Vitamin D is the “guardian of the organism” and may help reduce the risk of heart disease by stimulating healthier probiotic gut bacteria in humans, a Brazilian study has found.
Research involving 150 volunteers at the University of São Paulo’s Public Health School (FSP-USP) showed that those with higher levels of vitamin D circulating in their organisms tended to have lower levels of lipopolysaccharides (LPS), a marker substance for the presence of gram-negative bacteria.
The LPS molecule is linked to inflammatory responses in the organism. Higher bloodstream levels of LPS, therefore, can favour the development of a state of subclinical (chronic low-grade systemic) inflammation, a factor associated in several studies with the development of cardiovascular and metabolic diseases, including diabetes.
By contrast Bifidobacteria – the gram positive bacteria present in greater numbers in those with higher vitamin D levels – help control the growth of harmful bacteria and mitigate symptoms of allergies and inflammations.
The study published in the journal Metabolism was led by FSP-USP’s professor Sandra Roberta Gouvea Ferreira Vivolo, using volunteers from her undergraduate course in nutrition. The volunteers were aged between 20 and 30 (91% of them women).
“Vitamin D is known to be important for immune system homeostasis. Our study adds the finding that this relationship is due at least in part to interactions with gut microbiota,” said Prof. Vivolo. “We found evidence showing both that the nutrient can influence intestinal flora composition – since vitamin D is a sort of guardian of the organism that favours immune system homeostasis – and vice-versa, that a certain microbiota profile can influence vitamin D levels in the bloodstream.
However the links between vitamin D and cardiovascular disease are indirect and subtle, so more research is needed. Firstly, only 20% of vitamin D comes from diet, with the rest gained by exposure to sunlight. For city dwellers or those reluctant to expose themselves to sunshine, vitamin supplements are necessary.
The FSP-USP study is an offshoot of a larger longitudinal study known as the Nutritionist Health Study (NutriHS), which since 2013 has tracked the habits of a specific sample of nutrition students and nutritionists. Prof Vovolo’s is principal investigator for the research project supported by FAPESP.
To test her hypothesis, Vivolo and her group conducted a bacterial census in fecal samples using DNA sequencing techniques. This helped identify the most frequent phyla and genera among the trillions of microorganisms present in each group of volunteers.
“Only some of the genera identified showed statistically significant differences. For example, Haemophilus and Veillonella, both Gram-negative, were less abundant in participants with more vitamin D. On the other hand, these same volunteers had more bacteria of the genera Coprococcus and Bifidobacterium, both of which are Gram-positive,” Vivolo said.
The results of the analysis were adjusted for possible bias. The most significant factor was found to be the association between higher vitamin D levels and greater abundance of Coprococcus and Bifidobacterium, both of which are considered beneficial to human health. Bifidobacteria help control the growth of harmful bacteria and mitigate symptoms of allergies and inflammations.
There is a long, long road to be travelled before doctors might one day tell their patients: “A vitamin D per day keeps the cardio OK.”
You can read a more detailed article by Brazilian journalist Karina Toledo by clicking here: You can see the scientific paper by clicking on this link: sciencedirect.com/science/article/pii/S0026049517300112.