Flaxseed – Scientifically Proven Effects on Gut, Metabolism, and Immune System

Flax is one of the oldest cultivated plants known to humanity, but only in recent years has modern science fully uncovered its vast health potential regarding their seeds - the flaxseeds. Its effects on the digestive system, metabolism and immune function are now well-researched. Numerous studies show that the fibers and polysaccharides in flaxseed stimulate the production of short-chain fatty acids such as butyrate, acetate and propionate in the colon. These fatty acids play a key role in intestinal health: they have anti-inflammatory properties, strengthen the intestinal barrier and serve as an important energy source for intestinal cells.

The microbiome also benefits significantly from flaxseed consumption. Several studies have shown that flaxseed improves the bacterial balance in the gut, particularly the ratio of Firmicutes to Bacteroidetes - a ratio often disrupted in overweight individuals. Particularly notable is the stimulation of beneficial bacteria such as Akkermansia muciniphila, Lactobacillus and Bifidobacterium, which are considered highly supportive of metabolic and immune function.

Research into the so-called gut-brain axis further suggests that flaxseed may even contribute to improved mental well-being via its prebiotic effects. A healthy gut flora, as indicated by recent findings, may help prevent not only digestive disorders but also stress-related illnesses and depressive symptoms.

Another key area of research is the cardiovascular effects of flaxseed. One of the most impressive studies in this regard is the FLAX-PAD study, in which patients with peripheral artery disease consumed 30 grams of flaxseed daily for twelve months. The result was a significant reduction in systolic blood pressure - by up to 15 mmHg, comparable to the effect of antihypertensive medication. Regular flaxseed consumption has also been shown to improve cholesterol profiles. According to studies, LDL cholesterol can be reduced by up to 18 percent, while HDL and triglyceride levels remain largely unaffected. This benefit appears to be due to the combined action of soluble fiber, lignans and phytosterols.

Flaxseed also shows promise in managing type 2 diabetes. A controlled study by Javidi et al. (2016) documented a marked improvement in insulin resistance with a daily intake of 20 grams of flaxseed. Additional studies - such as those by Soltanian and Janghorbani (2019) and Hutchins et al. (2013) -reported lower plasma glucose levels in prediabetic individuals following flaxseed consumption. Its blood sugar-regulating effects are attributed to the combination of dietary fiber, anti-inflammatory omega-3 fatty acids and antioxidant plant compounds.

Taken together, recent scientific findings highlight flaxseed as a highly effective, plant-based food with both preventive and therapeutic potential. Its broad spectrum of positive effects ranges from improved digestion and better blood sugar and cholesterol regulation to enhanced immune resilience.

Source: 

Duarte, S., Shah, M. A., & Sanches Silva, A. (2025). Flaxseed in Diet: A Comprehensive Look at Pros and Cons. Molecules, 30(6), Article 6. Source

Hutchins, A. M., Brown, B. D., Cunnane, S. C., Domitrovich, S. G., Adams, E. R., & Bobowiec, C. E. (2013). Daily flaxseed consumption improves glycemic control in obese men and women with pre-diabetes: A randomized study. Nutrition Research (New York, N.Y.), 33(5), 367–375. Source

Javidi, A., Mozaffari-Khosravi, H., Nadjarzadeh, A., Dehghani, A., & Eftekhari, M. H. (2016). The effect of flaxseed powder on insulin resistance indices and blood pressure in prediabetic individuals: A randomized controlled clinical trial. Journal of Research in Medical Sciences, 21(1), 70. Source

Mueed, A., Shibli, S., Korma, S. A., Madjirebaye, P., Esatbeyoglu, T., & Deng, Z. (2022). Flaxseed Bioactive Compounds: Chemical Composition, Functional Properties, Food Applications and Health Benefits-Related Gut Microbes. Foods, 11(20), Article 20. Source

Nowak, W., & Jeziorek, M. (2023). The Role of Flaxseed in Improving Human Health. Healthcare, 11(3), 395. Source

Pramanik, J., Kumar, A., & Prajapati, B. (2023). A review on flaxseeds: Nutritional profile, health benefits, value added products, and toxicity. eFood, 4(5), e114. Source

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.  Source