Weaning a baby from breast milk or formula (homemade or commercial) can be a fun but stressful time. There are many theories on how to feed your baby. When should you start solids? How do you feed your baby? Do you follow Baby Led Weaning (BLW)? When do you start specific fruits, vegetables and grains? Do you make food or buy commercial food? Do you offer grains before the first birthday?
I have two children in which I have made and still make baby food with the foods we eat as a family. My blog is enriched with my family nutrition practices, traditions and my baby food recipes. Recently, I have come under fire regarding the appropriate age to introduce grains to a weaning infant. I personally started around 7 months without any rhyme or reasoning except to use it as a thickener for my BLW approach to feeding. It is easier for a baby to self-feed a thicker puree from a spoon than a thin runny puree- assuming the baby is ready to physically eat a thicker puree.
The debate to introduce grain after a year intrigued me to do my own research on the subject and make my own educated decision. As the opposing opinion believes to wait until the infant is over 1 year because infants lack the ability to produce pancreatic alpha amylase[i]. Pancreatic alpha amylase is a digestive enzyme secreted into the small intestine, which helps us digest carbohydrates (fruit, vegetables, milk, yogurt, legumes and grains). The blood concentration of alpha amylase at birth is only 1.6% of the adult concentration[ii].
I found this fact to be extremely educational and interesting. But it also raised other questions in my mind. Carbohydrate sources (listed above) are made up of polysaccharides (starches: amylose and amylopectin), oligosaccharides and disaccharides that are hydrolyzed by alpha amylase and other digestive enzymes. To further define amylose and amylopectin they consist of wheat grains, rice, tuber crops, peas and legumes. If the opinion is to wait a year on the introduction of grains, shouldn’t it be a year for fruit, vegetables, and legumes as well?
I had to answer this question because I am currently feeding my child who is under the age of one. As a mother and Registered Dietitian, I want to do what is right by my child and provide him with the best nutrition possible without any digestive complications. My only motivation.
Before we get into the science of digestive enzymes, we should understand the fundamental background of digestion. Carbohydrate digestion is dependent on the combination of pancreatic and salivary amylase along with the intestinal brush boarder enzymes glucoamylase and sucrase-isomaltase. Carbohydrates are broken down into the disaccharide maltose. Maltose and other disaccharides (lactose and sucrose) from foods are broken down to monosaccharies, which are absorbed and converted mostly to glucose in the liver.[iii]
After much research, this is what I learned: babies do have sources of other enzymes to help promote carbohydrate digestion and absorption. First, a breastfed baby will receive alpha amylase from their mother’s milk. This amylase is special as it has a broad range for pH tolerances; meaning the alpha amylase will survive the low pH of the stomach and help digest carbohydrates in the small intestine. [iv] This is great news for breastfeeding mothers and babies.
Secondly, an infant has other intestinal enzymes. I tell my nutrition class at Penn State University: “all the magic happens in the small intestine”. This seems to be true for an infant as well. While they may have low to zero levels of pancreatic alpha amylase, they do have other small intestinal enzymes that aid in the digestion of oligosaccharides and disaccharides. The enzymes present in the infant are sucrase-isomaltase and glucoamylase.[v] Their concentration is comparable with that of an adult at birth.[vi] Glucoamylase splits successive straight chained glucose molecules (alpha 1, 4 amylose) from the nonreducing end of the starch molecules indicating young infants may be able to digest and absorb the starch amylose.[vii],[viii] Sucrase-isomaltase attacks maltose, maltotriose and alpha 1, 6 bonds indicating an infant can digest the starch amylopectin.[ix]
In my opinion based on the science I researched, infants can certainly digest carbohydrates. The question is which ones and how much? Starch digestion for infants is dependent on glucoamylase and the small amount of salivary amylase that survives the passage through the stomach (mother’s breast milk and natural production). I think it is important to note that the degree of digestibility of a carbohydrate depends on it structures, size, branching and bonds.
