Flaxseed, or Linum usitatissimum, is derived from the flax plant, an annual originally from Egypt. Flaxseed has been used for centuries for medicinal and nutritional purposes and appears to have been well tolerated by humans with few reported side effects.
Flax grows best in moist sand-, silt- and clay-rich soils. The tiny, oval-shaped flax plant's seeds contain fiber, protein, lignans, essential fatty acids and oils called either flaxseed oil or linseed oil.
People should avoid flaxseed products if they have an allergy to flax seed, flaxseed oil or any member of the Linaceae or Linum plant families.
Throughout history, flaxseed has been used as a laxative, effective because of its high fiber and mucilage content. According to University of Maryland Medical Center, these substances expand when combined with water, adding bulk to stool and helping it move easily through the gastrointestinal tract.
The laxative effects of flaxseed may cause diarrhea, nausea and stomach discomfort when some people, including people allergic to flax, eat flaxseeds or flax seed products. To avoid these allergic reactions and symptoms of food intolerance, people suffering from allergies, irritable bowel syndrome, diverticulitis, inflammatory bowel disease, Crohn's disease or ulcerative colitis should not consume flaxseed products.
Ingesting large amounts of flaxseed may cause the intestines to stop functioning. People with conditions that cause narrowing of the intestine or esophagus should avoid flax seeds.
Ground flaxseed may cause flatulence, but it generally does not last long. Drinking plenty of water helps prevent ground flaxseed from swelling up and obstructing the throat or digestive tract.
Shortness of Breath
A flaxseed allergic reaction or overdose may cause shortness of breath, rapid breathing, weakness, difficulty walking, seizures or paralysis, reports the National Institutes of Health in a MedlinePlus review of research about flax seed and flaxseed oil.
Caution is advised for people who take prescription drugs to control blood sugar levels. The National Institutes of Health recommends that people with diabetes be especially careful about taking flaxseed products by mouth, in part because the fatty acids in flaxseed and flaxseed oil may increase blood sugar levels.
Flaxseed and flaxseed oil may increase the risk of bleeding by causing a decreased clotting of blood. An evidence-based monograph written by the Natural Standard Research Collaboration and published by the National Institutes of Health, advises patients with bleeding disorders, people taking drugs that increase the risk of bleeding and people preparing for medical, surgical, or dental procedures to be very cautious about using flaxseed products. People who have diabetes, are using anticoagulants or anti-platelet drugs, are scheduled for surgery or have a bleeding disorder should not use flaxseed in any form without their physician's advice and consent.
Consuming raw flaxseed or parts of the flaxseed plant, including unripe flaxseed pods, may increase blood levels of cyanide. People should not eat raw parts of the flaxseed.