Grey seal pups only suckle for 17 days. During this short period, they have time to build up their immune system and get their digestion going – which is achieved thanks to the milk.
The sugars found in milk help protect against viruses and bacteria, ensure that the gastrointestinal tract develops properly, and cultivate the flora of microorganisms found in the body.
“Incredible diversity”
When milk from five wild grey seals off the coast of Scotland was studied, approximately 33 percent more sugars were found than in human breast milk.
We saw an incredible diversity of sugar molecules in this milk, and that drastic changes occurred from day to day during the period when the cubs were suckling, says Daniel Bojar, associate professor of bioinformatics at the University of Gothenburg.
The milk changes its profile with different structures and molecules that we have never seen before.
In grey seals, 332 different sugar molecules were identified, compared to around 250 in breast milk. Some of the molecules were also considerably larger.
Can be used as a replacement
The great advantage of the sugar molecules is that they function in roughly the same way in different mammals. In the future, the newly discovered sugar molecules could therefore be produced industrially and then added to breast milk substitutes to strengthen the immune system in babies.
Some human sugar molecules, but very few, are already added to breast milk substitutes for nutritional, developmental and immune defense purposes, says Daniel Bojar.
But it takes a lot, not least financially, to be able to produce the sugar molecules on a sufficiently large scale.
Therefore, we should want to produce something that is as potent as possible. And what we see in seal milk are molecules that are more potent than those we humans produce.
