There's a lot of conflicting nutrition advice out there, but one thing most experts can agree on is that flaxseed oil has some pretty remarkable health benefits. But even though you may be well aware of that, you might still be looking for the right flaxseed oil dosage to reap those benefits.
The short answer is that there are no hard rules about how much flaxseed oil you should use each day. However, there are recommendations on the proper daily dose of alpha-linolenic acid, or ALA — the type of omega-3 fatty acid that's found in flaxseed oil. To get the most out of your diet, it's a good idea to consume about 1 tablespoon of flaxseed oil or one to three flaxseed oil capsules along with several other omega-3-rich foods each day.
Many studies on ALA, the main beneficial compound in flaxseed oil, use 600 milligrams per day. However, the current recommendation for daily ALA intake is 1,100 milligrams for women and 1,600 milligrams for men. Since 1 tablespoon of flaxseed oil provides 730 to 1,095 usable grams of ALA, that's about all you need each day, as long as you're eating other omega-3-rich foods too.
ALA Benefits of Flaxseed Oil
The main bioactive compounds in flaxseed oil are ALA and lignans. In fact, flaxseed is one of the richest plant sources of both of these beneficial compounds. Whole flaxseeds consist of about 22 percent ALA, but when those seeds are turned into flaxseed oil, that percentage jumps to 50 to 62 percent. And it's the ALA in flaxseed oil that's responsible for many of the health benefits associated with it.
Chronic inflammation is connected to many serious health problems, including obesity, metabolic syndrome, Type 2 diabetes and heart disease, the leading cause of death worldwide. One of ALA's major claims to fame is its anti-inflammatory properties. In one meta-analysis that was published in Nutrition & Metabolism in June 2018, researchers looked at several studies on how supplementation with ALA affected inflammation in people with metabolic syndrome.
They found that ALA could help reduce interleukin-6 (or IL-6) and tumor necrosis factor-alpha (or TNF-α), two inflammatory cytokines — signaling molecules that are sent out by your immune system to promote inflammation. In the same review, researchers noted that ALA also reduced C-reactive protein (or CRP), a protein that's produced and released by your liver in response to high levels of inflammation.
Researchers from another review that was published in the journal Nutrients in March 2016 looked at flaxseed and flaxseed oil specifically and found that this inflammation-lowering effect appeared to be even more significant in people who have obesity.
These studies varied from two weeks to 12 months and the dosage of ALA supplements ranged from 300 to 600 milligrams per day, although 600 milligrams was the most commonly used.
Read more: Flax Seeds: How Much Per Day?
Flaxseed Oil and Heart Disease
Researchers from another study that was published in the Nutrition Journal in April 2015 wanted to see how supplementation with flaxseed oil could affect different risk factors for heart disease. The study was small — only 15 participants were included — but the results were promising.
For 12 weeks, researchers gave Japanese men either 10 grams of flaxseed oil (which provided 5,490 milligrams of ALA) or 10 grams of corn oil (which only contained 90 milligrams of ALA) every day. Since 1 tablespoon of flaxseed oil weighs 13.6 grams, the participants were getting just under 1 tablespoon daily.
Researchers took blood samples at zero, four and 12 weeks and tested levels of lipids, fatty acids and cholesterol. They found that while the corn oil had little to no effect, the flaxseed oil significantly lowered the levels of small, dense LDL cholesterol particles — the kind that's connected to atherosclerosis and heart disease — even at the four-week testing. ALA has also been connected to:
- A reduced risk of stroke.
- Improvements in depression.
- Increases in brain-derived neurotrophic factor (or BDNF), which is connected to learning and memory.
- Lower odds of developing peripheral neuropathy in people with diabetes.
Lignans and Flaxseed Oil
But ALA isn't the only beneficial compound in flaxseed oil. It's also rich in lignans, compounds that act as two beneficial substances: antioxidants and phytoestrogens. Although lignans are a component of almost all plant-based foods, flax contains about 800 times more than other plant compounds.
According to a report that was published in the Journal of Food Science and Technology in September 2014, the lignans in flaxseed oil have also shown promise in helping reduce the growth of cancerous tumors, especially those that are closely related to hormonal changes, like breast, uterine and prostate cancers.
Lignans have also been connected to a reduced risk of heart disease and a lower risk of osteoporosis, but the research on this is still in the early (and limited) stages, so no definitive statements can be made on this yet.
In addition to loads of ALA and lignans, according to the USDA, 1 tablespoon of flaxseed oil contains:
- 120 calories
- 13.6 grams of total fat
- 2.5 grams of monounsaturated fat
- 9.2 grams of polyunsaturated fat
- 1.2 grams of saturated fat
Keep in mind that while ground flaxseed is also a rich source of fiber — a single tablespoon contains almost 2 grams — this fiber is removed when the flaxseeds are processed into oil. Because of this, you lose the fiber-associated health benefits, like weight loss, improved gut health and more bowel regularity. But, depending on what your health goals are, this may be a fair trade, since the oil is a significantly more concentrated source of ALA.
Flaxseed Oil Dosage
There's no one-size-fits-all answer when it comes to the right flaxseed oil dosage for you. However, there are guidelines on how much ALA you should be getting each day. The current recommendation is 1,100 milligrams per day for women and 1,600 milligrams daily for men. To put that into perspective, a single tablespoon of flaxseed oil contains a whopping 7,300 milligrams (or 7.3 grams) of ALA, well over the recommended amount.
