Flax and health in the Danish population
What it found
Increasing flax intake up to 45 g per day was estimated to benefit health more than any harm from cadmium, in a modelling study of the Danish population.
The benefit came mainly from extra dietary fibre.
What they found
Studies in people
Fibre and disease risk
More flax meant more dietary fibre, which was linked to fewer cases of type 2 diabetes, fatal coronary heart disease and colorectal cancer. The largest benefit was for type 2 diabetes.
Cadmium and kidney disease
The extra cadmium from flax did not increase the number of chronic kidney disease cases in any scenario. This was based on a model of how cadmium builds up in the body.
Overall health impact
The total health benefit ranged from 47.5 to 708 DALYs saved per 100,000 people per year, depending on how much flax was eaten. The benefit grew with higher flax intake.
ALA and heart disease
When alpha-linolenic acid (ALA) from flax was included in a sensitivity analysis, the estimated health benefit was even larger. This depended on how much ALA the body actually takes up from whole flaxseeds.
Other findings
Cadmium guideline levels
When using the highest cadmium levels found in flax, the tolerable weekly intake for cadmium was exceeded at intakes above 27 g per day. When using average cadmium levels, it was not exceeded.
What the authors conclude
- They conclude that a daily intake of up to 45 g whole flaxseeds has a beneficial impact on the health of the general Danish adult population.
- They advise that the benefits from increased fibre and ALA could also be achieved by supplementing flax consumption below 27 g per day with other dietary sources, thereby limiting cadmium exposure.
- They call for more research on the health effects of flax and its constituents, and on how much ALA and cadmium the body takes up from flax.
How it was done
Flax has been suggested to have health benefits, but it also contains cadmium, which can harm the kidneys. The authors wanted to weigh the good and bad effects together.
The authors used Danish diet survey data and food sales data to estimate what would happen if people aged 15 to 74 increased their flax intake from the current 1.5 g per day up to 45 g per day. They calculated the health impact in DALYs, a measure of healthy life years lost or gained.
What it can’t tell you
- This is a modelling study based on assumptions and existing data, not a trial in people. It cannot prove that eating more flax will cause these health effects.
- The authors note that different sources of uncertainty might affect the results, including the lack of an upper limit for fibre benefits and the exclusion of some flax components.
- The study looked at whole flaxseeds, not crushed, and the true uptake of ALA and cadmium from whole flax is not well established.
Who paid
- Conflicts
- Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
- Authors work at
- Technical University of Denmark, Denmark; Statens Serum Institut, Denmark
The paper
- Title
- Evaluating the health impact of increased linseed consumption in the Danish population
- Type
- Study
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Outzen M, Thomsen ST, Andersen R, et al (2024). Evaluating the health impact of increased linseed consumption in the Danish population. Food and chemical toxicology. doi:10.1016/j.fct.2023.114308Free full textPubMed 38056808DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error