Tag: Vitamin A

Categories : Respiratory DiseasesTags :

Higher Vitamin A Levels Linked to Better Lung Function in Asthmatic Kids and Adults

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Vitamin D shows similar benefits in adults with asthma, including slower biological ageing

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Higher levels of circulating vitamin A are linked to better lung function in children and adults with asthma, while vitamin D shows similar benefits in adults, including slower biological ageing, finds the first study of its kind, published online in the respiratory journal Thorax.

Poor lung function is a key predictor of death, irrespective of whether or not a person has lung disease. And making sure that the lungs keep working well is essential for staving off long term respiratory conditions, explain the researchers.

Previously published research suggests that vitamins A and D both protect against and worsen asthma, as well as influencing lung development, depending on the dose and context, they add.

To clarify the role of these vitamins, the researchers drew on two groups of participants with asthma: 1165 children in the GACRS (Genetic Epidemiology of Asthma in Costa Rica Study); and 1041 adults in the ODOLLFA (Omic Determinants of Longitudinal Lung Function in Asthma).

Small molecules that fine-tune the activity of genes (serum microRNAs or miRNAs for short) and those that mark genes as either active or inactive (DNA methylation), plus levels of vitamins A and D, were measured in all the participants.

Lung capacity/health was assessed through measures of forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and the FEV:FVC ratio.

In adults, further analysis assessed whether methylation status and miRNAs influenced the association between the vitamins and lung function or epigenetic ageing – the response of genes to external biological and environmental factors which then promotes cellular ageing.

The findings showed that children and adults with asthma and higher vitamin A levels had better lung function (FEV1 and FVC) than those with lower levels.

And among adults with asthma, those with higher vitamin D levels of at least 30 ng/ml had better lung function than those with lower levels. They also had less evidence of epigenetic ageing, suggesting that vitamin D may help slow biological ageing, particularly in people with asthma, say the researchers.

“These findings emphasise the value of adequate vitamin D, not only for lung health but also in slowing age-related processes,” they write.

In people with asthma, vitamin D deficiency is more common and is associated with more severe disease, worse asthma control, higher inhaled steroid need and more frequent  sudden worsening of asthma symptoms, they explain.

The researchers identified MiRNAs that regulate 248 genes commonly associated with vitamins A and D in both age groups, which, further analysis suggests, are involved in controlling inflammation and lung function.

This secondary analysis also revealed that changes in the expression of specific miRNAs strongly influence the effects of vitamins A and vitamin D on lung function and epigenetic ageing.

“To our knowledge, this is the first study to integrate vitamin A and D levels with lung function and epigenetic markers – miRNA expression and DNA methylation – in both children and adults with asthma,” write the researchers.

Lung function was inversely correlated with all age acceleration measures, reinforcing the link between respiratory health and ageing,” they add.

They conclude: “Our findings emphasise that epigenetic mechanisms play a key role in mediating the effects of vitamins on lung function in individuals with asthma, pointing to potential targets for personalised nutrition and therapeutic strategies in asthma care.”

In a linked editorial, Drs Sze Man Tse and Genevieve Mailhot of the CHU Sainte-Justine Research Center, Montreal, and the University of Montreal, caution: “While these findings open a novel line of investigation linking vitamin D, biological ageing and lung health, there is a need for further studies to clarify causality.”

But they add: “By examining the underlying biological mechanisms, [the researchers have] revealed a nuanced interplay between vitamins A and D, lung function, and their epigenetic mediators.

“Their findings highlight age-dependent and age-independent mechanisms, underscoring complex interactions between vitamin levels and lung physiology.”

And they conclude: “Overall, advancing our understanding of how nutritional exposures impact gene regulation may open new avenues for managing asthma across the lifespan.”

Source: The BMJ Group

Categories : Diet and Nutrition Obstetrics & GynaecologyTags :

Many not Getting Enough Nutrients in Their Pregnancy, Study Finds

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Source: Pixabay CC0

It’s generally estimated that around 10% of pregnant people struggle to meet their nutritional needs – but the real number could be far higher, according to new research in The Journal of Nutrition.

Over 90% of pregnant individuals are potentially failing to get enough iron, vitamin D, or vitamin E from the food they eat, while over one-third could be short of calcium, vitamin C, and vitamin A. Troublingly, almost two-thirds of pregnant people were also found to be getting insufficient dietary folate – a critical nutrient that helps prevent birth defects in the baby’s brain and spine.

