Annatto carotenoids and red blood cell resistance to damage in people
What it found
Taking annatto carotenoid capsules for 7 days helped human red blood cells resist breaking open when exposed to damaging chemicals in lab tests.
Bixin worked better than norbixin at protecting the cells.
What they found
Studies in people
Lab protection of blood cells
When red blood cells from 4 volunteers were mixed directly with bixin or norbixin in a dish, both compounds made the cells harder to break open. They protected the cells against three different chemicals used to cause damage.
Protection after taking capsules
After 13 volunteers took bixin capsules for 7 days, their red blood cells resisted damage from all three test chemicals. Norbixin capsules only protected the cells against one of the chemicals, sodium nitrite.
Bixin worked better overall
Bixin was more effective than norbixin at keeping red blood cells intact. The authors suggest this is because bixin mixes more easily into the fatty outer layer of the cell.
Less fat damage in cells
The chemicals used to damage the cells caused fats in the cell walls to break down. Taking bixin for 7 days stopped this fat breakdown completely, while norbixin only stopped it for one chemical.
Other findings
Dose compared to food coloring
The volunteers took 0.05 mg per kg of body weight each day. This is higher than what people usually get from food coloring, which ranges from 0.5 to 7 micrograms per kg of body weight daily for a 60-kg person.
What the authors conclude
- They conclude that taking annatto food-coloring extracts helps human red blood cells resist breaking open by reducing oxidative damage to the cell membrane.
- They note that bixin was more effective than norbixin and suggest it could be explored for functional foods or medicines for people at risk of certain types of anemia.
How it was done
Red blood cells can break open when their outer layer is damaged by oxidation, which happens in several diseases. The authors wanted to see if natural colorings from annatto seeds could protect these cells from that kind of damage.
In a lab test, they mixed red blood cells from 4 healthy volunteers with two annatto compounds and chemicals that cause cell damage. In a separate trial, 13 healthy adults took a daily capsule of bixin, norbixin, or a placebo for 7 days each. Their red blood cells were then tested outside the body to see how well they resisted breaking open.
What it can’t tell you
- All participants were young, healthy adults, so scientists do not yet know if older people or those with anemia would see the same results.
- The protective effects were measured on blood cells tested in a dish, not inside the living body during everyday life.
- The study lasted only 7 days, so it cannot show what happens with longer use.
Who paid
- Authors work at
- Federal University of Santa Maria, Brazil
The paper
- Title
- Dietary supplementation with annatto food-coloring extracts increases the resistance of human erythrocytes to hemolysis
- Type
- Study
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Beni AA, Rodrigues RF, Conte L, et al (2020). Dietary supplementation with annatto food-coloring extracts increases the resistance of human erythrocytes to hemolysis. Nutrition research (New York, N.Y.). doi:10.1016/j.nutres.2020.02.003Free full textPubMed 32217378DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error