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Study: Is asparagus linked to breast cancer metastasis?

A study published in the journal Nature shows that asparagine, a protein building block that takes its name from asparagus, promotes the spread of breast cancer in mice. The study by cancer experts from Britain, Canada and the U.S. investigated whether limiting the levels of asparagine in mice could reduce tumor metastasis. (3/2/18)

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Most relevant for: People diagnosed with breast cancer.

It may also be relevant for:

people with breast cancer
people with metastatic or advanced cancer

Relevance: Low

Strength of Science: Medium

Research Timeline: Animal Studies

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The Guardian

Spread of breast cancer linked to compound in asparagus and other foods
This article rates 4.5 out of 5 stars

Los Angeles Times

Also published in:

Baltimore Sun

Asparagus will not give you cancer, scientists plead after massive misunderstanding
This article rates 4.0 out of 5 stars

At a glance	Questions for your doctor
Findings	Limitations
Clinical trials	Resources
Guidelines

STUDY AT A GLANCE

This study is about:

Identifying new targets that reduce the ability of breast cancer cells to spread and become .

Why is this study important?

Breast cancer becomes deadly when it metastasizes—cancer cells leave the breast, enter the blood stream and then invade a secondary site such the brain, lungs or other organs. This study suggests that reducing the amount of the amino acid asparagine may be one way to decrease the likelihood of breast cancer becoming metastatic.

Study findings:

In mice that were bred to develop breast cancer:

limiting asparagine by either experimental approaches or diet reduced breast cancer .
increasing asparagine by either experimental approaches or diet increased breast cancer metastasis.

“When the availability of asparagine was reduced, we saw little impact on the primary tumor in the breast [in mice], but tumor cells had reduced capacity for metastases in other parts of the body," said Greg Hannon, lead study author and Cambridge University cancer researcher.

What does this mean for me?

Breast cancer that stays confined to the breast is not deadly. But it is more difficult to treat and can become fatal if it metastasizes—if cancer cells spread beyond the tumor and into other organs in the body. These preliminary study results imply that reducing bodily amounts of asparagine is one way to decrease the risk of breast cancer metastasis. This result, however, needs to be confirmed by other studies. In addition, it is important to remember that animal models of breast cancer do not always mimic the disease in humans.

Even if future guidelines were to support a reduction of asparagine to decrease the risk of breast cancer metastasis, it is virtually impossible to eliminate the substance from your diet. Foods rich in asparagine include not only asparagus, but also dairy, beef, poultry, eggs, fish, seafood, potatoes, legumes, nuts, seeds, soy and whole grains. Experts agree that you should not drastically change your diet in an attempt to reduce the amount of asparagine you consume. Asparagine is found in all protein rich foods, many of which are considered part of a healthy diet. In addition, your body naturally makes asparagine. If you are concerned about how your diet will affect your outcome consider discussing this with your doctor or a nutritionist.

Posted 3/2/18

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Reference

Knott, Simon RV, Wegenblast E, et al. “Asparagine bioavailability governs metastasis in a model of breast cancer.” Nature. February 15, 2018; Vol. 554:378–381.

Disclosure

FORCE receives funding from industry sponsors, including companies that manufacture cancer drugs, tests and devices. All XRAYS articles are written independently of any sponsor and are reviewed by members of our Scientific Advisory Board prior to publication to assure scientific integrity.

This article is also relevant for:

people with breast cancer
people with metastatic or advanced cancer

IN-DEPTH REVIEW OF RESEARCH

Study background:

Preventing or eliminating metastasis is an important goal of breast cancer treatment. Mouse models of breast cancer are often used to better understand how breast cancers metastasize and to identify potential targets for treatment that can reduce or eliminate the metastatic potential of breast cancer cells.

Asparagine is an amino acid that is a building block for proteins. Found in many foods, it is also made in the body by a cellular enzyme called asparagine synthetase. This study evaluated the effect of asparagine, either in the diet or produced by the naturally occurring enzyme asparagine synthetase, on breast cancer metastasis.

Researchers of this study wanted to know:

Which molecules can cause breast cancer cells to metastasize?

Population(s) looked at in the study:

This study used mice models of metastatic breast cancer. In addition, researchers looked at levels of asparagine synthetase in breast cancer patients and in a small sample of matched breast tumor and lung metastasis samples.

Study findings:

Initially the study authors used sophisticated in vitro (test tube) techniques to identify molecules that may cause metastasis. Among the top candidates, asparagine synthetase appeared to play a critical role. The researchers then conducted multiple areas of related mouse study:

Mice that were predisposed to breast cancer were intravenously injected with special breast cancer cells which had low levels of asparagine synthetase. These cells had reduced levels of asparagine). Control mice were injected with breast tumor cells with normal amounts of asparagine synthetase and asparagine.
- Mice with reduced asparagine synthetase had significantly fewer lung metastases than control mice.
Fat pads of mice that were predisposed to breast cancer were directly injected with breast cancer cells in which the function of asparagine synthetase was experimentally reduced (thereby reducing the level of asparagine).
- No significant change in the development of primary breast tumors was observed; however, lung metastasis was significantly reduced compared to mice in the control group.
Mice predisposed to breast cancer once breast tumors appeared were treated 5 times per week for 19 days with L-asparaginase, a chemotherapy drug that blocks the production of asparagine and is currently used to treat acute lymphoblastic leukemia, which is known to thrive on asparagine.
- Although no significant difference was detected in the primary tumor, metastasis was reduced in mice treated with L-asparaginase compared to controls.
Mice that were predisposed to develop breast cancer were fed a diet that was either low or high in asparagine.
- Dietary asparagine did not affect the primary tumors, however, mice with a low-asparagine diet had a lower metastatic burden than mice with a high-asparagine diet.