“It’s important to remember that many pregnant people take prenatal vitamin supplements, which might help prevent nutritional deficiencies,” says lead author Dr Samantha Kleinberg, professor at Stevens Institute of Technology. “Nonetheless, this is a startling finding that suggests we need to be looking much more closely at whether pregnant individuals are getting the nutrients they need.”

Where most previous studies of nutrition during pregnancy relied on a few days of food diaries, or on simply asking people what they remembered eating, the Stevens team asked pregnant people to take before-and-after photos of everything they ate over two 14-day periods. Experts then reviewed the photos to assess the amount of food actually eaten and determine the nutrients consumed during each meal.

That’s a far more accurate approach, because people are notoriously bad at estimating portion size or accurately reporting what they’ve eaten, Dr Kleinberg explains. A photo-based approach is also much less laborious for pregnant people, making it easy to collect data over a period of weeks instead of just a few days.

“Most surveys only track diet over a day or two – but if you feel off one day and don’t eat much, or have a big celebratory meal over the weekend, that can skew the data,” Dr Kleinberg says. “By looking at a longer time period, and using photos to track diet and nutrition, we’re able to get a much richer and more precise picture of what people actually ate.”

The study found significant dietary variations between individuals, but also among the same individuals from one day to the next, suggesting that shorter studies and population-based reports might be failing to spot important nutritional deficits. “Some people eat really well, and others don’t – so if you just take an average, it looks like everything’s fine,” Dr Kleinberg explains. “This study suggests that in reality, an alarming number of pregnant people may not be getting the nutrients they need from their food.”

Using food photos also recorded the exact timing of meals and snacks, and to explore the way that patterns of eating behaviour correlated with total energy and nutrient intake. When pregnant people ate later in the day, the data shows, they were likely to consume significantly more total calories – potentially an important finding as researchers explore connections between eating behaviours and health problems such as gestational diabetes.

The current research didn’t directly study health outcomes, so it’s too early to say whether insufficient nutrition or excessive energy consumption is adversely impacting pregnant individuals or their babies. “We’ll be digging into that in future studies, and looking at possible connections with eating patterns and changes in glucose tolerance,” Dr Kleinberg says.

Source: Stevens Institute of Technology

Categories : ImmunologyTags :

How Vitamin A Enters into Gut Immune Cells

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Source: Pixabay

Researchers have reported in Science how vitamin A enters immune cells in the intestines – findings that could offer insight to treat digestive diseases and perhaps help improve the efficacy of certain vaccines.

“Now that we know more about this important aspect of immune function, we may eventually be able to manipulate how vitamin A is delivered to the immune system for disease treatment or prevention,” said Lora Hooper, PhD, Chair of Immunology at UT Southwestern, Howard Hughes Medical Institute Investigator.

Vitamin A is a fat-soluble nutrient which is converted to retinol and then to retinoic acid before it is used. It is important for every tissue in the body, said Dr. Hooper, Professor of Immunology, Microbiology, and in the Center for the Genetics of Host Defense at UT Southwestern. It is particularly crucial for the adaptive immune system, a subset of the broader immune system that reacts to specific pathogens based on immunological memory, the type formed by exposure to disease or vaccines.

Although researchers knew that some intestinal immune cells called myeloid cells can convert retinol to retinoic acid, how they acquire retinol to perform this task was a mystery, said Dr. Hooper, whose lab investigates how resident intestinal bacteria influence the biology of humans and other mammalian hosts.

Lead author Ye-Ji Bang, PhD, a postdoctoral fellow in the Hooper Lab, and colleagues focused on serum amyloid A proteins, a family of retinol-binding proteins that some organs produce during infections. They used biochemical techniques to determine which cell surface proteins they attached to, and identified LDL receptor-related protein 1 (LRP1).

Drs. Bang, Hooper, Herz, and colleagues showed that LRP1 was present on intestinal myeloid cells, where it seemed to be transferring retinol inside. When the researchers deleted the gene for this receptor in mice, preventing their myeloid cells from taking up the vitamin A derivative, the adaptive immune system in their gut virtually disappeared, said Dr Hooper. T and B cells and the molecule immunoglobulin A, critical components of adaptive immunity, were significantly reduced. Researchers then compared the response to Salmonella infection between mice with LRP1 and those without. Those without the receptor quickly succumbed to the infection.

The findings suggest that LRP1 is what conveys retinol into myeloid cells. If a way could be developed to inhibit this process, explained Dr Hooper, it could calm down the immune response in inflammatory diseases that affect the intestines, such as inflammatory bowel disease and Crohn’s disease. Alternatively, boosting LRP1 activity could boost immune activity, making oral vaccines more effective.

Source: UT Southwestern Medical Center