What is already known on this topic
Vitamin A deficiency can cause intestinal inflammation and blindness, and it increases the risk of serious infections. Vitamin A deficiency is usually treated with β-carotene, the most abundant precursor of vitamin A, but the impact of β-carotene on intestinal health, especially during the intestinal imbalance associated with vitamin A deficiency, is poorly understood.
What this research adds
Researchers gave β-carotene to mice lacking vitamin A and found that dietary β-carotene increased the levels of vitamin A, reduced inflammation, and improved gut barrier integrity. It also lowered the mice’s intestinal levels of several microbes, including bacteria belonging to the Bacteroidetes, Firmicutes and Proteobacteria phyla.
Conclusions
The findings could inform diet-based interventions to treat conditions such as inflammatory bowel disease, whose intestinal symptoms are similar to those associated with vitamin A deficiency.
Vitamin A deficiency is associated with mortality from common childhood infections, and is the world’s leading preventable cause of childhood blindness. Now, researchers have found that β-carotene, a common treatment for vitamin A deficiency, improves the microbiota imbalance and intestinal dysfunctions in mice lacking vitamin A.
The findings, published in BBA – Molecular and Cell Biology of Lipids, could inform diet-based interventions to treat conditions such as inflammatory bowel disease, whose intestinal symptoms are similar to those associated with the lack of vitamin A.
Vitamin A deficiency can cause intestinal inflammation and blindness, and it increase the risk of serious infections. The condition is usually treated with β-carotene, the most abundant precursor of vitamin A, which is commonly found in fruits and vegetables.
However, the impact of β-carotene on intestinal health, especially during the intestinal imbalance associated with vitamin A deficiency, is poorly understood.
To address this question, researchers led by Lorena Quadro at Rutgers University analyzed the effects of giving β-carotene to a mouse model of vitamin A deficiency.
Microbial imbalance
The researchers fed mice lacking vitamin A and control mice a diet poor in vitamin A for two weeks. Then, they gave the rodents oral β-carotene every other day for another two weeks.
β-carotene was detected in the blood, liver and intestine of the animals, with the highest concentration found in feces. Dietary β-carotene was properly metabolized and it increased retinol levels in the gastrointestinal tract of both control mice and mice lacking vitamin A compared to a control treatment.
β-carotene also lowered the gut levels of several microbes, including bacteria belonging to the Bacteroidetes, Firmicutes and Proteobacteria phyla — but only in mice lacking vitamin A. This suggests that β-carotene improves the microbiota imbalance found in vitamin A deficient mice.
Gut dysfunction
Next, the researchers analyzed the effects of β-carotene on the barrier properties of the colon. Mice lacking vitamin A are known to show abnormalities of the intestinal physical barrier, which are associated with reduced levels of mucin, leaky gut and high concentrations of reactive-oxygen species in the gut.
Dietary β-carotene reduced inflammation, relieved oxidative stress and improved gut barrier integrity in both control mice and mice lacking vitamin A, although the beneficial effects were more pronounced in the vitamin A deficient mice.
The results suggest that β-carotene modifies the abundance of certain gut microbes and improves the animals’ intestinal dysfunctions. “Our findings may contribute to developing new therapeutic opportunities not only for [vitamin A deficiency] but other gut pathologies,” the authors say.
