I am surprised to find many textbooks on biochemistry and nutrition still using phrases to describe vegetarian and vegan diets as lacking in ‘essential’ or ‘complete amino acids’; which are the building blocks of proteins.
As far back as 1994, Young published the information in the table below, but the majority of textbooks still use the word ‘incomplete’ to describe proteins from vegetable sources. This may be appropriate in some cases where dietary sources of protein are limited, but it is not so in most developed Western countries.
Furthermore, to the best of my knowledge, none of the current recommendations for protein intake allows for, or considers, the environmental impact of meat consumption.
Plant Proteins in Human Nutrition—myths and realities
|Plant proteins are not complete;
they lack certain amino acids
|Most dietary combinations of proteins are complete; certain food proteins may be low in specific amino acids.|
|Plant proteins are lower in quality
than animal proteins.
|Protein quality depends not only on the source but also on the dietary mixture of plant proteins; plant proteins can be as high in quality as animal proteins.|
|Proteins from different plant foods
must be carefully mixed and eaten together in the same meal.
|Proteins do not have to been eaten at the same meal; the mixture over a day is important for nutritional value.|
|Animal procedures can provide good indices of the human nutritional
value of food proteins.
|Animal procedures may underestimate plant protein quality for humans and have overestimated human requirements|
|Plant proteins are difficult to digest.||Depending on the source and method of food preparation, plant proteins can be easy to digest.|
|People cannot meet protein needs with plant proteins alone.||Plant protein or animal protein can provide adequate protein for human needs.|
|Plant proteins are lacking in nutritional value because they are not balanced.||Plant proteins do not create a practical problem in terms of balance; possible imbalances are observed in amino acid supplementation.|
Table adapted from: Young VR, Pellett PL. Plant proteins in relation to human protein and amino acid nutrition. Am J Clin Nutr. 1994; 59(suppl):1203S–1212S.
The 2009 American Dietetic Association’s Position Paper on Vegetarian Diets says:
“Plant protein can meet requirements when a variety of plant foods is consumed and energy needs are met. Research indicates that an assortment of plant foods eaten over the course of a day can provide all essential amino acids’’.
If you go to the USDA Database Standard Reference 25 and look up the analysis of any one whole plant food, you will see that all the amino acids exist in the food.
Many people still believe they can only obtain ‘proper’ protein from animal sources and the repercussion of this on the environment, our health and animal welfare are extremely serious.
As Christians we have a duty of care for Gods world and all his creatures. Tear fund are just one of many organisations who are now campaigning to inform the public:
Meat is resource intensive. Producing it and getting it to us uses more land, water, fertiliser and fuel than most other types of food. Raising livestock causes 14% of all greenhouse gas emissions. Using crops that could feed people to feed animals instead pushes food prices beyond the reach of the poorest in some countries.’
Creation Care Team