I have seen 'whey protein' advertised in health food stores as the source of food protein with the highest nutritional value. Is this correct, and, if so, should I be eating it to ensure that I get enough protein? 

This answer is brought to you by many of the Australian nutrition professionals who regularly contribute to a nutrition email discussion group.

The nutritional value of a food's protein is determined by the mix of amino acids that it contains. Amino acids are the 'building blocks' of protein. Only some amino acids are essential in the adult human diet - that is, they must be obtained from food because they cannot be manufactured in the body. So the nutritional value of protein in a food is determined by the quantities of the essential amino acids in that food.

Apart from human flesh (and there are ethical considerations that generally preclude obtaining protein from this particular source!), the food with the protein of highest nutritional value is usually taken to be the humble egg (although for infants, breast milk is probably the most appropriate 'gold standard').

Therefore, one way of rating a food as a protein source is to give the egg the maximum rating and to compare all other foods against this according to their levels of essential amino acids.

Whey is the fluid that remains after the curd has formed (largely from the fat component of milk) in the process of cheesemaking. Whey contains not only protein, but also lactose (milk sugar). The protein in whey ('lactalbumin') is good quality protein and does make a useful protein supplement. However, it is not correct to state (as some practitioners of alternative nutrition do) that whey is the 'best source of protein'; it is simply another good source.

It is also true that Australians generally eat far more protein than we need. Protein is derived from a huge range of everyday foods. Fruit, honey and other sugary products are among the few supermarket foods that do not provide at least some protein. The recommended dietary intake is 55 g of protein per day for adult Australians. Dietary surveys show that most of us eat closer to 100 g of protein, so few (if any) healthy Australians need supplementary protein.

Many of the foods that are good sources of protein (meat, fish, eggs, milk/milk products, cereal foods, vegetables such as beans and other legumes) are also major sources of other essential nutrients. This means that it is better to eat a wide variety of nutritious foods rather than try to derive most of your protein needs from one source (eg from whey).

Back to Frequently Asked Questions Index

[Date issued: July 1999]

Disclaimer: This material is provided on the basis that it constitutes advice of a general nature only. It is not intended to replace the advice of a physician or a dietitian.