Flaxseed: Health Benefits, Nutrition, and More (2024)

Flaxseed comes from the flax plant (Linum usitatissimum), which is grown worldwide but is especially prevalent in Canada. This flowering plant produces small brown seeds (flaxseeds).

Flaxseeds can be used in whole, ground, or milled forms. Flaxseed oil can also be used and is the richest plant source of alpha-linolenic acid (ALA), an essential omega-3 fatty acid.

Various other important nutrients are also found in flaxseed, including:

• Fiber
• Protein
• Thiamine
• Copper
• Phosphorus
• Magnesium
• Manganese

The nutritional profile of flaxseeds has made them a topic of interest among researchers for years. Some studies have shown that flaxseed may benefit digestive issues, heart health, certain skin conditions, symptoms of menopause, and diabetes.

This article will look at the nutritional benefits and potential uses of flaxseed. It will also cover side effects, precautions, dosage, interactions, and ways to consume flaxseed.

Nutritional Benefits

Flaxseeds are a well-rounded food, containing all three macronutrients and a variety of micronutrients. They're also rich in beneficial compounds like fiber and various antioxidants.

Both soluble and insoluble fiber are present in flaxseeds. These fibers are thought to improve digestion and help you maintain regular bowel movements.

Flaxseeds have been described as a functional food because they are thought to provide health benefits beyond the scope of basic nutrition.

One tablespoon of whole flaxseeds in grams (g), milligrams (mg), and micrograms (mcg) contains:

• Calories: 55
• Protein: 1.9 g
• Total fat: 4.4 g
• Carbohydrates: 3 g
• Fiber: 2.8 g
• Calcium: 26 mg
• Magnesium: 40 mg
• Phosphorus: 66 mg
• Potassium: 84 mg
• Sodium: 3 mg
• Folate: 9 mcg
• Choline: 8 mg

Other nutrients found in flaxseeds include:

• Copper
• Manganese
• Zinc
• Selenium
• Vitamin C
• Thiamin
• Niacin
• Vitamin B6
• Lutein
• Tocopherols (compounds that make up vitamin E)
• Vitamin E
• Vitamin K
• Fatty acids (saturated and unsaturated)
• Amino acids

Uses of Flaxseed

Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian, pharmacist, or healthcare provider. No supplement is intended to treat, cure, or prevent disease.

Various scientific studies support the use of flaxseed for a range of health conditions.

Flaxseed is thought to have antioxidant, anti-inflammatory, and anticancer properties due to its many bioactive compounds. Accordingly, flaxseed may be used for:

• Symptoms of menopause
• Constipation
• Mental fatigue
• Wound healing
• High cholesterol
• High blood pressure
• High blood sugar
• Certain cancers

It's important to remember, though, that no single food or dietary supplement can cure any condition or disease. To reap the potential health benefits, flaxseed can be added to a well-balanced diet in several ways.

Following is a look at some of the research surrounding common uses of flaxseed.

Constipation

Due to its high fiber content, flaxseed may be useful for the treatment of constipation.

Flaxseed is made up of 25% soluble fiber and 75% insoluble fiber. While soluble fiber enhances the gut microbiome, insoluble fiber increases the bulk of stools, two factors that may help prevent constipation.

A small clinical trial in older adults (average age of 68) with chronic constipation tested the effectiveness of flaxseed.

Study participants took 50 g of flaxseed daily for one month and recorded bowel habits. Stool samples were also collected before and after the trial. Flaxseed treatment significantly increased the number of bowel movements, decreased bloating, and improved the diversity of bacteria in the gut.

In another human trial, flaxseed was compared to lactulose (a stool softener) for constipation. For four weeks, 90 study participants used either 50 g of flaxseed flour or 15 milliliters (ml) of lactulose daily. While both treatments improved constipation symptoms, flaxseed flour increased bowel movement frequency more than lactulose.

Heart Health

Although research on flaxseed for heart health is limited, some studies suggest that it may help with issues like high cholesterol and high blood pressure.

According to one review, the essential fatty acids, lignans, and fiber in flaxseeds may account for heart benefits. These benefits may include antihypertensive, anti-atherogenic (anti-plaque formation), cholesterol-lowering, and anti-inflammatory effects, as well as the inhibition of arrhythmias (abnormal heartbeat). However, research results confirming these effects have been conflicting.