Interestingly, when the study authors reviewed records of breast cancer patients (gene expression data from 2 data sets as well as a small number of matched breast tumors and lung metastases), they found that breast tumors with the highest levels of asparagine synthetase were most likely to metastasize, especially to the , brain, liver, and lungs.

Limitations:

It is important to remember that cancer therapies that work well in rodents don’t always translate to humans. While it is possible that dietary intake of asparagine may influence metastatic potential of breast cancer in humans, this hypothesis needs to be validated in human studies.

Conclusions:

Asparagine is a non-essential amino acid that our bodies naturally synthesize. This new study suggests that decreasing levels of asparagine in mice reduces metastasis. If after further study, reduction of asparagine levels proves to reduce the metastatic potential of human breast cancer, other methods to reduce cellular availability of asparagine may need to be developed, because regulating dietary levels of asparagine would be extremely difficult, if not impossible.

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Posted 3/2/18

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Expert Guidelines

Nutrition for people diagnosed with cancer

The National Comprehensive Cancer Network (NCCN) recommends the following for cancer survivors:

Think about your food choices and the amount of fruits, vegetables and unrefined grains you eat compared with red and processed meats, alcohol, and foods or beverages with added fat or sugar.
Think about your eating habits, including portion size, snacking, how often you eat out and the use of added fats or sugars.
All survivors should be encouraged to:
- Make informed choices about food to ensure variety and adequate nutrient intake.
- Limit refined sugars.
- Eat a diet that is at least 50% plant-based, consisting mostly of vegetables, fruit and whole grains.
- Track calorie intake; monitoring calories is an effective way to manage weight.
- Minimize alcohol to no more than one drink per day for a woman and two drinks per day for a man.
For patients desiring further dietary guidelines, the USDA approximate food plate volumes are:
- Vegetables and fruits should comprise half the volume of food on the plate
- Vegetables: 30% of plate; fruits: 20% of plate
- Whole grains: 30% of plate
- Protein: 20% of plate
Recommended sources of nutrients:
- Fast: Plant sources such as olive or canola oil, avocados, seeds and nuts, and fatty fish.
- Carbohydrates: Fruits, vegetables, whole grains and legumes.
- Protein: Poultry, fish, legumes, low-fat dairy foods, and nuts.

The Academy of Nutrition and Dietetics, the United States Office of Disease Prevention and Health Promotion and the American Institute for Cancer Research also publish expert guidelines on nutrition and health.

Updated: 12/12/2021

Questions To Ask Your Doctor

Can my diet affect my risk for breast cancer metastasis?
What should I be eating to maximize my health and ability to tolerate treatment?
Can you provide me with a referral to a nutritionist?

Open Clinical Trials

The following studies focus on nutrition for people diagnosed with breast cancer:

NCT05056077: Tools To Be Fit: Tools to Improve Nutrition and Physical Activity for Cancer Survivors. This study looks at which tools work best for helping cancer survivors improve their diet and exercise.
NCT05259410: Time-Restricted Eating During Chemotherapy for Breast Cancer. This study looks at whether intermittent fasting during treatment improves treatment-related outcomes and patient-related outcomes and limits treatment-related weight gain.
NCT04365569 Evaluating the Effectiveness of an Individualized Nutrition and Physical Activity Counseling Program. This pilot study looks at whether a tailored in-person and telephone-based nutrition and exercise counseling program helps breast cancer patients improve weight and fitness and thus improves cancer outcomes.
NCT03824145: Every Day Counts: A Lifestyle Program for Women With Metastatic Breast Cancer (EDC). This study examines the diet and activity, body composition, blood and quality of life in metastatic breast cancer patients from Milwaukee and Chicago.
NCT05984888: Pilot Study of a MIND Diet Intervention in Women Undergoing Active Treatment for Breast Cancer. The MIND diet is high in anti-inflammatory nutrients and limits the intake of brain-unhealthy foods (i.e., foods high in fat, red meat and sweets) that may help reduce the negative effects of cancer treatments on memory and thinking. This study investigates whether the MIND diet protects function in women with invasive breast cancer who start systemic therapies.

Visit our Featured Research Page and Research Search and Enroll Tool to find additional studies enrolling people with or at high risk for cancer.

Updated: 05/31/2024

Find Experts

The following resources can help you locate a nutritionist near you or via telehealth

Finding nutritionists

You can find a registered dietician in your area through Eatright.org, the website for the Academy of Nutrition and Dietetics. Search for nutritionists by specialty, including "cancer," "weight management" and "heart health."

Related experts

The Livestrong at the YMCA program includes a free 12-week membership and fitness training with certified exercise experts. You can search by zip code for a program near you.