Some things can be classified with high acidity, like lemon juice, or low acidity, like bicarbonate. Acidity is often measured on a pH scale. This is because Danish chemist invented the concept of pH as a convenient method for expressing acidity. Acidic things have a low pH whereas alkaline things have a high pH.
At first, the pH scale seems a little contradictory. Why does something with high acidity have a low pH? This is because the pH scale is a logarithmic scale based on the number of hydrogen (H+) ions in solution whereby pH = - log[H+]. So, the more H+ ions there are, the smaller the pH. The scale ranges from 0 to 14 and a pH of 7 is considered neutral. The pH scale is normally used to measure the acidity or basicity of liquids. Some solids can impact the pH of a solution if they change the H+ ion concentration. For example, adding baking soda, also known as sodium bicarbonate, to water will increase its pH and make it more alkaline.
The blood in our bodies has a pH range from 7.36 to 7.45 with an average of 7.4. Most of the chemical reactions catalyzed by enzymes in the body function optimally within this pH range. Deviances from this pH in the body, either in the form of acidosis or alkalosis, can have severe consequences on our health. Therefore, maintaining pH within this range is very important. Luckily, under normal circumstances, our bodies have several highly sophisticated mechanisms to ensure our blood does not deviate from this optimal pH.
The first mechanism is known as the bicarbonate buffer system. This buffer system consists of carbonic acid (H2CO3) which can then be broken down into hydrogen ions (H+) and bicarbonate ions (HCO3-). The reverse reaction is also possible. This means that if the body needs to make the pH more alkaline, it can produce more HCO3- ions and vice versa. The second mechanism relies on our respiratory system. Carbon dioxide (CO2) and water (H2O) can combine to form H2CO3. This means that if your blood becomes more acidic, for example in high endurance exercise, your breathing increases to reduce the CO2 in the blood and reduce the acidity. On the other hand, if your blood is too alkaline, your breathing rate decreases to increase the CO2 levels in your blood to make it more acidic. The final major mechanism relies on the renal system. The kidneys can excrete more or less bicarbonate if blood conditions are alkaline or acidic respectively. The respiratory system manages the short-term, fast response whereas the renal system manages the long-term, slower response.
It鈥檚 hard to see where alkaline water would fit into this tightly regulated system. Claims are that alkaline water, with a pH of around 8-9 can be used to neutralize acid in the bloodstream and help the body maintain a balanced pH. However, the acid in your stomach is likely to neutralize the alkaline water before it can even make it into your bloodstream. In addition, even if the water did make it into your bloodstream, it is unlikely to have a significant impact on the blood鈥檚 carefully regulated pH levels. Rather than balance your body pH, alkaline water is more likely to unbalance your wallet.
Daniela is a recent B.Sc. graduate from the program of Physiology at 捆绑SM社区.听She is very passionate about understanding the human body and how we can all individually adapt our daily lifestyles to improve its functioning.
Part of the OSS mandate is to foster science communication and critical thinking in our students and the public. We hope you enjoy these pieces from our听Student Contributors听and welcome any feedback you may have!
