Vitamin D, fibre important for pre-eclampsia prevention

Two new studies have suggested that simple dietary changes and more sunshine may be able to help women prevent pre-eclampsia — a common but serious pregnancy complication that can threaten the life and future health of both expectant mothers and their offspring.

Classified as a cardiovascular condition, pre-eclampsia occurs in up to 10% of pregnancies and is characterised by high blood pressure, protein in the urine and severe swelling in the mother. It also interferes with the child’s immune development while in the womb, with some evidence suggesting a link to higher rates of allergies and autoimmune disease later in life.

Damage to the maternal endothelium — the lining of the blood vessels — is a feature of the condition, reflected by a reduced number of specialised cells (endothelial progenitor cells, or EPCs) that circulate in the blood and help with the repair of the endothelium. Dysfunction of foetal umbilical vein endothelial cells and foetal EPCs may also occur in pre-eclamptic pregnancies.

With previous studies having shown that vitamin D plays a role in regulating the cardiovascular system — and that low levels of vitamin D are linked to the development of pre-eclampsia — researchers from Hannover Medical School and the University of Pittsburgh School of Medicine’s Magee-Womens Research Institute studied the effects of vitamin D on the interaction between EPCs and umbilical cord endothelial cells, which facilitate endothelial repair, in women with pre-eclampsia. The results of their study were published in the American Journal of Physiology-Cell Physiology.

The team found the EPCs and umbilical vein cells did not integrate and communicate as well with each other as when they were exposed to endothelial cells from healthy pregnancies. However, when the EPCs and umbilical vein cells were treated with vitamin D, these impaired interactions were reversed.

“We found a stimulating effect of vitamin D on cell-cell interactions that may be important for endothelial homeostasis and repair,” the researchers wrote.

“Even though vitamin D deficiency is only one risk factor for [pre-eclampsia], sufficient vitamin D status at conception and throughout pregnancy might improve maternal and offspring vascular health in pregnancy and thereafter. Whether the observed cellular changes persist in the neonatal period and childhood and are a possible early marker of an increased cardiovascular risk of the progeny of [pre-eclamptic] pregnancies has to be investigated by further studies.”

Meanwhile, Australian researchers have separately revealed that a fibre-rich diet could be particularly important during pregnancy to promote the wellbeing of mother and child.

Plant-based fibre is broken down in the gut by bacteria into factors that influence the immune system. Researchers from the University of Sydney’s Charles Perkins Centre, the Barwon Infant Study, Monash University, James Cook University and the Australian National University collaborated to investigate the role of these metabolic products of gut bacteria during pregnancy.

Published in the journal Nature Communications, the study found that in humans, reduced levels of acetate — which is mainly produced by fibre fermentation in the gut — is associated with pre-eclampsia. The study also found that pre-eclampsia affects the development of an important foetal immune organ — the thymus, which sits just behind the breastbone.

Foetuses in pre-eclamptic pregnancies were found to have a much smaller thymus than children from healthy pregnancies. The cells the thymus normally generates, called T cells (thymus-derived cells) — specifically those associated with the prevention of allergies and autoimmune conditions such as diabetes — also remained lower in infants after pre-eclampsia, even four years after delivery. Finally, experiments involving mice showed that acetate was central in driving foetal thymus and T cell development.

Together, these results showed that promoting specific metabolic products of gut bacteria during pregnancy might be an effective way to maintain a healthy pregnancy and to prevent allergies and autoimmune conditions later in life. They may also, in part, explain the rapid increase of allergies and autoimmune conditions, as Western diets are increasingly dominated by highly processed foods that are very low in fibre.

“The mother’s gut bacteria and diet appear to be crucial to promoting a healthy pregnancy,” said senior author Professor Ralph Nanan, from the University of Sydney School of Medicine and Charles Perkins Centre. He added that the simple recommendation to “eat real food, mostly plants, and not too much” might be the most effective primary prevention strategy for some of the most serious conditions of our time.

Image credit: ©stock.adobe.com/au/Halfpoint

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