Flaxseeds are one of the oldest crops in history, which has been cultivated since the development of human civilization, and its Latin name is Linum usitatissimum, which means a wide range of uses, and is currently the most rammed functional health food.
What is flaxseed?
Flaxseed Flax plants grow flat seeds that are yellow to reddish-brown in color and slightly nutty in taste, especially rich in omega-3 fatty acids (ALA), short-chain polyunsaturated fatty acids, dietary fiber, lignans and phenolic compounds.
Due to the above characteristics, flaxseed is a food with health benefits, with potential effects such as regulating metabolism and improving chronic diseases.
What are the recommended benefits of flaxseed?
1. Flaxseed is beneficial for blood pressure regulation
Hypertension is one of the most common noncommunicable diseases, with complications including heart failure, coronary heart disease, peripheral vascular disease, stroke and chronic kidney disease, with an estimated prevalence of up to 1 billion people and about 7.1 million deaths each year from hypertension and its complications.
Non-cooperation of patients, inappropriate treatment, endocrine diseases, kidney diseases, pregnancy, and methamphetamine and cocaine… and other drugs are the main cause of hypertensive crisis. In addition, early diagnosis, lifestyle changes, and pharmacotherapy are essential to reduce the risk of associated morbidity and mortality.
A meta-analysis (33 randomized clinical trials with 2427 participants) showed that flaxseed supplementation significantly reduced systolic and diastolic blood pressure. Note 1
The subgroup analysis also noted that the magnitude of improvement was particularly pronounced in patients with intervention time > 20 weeks, daily dose ≥30 g, body mass index (BMI) between 25 and 30, and hypertension.
*Conclusion: Eating flaxseed may bring positive benefits for blood pressure control, but due to the heterogeneity between studies and the small sample size, more large-scale experiments are still needed for further verification
2. Flaxseed is beneficial to blood lipid regulation
Dyslipidemia is a metabolic disorder that causes a persistent increase in plasma cholesterol and triglycerides.
There are currently three types of dyslipidemia, hypercholesterolemia, hypertriglyceridemia, and mixed hyperlipidemia, which are caused by abnormally high levels of cholesterol and triglycerides.
The most common form is hypercholesterolemia, which is defined as a total cholesterol level of 5 mmol/L or more than 190 mg/L.
According to statistics, the global prevalence of hypercholesterolemia is 39% in men and 40% in women, and nearly one-third of ischemic heart disease is secondary to hypercholesterolemia.
A systematic literature review and meta-analysis (62 randomized controlled trials, 3772 participants) showed that flaxseed supplementation (daily doses between 10 g and 60 g) significantly reduced total cholesterol, triglyceride, and low-density lipoprotein cholesterol) (but has no effect on HDL cholesterol). Note 1
*Conclusion: Flaxseed supplementation can bring positive help to blood lipid regulation, but due to the small sample size and high heterogeneity between studies, more studies are still needed to support it
3. Flaxseed improves inflammatory biomarkers
Inflammation, the immune system’s response to harmful stimuli such as pathogens, damaged cells, toxic compounds, or radiation, is a defense mechanism essential for health by eliminating harmful stimuli and activating the healing process.
Elevated levels of inflammatory biomarkers such as C-reactive protein and fibrinogen have been shown to be a co-pathogenesis of many chronic diseases, including cardiovascular disease, dementia, intestinal disease, diabetes, arthritis, and cancer.
A systematic literature review and meta-analysis (32 randomized controlled trials, 1502 participants) showed that ingestion of flaxseed and related derivatives helped reduce the sensitivity of C-reactive protein (hs-CRP) and tumor necrosis factor-alpha (TNFα), but there was no significant improvement in interleukin-6 and C-reactive protein (CRP). Note 2
*Conclusion: Oral administration of flaxseed confers anti-inflammatory benefits, but more studies are needed to support this due to heterogeneity between studies
4. Flaxseed is beneficial for diabetic blood sugar control
Diabetes is a cascade of metabolic disorders caused by high blood sugar, caused by defects in insulin secretion, poor dynamics, or both.
