A healthy and balanced diet during pregnancy and breastfeeding is essential in order to build the foundation for an enhanced immune system and to protect against many chronic diseases, including obesity. The number of fat cells each one of us has is determined during infancy, early childhood and adolescence. Reaching adulthood, we have a set number of fat cells and from then on we fill them up and empty them when we gain or lose weight respectively. Why not give our infants and children a good head start by limiting the excess fat cells that could be created at those sensitive ages, starting from infancy? You may think, ok during infancy, the child doesn’t eat sweets, pizzas and fast food, they only drink milk and start solids. True.
One of the simplest ways to protect infants from overweight (which is not so simple in practice but this is a different story) is breastfeeding. Numerous studies have proven its protective effect on health, including overweight and obesity. The World Health Organization recommends that when breastfeeding is possible, it should be continued at least for the first 6 months, as the ideal way of nutrition for the infant. It has immune system enhancing factors and the perfect balance of macronutrients i.e. protein, fat and carbohydrate. Being dynamic, it’s composition changes as the infant grows to accommodate its needs. In addition it protects from food allergies during the introduction of solids at 4-6 months.
So why are we interested in infant protein intake?
There is growing evidence to support the Early Protein Hypothesis. It has been suggested that one of the main reasons that breastmilk is protective against obesity is its much lower protein content compared to formula milk. Protein intake per kilogram body weight is 55–80% higher in formula-fed than in breastfed infants 1.
The mechanism behind the increased protein intake and overweight has been suggested to involve increased levels of branched chain amino acids that stimulate insulin and Insulin Growth Factor -1 production involved in stimulating cell growth, including number of fat cells 2.
So the high protein low carb diet-trends followed by adults, are not the case for infants, quite the contrary.
How much protein is enough for infants?
The mean volume of breastmilk intake by an infant 0-6 months of age has been determined to be about 0.78lt, with a mean protein content of 11.7gr/lt. Considering this, the Food and Nutrition Board of the Insitute of Medicine set:
- Adequate protein intake (AI) for the 0-6 month olds the consumption of 9gr protein per day or else 1.52g/Kg body weight per day.
- For the 7-12 month olds, the Recommended Dietary Allowance (RDA) is 11gr per day or 1.2gr per Kg body weight/day. It was based on studies of nitrogen balance, determining how much nitrogen from protein is sufficient to maintain body function and growth1.
Extrapolating these number to the exclusively formula fed infant we can see that if they are having a high protein milk (with 3-4gr of protein per 100 kcal) their protein intake will be 15-20gr protein, twice the recommended intakes, without adding the complementary foods.
One of the leading and well designed studies in this field is the multicenter EU Childhood Obesity Project including 1138 healthy formula fed infants. It showed that the consumption of lower protein infant formula with 1,77gr per 100 kcal and follow-on formula of 2.2gr per 100 kcal (compared to the higher protein infant formula with 2.9gr and follow-on with 4.4gr/100kcal) resulted in lower body mass index and weight for length at 2 years of age which continued at 6 years 3,4. The lower protein formula more than covered the recommended intakes for age and protein intake was well above the one consumed by exclusive breastfeeding.
In practice:
- When breastfeeding is possible it is recommended at least for the first 6 months.
- When formula milk is being used it is suggested to prefer the ones with lower protein content which is approximately 1.8gr per100 kcal for the 0-6 month olds and 2.2gr/100 kcal for the 7-12 month olds. We should give credit to the industry, they have already started lowering the protein content from the time of the 1970’s up to now, but check them out yourself and if in question ask a registered dietitian or pediatrician. Remember the lower protein formula will still provide much more protein than breastfeeding, which is considered the ideal, so go for it especially if there is history of overweight and obesity in the family.
- The quantity of high protein solid foods such as meat, chicken, fish for the 7-12 month olds should be enough to support growth but not excessive. One tablespoon (10-15gr meat or fish) once a day for the 7-9 month olds and twice a day for the 9-12 month olds is enough for the averaged weight infant and they do not need them daily. Of course this is adjusted to your infants height and weight, each one has its individual needs. The rest of the daily diet includes mostly fruit, vegetables, wholegrains and often beans.
Keep providing a variety of healthy foods to your little ones and enjoy healthy eating as a family!
REFERENCES
- Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids.; 2002.
- Luque V., Closa-Monasterolo R., Escribano J., Ferre N. Early programming by protein intake: The effect of protein on adiposity development and the growth and functionality of vital organs. Nutr. Metab. Insights. 2015;8:49–56.
- Koletzko B, von Kries R, Closa R, Escribano J, Scaglioni S, Giovannini M, Beyer J, Demmelmair H, Gruszfeld D, Dobrzanska A, Sengier A, Langhendries JP, Rolland Cachera MF, Grote V. European childhood obesity trial study group: lower protein in infant formula is associated with lower weight up to age 2 y: a randomized clinical trial. Am J Clin Nutr. 2009;89:1836–45.
- Weber M, Grote V, Closa-Monasterolo R, Escribano J, Langhendries JP, Dain E, Giovannini M, Verduci E, Gruszfeld D, Socha P, Koletzko B. European childhood obesity trial study group: lower protein content in infant formula reduces BMI and obesity risk at school age: follow-up of a randomized trial. Am J Clin Nutr. 2014;99:1041–51.
