Can Flax Seed Help Prevent Cancer?

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Flaxseed, a plant-based food that is rich in phytoestrogens, is known to have many health benefits. However, there is still no clear evidence that flaxseed intake reduces the risk of breast cancer, prostate cancer, or colorectal cancer, despite the large number of studies that have been done on this topic across the world. Cancer patients should not consume a flaxseed diet without consulting a nutritionist first, as it may result in negative side effects such as reduced platelet aggregation.


There are many ways to include flaxseed in your diet to take advantage of its health benefits. You can find flaxseed meals, flaxseed muffins, flaxseed juices, flaxseed smoothies, and flaxseed cereals. However, humans have been consuming flaxseed since ancient times. It has been grown for fiber to make clothing, as well as for medicinal purposes and as a nutritional product. Flax seeds are high in fiber, phytoestrogen lignans, and alpha-Linolenic acid (ALA), an essential omega 3-fatty acid. (Kajla P et al, J Food Sci. Technol, 2015)

Many people use flaxseed oil to improve their health in a variety of ways, including reducing inflammation for arthritis sufferers, potentially preventing cancer, managing diabetes, and improving cardiovascular health. Additionally, it can help with dry skin and eyes.

Nutritional Composition of Flax Seeds

Flaxseed has become a popular functional food due to the presence of three main bioactive compounds- alpha-Linolenic acid, fiber, and phytoestrogen. These compounds have the potential to provide many health benefits. (Kajla P et al, J Food Sci. Technol, 2015)

This food contains a lot of ALA, a type of fat that is good for reducing inflammation and essential for keeping our cells healthy. Nutritionists suggest we add omega-3 fatty acids to our diets, and flaxseed is the best source of omega-3 fatty acids for vegetarians.

Flaxseed is a rich source of phytoestrogen (lignans). This food has high protein and low carbohydrate levels. Flaxseeds contain phenolic compounds such as ferulic acid, chlorogenic acid, and gallic acid, which are known for their anticancer and antioxidant properties. Flaxseeds are also good sources of minerals such as phosphorus, calcium, and magnesium, as well as containing the antioxidant vitamin E.

Rich in Phytoestrogens

Flaxseed contains compounds called phytoestrogens, which are found in only a few edible plants. Certain plants contain nonsteroidal biochemicals with estrogen-like activity. These biochemicals, called phytoestrogens, mimic estrogens in the human body. There are two versions of estrogen receptors that can be found in both sexes on a variety of tissues throughout the body and brain. Phytoestrogens are thought to be responsible for the health benefits of soy and other phytoestrogen-rich foods because they are able to bind with estrogen receptors and influence the metabolism of estrogens. The benefits of investing in a good night’s sleep include better cardiovascular health, cancer prevention, decreased inflammation, protection of neurons from age-related decline, and improved bone health.

The presence of phytoestrogens in the body can influence the way cells communicate with each other, potentially impacting the likelihood of developing certain types of cancer, such as breast, endometrial, and colon cancer. Flaxseed may help to prevent certain cancers by changing the way the body processes estrogens. Flaxseed supplementation alters the urinary excretion of estrogen metabolites, resulting in a higher ratio of 2-hydroxy-estrone to 16-alpha-hydroxy-estrone. A low ratio of 2-hydroxy estrone to 16-alpha-hydroxy estrone is associated with an increased risk of estrogen-related cancers.

Association Between Flaxseed Intake and the Risk of Different Types of Cancers

There are several studies that show a correlation between flaxseed intake and a decreased risk of certain types of cancers.

Flaxseeds and Prostate Cancer Risk

Although there is some evidence to suggest that flaxseed may help reduce the risk of prostate cancer, the research is limited.

In general, observational studies that survey what people are eating and then follow them over time have found that lignans (phytoestrogens) in the diet do not protect against prostate cancer. The EPIC-Norfolk study found that dietary lignans may increase prostate cancer risk.

