Abstract: How Can Flaxseed Help Your Heart?
James Jolley and Jared Gonzalez
Flax is a crop native to Europe, Asia, and the Mediterranean. The seeds of flax range from golden yellow to reddish brown that contain phytoestrogens, as well as soluble fiber and oil. They are some of the richest food sources of alpha-linolenic acid (ALA), an essential omega3 fatty acid, and is made up of approximately 55% of this acid. 2 Flaxseeds are used for a wide variety of health conditions including hyperlipidemia, constipation, diarrhea, diverticulitis, irritable bowel syndrome, gastritis, enteritis, ulcerative colitis, and many others. It is also used topically and ophthalmically. However, this poster will focus on its uses for hyperlipidemia.
Flaxseed works in the body when it is converted to longer and more unsaturated omega-3 fatty acids, such as eicosapentaenoic and docosahexaenoic acids. 2 Commercially, it comes in many different forms such as flaxseed oil, crushed flaxseed added to dietary foods, and flaxseed extract. There are no major drug interactions with flaxseed, and therefore is a safer herbal medication to take. In terms of its cholesterol-lowering effects, this is specific to the ALA portion of flaxseed, which has shown to lower cholesterol, however, other mechanisms are likely
involved. Of the data collected regarding the cholesterol-lowering ability of flaxseed, it appears that taking 30-50 grams daily reduces total cholesterol by 5-15% and LDL by 8-18%.1,2,3,4,5 There is mixed data regarding its efficacy for lowing triglycerides. In fact, some studies have
shown it to increase triglycerides by up to 26%.
Cunnane et all performed a study in 1993 to determine the effects of flaxseed (alphalinolenic acid) on human nutrition. This study was conducted using nine undergraduate female students who were divided into two groups. One group used flaxseed flour which could be sprinkled onto foods or drinks while the other group mainly consumed flaxseed flour baked goods. Both groups consumed 50 grams of flaxseed per day over the course of 4 weeks and measured the cholesterol content in their blood. The finding showed that there was a 9% decrease in total cholesterol and a 18% decrease in LDL levels. The group who had flaxseed in baked goods saw that a metabolite of this product called cyanogenic glycosides were baked off and thus safe to consume. This study also highlighted the benefit of postprandial glucose reduction.
The second study performed by Soltanian & Janghorbani did a larger single-blinded, randomized controlled trial of 77 participants who had type 2 diabetes(T2D) and the benefits of this supplement. Each participant was placed in one of three groups flaxseed, psyllium, and placebo. Each participant ate 4 cookies per day, 2 at 10am and 4pm as a snack, over the course of 12 weeks and measured the benefits pertaining to constipation relief, weight loss, glucose levels, and lipid control. The study found that flaxseed was superior to psyllium and placebo in all these areas. The results from this study showed that flaxseed decreased total cholesterol on average 36.9 mg/dL over the course of 12 weeks and LDL by 21.0 mg/dL. This study also highlighted the benefits of flaxseed on T2D patients by reducing their HbA1C by 0.7%.
So how can flaxseed help your heart? It can effectively total cholesterol and LDL, however it may or may not decrease triglycerides and could, in fact, increase them. Therefore, it does have the potential to have benefit to a patient’s heart, but it could also make their heart worse. Clinically-speaking, decreasing cholesterol is more important than triglycerides and therefore is less concerning if they become increased by flaxseed oil. Therefore, it is our conclusion that patients should consider taking flaxseed if they desire a natural form to reduce cholesterol. However, they should always consider FDA-approved therapies and always maintain a healthy diet and exercise at the same time.
1. E Nordstr DC, A Honkanen VE, Nasu Antila YE, et al. Alpha-Linolenic Acid in the Treatment of Rheumatoid Arthritis. A Double.Blind, Placebo-Controlled and Randomized Study: Flaxseed vs. Safflower Seed. Vol 14. Springer-Verlag; 1995.
2. Cunnane SC, Ganguli S, Menard C, et al. High α-linolenic acid flaxseed (Linum usitatissimum ):some nutritional properties in humans. British Journal of Nutrition. 1993;69(2):443-453. doi:10.1079/bjn19930046
3. Laitinen LA, Ivi P, Tammela SM, et al. Effects of Extracts of Commonly Consumed Food Supplements and Food Fractions on the Permeability of Drugs Across Caco-2 Cell Monolayers.; 2004.