The main symptoms of hyperglycemia include polyuria, thirst, weight loss, and sometimes polyphagia and blurred vision.
A meta-analysis (25 randomized clinical trials with 2080 participants) showed that intake of whole flaxseed (non-flaxseed oil or lignans extract) significantly improved values related to glycaemic management (e.g., insulin resistance index, glycemic value, insulin level). Note 1
Subgroup analysis also noted that the magnitude of improvement was particularly pronounced in those with greater than 12 weeks of consumption and high baseline blood glucose levels.
The mechanism behind it may be related to the dietary fiber, plant antioxidants and omega-3 fatty acids contained.
*Conclusion: Eating flaxseed can bring positive benefits for blood glucose control, but due to the heterogeneity between studies and the small sample size, more large experiments are still needed to further confirm
5. Flaxseed helps with weight loss
Since the 1980s, the global obesity rate has increased threefold, and overweight and obesity have affected more than one billion people, and although most people will try to lose weight, the success rate is less than 3% due to genetic, behavioral and environmental factors.
Obesity has not only its cosmetic effects, but also increased incidence of type 2 diabetes, hypertension, coronary artery disease, many cancers and cognitive dysfunction.
A systematic literature review and meta-analysis (45 randomized controlled trials, 2,789 participants) pointed out that flaxseed supplementation had the effect of reducing body weight, body mass index and waist circumference, especially in groups with a use period of more than 12 weeks and a body mass index greater than 27 (kg/m²). Note 2
The mechanism behind it is related to the water-soluble dietary fiber contained in it (which can delay gastric emptying and cause satiety) and the anti-obesity effect of omega-3.
*Conclusion: Intake of whole flaxseed can bring positive weight management effect, and it is more significant for overweight patients
6. Flaxseed is beneficial for prostate cancer
Prostate cancer is the top three most common cancers in men, second only to colorectal cancer and liver cancer, with about one million new cases worldwide every year, and with the aging of the population, the number of people over 65 years old has increased by 4 times.
In addition to family inheritance, the currently known risk factors for prostate cancer may increase the incidence of disease, race, diabetes, obesity, smoking, vasectomy, diet, smoking, and sexually transmitted diseases.
A multisite/randomized controlled trial (30-day trial of 161 patients undergoing prostatectomy) showed that a flaxseed-rich diet (30 g daily) reduced tumor proliferation rates (as measured by the Ki-67 tumor cell proliferation index) compared with a low-fat or usual diet. Note 4
The mechanism behind it may be related to its reduction of 5oC reductase, regulation of natural killer cells, and vascular endothelial growth factor activity.
*Conclusion: Consumption of flaxseed can bring preventive and protective effects on prostate cancer, but the results still need more research to verify
Are there any side effects of flaxseeds?
For most people in good health, flaxseed is safe to consume in moderation, but it may cause side effects such as bloating, abdominal pain, constipation, diarrhea, stomach pain, nausea, etc., especially if the stomach function is poor or eating too much at one time.
Safety precautions (7 contraindications to use)
- Do not consume raw or immature flaxseeds, as they contain anti-nutrients: cyanogenic glycosides, which may cause poisoning if overdosed. Cyanogenic glycosides are heat-resistant substances that can be removed by heating
- Patients with intestinal obstruction, intestinal inflammation, esophageal stricture should not be used, because excess fibrous may cause symptoms to worsen
- If you have low blood pressure or take blood pressure-lowering drugs, please be careful because flaxseed has a blood pressure-lowering effect
- Pregnant women, lactating women and those with hormonal sensitivity should not be used, such as breast cancer, uterine cancer, ovarian cancer, endometriosis, uterine fibroids, etc., because the nutritional component lignans have a weak estrogenic effect, and the safety of users is unknown
- Do not use coagulation disorders or people taking anticoagulants, because they may have anticoagulant effects, related drugs such as Coumadin, Plavix, aspirin
- If you have diabetes or take hypoglycemic drugs, use it with caution as it may have a hypoglycemic effect
- Be careful if using birth control pills or hormone replacement therapy, as the nutrients in flaxseed may affect hormone levels and interfere with the drug’s effects