Thank you very much Dr Myatt for your response. I am also looking for articles on the subject and will share with this forum if I find something useful.

I was very glad to see at the end of a comment the reference to breastmilk - which is of course the most ideal protein for children, and can help to balance any incomplete vegetable sources. Other animal milks are also a useful source of protein, though not as good a match for the human infant as breast milk. One of the main reasons for eating meat in fact is not the protein content, but the iron and zinc content, and the protein can be fairly easily substituted with a mix of legumes and cereals and other vegetables.
Readers may be interested to look out for Edition 3 of "Nutrition for Developing Countries" currently being printed with Oxford University press, and publication expected within a month.

Dear Dr Felicity,

Thank you for your response and bringing attention to the book- I located a pre order option and look forward to reading it.

One clarification- The basic understanding of First class proteins being Animal protein especially meat vs Second class protein being from legumes and pulses or other vegetable sources - is this still valid? Or has more recent research told us otherwise?

For poor populations where no cultural barriers exist to consumption of animal meat the main barriers are cost. But costs of pulses and legumes are also on the rise and additionally do not "satisfy" a population which associates meat with the best nutrition. I look forward to any comments you might have from your extensive experience on this.

Many thanks

Dear Charulatha

The assessment of protein quality is discussed in a recent FAO WHO report available at:

http://www.fao.org/ag/humannutrition/35978-02317b979a686a57aa4593304ffc17f06.pdf

To answer specifically to your question, animal proteins are usually of better quality than plant proteins, but you can balance and improve the profile of plant proteins by mixing up different sources (cereals + legumes).

Animal source foods seem superior, however, to plant based foods to promote children growth. See for instance:

Dagnelie PC, van Staveren WA. Macrobiotic nutrition and child health: results of a population-based, mixed-longitudinal cohort study in The Netherlands. Am J Clin Nutr. 1994 May;59(5 Suppl):1187S-1196S.

It is not clear whether this effect is related to a better quality of proteins. Another possible explanation is that nutrients needed for growth (in particular Zn and phosphorus) are better absorbed in animal source foods which don’t have antinutrients preventing their absorption.

Thank you very much for the links and your very clear response Dr Briend. Much appreciated. Cheers