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The Dangers of High Lignan Flax Oil

author image Natalie Stein
Natalie Stein specializes in weight loss and sports nutrition. She is based in Los Angeles and is an assistant professor with the Program for Public Health at Michigan State University. Stein holds a master of science degree in nutrition and a master of public health degree from Michigan State University.
The Dangers of High Lignan Flax Oil
Flax oil and seeds. Photo Credit: humonia/iStock/Getty Images

Flax oil, or flaxseed oil, comes from flaxseed, which is the seed of the plant called Linum usitatissum. Manufacturers may add lignans to flax oil dietary supplements for more possible health benefits; the University of Maryland Medical Center notes that lignans may play a role in the prevention of cancer. However, taking high-lignan flax oil may have side effects. Talk to your doctor before taking high-lignan flax oil or any other dietary supplement.

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Lignans, or phytoestrogens, are a group of phytonutrients, or plant chemicals, and flaxseed is a natural source. Pure flax oil does not a have lignans, but you can purchase high-lignan flax oil as a dietary supplement. Compared to flaxseed, flax oil has a higher concentration of a heart-healthy omega-three fatty acid called alpha-linolenic acid, or ALA, according to the Linus Pauling Institute Micronutrient Information Center. A disadvantage of taking high-lignan flax oil as a dietary supplement instead or purchasing regular flax oil as a food product is that the FDA does not verify the safety of dietary supplements as rigorously as foods.

Weight Gain

High lignan flax oil supplements contain about 130 calories per tablespoon, and it can lead to unwanted weight gain if you do not monitor your intake. You gain weight when you have a positive energy balance, or eat more calories than you consume. An alternative to taking oil supplements is to get your lignans and alpha-linolenic acid by eating a variety of more filling foods such as flaxseed, walnuts, fruits and vegetables. High-lignan flax oil and regular flax oil have nearly the same calorie content.

Drug Interactions

Omega-three fatty acids, such as alpha-linolenic acid, have blood-thinning effects, and high-lignan flax oil may interact with blood thinners, such as aspirin or warfarin, according to the University of Maryland. Omega-three fats may raise your blood sugar and interact with medications for regulating blood sugar. To reduce your risk of dangerous consequences, be sure to inform your doctor about the medications and supplements you are already taking before you start taking high-lignan flax oil. High-lignan flax oil is not likely to cause more drug interactions than regular flax oil because lignans are not known to have long-term adverse effects, according to the Linus Pauling Institute Micronutrient Information Center.

Gastrointestinal Distress

A potential risk of high lignan flax oil is mistaking it for ground flaxseed for the treatment of constipation. Flaxseed is common laxative because of its soluble and insoluble fibers, but high-lignan flaxseed oil does not contain high amounts of these fibers and is not as effective, according to Your doctor can advise you about treatment options if you have constipation. A sudden increase in consumption of lignans may lead to diarrhea, according to the Linus Pauling Institute Micronutrient Information Center. Drink plenty of water when you take high-lignan flax oil. Flax oil without lignans will not cause the side effects of diarrhea from lignans.

Lack of DHA and EPA

A risk of taking high-lignan flaxseed oil is using it as your only source of omega-three fatty acids. The omega-three fatty acid in flaxseed, ALA, is an essential nutrient, but your body can only convert some of it into long-chain omega-three fatty acids called DHA and EPA, according to the UMMC. A diet with at least 250 mg per day of DHA and EPA may lower your risk of heart disease, and the best sources are fatty fish and shellfish. The amount of ALA in high-lignan flax oil is the same as the amount in regular flax oil.

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