Starving Cancer Cells

Kill Cancer By Restricting Methionine-Rich Foods

Jul 9, 2014 Brian D. Lawenda, M.D.

Methionine

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 anti- cancer 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 reported in many studies using animals implanted with tumors. When fed a methionine-restricted diet their tumors grew more slowly, spread less often and also 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 important amino acid that is used as a building block for proteins that are essential for cell development and growth. This is particularly important for cancer cells that are rapidly dividing (whereas normal cells tend to grow more slowly and require less methionine.) This amino acid is so critical that there is even a complex biochemical process that is named after it called, the Methionine (or Yang) Cycle.

Additionally, it is now believed that methionine-dependent cancers have mutations in important tumor growth suppressor genes (genes responsible for stopping cancer cell growth.) If these genes are mutated the cancer cells grow without inhibition. That’s not a good thing.

How Do You Restrict Methionine In your Diet?

If you are willing to switch to a vegan diet you will dramatically reduce your consumption of methionine-rich foods. Meat, fish, poultry, eggs, cheeses, soybeans, sesame seeds and brazil nuts are high in methionine (see table), whereas most vegetables and fruit are low in methionine.

Frequently Asked Questions:

Will this diet help improve my cancer outcomes?

We don’t have human studies to guide us on this.
Not all cancers are methionine-dependent and unfortunately we don’t have a simple test to determine if your cancer is susceptible to this diet.

Is it safe for me to follow this diet?

You need to ask your treating oncology team “if ” they think it is safe for you based on your specific circumstances. If you are actively losing weight it is not advisable to start a diet which could accelerate additional weight loss. Reassuringly, although methionine is an essential amino acid (meaning your body requires it), it’s very uncommon for someone following a vegan diet to develop problems due to a methionine deficiency. Just make sure you are consuming adequate calories and a wide variety of plant foods. So that you can better ensure you are receiving the full range of nutrients your body requires (vitamins, minerals, fats, proteins and carbohydrates.)

What foods can I eat that are both low in methionine but high in protein?

Since many protein-rich foods like meat, poultry, fish, and certain beans that are high in methionine you may be wondering what foods you can eat that will allow you to consume enough protein to meet your daily allowance are also low in methionine. The best website I have found to help me answer questions like this is SelfNutritionData.org (see this link for a list of foods that are high in protein and low in methionine.)

The Bottom Line:

If your cancer is methionine-dependent, it is possible that by switching to a vegan diet (inherently low in methionine) or a diet that is predominantly plant-based with limited amounts of meat, fish, eggs and poultry (i.e. Mediterranean diet), you might be able to take advantage of this promising anticancer effect.

Since there are no simple tests that you can easily order from most labs to tell you whether your cancer is methionine-dependent you may not get any anticancer benefits from methionine-restriction. That said, switching to a plant based (or predominant) diet will still provide you with many other anticancer properties regardless of the cancer’s dependency on methionine:

Whole plant foods are full of cancer-fighting phytonutrients, antioxidants and anti-inflammatory compounds, and
Whole plant foods generally have a lower glycemic load (meaning they don’t cause a large and rapid rise in blood sugar and insulin levels after consuming them…read Sugar and Carbohydrates 101 to learn more.)

Before you start any dietary changes discuss it with you oncology care team.

Watch this excellent (5 minute) video by NutritionFacts.Org on this topic:

Preview YouTube video Starving Cancer with Methionine Restriction