A review of clinical trials concluded that flaxseed consumption may reduce blood pressure, but only slightly. However, researchers believe that even a small reduction in blood pressure may be beneficial for certain people, especially those with high blood pressure (hypertension). It's worth noting, too, that both whole and ground flaxseed may be more effective than flaxseed oil in producing these results.

More research should be conducted to further prove flaxseed's role in heart health.

Cancer

Lignans are a type of phytoestrogen (a plant compound that acts similarly to estrogen) in flaxseed. Because of the potential for lignans to influence estrogen receptors in the body, flaxseed has been studied for its potential role in certain hormone-related cancers.

It is thought that flaxseed can provide additional protective effects when taken along with the standard of care treatment.

In animal studies, pairing flaxseed with tamoxifen (a medication sometimes used for breast cancer) reduced tumor size. However, there have been no clinical trials on the benefits of flaxseed ingestion in humans with breast cancer during tamoxifen therapy.

The review also found that flaxseed may inhibit the growth of estrogen-receptor-positive (ER-positive) breast cancer and lead to an overall reduced breast cancer risk, especially in postmenopausal women.

However, not all research results have been positive. When it comes to prostate cancer, it is unclear if flaxseed plays a role. Some studies have even found that lignans may increase the risk of prostate cancer.

The Academy of Nutrition and Dietetics recommends that people with breast cancer only use flaxseed in amounts found in foods and avoid using flaxseed supplements. The same goes for people with prostate cancer.

Overall, whether flaxseed can help with certain types of cancer remains unclear. More research is needed.

Menopausal Symptoms

Since it contains phytoestrogens, researchers have looked at flaxseed as a potential treatment for menopausal symptoms, especially hot flashes.

Research results have been mixed, with some studies reporting positive effects of flaxseed and others reporting no effects at all.

According to one review, flaxseed improved hot flash frequency and intensity, but not significantly. The review covered other symptoms of menopause as well, including vagin*l atrophy. But flaxseed did not show conclusive, positive effects for other menopause symptoms.

More definitive results will be needed to determine whether flaxseed can treat menopause symptoms.

Diabetes

Diabetes is multifaceted, and flaxseed may be able to help with various aspects of the disease.

In one clinical trial, people with prediabetes were randomized to receive a placebo (an intentionally ineffective treatment), 40 g per day of flaxseed powder or 20 g per day of flaxseed powder. At the end of the 12-week study, fasting blood sugar was decreased in all groups. The most significant decrease was in the group who took 40 g of flaxseed daily. However, flaxseed did not provide any benefits for insulin resistance (when cells don't respond well to the hormone insulin, which controls the amount of sugar in the blood, and can't take up glucose, or sugar, from the blood, causing a glucose buildup).

Although, a systematic review found that flaxseed may indeed help with insulin resistance. Per the studies included in the review, flaxseed supplementation may improve fasting blood sugar, hemoglobin A1c (HbA1c), and insulin resistance in people with type 2 diabetes or prediabetes.

Another small study took a different approach by looking at how flaxseed may affect constipation, weight, blood sugar control, and lipid levels in people with type 2 diabetes.

During the 12-week study, some participants consumed cookies that contained 10 g of flaxseed, while others consumed cookies containing no flaxseed two times a day. At the end of the study, those who consumed the flaxseed cookies had significant improvements in body mass index (BMI), fasting blood sugar, cholesterol, triglycerides (a fat in the blood), and constipation compared to those in the placebo group.

What Are the Side Effects of Flaxseed?

Flaxseed side effects are rare. Very few side effects have been reported for flaxseed and flaxseed supplements.

There have been some reports of allergic skin reactions caused by flaxseed. Using flaxseed improperly may also cause worsening constipation or intestinal blockage.

However, limited safety studies have been performed on flaxseed, so more side effects may be possible. To prevent any possible side effects, use flaxseed only as directed.

Precautions

Flaxseed is thought to be safe for most people, but some may need to avoid it.

It is unclear if flaxseed is safe during pregnancy. There is some concern that flaxseed may cause hormonal changes that could be unsafe for the health of the pregnancy. For this reason, it's best to avoid using flaxseed during pregnancy.

There isn't much data on whether flaxseed is safe during breastfeeding either. It is believed to be safe, but it's best to talk with a healthcare provider if you plan to use flaxseed while breastfeeding.

Of course, you should avoid using flaxseed if you know you are allergic to it.

