Nutrition Myths
Is alkaline diet cancer-protective?


  • Diet does not change the body alkaline balance and cancer produces its own acidic environment, independently of the blood pH.
  • Nevertheless, there is no doubt that eating plenty of vegetables and fruits and avoiding processed foods is cancer preventive, but for other reasons than their alkalinity.

Is alkaline diet cancer – protective?

One misconception about cancer is that its cells are acidic and/or cancer thrives in acidic environments resulting from an acid-forming diet.

The alkaline diet supporters claim that by increasing the consumption of alkaline foods, the environment becomes more alkaline, resulting in a reduction of the risk of cancer, the suspension of the cancer cell growth or even the elimination of cancer cells.

The following are the three main reasons why this theory is incorrect:

  1. What we eat does not change the blood pH or extracellular fluid (read more..) and has nothing to do with the acidic environment around cancer cells. (1, 2, 3)
  2. Cancer cells have a neutral or slightly alkaline pH, but never acidic.

    However, outside the cancer cells, the environment may be slightly acidic. The acidity in the cancer cell environment is caused by a homeostatic mechanism in which the cancer cells expel hydrogen ions and lactic acid to maintain a constant neutral or alkaline pH within the cells.

    Therefore, cancer cells are actually causing the acidic environment around them. (4, 5)

  3. Cancer creates its own acidic environment in which it thrives. It’s rapidly multiplying cells increase glucose consumption, leading to an increased acid production.

    This excess of acid is then exported outside the cancer cells in order to maintain a near neutral pH. Meanwhile, in this process, the cells become more resistant to acid-induced cell toxicity.

    The increased acidic environment outside the cancer cells helps them to expand by invading other tissues not resistant to this acidic environment.

    The microenvironment created by cancer cells has a reduced circulation making it difficult for the blood to influence its pH. (6, 7)

    This biological fact is often omitted in the studies that try to prove that cancer is a result of the acidosis caused by diet.

Related Posts

Do acid-forming foods make urine more acidic? Acid-ash foods contain minerals which lower the fluids' pH. To maintain the blood at its optimum acid-base level the body removes the acidic substances trough urine, making it more acidic.
Did our ancestors really eat mostly alkaline foods? Contrary to what the supporters of the alkaline diet believe, only 40%-50% of people before the beginning of agriculture had a net acid-producing diet.
Do acid-forming foods cause osteoporosis? Acid-forming diets can cause osteoporosis if combined with a calcium intake consistently below the recommended daily value. Increasing the calcium intake may improve the bone health.
Does a diet high in acidic foods make the urine acidic? Acidic foods (foods with low pH) don't necessarily influence the acid-base balance of the urine. Urine's pH depends rather if the they are acid-forming or base-forming foods.
Does the urine pH test measure the body’s alkaline balance? The blood's pH or body's alkaline balance is determined using blood samples. The urine pH test only measures the acidity of the urine.

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