Sage Advice Blog


October 27, 2017

Alex Speers ND, MS


Vascular Endothelial Growth Factor, commonly referred to as VEGF, is a protein that plays an important role in the formation of new blood vessels, a process called angiogenesis. There are many times in our life when angiogenesis is a completely normal and necessary function, such as in wound healing when VEGF stimulates angiogenesis to replace damaged blood vessels and to bring oxygen and nutrients to the wound. In the setting of cancer, however, VEGF becomes a dangerous weapon of growing tumors.


During cancer progression, a tumor can only grow to a size of 1-2 millimeters (roughly the width of a pencil tip) before it needs its own blood supply. VEGF, one of the most potent stimulators of angiogenesis, can help a tumor accomplish this goal. Tumor cells begin to overproduce VEGF, which is released into the surrounding area where it attaches to local blood vessels and signals them to branch off and grow towards the tumor. The new blood vessels bring oxygen and nutrients to the tumor, allowing for continued growth, while also providing a way for tumor cells to enter the bloodstream and spread throughout the body.


In breast cancer, high levels of VEGF have been associated with decreased survival and poor prognosis. As a result, VEGF has become a target for anti-cancer therapies. The breast cancer drug Avastin directly binds to VEGF, preventing it from attaching to local blood vessels. Other drugs target the cell receptors where VEGF proteins normally bind.


In the world of natural medicine, research shows that flaxseed may have anti-VEGF effects. A 2002 study investigated whether flaxseed affected the growth and spread of breast tumors in mice. Twenty mice with estrogen-receptor negative breast tumors were fed either a normal diet or a diet supplemented with flaxseed. The researchers found that while none of the tumors went into complete regression, the flaxseed mice had slower tumor growth when compared to the no-flaxseed mice. In addition, metastasis (the spread of cancer throughout the body) was only observed in 10% of the flaxseed mice compared to 70% of the no-flaxseed mice. These results were explained by the finding that in mice with the largest tumors, flaxseed significantly decreased levels of VEGF compared to the no-flaxseed mice.


A study conducted by the same researchers in 2007 found similar results for estrogen-receptor positive breast tumors. Flaxseed is one of the richest food sources of lignans, a plant compound that is considered a type of phytoestrogen. Phytoestrogens are natural chemicals found in plants that can alter the effects of estrogen within the body. Phytoestrogens can have both pro-estrogen and anti-estrogen effects, which is why it is important that the researchers found flaxseed to have positive benefits in both estrogen-receptor negative and positive tumors.


Human studies have shown associations between eating flax and lower mortality among patients with breast cancer, better mental health, and lower risk of developing breast cancer in the first place. In addition, a handful of human trials have found positive effects of flaxseed on various cancer markers at a dose of 25 grams per day, which is roughly 2 Tbsp. of whole flaxseed or 4 Tbsp. of ground flaxseed. While flaxseed can be eaten by itself, it can also easily be mixed into a smoothie or sprinkled on top of other foods. Based on the available research, flaxseed is a healthy addition to any diet, but especially for those with breast cancer or those who are at risk for developing breast cancer.


Dabrosin C, Chen J, Wang L, Thompson L. Flaxseed inhibits metastasis and decreases extracellular vascular endothelial growth factor in human breast cancer xenografts. Cancer Lett. 2002;185(1):31-37.


Bergman Jungeström M, Thompson L, Dabrosin C. Flaxseed and its lignans inhibit estradiol-induced growth, angiogenesis, and secretion of vascular endothelial growth factor in human breast cancer xenografts in vivo. Clin Cancer Res. 2007;13(3):1061-1067.


Flower G, Fritz H, Balneaves L, et al. Flax and breast cancer: a systematic review. Integr Cancer Ther. 2014;13(3):181-192.


DISCLAIMER: These statements have not been evaluated by the Food and Drug Administration. There are no financial ties to any supplement companies, pharmaceutical companies, or to any of the products mentioned in this post. This post is not meant to treat, cure, prevent, or diagnose conditions or diseases and is meant for educational purposes. As always, please consult your doctor before trying any new treatments or supplements.



Return to Sage Advice Blog Main Page