Disclaimer:
This post is for information purposes only and to raise awareness of areas of research in nutrition and triple negative breast cancer. It is not intended as dietary advice, recommendations or suggestions. Changes to dietary intake and avoidance of foods without appropriate clinical assessment, guidance and monitoring can lead to unwanted nutritional deficiencies that can adversely affect health and well-being.
What exactly is Methionine?
Protein is made up of amino acids.
Essential Amino Acids – these are the building blocks of protein
- Valine
- Leucine
- Isoleucine
- Lysine
- Methionine
- Phenylalanine
- Threonine
- Tryptophan
- Histadine
Methionine is classified as an essential amino acid and it is one of the building blocks of protein. It is essential because our body cannot make methionine – Note: our body can make other amino acids that are not listed above. Because we are unable to make methionine, we must obtain it from our diet.
To be more specific, methionine is classified as an essential amino acid which comprises a 4 carbon amino acid chain and contains the element sulphur in it’s chemical structure. A quick overview of essential amino acids can be found in an earlier blog post here.
Breast Cancer Research
Methionine and triple negative breast cancer
- There is evidence from early animal and laboratory studies to suggest that reducing the amount of methionine in the diet may inhibit metastasis in triple negative breast cancer cells by influencing a number of key pathways and processes.
- Jeon H, Kim JH, Lee et al. Methionine deprivation suppresses triple negative breast cancer metastasis in vitro and in vivo. Oncotarget. 2016; 7(41): 67223 – 67234.
- Evidence from early studies suggest that a low methionine diet may increase the number of ‘cell death’ receptors on TNBC cells – receptors that could possibly cause a weakness in the cancer cells ability to survive.
- Strekalova E, Malin D et al. Methionine Deprivation Induces a Targetable Vulnerability in Triple Negative Breast Cancer Cells By Enhancing Trail Receptor-2 Expression. Clinical Cancer Research. 2015; 21(12): 2780-2791.
- There are also other important processes that appear to be affected by methionine restriction. Key references looking at methionine restriction in TNBC cells have been provided at the end of this post.
- Findings from early studies paved the way for the development of the first clinical trial specifically looking at a low methionine diet in TNBC in 2017.
- Clinical trials are conducted under close medical supervision. This is to ensure that overall energy and nutritional intake is optimised and to prevent any macronutrient deficiencies – i.e. protein – or micronutrient deficiencies or unfavourable outcomes.
Methionine In Foods
We need methionine – and all essential amino acids – in our diets to keep healthy, as well as adequate protein, energy and micronutrients.
♦ Fruits and most vegetables are naturally low in methionine. Plant-based foods generally tend to have the lowest levels of methionine (per 100g).
♦ Foods with the highest levels of methionine (per 100g) are listed below:
- meat
- chicken
- fish
- animal derived products
Protein
I have written a separate and more informative post on the importance of protein in the diet and how much protein we can obtain for food sources here: How much protein do we really need?
Methionine Content of Common Foods
(Average Values per 100g)
Fruits
Average: 1mg to 10mg methionine per 100g
Apple
Strawberries
Tangerines
Papaya
Pears
Cranberries
Nectarines
Mango
Plums
Bananas
Average: 10mg to 15mg methionine per 100g
Peach
Blueberries
Pineapple
Guava
Average: 20mg to 25mg Methionine Per 100g
Grapes
Kiwi Fruit
Vegetables
Average: 5mg to 10mg methionine per 100g
Celery
Cucumber
Cabbage, cooked
Sweet Peppers
Tomatoes
Leeks, cooked
Aubergine, cooked
Taro (Eddo/Dasheen) cooked
Pumpkin, cooked
Turnip, cooked
Average: 10mg to 20mg methionine per 100g
Onions, cooked
Courgette
Kale, cooked
Beets, cooked
Cauliflower
Carrots
Okra, cooked
Olives
Squash, cooked
Plantain, raw
Yam, cooked
Average 20mg to 30mg methionine per 100g
Mushrooms
Green Beans
Average: 35mg to 50mg methionine per 100g
Avocado
Brussels Sprouts
Sweet Potato, cooked
Potato
Barley, cooked
Broccoli
Black eyed peas, cooked
Average: 55mg to 70mg methionine per 100g
Spinach, cooked
Rice, Brown
Rice, White
Pasta, wheat, cooked
Sweetcorn
Millet, cooked
Average: 60mg to 85mg methionine per 100g
Pigeon Peas, red gram
Lentils, cooked
Mung Beans, cooked
Split Peas, cooked
Peas, cooked
Tofu, soft
Average: 100mg to 120mg methionine per 100g
Quinoa, cooked
Kidney Beans, cooked
Chickpeas, cooked
♦ Foods Highest in Methionine
Average 300mg methionine
Brazil Nuts (per 25g)
Average: 200mg methionine per Large Egg (50g)
Average: 500mg to 550mg methionine per 100g
Cod
Ham
Average: 600mg to 700mg methionine per 100g
Shrimp, cooked
Average: 700mg to 800mg methionine per 100g
Pork, cooked
Salmon
Beef, lean, cooked
Turkey, roasted
Chicken Breast, cooked
Important Disclaimer:
This post is for information purposes only and to raise awareness of areas of research in nutrition and triple negative breast cancer. It is not intended as dietary advice, recommendations or suggestions. Changes to dietary intake and avoidance of foods without appropriate clinical assessment, guidance and monitoring can lead to unwanted nutritional deficiencies that can adversely affect health and well-being.
References:
- Jeon H, Kim JH, Lee et al. Methionine deprivation suppresses triple negative breast cancer metastasis in vitro and in vivo. Oncotarget. 2016; 7(41): 67223 – 67234.
- Strekalova E, Malin D et al. Methionine Deprivation Induces a Targetable Vulnerability in Triple Negative Breast Cancer Cells By Enhancing Trail Receptor-2 Expression. Clinical Cancer Research. 2015; 21(12): 2780-2791.
♦ Suggested Reading and Related Posts on TNBC:
http://www.demeraradelight.com/category/breast-cancer/
http://www.demeraradelight.com/copper-chelation-triple-negative-cancer/
http://www.demeraradelight.com/luteolin-and-triple-negative-breast-cancer/
http://www.demeraradelight.com/blueberries-triple-negative-breast-cancer/