4. Khalesi S, Irwin C, Schubert M. Flaxseed consumption may reduce blood pressure: A systematic review and meta-analysis of controlled trials. Journal of Nutrition. 2015;145(4):758-765. doi:10.3945/jn.114.205302
5. Soltanian, N., & Janghorbani, M. (2019). Effect of flaxseed or psyllium vs. placebo on management of constipation, weight, glycemia, and lipids: A randomized trial in constipated patients with type 2 diabetes. Clinical Nutrition ESPEN, 29, 41– 48. https://doi.org/10.1016/j.clnesp.2018.11.002
Hello James and Jared – what are the two main things you learned from preparing and developing this topic?
Hi Dr. Shane-McWhorter,
I learned that flaxseed is used for many reasons, even if there isn’t very much data to support such uses. I also learned that flaxseed is very beneficial for those wanting to lower their LDL. However, it shouldn’t replace healthy eating, exercise, and traditional lipid-lowering medications such as statins. Rather, be used in conjunction with such.
I became interested in this topic because my dad uses flaxseed with his cereal and pancakes in the morning.
– I learned that flaxseed flour is being studied as a potential substitution/additive to baked goods for diabetic patients because of the reduction of postprandial glucose.
– I also learned that this product is relatively safe to use with no major drug interactions to worry about.
Interesting topic. What were the actual cholesterol and LDL values pre and post flaxseed in the first study? Who would be good candidates for flaxseed use? Would you recommend ongoing treatment with flaxseed?
The Soltanian et all study showed flaxseed decreased LDL by 21 mg/dL which was a significant decrease compared to placebo. HDL did increase, but it was not significant. I would recommend that those with slightly elevated LDL take flaxseed oil, along with a good diet and exercise, to reduce the need of adding a statin as lipid-lowering therapy. I also would recommend that patients watch INR levels closely if they are on warfarin as although flaxseed does not have any major drug interactions, Natural Medicines does list anticoagulants as a moderate drug interaction due to flaxseed’s tendency for have platelet aggregation.
In the Soltanian et all study the baseline average total cholesterol level was 178.1 mg/dL and average reduction after 12 weeks was -36.9 mg/dL. As for the LDL pre average level was 115.1 mg/dL and a reduction of -21.0 mg/dL after 12 weeks. Both levels had a p-value of <0.001.
Very interesting topics and studies! Did any of the participants have pre-existing cardiovascular problems or any relevant baseline characteristics? Also, any long-term studies of the effects of flaxseed on heart health that you guys came across?
Hi Gisoo! Some of the studies were performed on type-2 diabetic patients since it is very important to keep lipids down with T2DM. It appeared that most other baseline characteristics were similar in these studies between the flaxseed, other interventions, and placebo groups. As far as the long-term effects go, I did a quick search in Natural Medicines and it looks like alpha-linoleic acid which is one of the ingredients in flaxseed has mixed information regarding prostate cancer risk. Essentially, it’s possible, but not so much to recommend that men do not use it long term.
Hello James and Jared!
It seems that there are many different ways patients could get the heart benefit of flaxseeds (examples: tea, capsules, etc.). Is there a particular formulation or method of taking the flaxseed you would recommend for a patient?
HI Ryley! Flaxseed oil capsules are very common. I would recommend a USP certified formulation of flaxseed oil that is less than 45g of flaxseed as consuming this amount or more has shown to cause GI upset. I also would recommend that patients take it with a meal or a tall glass of water.
Hi James and Jared
Interesting topic! Flaxseed is in the news a lot so it is interesting to learn about the available literature investigating its use. The studies utilized small numbers so I am not sure you can say there is strong evidence yet. Regarding the second study, what was the % reduction for total cholesterol so the reader can compare study 1 and study 2? Your poster showed good background work on flaxseed. It can definitely rumble the bowels for sure! (I work with geriatric patients!) Thank you for sharing your expertise on this important topic!! Nice work!!
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