Vitamin D in pre-conception by dads improves children's growth

Vitamin D consumption by fathers-to-be in the period leading up to pregnancy may affect growth and obesity risk in children. In particular, the amount of vitamin D introduced through food, by men, is statistically associated with the height and weight of the offspring. In the preconception period, therefore, it is not only mothers' eating habits that influence the development of the baby, but also paternal habits. Nutrition could, in fact, act on the health and function of sperm-forming cells.

This is according to new research conducted by Dr. Cilia Mejia-Lancheros and her colleagues at University College Dublin, Ireland. The findings were presented at the European Congress on Obesity held in Portugal last May.

Sunshine vitamin is important for growth and bone health

Vitamin D is a fat-soluble molecule that exists in two forms: cholecalciferol and ergocalciferol and performs numerous vital functions in the human body. The amount of vitamin D taken in through the diet is often insufficient for daily requirements; in fact, few foods naturally contain it, and these are oily fish, dried mushrooms, whole milk products, and eggs. 

Ninety percent of the vitamin D molecules in the human body are produced through skin exposure to the sun's ultraviolet rays. The main function of vitamin D is to maintain normal levels of Calcium and Phosphorus in the blood and promote Calcium absorption, contributing to the formation of bones and teeth and maintaining their stability. Vitamin D deficiency can be a cause of rickets and osteomalacia, as well as other non-skeletal dysfunctions. 

The vitamin is in fact also very important for the proper functioning of the immune, respiratory and cardiac systems. Several studies have shown that maternal consumption of vitamin D plays an important role in maintaining general and musculoskeletal health in children. Little attention, however, has been paid until now to the potential link between child growth and vitamin D status in fathers-to-be in the period before conception.

Unexpected finding: paternal nutrition may influence children's weight and height

The new analysis investigated precisely the relationship between vitamin D consumption in pairs of parents in the preconception period and the height and weight of their children, measured at ages five and nine years. Their results suggested that fathers' consumption of the vitamin is significantly associated with their children's height and weight at five years of age. However, the association was found to be statistically nonsignificant when the offspring had reached nine years of age. Incredibly, the results showed no link between the mother's vitamin D level during the first and second trimesters of pregnancy and the children's weight and height at age five or nine. "One reason why this may be the case is that the nutritional status of the father may somehow influence the health, quality and function of germ cells, which are involved in reproduction," the researchers said; "Thus, maternal nutritional status may not be the only key factor in the development and growth health of children," they continued. 

As is well known, skin exposure to sunlight is essential for the body to produce vitamin D, so the study authors also considered the number of hours children spent outdoors during the summer. They found that spending 3 or more hours playing "outside" on weekends was correlated with greater height.

Some details of the study

The researchers analyzed data from the Lifeways Cross-Generation Cohort Study, a database that collects health information on babies born in Ireland as of 2001 and their parents. Measures of children's height and weight were available for 213 and 148 father-child pairs when the children were 5 and 9 years old, respectively. Information on paternal vitamin D intake was obtained from food consumption questionnaires. The results of the study showed that at the age of 5 years, the mean height and weight of the children was 112.12 cm and 20.95 kg, respectively, and the paternal vitamin D intake was 3.46 μg per day in the preconception period. 

At age 9 years, the mean height and weight for the children was 138.61 cm and 34.09 kg, and paternal vitamin D intake was 1.25 μg per day. The association between fathers' vitamin D intake during the three months prior to pregnancy, and children's height and weight was calculated using specific statistical analyses adjusted for possible confounding factors, including: father's age, height, and weight; mother's age, vitamin D levels, height, energy intake, and weight; child's sex, age, vitamin D levels, and energy intake; and outdoor physical activity during summer.

A study that will continue with new investigations 

The results showed that paternal vitamin D concentration is positively associated with children's height and weight at age 5, paving the way for further investigation of family nutrition. In the coming months, the authors will collect additional data on father-child pairs, including anthropometric data, on the health, lifestyle and behavior of the children involved in the study, including upon reaching adolescence, studying their health status and that of their future generations.

Source: Mejia-Lancheros, et al, Paternal antenatal vitamin D intake is associated with offspring's height and weight aged five and nine years in the Lifeways Cross-Generation Cohort Study, Ireland, 24th European Congress on Obesity (ECO2017), Porto, Portugal, May 17-20, 2017.