Ask the experts: Seeds

Q. "To get the goodness out of seeds like sesame seeds, do they have to be cracked, broken or excessively chewed? Or are they just a bit of 'roughage' if they are eaten whole?"

Gillian

A. Christchurch-based dietitian, Kristen Corselius White responds:

"Flaxseeds' omega-3 fatty acids, lignins and fibre have been associated with beneficial cardiovascular and anti-inflammatory properties. Research shows that grinding or milling flaxseeds (also known as linseeds) increases the bioavailability of these compounds which are otherwise limited by the seeds' hard outer coating. Sesame seeds have a softer seed coating than flaxseeds and could potentially be ground more easily in the mouth. However there is some evidence that they generally pass through our systems intact, adding only to the fibre content of the diet. To get the most nourishment from them, grinding sesame seeds is often advised. Their healthy constituents include lignins and dietary fibre as well as small amounts of vitamin E and calcium. Sesame seeds are often quoted as being high in calcium, but due to the oxalates and phytates in the seed, this calcium is not highly available to us.

So it seems that small seeds are probably more decorative than nutritive because they are often consumed intact, in small quantities, and/or not very often. However, these small seeds can be nutritious when ground."