Gerson Therapy: a critique

A critique of Gerson’s Therapy

If you have spent any time researching cancer nutrition, you most certainly have stumbled across Gerson’s Therapy (also known as Gerson’s Diet or Gerson’s Protocol). In this article, I will attempt to succinctly give a balanced point of view on Gerson’s Therapy.

What is Gerson’s Therapy?

According to the Gerson Institute, it is a therapy plan that aims to activates the body’s ability to heal itself through an organic, plant-based diet, raw juices, coffee enemas and natural supplements. Here is how it works in a nutshell:

  • Juicing of up to 20 pounds of organic fruits and vegetables per day.
  • Having a plant-based diet.
  • No salt, fat, animal proteins. Plant proteins are also restricted.
  • Several coffee enemas per day.
  • Some supplements such as potassium, iodine, B12, flaxseed oils and some enzymes.

Gerson’s Therapy has not been independently tested or subjected to scientific trials, and thus is illegal to market in the United Kingdom and United States – and probably several other countries. The principles behind it are not widely accepted by the medical community.

Gerson's Therapy: juicing and enemas for cancer treatment?

Do we have any proof?

Proponents of the therapy claim a high cure rate, but this is not supported by any credible research. A five-year survival rate retrospective study of 153 cancer patients found higher survival rates in patients undergoing the Gerson regime than for patients undergoing other therapies. However, it should be noted this work was conducted by members of the Gerson Research Organisation and has been criticised as being seriously flawed. A few additional attempts at studying the therapy have been made over the year without any real success. I have personally listened to a few interviews of the supporters of the therapy and the only mechanism of action which was put forward was some vague referral to “energy”.

Is it safe?

In the sense that this therapy is often portrayed as an alternative treatment, leading people to delay conventional treatment, then no. It is not safe. In fact, this very issue has recently attracted media attention following the death of Gerson advocate Jess Ainscough  (a.k.a. “the wellness warrior”).

Are Gerson’s therapy arguments valid?

Let’s see point by point what constitute the Gerson regimen:

1. Coffee enemas.

Coffee enemas in Gerson's therapy

Whilst enemas are actual medical interventions practised routinely in hospitals to help relieve constipation, coffee enemas do not have much science behind it. The theory behind the use of coffee enemas is that the components in the coffee might, according to proponents of the therapy, cause the bile ducts to open and the liver to release its bile. Well, yes, coffee might help with bile flow (source), but there is no proof that an enema is better at doing so than drinking (and enjoying) a good coffee like everyone else. A second point of interest is that coffee enemas could have an analgesic effect. Maybe, but maybe also this could be due to the caffeine alone (source) and there is no proof that an enema is better at pain decrease than drinking coffee. In fact, the pharmacokinetics (study of the speed of action of a pharmaceutical product) of coffee enemas has shown that they are 3 times less effective than drinking coffee at supplying someone with caffeine (source), and doesn’t supply any more antioxidants than drinking coffee normally (source).

On the negative side, coffee enemas will supply you with quite a bit of caffeine. Less so perhaps than drinking normal coffee, but the increased frequency of enemas in Gerson’s protocol could contribute to mess-up your hormones (cortisol to start with), promote the breakdown of muscles to produce glucose in the liver (gluconeogenesis, a direct result of an increase in cortisol) and overall be counter-productive to cancer patients.

So overall, I do not recommend coffee enemas as an alternative therapy for cancer.

2. A very restrictive diet.

Gerson’s therapy aims to very severely restrict salt, fat and proteins, from any source. This is basically unwise. All of those contain essential nutrients. This means they contain chemicals the body cannot make. The chloride in salt is necessary for stomach acid, and sodium in salt is required for nerve conduction. Essential fatty acids in fats are necessary for you to manufacture many hormones and healthy cell walls. Essential amino-acids in proteins are required to make enzymes, muscles, cells, immune system components and others. Such a restrictive approach to diet as in the case of Gerson’s therapy, especially over the course of several months or years, is totally counter-productive, will lead to deficiencies, and pretty much will guarantee that your health will deteriorate.

I do not recommend such a restrictive diet for cancer patients.

3. Juicing

Juicing for cancer

Ok, we’ve all heard that consumption of fruits and vegetables is good for you and may help reduce your cancer risk. So it would be easy to believe that juicing fruits and vegetables is even better, because you get them more concentrated…? Except for the two following points:

  • When juiced, the fibres of the fruits and veggies are taken out. With nothing to slow down the carbohydrates, you end up with a high glycaemic index beverage. This will possibly make your blood sugar skyrocket and is not recommended when living with cancer.
  • During the juicing process, most of the food fibres are discarded. This will starve the gut microbiome (beneficial bacteria in the intestine, which feast on nutritional fibres), and lead to additional inflammation and decreased immunity.
  • The green smoothing fad that has taken the internet, and which may be present in some practices of Gerson’s therapy, is actually dangerous. Some of the veggies presents in those green smoothies (spinach in particular) have a high oxalate content, and making a smoothie or a juice out of it can expose you to high levels of this chemical. Oxalate will bind to calcium (and some other minerals) in your body, and make crystals in tissue and stones in kidneys.
  • Juicing every hour as recommended in Gerson’s protocol will compound the blood sugar issue. This is going the exact opposite way that one should go to comply with the metabolic approach to cancer diet.
  • On the flip side, such a high amount of juicing will bring a lot of antioxidant and phytochemicals, which may have a positive effect on cancer diagnosis.

Overall I recommend caution when raw-juicing as part of a cancer diet. I would suggest to choose non-nightshade, non-beans vegetables low in sugar, low in oxalate, low in goitrogens… and low sugar fruits. I would also add healthy fats to the drink to slow down the absorption of carbohydrates. That would restrict your options quite a bit. And please, do not make this your primary source of calories, and do not add protein powders.

4. Organic food

Yes! As said in other posts I do recommend organic.

5. Raw food

Yes! Cooking can destroy some nutrients, and I do recommend some of your food to be raw – but not all, and in particular some food must be cooked for various reasons. In particular, do not eat raw spinach, cruciferous vegetables, tomatoes, potatoes, beans, pork, chicken… (there are several others). Perhaps I will cover this more in details in a future post.


One has to acknowledge Max Gerson for being a pioneer in the field of cancer nutrition. And indeed, for some people the Gerson Diet may be an improvement on what they are eating on a daily basis. However, Gerson’s therapy is now obsolete in its concept, and potentially counter-productive if not dangerous on many of its recommendations.

Overall, I do not recommend the use of Gerson’s Therapy either as an alternative or as a complement to modern cancer therapy. I wouldn’t suggest either that diet alone is sufficient to cure cancer.

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