Be sure to talk with a healthcare provider before adding flaxseed to your routine, especially if you have any medical conditions or take any medications.

How to Consume Flaxseed

If you're considering using flaxseed or flaxseed supplements for health benefits, you may be wondering how much to take.

Flaxseed hasn't been approved by the FDA or other U.S. governing agencies to treat any health condition. Therefore, there aren't any dosage guidelines for flaxseed products.

Flaxseed dosage may depend on the product or type of product you're using. For example, you may need to take more ground flaxseed than whole flaxseed simply due to the difference in the density of the two forms.

If you decide to use flaxseed in its food form rather than as a supplement, there are many ways to use it.

Whole flaxseeds may be added as a topping to various snacks and dishes, like yogurt parfaits, smoothies, soups, and salads. Ground flaxseeds can easily be added to food when baking.

It is recommended that you drink plenty of water when you consume whole flaxseeds due to their high fiber content.

What Happens If I Take Too Much Flaxseed?

Even though flaxseed is generally considered safe, it may be possible to take too much.

Despite a lack of reliable information, taking too much flaxseed may increase the risk of side effects. For example, consuming large amounts of flaxseed, especially without water, may cause constipation or an intestinal blockage.

There are also limited reports of toxic compounds in raw or unripe flaxseeds. Toxic effects may be more likely if you consume flaxseed in large amounts. To be safe, avoid consuming more than the recommended dose or serving size.

Interactions

Flaxseed and flaxseed supplements may interact with certain medications, foods, and other herbs and supplements. However, possible interactions are not well documented.

It's best to talk with a healthcare provider before using flaxseed if you take any prescription medications or other supplements.

It is also essential that you carefully read the ingredients list and nutrition facts panel of a supplement to know which ingredients and how much of each ingredient is included. Please review supplement labels with a healthcare provider to discuss any potential interactions with foods, other supplements, and medications.

How to Store Flaxseed

Flaxseed does not require refrigeration, but you should store it in a cool, dry place. Flaxseed should also be kept out of direct sunlight. This goes for whole flaxseed, ground flaxseed, and flaxseed supplements.

It's best to keep flaxseed products in an airtight container to maximize freshness (their original packaging is usually recommended). Flaxseeds should also be kept out of reach of pets and small children who could accidentally consume too much.

Discard flaxseeds once they show signs of spoilage or pass their expiration date.

Types of Flaxseed & What to Look For

Flaxseed comes in food form or as a dietary supplement.

If possible, take a food-first approach and use natural flaxseeds rather than flaxseed supplements. Flaxseeds are considered safest when used in amounts commonly found in foods, which means you may be less likely to experience side effects by staying within a standard range. Also, flaxseed supplements may not contain the same amount of fiber and other nutrients as whole or ground flaxseeds.

Food Sources of Flaxseed

Flaxseeds may be consumed in whole form, ground, or added to various recipes and products.

If you're using flaxseeds at home, you may consider adding them to smoothies, yogurt, salads, soups, or other dishes. Whole or milled flaxseeds may be added to batters, doughs, and other baked goods. A mixture of flaxseeds and water can also serve as an egg substitute for vegans or vegetarians who like to bake.

Products containing flaxseeds include breads, cookies, muffins, snacks, and energy bars. These products can be purchased online or in grocery stores.

Flaxseed Supplements

Flaxseed supplements are available online or in various health food stores. Several grocery stores carry flaxseeds and flaxseed supplements as well.

Keep in mind that most flaxseed supplements contain flaxseed oil rather than flaxseeds. However, you can find flaxseed powders and flours that are made from whole flaxseeds rather than flaxseed oil. Flaxseed oil supplements are typically sold as capsules and soft gels.

If you go the supplement route, remember that supplements are largely unregulated in the United States. Whenever possible, choose supplements that have been reviewed and approved by agencies like USP, ConsumerLab, and NSF. These third-party agencies perform rigorous supplement reviews to ensure product labels are accurate and that no contaminants are present.

Summary

Flaxseeds come from the flax plant and provide many nutritional benefits, including omega-3 fatty acids, fiber, and antioxidants.

Many people use flaxseeds for their purported health benefits, which include heart health, gut health, and diabetes management. While some flaxseed uses are supported by scientific evidence, more research is needed in many areas.

If you're considering giving flaxseed a try, talk with a healthcare provider first to ensure it's the right fit for you.