, you will need to remember to eat in an alkalizing manner for the rest of the day. This is also the case for a day that is too acidic, in which case it will be recommended to alkalize your plates the next day. Indeed, the consumption of acidifying foods is normal and beneficial to the body, it is nevertheless preferable to accompany this consumption of alkalizing foods to strive for balance.

Breakfast :

• 1 cup of coffee or 1 cup of tea
• One or two slices of wholemeal bread
• A lawyer

Lunch :

• Chicken cutlet
• Brown rice with turmeric
• Spinach
• A natural yogurt

Snack :

• Macadamia nuts
• An Apple

Dinner :

• Omelette with onions and parsley
• Plantains
• Broccoli
• Piece of Camembert

The answer is no, or at least not completely. Indeed, the urinary pH strip only allows you to see the acidity at a given time, but not in the long term. Furthermore, the results can be distorted as part of taking medications (aspirin, corticosteroids) or in the event of a pathology such as cystitis (what to eat if you have a urinary tract infection), hyperuricemia or diarrhea. The link between urine and excess acids is also indirect, because despite urine with a normal pH, your body may struggle to evacuate acids.

However, if these circumstances are excluded, it can be part of the diagnosis. Indeed, even though the diagnostic ability is very complicated nowadays, acidosis can be estimated at the level clinical (via the PRAL index) and at the level biological via measurement of urinary pH, net acid excretion, sodium/potassium ratio and anion gap. The latter is defined as the difference between the sum of positive ions (cations) and negative ions (anions) in blood plasma.

Therefore, it is possible to carry it out, but while respecting a very specific protocol to be able to be objective. You must first measure the pH on the second urine in the morning since the first does not objectively reflect an acidic terrain. Indeed, at night, the body sorts waste which will be evacuated by the first urine in the morning. Then, the results are read using a pH indicator paper which will change color depending on the pH of the urine in which it is soaked. It is recommended to repeat the same operation before lunch and dinner. Urinary pH is considered normal for values ​​between 6.5 and 7.5. Below a pH of 6, we will speak of acidic soil. It is optimal to carry out these urine tests over 4 to 5 days, and ideally over a week. In this way, it is possible to have a vision, certainly indirect, but acceptable of the acid-base balance.

To conclude on this point, the best way to know if you are in an acid-base imbalance is to contents of the plate. Only you can know if your diet is a vector of an acid-base imbalance, and we hope to have helped you with our lists on the acidifying foods and the alkalizing foods.