If you have spent any amount of time online researching anti-cancer diets, you have surely come across websites promoting the alkaline diet. The philosophy is that some foods are acidic on the pH scale (less than 7), while other foods are alkaline (greater than 7), and that a more alkaline body prevents disease. The theory is that eating alkaline foods creates an internal environment that is inhospitable to cancer, and that eating acidic foods encourages cancer’s development and growth.
The desire to “alkalinize” the body comes from the fact that the tumor microenvironment – the area around clusters of cancer cells – tends to be more acidic. However, there are several major problems with this theory.
The first problem is that this acidic environment does not occur because that person ate too much acidic food, but rather, because cancer cells create lactic acid as a waste product, as a result of their energy production process. This acid, which occurs regardless of what is or isn’t in the diet, must be expelled from the cancer cell in order for cancer to survive. Once the acid is in the tumor microenvironment, it helps cancer to spread and become more aggressive.
The second problem with the alkaline diet is the belief that eating more alkaline foods neutralizes this acidic environment. Proponents of the alkaline diet often recommend the use of pH test strips to test the pH of the urine. When one begins eating a more alkaline diet, the pH of the urine will read more alkaline as well. However, this is not because the body is more alkaline, but because the kidneys are doing their job. The kidneys act as buffers in the body, monitoring the internal pH very closely and making changes.
The belief that the diet can somehow change the body’s pH shows a lack of knowledge of how the body works. More specifically, it shows that proponents of the alkaline diet don’t understand the very important role of the kidneys. In addition to generating urine to eliminate waste from the body, the kidneys also work hard to make sure that they overall pH of the body is appropriate. The body’s pH is maintained between 7.35 and 7.45, as this narrow range is needed for the body to function properly. When you eat acidic foods, the kidneys will sense the presence of additional acid and will thus create more acidic urine. When you eat more alkaline foods, the kidneys sense this additional alkalinity, and create more alkaline urine. When using test strips to measure the urine’s pH, all you are measuring is what the body is eliminating, and not the pH of the body.
This is supported by science. One recent study concluded that alkaline diets and alkaline water are not supported by research, and that their promotion to treat or prevent cancer is unjustified. (1)
To truly measure the body’s pH, we must measure the pH of the blood. Contrary to what proponents of the alkaline diet would have you believe, no food or drink has the ability to affect the pH of the blood. (2)
Although the alkaline diet does not affect the body’s pH, it is interesting to note that many alkaline foods are quite healthy. Fresh, organic fruits, vegetables, and legumes provide outstanding nourishment for the body and should be the foundation of the anti-cancer diet. They also provide positive contributions to our intestinal bacteria and our immune system.
In conclusion, don’t be fooled by the pseudoscience of alkaline diets. You can’t change the pH of the body by eating alkaline foods or drinking alkaline water, nor would you want to if you could. However, you do want to provide the body with the right foods, and it just so happens that the fruits, vegetables, and legumes you should be focusing on also happen to be more alkaline.
Fenton TR and Huang T. Systematic review of the association between dietary acid load, alkaline water, and cancer. BMJ Open 2016; 6: e010438.
Bonjour JP. Nutritional disturbance in acid-base balance and osteoporosis: a hypothesis that disregards the essential homeostatic role of the kidney. Br J Nutr 2013; 110(7): 1168-77.