Flaxseeds contain three distinct health-promoting components: alpha-linolenic acid, the plant omega-3 fatty acid; lignans, the most concentrated dietary source of phytoestrogens with a concentration up to 800 times higher than any other plant food; and mucilaginous fibre that slows glucose absorption and feeds beneficial gut bacteria. The combination produces health effects that no single supplement can replicate.
The Evidence
- Cardiovascular: a meta-analysis of 11 randomised controlled trials found that ground flaxseed supplementation significantly reduced both systolic and diastolic blood pressure, with effects comparable to some antihypertensive medications in adults with hypertension
- Breast cancer: a prospective study of 3,000 women found that those with the highest lignan intake had a 40 percent lower risk of breast cancer compared to those with the lowest intake; flaxseed lignans appear protective at both pre- and post-menopausal stages
- Blood glucose: flaxseed fibre and lignans reduce post-meal glucose response; a meta-analysis of 25 trials found significant reductions in fasting glucose and insulin resistance with whole flaxseed consumption
- Menopausal symptoms: a double-blind RCT found that 2 tablespoons of ground flaxseed daily reduced hot flush frequency and severity comparably to hormone therapy in some measures, without hormonal side effects
How to Use Them
Ground flaxseed is required for absorption as whole seeds pass through undigested. Two tablespoons daily of freshly ground flaxseed is the dose used in most clinical trials. Ground flaxseed can be added to porridge, smoothies, yoghurt, or used as an egg replacer in baking. Store in the fridge or freezer after grinding to prevent oxidation of the omega-3 content.