Vitamin supplementation and breastfeeding
Previous studies have shown a protective role of maternal
supplementation with B-vitamins and folic acid for childhood cancers,
such as ALL, neuroblastoma, CNS tumors and germ cell tumors. Folate is
important for cell division because of its role in de novo purine and
pyrimidine synthesis, and also in the DNA repair mechanism. The rapid
turnover of cancer cells entails greater DNA synthesis which, in turn,
increases folate requirements to maintain this high rate of cell
proliferation. Folate and other B-vitamins involved in 1-carbon
metabolism are essential for the high-fidelity synthesis of DNA and
activated methyl groups that are required for DNA methylation and
regulation of chromatin structure. Genetic mouse models have shown that
impaired 1-carbon metabolism interferes with genome integrity, which
might explain the folate- and vitamin-related pathologies including the
risk of childhood cancer, especially leukemia. In the present study,
maternal vitamin supplementation during pregnancy was inversely
associated with decreased risk, by around 20%, of childhood ALL, which
is congruent with the results of large studies and the general
recommendations that a healthy maternal diet around conception and early
pregnancy based on the intake of B-vitamins (B9, B6, B12) is protective.
Consistent with other studies, the present results also showed a
decreased risk, by 20%, of ALL in children breastfed for more than 6
months. Breast milk contains immunologically active components, exosomes
and exosomal RNAs, as well as anti-inflammatory defense mechanisms that
influence the development and maturation of the immune system. It also
contains antibodies that have a prebiotic effect and promote a more
favorable infant gut microbiome. The more mature immune system of
breastfed infants involves a greater abundance of natural-killer and
stem cells compared to formula-fed infants. Encouraging breastfeeding
into clinical practice seems to be a cost-efficient and beneficial
public health measure.