When doctors give you advice, they usually refer to some information, and the quality of this information determines the reliability of the advice given to you. Why can’t we look up this information ourselves? For example, the timing of adding complementary foods, a problem that countless people are overwhelmed with. 1, why can’t you eat some rice soup, porridge, bone broth, fish soup and so on right after birth? Can not eat rice flour? Newborn babies lack amylase, high pH of stomach acid, insufficient protease activity, insufficient lipase activity, etc. (from textbooks), and they do not digest when they eat. In addition, studies have concluded that breast milk provides all the nutrients needed for normal growth for 6 months, so why eat something that has little nutrition and is not digestible? Also, is adding too early harmful to the digestive tract? There is no answer because no one thinks it is right to add these things right after birth, so no one would do this kind of research (it would not pass ethical review). What about adding a thinner rice flour? Newborn babies can’t swallow food masses yet, they can only eat liquid food. This involves the development of tongue function and swallowing function. 2. When can infants swallow thicker foods? This depends on the development of the infant. Most infants have good swallowing function at 3-4 months of age and good development of tongue control of food. Signs include the ability to lift and move the head freely, drooling (salivary gland development with amylase), interest in adult foods, and the ability to drink from a small spoon (good tongue and swallowing function). Since breast milk can provide sufficient nutrition within six months, the recommended time to start adding complementary foods is 17-26 weeks after birth (4-6 months) according to the American Academy of Pediatrics (AAP) and the European Society of Nutrition (ESPGHAN). 3. Why can’t it be earlier than 4 months? In an article published in Pediatrics in 2013, 41 infants diagnosed with food allergies at 2 years of age were compared with 82 infants without food allergies (case-control study). Infants with food allergies at 2 years of age were found to have started complementary foods earlier in their first year of life (16-21 weeks compared to 17-23 weeks in the control group) and breastfed for a shorter period of time (21 vs. 24 weeks). Another systematic review concluded that adding complementary foods earlier than 4 months may increase the risk of obesity. Still more studies have concluded that adding complementary foods earlier than 4 months increases the risk of diabetes, hypertension, and bowel disease. 4, can be later than 6 months? The main concern is whether the growth and development of infants later than six months is affected. However, there is no basis for this. Secondly, can late addition of complementary foods lead to food allergies? One study concluded that adding egg yolk later than 8 months increases the risk of food allergies. Another aspect is that adding complementary foods later than 6 months may increase the risk of bowel disease in adulthood. This review concluded that adding gluten-containing foods earlier than 4 months was associated with a 23-fold increased risk of bowel disease compared to adding complementary foods at 4-6 months, and later than 6 months was associated with a 4-fold increased risk. However, there are reports that consider the basis. 5. Why make this issue so complicated? Pediatricians are giving a recommendation that may affect the long-term health of the infant; if society as a whole does not care about this issue and the research is not rigorous, the impact will be for a generation or even for generations. This is by no means a trivial issue. 6. Why do we need to refer to foreigners’ information? Lack of rigorous research and inability to find appropriate information. It’s a shame! Compared with the research results of Europeans and Americans for decades, our information is like a baby’s haphazard scribble comparing to a doctor’s thesis. Based on the above analysis, my specific recommendations for adding complementary foods for healthy full-term infants are: breastfeeding at least until 6 months, try spoon feeding water at 4 months (to exercise the tongue and swallowing function, as well as to discover the child’s interest), adding complementary foods from 5-6 months period, adding rice flour at the earliest (because it is easy to make and does not require much chewing; of course, it can be other foods if pureed). In fact, there is no clear specification from what type of food (all solid food) to start adding. After 6 months, you can try different types of food. The general rule is from simple to complex, from thin to thick, from fine to coarse, from one to many. The reason why I talk about these previous things is that I really want to explore when preterm babies should add complementary foods, and what is my basis for this. 7.When do countries add complementary foods to preterm infants? In a survey conducted in the UK 15 years ago, among 253 preterm infants, the average age at which complementary feeding was started was 17 weeks (4 months) according to the actual age at birth, and 95% of the infants were earlier than 17 weeks (11.5 weeks on average) according to the corrected age at birth. In an Italian survey 10 years ago, 156 preterm infants, 6.5% started complementary feeding before 4 months according to actual age (mean 22.2 weeks) and 60% started before 4 months according to corrected age (mean 15.1 weeks). A 2015 survey by Braid S, Chicago, USA, showed that using corrected months of age, about 10% of preterm infants at 22-32 weeks started complementary feeding before 4 months and about 6.2% of preterm infants at 32-36 weeks. A trend can be seen here that fewer and fewer preterm infants are adding complementary foods at a very early age. 8. Should I use actual age or corrected age? Moms and dads who have read my book “Corrected Months of Age for Prematurity” should know the huge difference between these two times. There are no clear guidelines recommending whether preterm babies should be added according to actual or corrected age. There are also some views according to body weight, and it is considered that supplementation can be considered at more than 5kg, which was the view in the UK in 1994. Now, 20 years later, the nutrition and growth of preterm infants have changed dramatically, usually reaching about 5kg by 2 months of corrective age. There is also the view that it starts at 6kg, which is basically to correct 3 months of age or more. The basis for the calculation according to the actual age of the month is that the risk of iron deficiency in the nutritional intake of preterm infants with early addition is low, but there are no good studies that suggest that the indicators of growth are better with early addition of complementary foods (some observational studies suggest that weight is slightly better, with no difference in length and head circumference; others suggest that weight gain is slower with complementary foods before 12 weeks). Considerations according to corrected age for months are a signal to add complementary foods. This is because many exceptionally early infants do not have good swallowing ability by the actual 4 months, and their heads are not yet stable enough to hold them in a sitting position. And correcting 4 months basically has the conditions to add. 9.What are the signals for adding complementary foods? Emphasize the signs of adding complementary foods: stable head lifting, able to sit with support, interested in adult food, drooling (amylase), and will eat with a spoon (try with water). Talk about my clinical observations. Take the example of a premature infant born at 28 weeks. By 4 months of age the corrected age is about 1 month, at which time there is no sign of the above and it is not appropriate to add complementary foods; by 6 months of age it is 3 months corrected, it can lift its head, it has drooling, and the tongue control of food is obviously perfect. One article investigated the satisfaction of mothers when adding complementary foods. It was found that if the mother was told the corrective age of the child and started adding when the child showed signs of adding complementary foods, satisfaction was better and the child had fewer swallowing and choking problems. 10.What are the concerns about adding too early? (1) Can infections occur? Current research has not found that adding too early increases the risk of infection. Of course, if the child is not ready, he or she may easily choke on the food. (2) Can allergies occur? Some observational studies have not found that preterm infants are more likely to develop food allergies than full-term infants. However, premature introduction of complementary foods (Morgan J, 2004; corrected for those who added several complementary foods before 4 months of age) increased the risk of eczema by 3.5 times by 1 year of age. (3) Does it increase the kidney burden? It is generally believed that the kidneys of preterm infants mature rapidly after birth and quickly catch up with those of full-term infants. Based on the above analysis, my recommendation is to use corrected months of age as the time to add complementary foods. More importantly, it is important to start based on the infant’s signs of complementary feeding (that the child is ready), as the corrective age at which these signs occur may vary from gestational age to gestational age. Of course, we need to evaluate and follow up over a longer period of time to determine what is better for the health of our preterm infants.