For adult nutrition, following a high protein diet has become very fashionable with the increasing popularity of the paleo diet. There has been a lot of scientific debate on the efficacy of that diet in adults, I am however more worried about this trend blowing over into nutrition in early childhood.
Over the last year, more and more parents have been asking me about the value of increasing protein intake in their babies complementary food and I have seen also some of the baby food company advertising their food as “high in protein”, as if this is a good thing. Firstly, I want to say, that today’s blog entry is for healthy babies, without any underlying medical diagnoses, where there may be a need to alter protein intake. The latter need to get individualised help from a paediatric dietitian.
I am just going to come out with it – high protein intake during early childhood is NOT good! In breastmilk about 6% (give or take) of the energy comes from protein. Breastmilk is the ideal source of nutrition in babies and recommended alongside solids until 2 years of age. So breastmilk is in fact low in protein, high in fat and carbohydrates and this is the ideal source of nutrition for babies. More than 10 years ago, studies started to emerge that babies who were on infant formulas, which then had a higher protein content, had a higher BMI in later life, than breastfed children. As a result ALL standard infant formulas dropped their protein content since then. It was initially thought that the link between higher protein intake and obesity in later life was related to milk protein specifically, but over the last 5 years, it has transpired from research, that it is high protein intake per se (so that means any protein from meat, fish ect) that is linked to obesity in later life. How does excessive protein intake lead to obesity in later life? The “early protein hypothesis” has been generated to try to explain this phenomenon. It is thought that high early protein intakes increases plasma concentrations of insulin-releasing amino acids, which in turn stimulate the secretion of insulin and insulin-like growth factor I, which enhance weight gain and body fat deposition, as well as the later risk of obesity, adiposity, and associated diseases.
I am sure that you are now wondering, what is high protein intake? Research points towards a protein intake within the first 2 years that exceeds 15% being linked to obesity. So what does 15% of protein mean? If you had a meal of 100 kcal, it should ideally not contain more than 3.75 g of protein (1 g = 4 kcal and 3.75 g = 15 kcal). I have looked through many of the commercial foods and quite a number of these, exceed this threshold. Is this against the law? No, not at this stage, as companies in the EU can go up to 5.5g of protein per 100 kcal (that would be 22% of energy from protein). This legislation is from 2006 and was put in place before all of this research emerged of the impact of high protein intake. I understand, the EU is due to update this in 2020.
So what would I practically suggest – first of all monitor the protein content in baby foods (see above guidance), AND do not fall for any marketing saying “high protein is good in babies”. If you have a pouch that is higher in protein, you can bring down the ratio by adding vegetables/carbohydrates to the pouch. When you cook your own food, try not to exceed the following ratios 1:5 protein and 2:5 starchy foods and 2:5 veg/fruit. There is also no need in a young babies on solids to limit fat intake, remember breastmilk is very high in fat.
I hope that this provides parents with some clarity on the topic.