Starches are polymers of glucose with alpha 1, 4 amylose (straight chain) and alpha 1, 6 amylopectin (branched chain) linkages. Starches vary in digestibility, size and shape based on the proportions of amylose and amylopecitin. Starches have been classified three forms based on digestibility. Type A (rice, wheat starch) has an easily digestible because it has an open helical structure. Type B (potato starch and banana) has a dense hexagon pattern with double helices denying access to amylases making it harder to digest. Type C (peas and legumes) is a mixture of both type A and B. All types are easily digested in the cooked form.[x],[xiii]
It should be noted that the above paragraph has only been studied in adults and not infants.
I firmly believe more information and studies are needed on the infant digestibility of grains and other food groups. As a mother and Dietitian, I feel comfortable and confident in my decision to feed my infant gluten free grains and other carbohydrate sources under the age of one. I agree infants do not have the complete carbohydrate digestion and absorption package as adults, which is why I will alter how I feed my child to a degree.
The current recommendation is to introduce solids around the ages of 4-6 months with commercially infant rice cereal thinned with breast milk or formula as a first food.[xi] I personally did not do this but introduced mashed (very) ripe banana, mashed avocado and crumbled hardboiled egg yolk as a first food but thinned with breast milk. For information on the recommendations of the World Health Organization (WHO), click here. For information on the National Institute for Health’s recommendations, click here.
In the future, I will still feed grains (non gluten grains-rice, oat, and millet) to my child who is not a year but I will also incorporate some of the recommendations of the Weston A. Price Foundation. I will soak my grains in a mixture of water and yogurt or buttermilk for 24 hours prior to cooking. According to Nourishing Traditions, this speeds up the hydrolysis (breakdown) of the harder to digest foods.[xii] I will continue to offer my infant fully cooked tuber vegetables (yams, potato), peas and legumes with a peace of mind but make sure they are still warm during the meal time. I will also ensure the banana I serve is over-ripe.
[i] Zoppi G, Andreotti F, Pajno-Ferrara F, Njai DM, Gaburro D. Exocrine pancrease function in premature and full term neonates. Pediatr Res 1972;6:880-6.
[ii] Gillard BK, Simbala JA, Goodglick L. Reference intervals for amylase isoenzymes in serum and plasma of infants and children. Clin Chem 1983;29:119-23.
[iii] Whitney E. Rofes SR. Understanding Nutrition 12th edition. Wadsworth, Cengage Learning: 2011:97-105.
[iv] Lindberg T, Skude G. Amylase in human milk. Pediatrics 1982;70:235-8.
[v] Lebenthal E, Lee PC. Development of functional response in human exocrine pancreas. Pediatrics 1980;66:556-60.
[vi] Auricchio S, Rubino A, Muerset G. Intestinal glycosidase activities in the human embryo, fetus and newborn. Pediatrics 1965;35:944-54.
[vii] Pazur JH, Cepure A, Okada S, et al. Comparison of the action of glucoamylase and glucosyltransferase on D-glucos, maltose and malto-oligosaccharides. Carb Res 1977;58:193-202.
[viii] Heyman H, Gunther S. Calculation of subsite affinities of human small intestinal glucoamylse-maltase. Biol Chem Hoppe-Seyer 1994;375:451-5.
[ix] Auricchio S. Genetically determined disaccharidase deficiencies. In: Walker AW, Durie PR, Hamilton JR, WalkerSmith JA, Watkins JB, eds. Pediatric gastrointestinal disease. St. Louis: Mosby, 1996:761-85.
[x] Englyst HN, Kingman SM. Dietary Fiber and resitant starch. A nutritional classification of plant polysaccharides. In: Kritchevsky D, Bonfield C, Anderson JW, eds. Dietary fiber. London: Plenum, 1990:49-65.
[xi] Fomon S. Feeding normal infants: Rationale for recommnendations. J Amer Diet Assoc. 2001;101:1002-1005.
[xii] Fallon, Sally. Nourishing Traditions. NewTrends Publishing. 1999