I enjoy working with clients’ ayis because I often end up learning as I teach. Typically I get to explore local and regional food beliefs and practices with them and that inspire me to think a little more about certain issues, particularly about cross-cultural communication regarding nutrition.
One of the common themes that crop up in my encounters is the issue of eggs, in particular giving egg yolks to a baby starting out on solids. In China, egg yolks are often used as one of the first foods that is added to rice or millet based porridge (congee). Often this means starting them on eggs earlier than many pediatricians recommends due to concerns about the child developing allergies.
So between eastern traditions and modern pediatric recommendations, what we end up with is a potential for some conflict.
Maybe traditions have some foundations and in this case it turns out, egg yolks really do make a good starter food. The lao nainai in your compound insisting in feeding babies yolks was on the right path but perhaps just simply could not tell you why.
To start, yolks are are really rich in easily absorbed iron and it is readily digested by delicate tummies. In fact, spoon for spoon, egg yolks and beef have just about equal amounts of iron.
Iron deficiency is a big issue with babies around 4-6 months age. Low iron levels long before deficiency symptoms such as anemia appear, is believed to permanently alter an infant’s brain development, and that is why many pediatricians often recommend iron supplements or to exclusively breast fed babies starting at 4 months of age.
However long before such things as iron drops existed, folk knowledge passed down over generations in China recommended using yolk as an acceptable first food in order to fortify or 补（bǔ) an infant.
So that is possibly why your ayi keeps insisting on feeding some egg yolks to baby. They are really a nutrient powerhouse with a rich source of heme iron (the easy absorbed type, unlike say iron from spinach or grains).
Plus in free range or specially fed chickens, you get an extra kick of DHA (brain building Omega3 fatty acid) too.
No worries about the cholesterol either because babies brains really need it to grow. Finally, eggs are also a great source of choline, and that is another important to brain growth nutrient too!
Concerns about sensitivity/allergies
I have asked the ayis why they think the yolks are necessary and the most frequent answer I get is that everyone does it, it has been done for generations and therefore it must be right. When told about the egg allergy worries I got very quizzical looks from them. Yes we hear the westerners have a lot of allergies, its practically unheard of here. Are their bodies that different? …Indeed. Are the bodies different or the amount of exposure different?
Now many reading this have probably heard of the hygiene hypothesis. Here is a quick recap.
Dirt is good for babies and kids. Moderate exposure to germs is good for growing and training a developing immune system. Over-sterilizing a child’s environment removes opportunities for their little immune systems to get an education.
More of that here in this New York Times article.
Turns out this same principle might possibly be applicable to food exposure too. There is growing evidence that the less they are exposed to, the more likely they have allergies later in life.
A lot of experts are now saying that avoiding exposure even during pregnancy and early infancy does not diminish the incidence of food allergies. There are more complex forces at play. Studies are now probing other factors that influence the ability to develop immune tolerance. Some of these factors include the amount of folic acid exposure in early fetal life, the amount of Omega-3 consumed, presence of gut bacteria friendly compounds called oligosaccharides, probiotic intake, vitamin D and antioxidants are being studied on its influence on the immune function and immune development.
So with the lack of any significant direct link, it is no surprise that in January 2008, the American Academy of Pediatrics reversed its stance on delaying the introduction of common allergens like dairy, eggs, and nuts, stating that there was:
“…no current convincing evidence that delaying their introduction beyond [the age of four to six months]has a significant protective effect on the development of atopic disease.”
So you can rest easy. Let ayi introduce yolks progressively. As always, monitor for reactions over 3-4 days just like you would with any new food and also check with the pediatrician about it especially if the baby has a family history of food sensitivities or has shown some form of sensitivity to any foods.
Bright I. Nwaru, MPhil, MSca, Maijaliisa Erkkola, et.al. Age at the Introduction of Solid Foods During the First Year and Allergic Sensitization at Age 5 Years. PEDIATRICS Vol. 125 No. 1 January 2010, pp. 50-59
Frank R. Greer, MD, Scott H. Sicherer, MD, A. Wesley Burks, MD and the Committee on Nutrition and Section on Allergy and Immunology. Effects of Early Nutritional Interventions on the Development of Atopic Disease in Infants and Children: The Role of Maternal Dietary Restriction, Breastfeeding, Timing of Introduction of Complementary Foods, and Hydrolyzed Formulas. PEDIATRICS Vol. 121 No. 1 January 2008, pp. 183-191
M. Makrides, J. Hawkes, M. Neumann, et al. Nutritional effect of including egg yolk in the weaning diet of breast-fed and formula-fed infants: a randomized controlled trial. Am J Clin Nutr 75:1084-1092 (June, 2002)