Can Drinking Alkaline Water Help to Prevent Disease?

Blog Post

Stephen W. Farrell, PhD, FACSM
The Cooper Team
January 19, 2023

As you browse the bottled water aisle of the supermarket, you will notice a fair amount of alkaline water products. You will also notice that alkaline water is considerably more expensive than standard bottled water. Have you ever wondered why alkaline water is manufactured and sold in the first place and why people might want to drink it? Let’s dive in! (pun intended).

There are an endless number of dietary programs out there, many of which have been developed by individuals with little to no background in nutrition.

In order for a dietary approach to stand out from the rest, one must have a gimmick. For example, one diet might urge us to eat like a caveman, while another may emphasize avoiding high glycemic index or processed foods. One of the more recent dietary fads is The Alkaline Diet. This approach is based on the acid/alkali theory regarding disease. When our body breaks down the foods and beverages that we consume, the waste products are sometimes called ‘ash.’ The ash can be acidic or alkaline. The sales pitch is that by consuming more foods and beverages that produce alkaline ash and fewer foods that produce acidic ash, you can change the pH of your body. Since 60-70% of adult body weight is water, and blood has a very high water content, it seems plausible to the average person that drinking alkaline water would help to make our body (and our blood) less acidic. Proponents claim that this shift in pH will lead to weight loss, increased energy, and a decreased risk of chronic conditions such as cancer, arthritis, osteoporosis, kidney stones, gallstones, etc. These claims should remind us of a wise old saying: “If it sounds too good to be true, it probably is.”

Before continuing, we should discuss a bit of basic chemistry. The pH scale consists of numbers between 0 and 14. Numbers at the lower end of the scale indicate strong acids, while numbers at the upper end represent strong bases (alkaline). For example, tap water has a pH of 7.0, which is neutral. This simply means that it is neither acidic nor alkaline. It is important to note that pH levels vary significantly throughout the body. Blood normally has a pH of 7.4, while the pH of muscle tissue at rest is 7.2. Bile and pancreatic juices typically have a pH of about 8.0, while our stomach is always very acidic with a pH of approximately 1.7. The very low pH value in the stomach is due to the presence of hydrochloric acid, which helps to break down food during the digestive process. None of these pH values is the least bit controversial; in fact, you will find this information in all standard medical and nutrition textbooks. It is also well established that some foods are more on the acidic end of the continuum, while other foods are more alkaline.  

Alkaline water products typically have a pH of 8 or 9. As mentioned previously, alkaline water proponents claim that this water will change the pH of the blood. At this point, a basic review of human physiology is in order!

One of the major functions of the kidneys is to regulate the acid-base balance of the body. This includes keeping blood pH at a constant level of 7.4. Despite what proponents of alkaline water claim, there is not a shred of scientific evidence that what you eat or drink will change the pH of your blood (or anything else in your body). Another misconception supported by alkaline proponents is that you can test your body’s overall pH by testing the pH of your urine. Any board-certified urologist will tell you that the pH of urine is not an indicator of pH in the rest of your body. Regardless of the pH of your urine, if your kidneys are functioning normally, the pH of your blood will always be 7.4. In fact, any licensed health care professional will tell you that a significant deviation from this number for more than several minutes, i.e. metabolic acidosis, is quite lethal!

Some individuals claim that there is proof that drinking alkaline water prevents cancer and a host of other diseases. Actually, there is no proof of this at all. If there was, it would be the lead story in the national news, on the front page of every newspaper and magazine, and be featured prominently on the American Cancer Society, American Diabetes Association,  American Heart Association, and the National Institutes of Health websites. The fact is that not a single evidence-based health organization endorses consuming alkaline water.    

So, when a product such as alkaline water sounds too good to be true, it’s wise to be very skeptical. An endorsement from a Hollywood celebrity or a star athlete is typically not based on solid science. Just because a dietary approach is hip and trendy does not mean that it is effective. Save your money and help save the environment by drinking less bottled water (particularly alkaline water). If you are concerned about the quality of water coming from your tap, then please consider using a water filter. Such filters are widely available and relatively inexpensive.


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