The Dutch researchers found the women with the least amount of the vitamin B12 nutrient in their blood had babies who were eight times more prone to crying.Leading UK Nutritionist, London Yvonne Bishop-Weston explains the implications of the new findings.The new study (reference) has shown a link between the level of vitamin B12 in the mother and excessive infant crying (more than 3 hours a day for more than 3 days a week for more than 3 weeks). The reasons for this are not fully understood but it could be due to the fact that a lack of vitamin B12 and folic acid hinder the foetal development of the nervous system before birth and also that in the first 6 months after birth lack of these vitamins can affect the development of the protective myelin which surrounds the nerve cells and helps them communicate.