Seeds are packed full of protein, healthy fats, vitamins and minerals. HFG senior nutritionist Rose Carr investigates the wide range of nutritional benefits that seeds offer – and how to include them in your diet.
Seeds and health
Full of nutrients, seeds are a great addition to any diet. They are rich in fibre, phytonutrients and healthy mono- and polyunsaturated fats (such as omega-3 and omega-6 fats) which are beneficial for heart health and reducing inflammation. Flaxseeds and chia seeds in particular are rich sources of ALA, the plant-based short-chain omega-3.
While fatty fish is the best source of long-chain omega-3s, our body can convert some of the ALA found in seeds into long-chain omega-3s – but this conversion rate is considered to be quite low (about 5%). However, with all of the other healthy nutrients in seeds, research has shown that eating them regularly is associated with a lower risk of developing some diseases, such as cardiovascular disease and type 2 diabetes.
With up to 50 per cent fat, seeds are also very high in energy – so if you are watching your weight, it’s best to include them in small amounts in your diet (about 1–2 tablespoons per day).
Buying, handling and storing
The high oil content of seeds means they need to be handled and stored with care. The oils can absorb odours from other foods and are prone to oxidation – meaning they can become rancid and smell ‘off’ or stale if they aren’t looked after properly. Bruising, light, heat and moisture will speed up this process.
When buying seeds, look for signs of appropriate handling and storage. For example, are the seeds exposed to direct light where they are displayed in store? Are they in see-through packaging? If possible, taste a small amount of seeds to ‘try before you buy’. You can taste the difference between ‘fresh’ dried seeds and ones that have started to go off from poor handling.
Ideally, seeds should be stored in an opaque, airtight container at a cool temperature. Seeds will keep for longer in the fridge, and can also be frozen for up to six months.
Ways to use seeds
Snack on sunflower or pumpkin seeds, either raw or dry-fried.
Garnish salads with seeds to add texture and flavour.
Add seeds to muesli or other cereals.
Use them in breads and baking, either whole or ground.
Ground flaxseeds (also known as linseeds) or chia seeds can be added to smoothies to add fibre, texture and flavour.
Dry-frying seeds enhances their flavour. Place a small amount of seeds into a dry frying pan (do not spray with oil) and place over medium heat. Take them off the heat once they start to colour as they will continue cooking for a little while. Keep in mind, the heat will affect the oils in the seed, so it is advisable to dry-fry only the amount you are going to use straight away. If kept, dry-fried seeds will quickly go rancid.
Different types of seeds
Around 280kJ per tablespoon
Also known as pepitas, pumpkin seeds or kernels are found in the centre of the pumpkin. The shell or husk is removed from the kernel, which is then dried. Per tablespoon, pumpkin seeds contain 1.2g fibre and are a source of zinc.
Around 290kJ per tablespoon
Chia seeds look like tiny black or white sesame seeds. They contain about one-third fat (which is lower than other seeds) and one tablespoon provides around 5.4g fibre (which is quite remarkably high). Chia is also rich in ALA omega-3 fats, with 1.4g per tablespoon.
Around 245kJ per tablespoon
Poppy seeds are from a west Asian plant, Papaver somniferum, the same plant from which opium is extracted. Poppy seeds are very tiny – in fact, there are about 3300 seeds in just one gram. Poppy seeds are particularly high in calcium, with 160mg per tablespoon. However, this is not comparable to the calcium found in dairy products — the calcium from poppy seeds is less bioavailable, meaning it’s not well absorbed by the body.
Flaxseeds (also known as linseeds)
Around 230kJ per tablespoon (whole seeds) and 160kJ per tablespoon (ground seeds)
Flaxseeds, from the Linum plant, have been used for over 7000 years to produce both food and linen fibres. Of all seeds, this one is the richest source of ALA, the plant-derived omega-3 fatty acid, with around 1.6g per tablespoon of ground flaxseeds. They are also one of the richest sources of polyphenols (a type of antioxidant). Flaxseeds also provide a great fibre boost: 2.8g fibre per tablespoon whole flaxseeds, or 1.9g per tablespoon ground flaxseeds.
Around 240kJ per tablespoon
Sunflower seeds are from the flower of Helianthus annuus, a north American native plant from the daisy family. With a mild nutty flavour, these seeds are particularly rich in vitamin E – containing even more than almonds. Just one tablespoon of sunflower seeds provides 3mg vitamin E – that’s 20 per cent of the suggested daily dietary target for women and 16 per cent for men.
Around 280kJ per tablespoon
Small and pear-shaped, sesame seeds have a rich, nutty, earthy flavour and are sold in white, brown or black. One tablespoon of sesame seeds contains around 1mg non-haem iron, although it is less bioavailable than the haem iron found in meat.
Did you know?
The pods of early strains of the sesame plant had a tendency to suddenly split open when ripened, scattering the seeds. It’s thought this may account for the term ‘open sesame’!
If you continue grinding seeds past the ‘meal’ phase, you end up with a paste similar to a nut butter. Tahini, an essential ingredient in hommous, is made in this way from ground sesame seeds.