How calcium changes pectin's effect on immune receptors in lab cells
What it found
In lab tests on human cells, adding calcium reduced how strongly certain types of pectin blocked an immune receptor called TLR2.
Calcium had less effect on a high-DM type of pectin.
What they found
Animal and lab studies
No activation of TLR2
None of the three pectin types turned on the TLR2 immune receptor in the lab cells. This was true at every calcium level tested.
Pectins blocked TLR2
All three pectins blocked TLR2 from being turned on by other signals. Without any calcium, the DM18 and DM52 pectins were the strongest blockers.
Calcium reduced blocking
Adding 1 mM or 10 mM calcium made the DM18 and DM52 pectins much weaker at blocking TLR2. For example, DM18 blocking dropped from about 74.7% to around 31.7% with 1 mM calcium.
High DM pectin reacted differently
The DM69 pectin was less affected by calcium than the other two types. Only the very highest calcium level of 10 mM reduced its ability to block TLR2.
Calcium weakened binding
In a separate binding test, TLR2 stuck to the DM18 pectin 33.8% less when 1 mM calcium was present compared to no calcium. Calcium did not change how well TLR2 stuck to the DM69 pectin.
What the authors conclude
- They suggest that taking in more calcium alongside pectin may help keep TLR2 signalling working properly in the gut.
- Their results point to a possible reason why eating both fibre and calcium together is linked to fewer Western diseases.
- They advise that calcium intake should not be too close to 10 mM, because that would also stop the high DM pectin from blocking TLR2 when needed.
How it was done
People who eat more fibre and calcium tend to have fewer Western diseases like obesity and bowel problems. Scientists do not yet know how fibre and calcium work together in the body to cause this.
Researchers tested three types of lemon pectin with different chemical structures, labelled DM18, DM52 and DM69. They exposed human cells grown in a lab dish to these pectins under three calcium levels: 0 mM, 1 mM and 10 mM. Each test was repeated at least five to eight times.
What it can’t tell you
- These tests used human cells grown in a lab dish, so they cannot show what happens inside a living person eating pectin and calcium.
- The study measured effects on one immune receptor, not actual disease outcomes.
Who paid
- Authors work at
- University Medical Center Groningen, The Netherlands; Wageningen University, The Netherlands
The paper
- Title
- The influence of calcium on pectin's impact on TLR2 signalling
- Type
- Study
- Evidence
- Animals and lab studies
- Summarised from
- Full text
- Cite
- Beukema M, Jermendi É, Schols HA, de Vos P (2020). The influence of calcium on pectin's impact on TLR2 signalling. Food & function. doi:10.1039/d0fo01703eFree full textPubMed 32902547DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error