Are dietary seeds digested?

Thanks to King's College London's Sarah Berry for the answer!

James - I'm delighted to be joined by nutritionist Sarah Berry who's going to help us answer this question. Fraser is right, isn't he? Seeds can pass through our digestive system without actually being digested.

Sarah - It's a double-edged sword. In one respect, by them passing through our system, it means that they actually have a lower energy content and the back of pack labelling would show. So for people that are wanting to control their weight, they might be a great choice, but it does mean that you are not extracting all of the wonderful nutrients that are within many seeds.

James - Fraser mentions the scientists who crunch, grind, dissolve, and whatever else they do. And I think he's referring to you when he says that. What do your tests reveal about the nutritional benefits of seeds, particularly, as he mentions, in support of our healthy microbiome?

Sarah - Yeah, so I think first it would be good to quantify a little bit about how much actually reaches our large intestine. And this is something that I've been particularly interested in during my research at King's. And we've been using the almond nut to illustrate this. And the almond nut actually is a seed. Many nuts are actually seeds and we've done some work where we feed people whole nuts or we feed people really finely ground nuts. And what we see is if you feed people whole nuts, a large proportion, as you've said actually, is excreted, comes out in the poo. But the advantage of this as well as its meaning that for those that are wanting to lose weight, it's a lower calorie food, is that you are feeding, instead of yourself, you are feeding all of these trillions of gut microbes. So species that are associated with lower inflammation, lower body fat, lower blood cholesterol, lower blood pressure, and so forth. And we think this is because all of this fibre and other parts of the seeds reach the large intestine, allowing healthy gut species to grow and then have their favourable impacts on our health.

James - So you heard it here, Fraser, a big thumbs up to lots of different seeds in your diet. Thanks for sending that question in. And thanks to you, Sarah, for helping us find the answer.