Can Flaxseed benefit your digestive health?
Flaxseed (or linseed as it is also known) – what are the benefits of consuming this seed? Actually there are many!
Flaxseed provides many essential nutrients; specifically, it is rich in fibre, omega 3-fatty acids, and lignans.
Flaxseeds are the richest sources of lignans, a type of phytoestrogen
What are Lignans?
Lignans are a type of polyphenolic compound found in plants. They actually function as defensive chemicals, protecting them from attack by insects etc.
Lignans are what’s called precursors to phytoestrogens.
A phytoestrogen is a plant nutrient that is somewhat similar to the female hormone oestrogen. Due to this similarity, lignans may have oestrogenic and/or anti-oestrogenic effects in the body.
Whole flaxseeds – When the flaxseed is eaten whole, you will receive the benefits of the fibre and the lignans. In order to get the omega 3-fatty acid benefit of the flaxseeds, you must chew the seeds very well or grind them. In terms of storage, whole flax seeds can be kept at room temperature for up to 10 months.
Ground flaxseeds or flax meal – I recommend buying ground flaxseeds. All nutritional benefits (omega 3-fatty acids, fibre, and lignans) of flaxseeds are obtained when eaten ground. Ground flaxseeds are best stored in the fridge or freezer for no longer than 3 months after opening, otherwise they will become rancid. If grinding the seeds yourself, grind as needed to prevent spoilage. There are approximately 1.6 grams of omega 3-fatty acids in 1 tbsp of ground flaxseeds.
It’s interesting to note, the most common foods in which to have flaxseed are baked goods. The process of baking even up to 180 ℃ for two hours does not alter the composition or content of ALA in a baked muffin, for example so you can get baking!
Here’s some of their benefits, backed up by studies.
Flaxseed and Gut Health
Flaxseeds are often considered prebiotics, or “probiotic food,” due to their high fibre content. And in the body, prebiotic foods get broken down in the gut and end up providing good bacteria to the gut’s microbiome.
In addition, flaxseed is recommended for relief from constipation. In one trial flaxseed baked into cookies was ingested in constipated patients with Type 2 diabetes. They found the flaxseed reduced constipation symptoms, weight, fasting plasma glucose, triglycerides and LDL (so-called ‘bad’) cholesterol levels.
The high fibre content of flaxseed helps to stimulate stool output and as mentioned above, is often found to be helpful for those who suffer with constipation. In addition, it has been found to help normalise stool output in both normal and constipated people. So flaxseed may be of use in reducing the symptoms of irritable bowel syndrome; however, further research is required.
Lignans that are unusually high in content within flaxseed need to be metabolised by gut bacteria in order to be processed by your digestive system. Because of this it is best to consume milled flaxseed rather than whole flaxseed
Flaxseed and Female Hormonal Status
Dietary flaxseed may exhibit a protective effect against menopausal symptoms. Several studies have examined the effects of flaxseed (its bioactive ingredients) on the quality of life and the frequency and severity of hot flushes in post-menopausal women. The oestrogenic action of certain metabolites of flaxseed suggested a potentially positive effect on these post-menopausal symptoms.
A 2015 study of 140 postmenopausal women found that menopausal symptoms decreased and the quality of life increased in women who ingested a flaxseed supplemented diet.
Although it’s not all positive! A few randomised controlled trials and systematic reviews of clinical trials found no significant effect of flaxseed on quality of life or hot flushes during menopause.
In addition, caution has been advised for flaxseed consumption during pregnancy and lactation and therefore consumption is not recommended during this time.
Flaxseed, Insulin and Type 2 Diabetes
Flaxseed has been found to impact diabetes. Supplementation of this seed reduced blood glucose in subjects with type 2 diabetes and lowered blood glucose in subjects with pre-diabetes.
Daily use of flaxseed, but not a probiotic, has been shown to improve gut bacteria and insulin sensitivity in overweight women.
Improving the health of your gut bacteria could improve the health of your whole body, which is why simple nutritional interventions such as prebiotic and probiotic foods are so promising.
Dietary manipulation of gut flora with a probiotic or flaxseed mucilage (extracted from whole flaxseed) was studied in a group of post-menopausal obese women, and the study aimed to look at the effects of these interventions on the gut microbiota and metabolic risk markers.
Over 6-weeks the flaxseed, but not the probiotic improved insulin release during an oral glucose tolerance test and improved insulin sensitivity. Flaxseed mucilage also changed the abundance of thirty-three metagenomic species of gut bacteria.
‘The present study shows that daily intake of flaxseed mucilage over 6 weeks can improve insulin sensitivity and modify the gut microbiota in individuals with obesity,” wrote the study investigators.
I’ve recently re-introduced it into my diet at breakfast and will report back in a few weeks.
Introducing Flaxseed into Your Diet
PLEASE NOTE: always introduce flaxseed slowly, so if the recipe states more than 1 tablespoon in a smoothie for example, begin by consuming less than 1 tablespoon and increase gradually over a few days to help your digestive system get used to it.
Brahe LK, et al. Dietary modulation of the gut microbiota – a randomised controlled trial in obese postmenopausal women. Br J Nutr. 2015 Jul 2:1-12.
Cetisli, N.E.; Saruhan, A.; Kivcak, B. The effects of flaxseed on menopausal symptoms and quality of life. Holist. Nurs. Pract. 2015, 29, 151–157
Chen, Z.Y.; Ratnayake, W.M.N.; Cunnane, S.C. Oxidative stability of flaxseed lipids during baking. J. Am. Oil Chem. Soc. 1994, 71, 629–632.
Cockerell, K.M.; Watkins, A.S.; Reeves, L.B.; Goddard, L.; Lomer, M.C. Effects of linseeds on the symptoms of irritable bowel syndrome: A pilot randomized controlled trial. J. Hum. Nutr. Diet. 2012, 5, 435–443
Parikh, Mihir, Thane G. Maddaford, J. A. Austria, Michel Aliani, Thomas Netticadan, and Grant N. Pierce 2019. “Dietary Flaxseed as a Strategy for Improving Human Health” Nutrients 11, no. 5: 1171. https://doi.org/10.3390/nu11051171
Landete, J.M.; Arqués, J.; Medina, M.; Gaya, P.; de Las Rivas, B.; Munoz, R. Bioactivation of phytoestrogens: Intestinal bacteria and health. Crit. Rev. Food Sci. Nutr. 2016, 56, 1826–1843.
Lewis, J.E.; Nickell, L.A.; Thompson, L.U.; Szalai, J.P.; Kiss, A.; Hilditch, J.R. A randomized controlled trial of the effect of dietary soy and flaxseed muffins on quality of life and hot flashes during menopause. Menopause 2006, 13, 631–642
Power, K.A.; Lepp, D.; Zarepoor, L.; Monk, J.M.; Wu, W.; Tsao, R.; Liu, R. Dietary flaxseed modulates the colonic microenvironment in healthy C57BI/6 male mice which may alter susceptibility to gut-associated diseases. J. Nutr. Biochem. 2016, 28, 61–69
Soltanian, N.; Janghorbani, M. A randomized trial of the effects of flaxseed to manage constipation, weight, glycemia, and lipids in constipated patients with type 2 diabetes. Nutr. Metab. 2018, 15, 36.