Restrict Methionine-Rich Foods and Kill Cancer Cells

Posted: September 18, 2015 in Research

Although I’m hardly surprised, it is a tragedy that that there has yet to be a single, high-quality clinical (human) trial conducted to investigate a very promising anticancer phenomenon that researchers have known about since 1959.

It was discovered that if you try to grow cancer cells in a medium with little-to-no methionine (an essential amino acid), often the cells would stop growing, dividing and they would undergo apoptosis (“cell suicide”.) Similar findings were subsequently untitledreported in many studies using animals implanted with tumors. When fed a methionine-restricted diet their tumors grew more slowly, spread less often and the animals survived longer then those fed a regular diet.  Importantly, harmful effects due to short-term methionine restriction were rarely seen in the animals or normal cells studied.

These studies discovered that a wide-range of cancer types require methionine to grow and divide (this is called “methionine-dependent”), such as:

  • breast cancer
  • bladder cancer
  • pancreatic cancer
  • lung cancer
  • brain tumors
  • stomach cancer
  • leukemia
  • lymphoma
  • head and neck cancer
  • melanoma
  • sarcomas
  • etc…

Methionine restriction has been shown to be safe in at least one study with cancer patients who were placed on a low-methionine diet for 17-18 weeks. The patients lost on average 0.5 kg per week while on the study but it is not known whether this weight loss was due to the diet (0.6-0.8 g of protein, 25-35 kcal, and 2 mg of methionine per kilogram per day) or cancer progression since all the patients had advanced disease (metastatic cancer.)

How Does Methionine Restriction Cause Anticancer Effects?

Methionine is an essential amino acid, which plays a role in protein synthesis, methylation of DNA, and polyamine synthesis. It is thought that restriction of methionine may help control cancer growth, especially in cancers that are dependent on methionine for survival and proliferation.

The biochemical mechanism for methionine dependency is not clearly understood. In coculture with normal cells, methionine-dependent cancer cells were killed by using a culture media deficient in methionine. In several animal studies, a methionine-restricted diet inhibited cancer growth and extended life span. Vegan diets, therefore, might provide a useful strategy for controlling cancer growth.


In animal models, a methionine-free diet or methionine-deprived total parenteral nutrition led to regression of a variety of animal tumors. Methioninase also is used for methionine depletion. Several studies have demonstrated synergy between methionine restriction and certain chemotherapy drugs.

The methionine restriction protocol put forth by the Nutritional Oncology Research Institute calls for the restriction of animal protein, including beef, pork, poultry, dairy, eggs, and seafood. It also is necessary to eliminate soy and restrict nuts, seeds, grains, and legumes. The mainstay of the diet is fruit. According to the developers of the restriction, the diet also will improve insulin resistance and insulin. Insulin-like growth factor-1 is what stimulates cancer cell growth. Simple refined sugars and fruit juice are discouraged, except for organic Concord grape juice, which is allowed in small amounts at a time.

The protocol is divided into two phases. The restriction phase is for 10 days, and the methionine repletion phase can last for 3 to 5 days. In both phase 1 and 2, the diet is free of all animal-based foods. Phase 2 allows a greater variety of plant foods. Cycling between phase 1 and 2 prevents the body from adapting to the low amino acid intake.

During the restriction phase, the preferred fruits are mango, papaya, pineapple, strawberries, and kiwi. Small amounts of vegetable juices are acceptable during the restriction phase. During the restriction phase, it is necessary to avoid nuts, seeds, grains, green vegetables, and potatoes. The repletion food can include any plant-based food, with 75% of it raw.

Here you can watch my friend Chris Wark interviewing Mark Simon of Nutritional Oncology Research Institute. He talks in great depth in the role methionine has on cancer cells

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