Enteral nutritional supplements - background information

Introduction

There is very little data on the vitamins and mineral requirements of preterm infants. Preterm requirements of babies >35 weeks is generally assumed to be the same as term infants. The very low birth weight infants, however, may not be able to metabolise and eliminate these nutrients as well as term gestation infants. These revised best guess recommendations, although they have not been evaluated, are based on available data (see references and appendix 1-Vitamin compositions feeds and Appendix 2 mineral compositions of enteral feeds). These clinical guidelines provide additional information on the rationale for vitamins and mineral supplements.

Summary of use of supplements

FEED	VITAMIN SUPPLEMENT	IRON SUPPLEMENT
Exclusive formula milk	Yes	Yes, start when 6 weeks old
Fortified Breast Milk (SMA BMF)	No	No
Unfortified Breast Milk	Yes: 0.6 ml Dalivit / day (as per guideline)	Yes, start when 6 weeks old
Breast milk and formula milk (when breast milk supply is low)	Yes: 0.6 ml Dalivit / day (as per guideline)	Yes, start when 6 weeks old

Vitamins

Vitamins (oral)

The Neonatal Unit has traditionally used Abidec® , a proprietary product which contains vitamin A, B1, B2, B6, C and nicontinamide. Vitamins are essential for growth and development. Preterm infants are a particularly high risk group as they have poor stores at birth and increased requirement due to rapid growth. The Department of Health (DOH) recommends (1,2) that term babies receive vitamin supplements from 6 months (if in any doubts of vitamin status of mother during pregnancy start at 1 month) and continue until 5 years unless adequate vitamin status can be assured by a diverse diet and regular and moderate sunlight exposure. The COMA report (2) also stresses the need for vitamins in preterm infants.

Duration of administration of vitamins

In 2012 the Chief Medical Officers of the devolved nations issued the following joint statement:

'All infants and young children aged 6 months to 5 years should take a daily supplement containing vitamin D in the form of vitamin drops, to help them meet the requirement set for this age group of 7-8.5 micrograms of vitamin D per day.'

Our policy is that parents of preterm babies discharged on Abidec or Dalivit should be advised to continue a vitamin supplement containing vitamin D from the time of discharge from NNU until the age of 5 years.

Minerals

Iron

In the UK, iron deficiency is the most commonly reported disorder during early childhood (2,5). Anaemia can increase risk of developmental problems and this may be related to duration of iron deficiency, severity of anaemia and of the child’s age at the time of the deficiency. It is unclear whether these adverse developmental effects are reversible. Preterm babies do not have stores and are particularly vulnerable to iron deficiencies especially during the first year of life. Dietary iron has to meet increasing requirement as well as replace normal daily losses.

Iron is better absorbed from breast milk compared to formula. By 6 months of age, the amount of iron for breast milk is insufficient to meet increasing needs and has to be obtained for dietary sources. Non-haem iron present in plants are less well absorbed. For example phytic acids in cereals and vegetables can bind available iron and reduce absorption. Many foods are in fact, poor sources of iron. Vitamin C when taken at same time as iron can improve bioavailability.

Calcium

Calcium is also poorly absorbed. From breast milk about 66% is absorbed compared to formula of 40%. Milk and milk products as well as products made from fortified white flour are good sources of calcium. Calcium supplements at discharge is not usually required.

Phosphate

In breast fed babies with evidence of metabolic bone disease supplementation should be considered if serum phosphate is low and alkaline phosphatase is >1000 units/L. This is particularly relevant for babies with severe BPD with recession which may be made worse. In these babies supplementation at discharge may be considered after discussion with consultant.