However, Harvard Health Publishing points out something important. While your body can convert ALA into EPA and DHA, it's not very good at it. About 10 to 15 percent of the ALA you consume from flaxseed oil gets converted into usable omega-3s, while the remaining 85 to 90 percent gets used as energy or in other ways.
That means that even though the label says that a tablespoon of flaxseed oil contains 7,300 milligrams of omega-3s, only about 730 to 1,095 milligrams of that gets converted to a form that your body can use.
A study that was published in the European Journal of Clinical Nutrition in May 2018 added to this, stating that while supplementation with flaxseed oil increased blood levels of eicosapentaenoic acid (EPA), the levels of docosahexaenoic acid (DHA) stayed the same.
Because of this, you shouldn't rely solely on flaxseed oil as an omega-3 supplement. That's because it's important to get the other two omega-3 fatty acids — EPA and DHA — too.
Choosing a Flaxseed Oil Supplement
You have a couple of options when it comes to how you incorporate flaxseed oil into your day. You can take flaxseed oil capsules, which often provide 1,000 to 1,400 milligrams of flaxseed oil (and 500 to 700 milligrams of ALA) per capsule. Generally, the recommended dosage is between one and three capsules per day.
You can also forgo the supplement and include flaxseed oil in your diet directly, by drizzling it on top of salads, adding it to smoothies or yogurt, or stirring it into vegetable soups before you eat them. Two teaspoons to 1 tablespoon per day is enough for most people.
You can meet your remaining ALA needs, and your needs for EPA and DHA, by combing flaxseed oil or a flaxseed oil supplement with other omega-3 rich foods. Choose from:
- Chia seeds
Keep in mind that since flaxseed oil is high in fat, it can oxidize and go rancid quickly. To increase its shelf-life, it's a good idea to store it in the refrigerator or in another cool, dark place, like a pantry, instead of right next to the stove.
While you can add flaxseed oil to your food dishes after cooking, you should also avoid cooking flaxseed oil directly. Since it has a low smoke point, heating it can break down the fatty acids and create free radicals, potentially harmful substances, in the process.
Read more: Golden Flax Seed Vs. Brown Flax Seed
A Word of Caution
Flaxseed oil has lots of potential health benefits, but that doesn't mean that flaxseed oil supplements or a high flaxseed oil dosage is a good idea for everyone. The Mayo Clinic points out that flaxseed oil has the potential to decrease blood clotting. If you're taking blood-thinning medications, like anti-coagulants or anti-platelet medications, the combo effect could increase the risk of uncontrollable bleeding.
Because of this, it's also a good idea to avoid taking flaxseed oil at least two weeks before any type of surgery. And make sure you let your surgeon or doctor know if you're taking it too.
Flaxseed oil can also lower blood pressure. While this may seem like a good thing, especially for those with high blood pressure, it can create a problem when taken with blood pressure-lowering medications or other supplements or herbs that lower blood pressure. Other contraindications for flaxseed oil include:
- Diabetes drugs: Flaxseed oil can lower blood sugar and, when combined with insulin or other blood sugar-lowering medications, this can result in dangerously low blood sugar.
- Oral contraceptives/estrogen replacement therapy: Because of its anti-estrogen effect, flaxseed oil may reduce the effectiveness of birth control and interfere with hormones.
The Mayo Clinic also notes that flaxseed oil may interfere with your body's ability to absorb any oral medications in general. Because of this, it's a good idea to talk to your doctor before adding flaxseed oil to your daily diet.
Read more: What Are the Benefits of Flaxseed Oil Pills?
- Biomed Research International: "Alpha-Linolenic Acid: An Omega-3 Fatty Acid With Neuroprotective Properties—Ready for Use in the Stroke Clinic?"
- Nutrition & Metabolism: "The Effects of Alpha-Lipoic Acid Supplementation on Inflammatory Markers Among Patients With Metabolic Syndrome and Related Disorders: A Systematic Review and Meta-Analysis of Randomized Controlled Trials"
- Nutrients: "Effect of Flaxseed Intervention on Inflammatory Marker C-Reactive Protein: A Systematic Review and Meta-Analysis of Randomized Controlled Trials"
- Canadian Journal of Cardiology: "The Cardiovascular Effects of Flaxseed and Its Omega-3 Fatty Acid, Alpha-Linolenic Acid"
- USDA FoodData Central: "Flaxseed Oil"
- Journal of Food Science and Technology: "Flax and Flaxseed Oil: An Ancient Medicine & Modern Functional Food"
- European Journal of Clinical Nutrition: "Effect of Supplementation With Flaxseed Oil and Different Doses of Fish Oil for 2 Weeks on Plasma Phosphatidylcholine Fatty Acids in Young Women"
- Harvard Health Publishing: "Why Not Flaxseed Oil?"
- Linus Pauling Institute at Oregon State University: "Lignans"
- Advances in Nutrition: "Challenges of Utilizing Healthy Fats in Foods"
- National Institutes of Health Office of Dietary Supplements: "Omega-3 Fatty Acids"
- Nutrients: "Dietary Flaxseed as a Strategy for Improving Human Health"
- Mayo Clinic: "Flaxseed and Flaxseed Oil"
- Nutrition Journal: "Flaxseed Oil Intake Reduces Serum Small Dense Low-Density Lipoprotein Concentrations in Japanese Men: A Randomized, Double Blind, Crossover Study"
- USDA FoodData Central: "Seeds, Flaxseed"