The first 1,000 days after conception are critical for the development and future health of a baby, so a mother’s health and dietary intake during this time is all-important if the child is to get all the nutrients he or she needs.

 

 

Many organs and systems mature in utero – only the brain, liver and immune system are subject to further development after birth. If the intake of certain nutrients during pregnancy and early life is insufficient, this could lead to lifelong adverse health consequences for the offspring. So which nutrients require extra vigilance?

Folic acid

Any woman intending to become pregnant should be advised that dietary supplementation with folic acid, before conception and throughout the first 12 weeks, reduces the risk of having a baby with a neural tube defect (e.g. anencephaly or spina bifida). Folic acid needs to be taken in early pregnancy, because the neural tube forms during the early weeks of life. A woman who discovers she is pregnant should start taking folic acid as soon as possible and continuing taking it until she is 12 weeks pregnant.

The recommended dose of folic acid is 400mcg per day.¹ A higher dose will be needed if the woman has had a baby with a neural tube defect before, takes medicines for epilepsy or has diabetes and/or coeliac disease. It is also a good idea to recommend eating more foods containing folic acid, such as green leafy vegetables, fortified breakfast cereals, wholemeal bread and brown rice.

Iodine

Inadequate iodine at critical points during pregnancy can lead to irreversible brain damage in the baby. Thyroid cells are the only cells in the body that can absorb iodine and convert it into thyroxine. The growing foetus is dependent on its mother for thyroxine, especially during the first trimester, before foetal thyroid production commences.

Increased iodine is required during pregnancy and also when breastfeeding to ensure there is adequate iodine in breast milk. Anyone avoiding dairy products and fish (e.g vegans) is more likely to be short of iodine while there are concerns that, because many young women don’t drink enough milk, they are also deficient. Iodine is found in fish and seafood, especially sea fish and shellfish.

Evidence shows a positive association between maternal seafood consumption and child IQ, which could be at least partly due to the high iodine content of seafood.²

Iron

Although iron deficiency anaemia is common during pregnancy, iron supplementation will not be needed by all pregnant women.³ Screening should be offered in early pregnancy and at 28 weeks, allowing enough time for treatment if anaemia is detected. Iron deficiency anaemia is common between six and 24 months of age, coinciding with the latter part of the brain growth spurt.⁴

Iron deficiency in infancy is associated with poorer cognition and school achievement, and more problem behaviours into middle childhood. It is unclear whether the effect can be reversed with iron treatment. Studies in older children (>2 years) have shown they generally catch up in cognition but iron deficiency may place infants on different developmental trajectories to those that are iron-replete,⁵ although few studies have followed children up long-term.⁶

Magnesium

Magnesium has a major role to play in the regulation of blood pressure. Hypertension associated with pre-eclampsia appears to be alleviated when magnesium is administered,⁷ while women with adequate magnesium intakes are less likely to develop pre-eclampsia. Magnesium also appears to play a role in a number of chronic conditions including cardiovascular disease, diabetes, obesity and metabolic syndrome.

Increased magnesium intake may improve serum lipid profiles. An inverse relationship between magnesium intake and blood pressure appears to be strongest for dietary rather than supplemental magnesium. Good dietary sources of magnesium are green leafy vegetables, nuts, meat, fish, dairy and wholegrains.

Zinc

Zinc deficiency is a high risk in infants, children and pregnant women and can lead to increased susceptibility to infectious disease (e.g. respiratory disease, measles). Deficiency is associated with poor pregnancy outcomes including low birthweight, intrauterine growth retardation, pre-term delivery, and complications of labour and delivery.⁸ High levels of zinc are found in seafood, especially oysters, and red meat.

Selenium

Low selenium status is associated with an increased risk of preterm birth⁹ and pre-eclampsia.¹⁰ A UK selenium supplementation study (60mcg/day versus placebo from 12 weeks gestation) was associated with a decrease in the risk of developing pre-eclampsia in those who had the lowest selenium status at baseline.¹¹

High dietary sources of selenium include fish and organ meats, brazil nuts, eggs and cereals, although availability from foods relates to the selenium content of the soil. Cereals grown in Europe, for example, have much lower selenium content than those grown in North America.

