Although there are many purported benefits for borage, flaxseed and fish oils -- and some research papers that give credence to them -- there are also potential side effects you should be on the lookout for.
If you've taken fish oil, you may have experienced common side effects such as burping or fishy aftertaste. These effects can be reduced if the fish oil is frozen or taken with food, reports the National Institutes of Health. In addition, fish oil with a pungent fish smell may have gone rancid and should be avoided. Look for fish oils with added antioxidants to help prevent the oil from going bad. There are also potentially more severe side effects of fish oil. Taking over 3 grams per day may reduce the ability for blood clots to form in your body.
Women who are pregnant or breast-feeding should avoid borage oil because the effects on fetuses and babies are not well-studied. Other potential side effects of borage oil include loose stools and digestive issues. Borage oil may contain amabiline, a toxic compound that can potentially cause liver problems and promote the development of some cancers. How much amabiline is in borage oil is still not known. Experts at WholeHealth Chicago suggest caution against taking more than 1 gram of borage oil because there is a lack of clinical research on borage oil, and the potential health effects of borage oil need to be better understood.
Taking more than 30 grams per day of flaxseed oil can lead to GI problems, including diarrhea. Flaxseed oil can also slow blood clotting, though a dosage where this may occur has not been established. Avoid taking flaxseed oil if you are pregnant; some studies have demonstrated a link between flaxseed oil and increased risk of preterm birth. Alpha-linolenic acid, the type of omega-3 fatty acid found in flaxseed oil, has been weakly associated in some studies with increased risk of prostate cancer, according to researchers at St. Michael's Hospital. Despite this association, ALA from plant sources such as flaxseed has been found to be safe.
Dietary Supplements: A Dose of Common Sense
Clinical evidence points to a positive effect of fish oil in patients with heart disease, according to a 2014 literature review published in the "Ochsner Journal." Flaxseed and borage oils are less well-studied but have shown promise. The potential benefits of each of these oils should be weighed with the risk of side effects, which is reduced when these oils are taken at lower doses. Talk with your doctor if you are considering adding one of these oils to your diet. It is vital to pay attention to your body as well: If you feel like something is off since you started taking these oils, that may well be the case.