Flaxseeds may improve prostate health, according to some studies. A study involving men diagnosed with prostate cancer found that those who took flaxseed supplements and were on a low-fat diet saw a reduction in their prostate-specific antigen (PSA) levels, a biomarker for prostate cancer. Other studies have shown that flaxseed and alpha-linolenic acid have no positive effect on prostate health. In a study investigating the effect of a high-fat diet on in vitro fertilization (IVF), it was found that a high-fat diet negatively impacted oocyte quality and cumulus cell function. A study has found that a high-fat diet can negatively impact oocyte quality and cumulus cell function during in vitro fertilization (IVF).

Although flaxseed has shown some potential in reducing the risk of prostate cancer, more research is needed to confirm these effects.

Flaxseeds and Colorectal Cancer Risk

Both animal and human studies have shown that consuming flaxseed can improve colon health and reduce the risk of colorectal cancer. In a rat study, rats fed with flaxseeds were found to have a significant reduction in precursor lesions in the colon and were found to be chemopreventive. (Williams D et al., Food Chem Toxicol., 2007)

All of the flaxseed’s bioactive components, like fiber, the omega-3 fatty acid alpha-linolenic acid, and the phytoestrogen lignans, were shown to reduce the risk of colorectal cancer.

Eating fiber regularly has been linked to a decrease in the likelihood of developing colorectal cancer, most likely because it affects the way colonic microorganisms function. The microbiota in our gut can ferment the complex dietary fibers, which provide energy to keep a healthy gut microbiome. This, in turn, maintains the mucus lining of the colon and suppresses inflammation and carcinogenesis.

A component of flaxseeds known as alpha-linolenic acid has been shown to have beneficial anticancer effects. Flaxseeds are a source for omega- 3 polyunsaturated fatty acids (PUFA). The link between dietary omega-3 fatty acids intake and a reduced risk of colorectal cancer is supported by epidemiological evidence. Furthermore, consuming PUFAs also made cancer chemotherapy drugs more effective and easier to tolerate. The mechanism of anticancer effects associated with PUFA intake has been determined to be due to the reduction of inflammatory mediators, such as prostaglandin E2. (Cockbain et al, Gut, 2012)

There is no consensus on whether the lignan in flaxseeds has an effect on colorectal cancer risk. Some studies suggest it may be beneficial, while others show no effect. (Viggiani M T et al, Nutrients, 2019)

Benefits of Flax Seed

Thwarting Cancer

Researchers in New York studied the link between breast cancer and dietary lignan intake by surveying more than 3,000 women, 1,100 of whom had breast cancer. The remaining women surveyed served as controls. The scientists used statistical analyses to determine that premenopausal women with the highest lignan intake had a reduced risk of developing breast cancer.

Last year, scientists in Italy reported similar findings. Their research indicates that the primary lignan derived by the body from flaxseed, enterolactone, is associated with a lower risk of breast cancer when levels of it are higher in the blood. The researchers found that women who had higher levels of phytoestrogen enterolactone were less likely to develop breast cancer.

Lignans may also help protect against endometrial cancer, which is caused by extended exposure to estrogen without a counterbalance. Flax lignans may protect the body by reducing the levels of estrogen. The researchers evaluated the intake of lignan by nearly 1,000 women in the San Francisco area and found that the women who had the highest dietary intake of lignan had the lowest risk of developing this type of cancer of the uterine lining. Lignans may play a role in endometrial cancer risk, especially in postmenopausal women.

Emerging evidence = new evidence flaxseed = a type of seed colon cancer = a type of cancer New evidence suggests that flaxseed may help protect against colon cancer. The effects of flaxseed supplementation on colon cancer were examined in both short- and long-term animal studies. The study found that flaxseed may help prevent precancerous changes in the colon, such as polyps, microadenomas, and aberrant crypts and foci. Additionally, studies done in a laboratory setting found that lignans present in flaxseed prevent the growth of human colon tumor cells. Because of this, researchers think that flaxseed has the potential to reduce the chances of developing colon cancer.

