This content was updated on November 2, 2020.
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Question from Kathy:
Does eating an “alkalizing” diet help prevent cancer? I’ve never read a medical study that says this is the case, but boy, there are a lot of books touting eating foods that “alkalize” the body. Is there merit to this, or is it just the fact that most “alkalizing” foods happen to be vegetables that this way of eating may help prevent cancer?
Does an alkaline diet prevent cancer?
The alkaline diet is one that has proved to be popular in celebrity culture, with claims that the diet can help protect the body against medical conditions such as cancer and arthritis, as well as help you lose weight. The diet is supposedly able to protect you against cancer because it reduces the amount of acid your body produces. This theory is based on the claim that cancer cells thrive in an acidic environment and can’t survive in alkaline surroundings, so an “alkalizing diet” would promote a more alkaline environment in the body and prevent cancer from developing. However, there are problems with this claim.
- The studies finding that cancer cells thrive in an acidic environment were done in a laboratory setting. Your body is very good at maintaining its pH levels, without dietary influence. It would be nearly impossible to alter the cell environment to create a less-acidic environment in our bodies. For example, the stomach is very acidic for proper digestion, so we wouldn’t want it more alkaline.
- Our acid-base balance is well regulated – blood pH is tightly controlled normally by the body between 7.35 and 7.45. If the pH level becomes too acidic or alkaline, that could be life threatening and is typically an indication of a serious health problem, though it’s not the underlying cause.
- It’s actually very difficult for you to change the pH levels in your blood, as your body works hard to regulate and maintain these levels. Other areas of your body contain different levels of acidity, with your stomach being more acidic in order to breakdown any food you consume. So whilst you might stick to a strict alkaline diet, the pay-off may not be what you expect.
The diet does encourage an individual to eat healthily, owing to the emphasis on fruit and vegetables and avoidance of processed foods, so it does help with weight loss. However, it doesn’t have strong influence over the pH balance of your body.
Which foods are considered alkaline and which aren’t?
Generally, vegetables, fruits and seeds are considered to be alkaline, whilst meats, beans, nuts and grains are acidic. So, an alkaline diet would be rich in vegetables and fruit with little meat consumption. Dairy, eggs and processed foods aren’t considered alkaline and would be avoided in this diet. A diet focused on plant-based ingredients is similar to AICR’s diet recommendations for lowering cancer risk – with red meat limited to no more than 18 oz. per week, and avoiding processed meat.
However, some very healthy foods are listed as “acidic” such as whole grains, beans and even some vegetables such as carrots. So keep it simple and follow AICR’s New American Plate to lower cancer risk simply by filling at least 2/3 of your plate with vegetables, fruits and whole grains, and 1/3 or less with meat, poultry and fish.
What is the alkaline diet?
The alkaline diet is where an individual consumes food and drink that is categorized as alkaline. This means that on the pH scale* the item has a pH between 7-14. The aim is to reduce the amount of acidic food and drink consumed. The diet is derived from the notion that the different foods we eat affect the overall pH balance of our bodies. A quick search on Google for “alkaline diet” or “pH diet” results in hundreds of thousands of hits, so yes, it is very popular. The diet is also known as the “alkaline ash diet”, or the “alkaline acid diet”. Food is considered alkaline or acid based on laboratory combustion of the food.**
What other health benefit does the alkaline diet claim to offer?
There are many claims about this diet including weight loss, more energy and solutions to other common problems, such as stronger bones, lowering the risk of type 2 diabetes improving brain and heart health, but according to the American Dietetic Association, “large, well-designed clinical trials on the effectiveness of the many claims made for the alkaline diet are lacking.”
Just a note: the pH of urine can be changed somewhat by diet because the kidney is key in maintaining the proper body pH. Some proponents of this diet encourage checking your urine pH to see if your diet is alkaline or acid. Keep in mind that an increase in acid or alkaline in the urine reflects the fact that the kidney is doing its job. A change in urine status does not indicate a change in “overall body pH.”
*pH is a measure of acidity/alkalinity on a scale of 1-14. Seven is neutral, with anything above that alkaline and anything below that acid.
**Alkaline-ash foods or Acid-ash foods: This is based on the ash that remains after the combustion of foods under laboratory conditions.