Appendix 1: vitamin composition of enteral feeds - no vitamin supplementation

Vitamins	Breast milk (BM) 150ml/kg/d	Pre-Aptamil® (150ml/kg/d)	Aptamil® (150mg/kg/d)	BM + Fortifier (150ml/kg/d)**	*Growing stable preterm infant (/kg/d)
A (iu/kg/d)	300	535	300	945	700-1500 (lung disease 1500-2800)
D (iu/kg/d)	0.6	144	60	300	150-400
B1 (mg/kg/d)	0.03	0.21	0.06	0.23	0.18-0.24
B2 (mg/kg/d)	0.05	0.30	0.18	0.3	0.25-0.36
B6 (mg/kg/d)	0.02	0.18	0.06	0.18	0.15-0.21
C (mg/kg/d)	5.7	24	12	24	8-24

Appendix 2: mineral composition of enteral feeds

Calcium	mg (mmol) /kg/day
Breastmilk+ fortifier (150ml/kg/d)	143 (3.5)
Prematil® 150mg/kg/d	105 (2.6)
Aptamil® 150ml/kg/d	90 (2.3)
Preterm stable/growing infant** (/kg/d)	120 - 230 (3 – 5.7)
Comment	With current formula feeds it is difficult to attain in utero accretion rates of calcium. At best enteral feeds provide about two thirds of requirement. Consider supplementation if serum calcium <1.6mmol/L. Dosage: 0.3mmol/kg 6 hourly

Phosphate	mg (mmol) /kg/day
Breastmilk+ fortifier (150ml/kg/d)	83 (2.8)
Prematil® 150mg/kg/d	63 (2.1)
Aptamil® 150ml/kg/d	63 (2.1)
Preterm stable/growing infant** (/kg/d)	60 - 140 (2 - 4.6)
Comment	Supplementation is guided mainly by low serum phosphate <1mmol/L or raised alkaline phosphate >1000 units/L. In high risk babies (VLBW) the presence of low serum phosphate and high alkaline phosphatase merely flags up the likelihood of low bone minerals. Dosage: 1mmol/kg 12 hourly.

Iron	mg /kg/day
Breastmilk+ fortifier (150ml/kg/d)	0.11
Prematil® 150mg/kg/d	1.4
Aptamil® 150ml/kg/d	1.1
Preterm stable/growing infant** (/kg/d)	2
Comment	During the first 6-8 weeks of life iron is very poorly absorbed. The baby’s haem iron and blood transfusion can usually meet requirements. By 4-6 months, iron reserve becomes depleted and requirements have to be obtained from dietary sources. LBW infants iron reserve is depleted earlier hence babies will start iron at 6 weeks after birth. Iron absorption is probably about 6-10% from formula milk compared to about 80% from breast milk so formula milk is fortified with higher iron content to compensate for poor absorption. Vitamin C can increase iron absorption. Dosage: 0.2ml (1.1mg Fe)/kg once daily in <35 weeks gestation or 1.8kg at birth once receiving full enteral feeds starting at 6 weeks of age.

**Note - consensus recommendation are based on ESPGAN, Committee on Nutrition of Preterm Infant and American Academy of Paediatrics, Committee on Nutrition. The dosage recommended is the amount provided from enteral nutrition not the amount absorbed.

References

Powers H. Vitamin requirements for term infants, consideration for infant formulae. Nutri Res Rev 1997; 10 : 1-33.
Weaning and the weaning diet. Report of the working group on the weaning diet of the Committee on the Medical Aspects of Food Policy. HMSO 1994 (ISBN D11321 8389).
Greene H L, Porchelli P, Adcock E, Swift L. Vitamins for newborn infant formulas: a review of recommendations with emphasis on data from low birth-weight infants. Eur J Clin Nutrition 1992; 46; Suppl. 4 : 51-8.
Tsang, R C, Lucas A, Uauy, R, Zlotkin S (eds), Nutritional Needs of the Preterm Infant. Scientific Basis and Practical Guidelines, 1993.
Fairweather - Tait S J. Iron deficiency in infancy; easy to prevent - or is it. Eur J Clin Nutrition 1992; 46 : Suppl. 4 : S9-S14.
Stevens R. Nutritional aspects of metabolic bone disease in the newborn. Arch Dis Child 1996; 74: F145-148.

Last reviewed: 08/12/2022

Next review date: 08/12/2032

Author(s): Yvonne Freer, Hester Blair, Caroline O'Hare.