Preventing Metastasis

Flaxseed may help prevent the spread of cancer cells. The scientists found that the mice that ate the flaxseed had smaller and fewer tumors than the other mice— adding flaxseed to the diets of mice that had been injected with melanoma (skin cancer) cells resulted in smaller and fewer tumors, according to the scientists. The mice who were fed flaxseed had less metastasis, meaning the spread of the deadly melanoma tumors. The reduction in tumors was greater the more flaxseed the rodents consumed.

A University of Toronto research team demonstrated that supplementation of the animals’ diet with 10% flaxseed resulted in significantly reduced tumor growth and metastasis. This was done using a rodent model of human breast cancer. Mice receiving flaxseed had a 45% reduction in the spread of tumors to other sites compared to control animals. Mice who were fed flaxseed had a significantly lower chance of developing tumors in their lymph nodes compared to mice who were fed a standard ration. The research team also found that levels of insulin-like growth factor I and epidermal growth factor receptor, which have both been linked to cancer progression, were reduced in mice that were fed flaxseed.

The Toronto research team showed that giving mice supplements that contain established human breast tumors decreases the amount of vascular endothelial growth factor in the area around the tumor. The vascular endothelial growth factor is a substance that tumors need in order to maintain an adequate blood supply (angiogenesis). The researchers suggest that flaxseed supplementation may help to reduce tumor growth and spread in rodents that have a model of human breast cancer.

Improving Blood Sugar

Over ten years ago, researchers from the University of Toronto discovered that consuming flaxseed can lower an individual’s total cholesterol and LDL levels. In addition to this, they found that eating 50 grams of flaxseed with a high ALA content also decreases the amount of glucose in your blood after a meal. People with type II diabetes are often advised to control their post-meal blood sugar response in order to prevent the disease from getting worse.

Relieving Menopausal Symptoms

Around ten years later, scientists in Quebec made similar discoveries. The study found that hormone replacement therapy was more effective than flaxseed in reducing the number of hot flashes experienced by menopausal women. The study found that menopausal women who were assigned to receive hormone replacement therapy experienced fewer hot flashes than those who were assigned to receive supplemental dietary crushed flaxseed. The researchers looked at different indicators of health, such as blood sugar and insulin levels after a meal, and total cholesterol. The researchers discovered that 40 grams of flaxseed is just as effective as oral estrogen-progesterone in reducing mild menopausal symptoms and lowering glucose and insulin levels, but it did not have a significant effect on reducing total cholesterol.

Cardiovascular Benefits

Flaxseed offers multiple health benefits, including improved cardiovascular health. In the Netherlands, researchers looked at the diets of more than 300 postmenopausal women to see how phytoestrogens affected heart health. The effects of dietary isoflavones were compared with the effects of dietary lignans. The researcher found that while isoflavones did not have a significant effect on blood pressure, dietary lignans were associated with lower systolic and diastolic blood pressure values and a decreased prevalence of hypertension. Even a small amount of lignans in your diet can help protect your blood pressure.

Researchers from both teams say their findings suggest that flaxseed may be beneficial in reducing blood pressure; the findings of the two teams suggest that flaxseed may help to reduce blood pressure, specifically in postmenopausal women with vascular disease. The women were given a mental challenge after eating a diet rich in flaxseed. The blood pressure of the subjects was monitored, and the results were interpreted based on the subjects’ known atherosclerotic disease. Flaxseed significantly reduced blood pressure related to mental stress. The researchers concluded that flax phytoestrogens may help protect against atherosclerosis by improving the body’s response to stress. The authors noted that two possible mechanisms could explain the blood pressure-reducing effect of flaxseed. These mechanisms are the presence of alpha-linolenic acid, an omega-3 fatty acid, and lignan phytoestrogens in flaxseed.


Flaxseed appears to be a simple and effective way to improve your overall health when added to your diet. Flaxseed has many nutritional benefits that may help to lower cancer risk, optimize cardiovascular health, and relieve mild symptoms of menopause. These benefits come from its combination of natural lignans, phytoestrogens, dietary fiber, and omega-3 fatty acids. There are many health-conscious adults who think that adding ground flaxseed to their smoothies, hot cereal, salads, and steamed vegetables makes them taste better and more nutritious.


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