The health benefits of fish oil are believed to derive principally from two omega-3 fats, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Flaxseed oil contains a third, plant-based omega-3, alpha-linolenic acid (ALA). Other foods (especially walnuts) and oils (canola and soybean, for example) contain ALA. But at about 7 grams per tablespoon, flaxseed oil is by far the richest source.
The main problem with ALA is that to have the good effects attributed to omega-3s, it must be converted by a limited supply of enzymes into EPA and DHA. As a result, only a small fraction of it has omega-3’s effects — 10%–15%, maybe less. The remaining 85%–90% gets burned up as energy or metabolized in other ways. So in terms of omega-3 “power,” a tablespoon of flaxseed oil is worth about 700 milligrams (mg) of EPA and DHA. That’s still more than the 300 mg of EPA and DHA in many 1-gram fish oil capsules, but far less than what the 7 grams listed on the label might imply.
The bottom line on flaxseed oil
Flaxseed oil will give your diet a nice little omega-3 boost in the form of alpha-linolenic acid. You might try adding flaxseed oil to your salad dressing. But flaxseed oils a backup, not a substitute, for the omega-3s in fish and fish oil because of the conversion factor. If you’re in need of omega-3s but are concerned about mercury, salmon, pollock, and catfish are all low in mercury. And canned light tuna tends to be lower in mercury than albacore (“white”) tuna.
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Harvard Health Publishing
Health Benefits of Flaxseed Oil
While linen is the major area where you would encounter flax, the nutritional and dietary market around the globe is starting to show a marked increase in interest. Let’s take a look at some of these intriguing health benefits of flaxseed oil!
Controls Cholesterol Levels Out of all the vegetable oils on the market, flaxseed oil has the highest content of omega-3s, which is very important. While both forms of cholesterol are necessary for the body, omega-3 is considered as the “good” form, called HDL cholesterol. Omega-3 fatty acid helps scrape off the bad form of cholesterol, called LDL cholesterol and helps balance the cholesterol in your body. This means that you won’t have plaque buildup on the walls of your arteries and blood vessels, thereby helping in reducing blood pressure, lowering your chances of developing atherosclerosis, and effectively preventing heart attacks and strokes. In other words, protect your heart with flaxseed oil! Flaxseed oil contains fiber, which is also important for maintaining cholesterol levels in the body.
Flaxseeds and flaxseed oil have been treasured for their omega-3 fatty acid and lignan content. These compounds are also known to help in reducing your risk of colon cancer and breast cancer. According to Lilian Thompson’s report, (a researcher at the Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Ontario, Canada), published in the Carcinogenesis Journal, lignans found in flaxseeds have a colon cancer protective effect. Research by Cynthia Mannion, The University of Calgary, Canada also suggests that flaxseed oil is an important part of an anticancer diet.
Improves Digestive Health
The high fiber content of flaxseed means that the digestive system gets regulated. Fiber helps bulk up the stool and move it through the digestive tract, thereby preventing constipation, as well as diarrhea, since it absorbs watery stool.
Prevents Dry Eyes
The hormones in flaxseed improve the quantity and quality fluid in your eyes, the lack of which can be very annoying. Dry eyes can be prevented with the consistent use of flaxseed oil in the diet. It can also prevent more serious forms of this condition, such as Sjogren’s syndrome. 
The anti-inflammatory capacity of flaxseed oil means that it can prevent various forms of inflammation in the body, including natural aches and pains in the joints and muscles, as well as more serious conditions like arthritis and even gout! Flaxseed oil is a natural anti-inflammatory agent, so make sure to include it in your diet if you suffer from inflammatory conditions.
Prevents Crohn’s DiseaseCrohn’s disease is a health condition that afflicts people all around the world. Research on flaxseed oil has shown a reduction in the inflammation of the colon and intestinal tract with the consumption of this oil. This, in turn, helps prevent Crohn’s disease. 
Maintains Hormonal Balance
After women go through menopause, their body changes in dramatic ways, particularly in terms of the balance of hormones, such as estrogen. The lignans in flaxseed oil, namely, secoisolariciresinol, matairesinol, and pinoresinol, have a dramatic effect on hormonal balance, thereby helping many post-menopausal women function better. Word of Caution: Although most specialists regard flaxseed as a healthy oil, there is still a great deal of research being done. It has shown to increase the flow of blood because of being a vasodilator. This includes faster healing after surgery as well. Furthermore, it is unclear as to whether women should consume flaxseed oil during pregnancy or breastfeeding as the effects of this have not yet been adequately researched.
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