Vitamin D

Vitamin D is essential for skeletal growth, bone health and to support the immune system. Adequate vitamin D status seems to be protective against adverse pregnancy and birth outcomes.¹² The major natural source of vitamin D is from exposure to sunlight but, as there is no ultraviolet sunlight of the appropriate wavelength for skin synthesis in the UK from October to April, the body has to rely on its own stores of vitamin D and dietary sources.

Oily fish is the only significant dietary source of vitamin D but small amounts are found in egg yolk, red meat and fortified foods (e.g. infant and toddler formula milks) and some breakfast cereals. All pregnant and breastfeeding women (particularly teenagers and young women), and infants and children under five years of age, are at higher risk of having a low vitamin D status and are recommended to take a supplement appropriate to their age group:

• Infants aged up to six months: 8.5mcg/day (340 IU)
• Older infants and children up to the age of five years: 7mcg/day (280 IU)
• Adults: 10mcg/day (400 IU)

NICE guidance advises that all infants and young children aged six months to five years should take a daily vitamin D supplement. Infants fed more than 500ml of infant formula a day (which is fortified with vitamin D) will not need a supplement. Breastfed infants may need vitamin D drops from one month of age if their mother has not taken vitamin D supplements throughout pregnancy.¹³

Omega-3 essential fatty acids

The omega-3 essential fatty acid docosahexaenoic acid (DHA) is the most abundant fatty acid in the central nervous system, brain and retina.¹⁴ Brain DHA content increases considerably during the brain growth spurt (from approximately the start of the third trimester to 18 months after birth) when there is a 10-fold increase in brain size. Peak growth is around birth.¹⁵

During pregnancy, DHA is transported across the placenta to foetal circulation – a process that increases with higher maternal dietary intake, suggesting preferential foetal transfer.¹⁶ Maternal supplementation with sardines and fish oil during pregnancy can significantly improve DHA essential fatty acid levels in the neonate at birth.¹⁷ However significant enhancement of DHA levels in the neonate after supplementation with a DHA-rich fish oil has not been demonstrated, suggesting that the neonate may obtain DHA from maternal stores.¹⁸

DHA status can influence early cognitive function. Higher maternal DHA intake or status has been linked to more advanced behaviours in infants and children¹⁹, including visual attention, problem-solving and recognition memory.²⁰ Studies in UK schoolchildren have shown that:

• Low blood levels of omega-3 fatty acids are associated with poor cognitive performance and behaviour²¹
• Supplementation with a DHA oil supplement has shown improvements in reading and behaviour in healthy but underperforming children.²² The best dietary sources of DHA are oily fish, such as salmon, mackerel and sardines. White fish (e.g. cod, haddock and plaice) also contain DHA, but in smaller quantities.

 

The best dietary sources of DHA are oily fish such as salmon

Probiotics

Probiotics are called ‘friendly bacteria’ because they are thought to both improve the balance of organisms that inhabit the gut and reduce the risk of colonisation by pathogenic bacteria. In utero, the infant is in a sterile environment but, when born, the infant’s mouth/gut becomes colonised with probiotic microbes from the mother’s birth canal. This colonisation appears to be important for the development of the baby’s immune system.

Studies have shown that there is a greater risk of developing immune diseases, such as asthma, allergies, type 1 diabetes and coeliac disease, when a baby is born via caesarean section.²³ Breastfeeding also appears to be important for the development of a healthy immune system. In addition to satisfying nutritional requirements, colostrum and milk have been shown to have a positive effect on immune function.

Human milk contains a mix of oligosaccharides, which act as prebiotics and are fermented by colonic microbiota in the infant. The impact of breastfeeding on the building of the gut microbiome is confounded by factors other than caesarean delivery, including the use of antibiotics and the supplementation of breastfeeding with formula milk.²⁴ Probiotics are becoming increasingly available as capsules and food supplements.

Studies have shown that:

• Probiotics are both safe and effective in preventing Clostridium difficile-associated diarrhoea in adults and children²⁵ 
• When used alongside rehydration therapy, probiotics appear to be safe and have clear beneficial effects in shortening the duration and reducing stool frequency in acute infectious diarrhoea²⁶ 
• They have a protective effect in preventing paediatric antibioticassociated diarrhoea²⁷ 
• They may be more beneficial than placebo for preventing acute upper respiratory tract infections.²⁸

Probiotics also feature naturally in fermented foods such as live yogurt, while microbes are also added to a number of functional food dairy products.

 

 

References for this feature are available from the Editor.