Chia Seeds —Worthy Superfood?

Or just plain silly?

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Whatever the nutritional qualities of chia, you have to respect a food that manages to achieve superstar status whilst tasting of, well, nothing in particular. Milled gravel, perhaps. A food that you’d be unlikely to crave even in the throes of an intermittent fast.

But then, taste is irrelevant when you have lofty ideals about diet. Healthniks enthuse that chia seeds are “packed” with nutrients. So let’s unpack those big guns: omega-3 fatty acids, protein, calcium and zinc. Then there’s the fibre. They are “packed” with fibre too. They are a veritable powerhouse.

Should you wish to learn more, there are plenty of websites eulogizing the chia seed, all more or less telling you the same thing. Some helpfully provide the Latin name of chia, Salvia hispanica. It’s also helpful to know that the Aztecs liked to eat chia seeds. There’s an endorsement if ever there was one. These otherworldly Mesoamericans were surely in possession of profound esoteric wisdom relating to human dietary requirements.

By now you have been well and truly inducted into the world of barstool nutribabble.

Perhaps I’m being unfair: chia seeds do have an impressive level of the much sought-after, health-giving omega-3 fatty acids, which is quite rare in seed world. This puts them on a par with oily fish, right? Wrong. The reason you eat oily fish is to get those ready-made, ultra-healthy fatty acids EPA and DHA. Seeds don’t give you those.

Nuts and seeds and other plant foods are often suggested as a suitable vegetarian source of omega-3 fats. Although it is true that the body can make some limited DHA (and EPA, its precursor) from plant sources, its ability to do so is poor, and effectively meaningless. The liver converts less than 0.5% of the omega-3 fat in plant sources to DHA. That’s on a good day: in many studies, that conversion rate has been shown to be less than 0.1%, making it “negligible”.

Chia seeds can rightly claim to be a rare plant source of a complete protein, that is a protein containing all the essential amino acids the body needs. They also contain 17g protein per 100g serving, which is a decent amount of protein, if you can eat that much chia. Have you seen that much chia?

Good luck getting that lot down your throat. Realistically, you will only consume a small amount of chia — a teaspoon or two with your porridge, or power smoothie, or whatever it takes to camouflage the utter blandness.

And even if you did manage such a prodigious feat, you will absorb only a small proportion of that protein.

The protein content of chia seeds has low digestibility. Whether raw, toasted, blended or soaked, laboratory analyses reveal that protein digestion of chia seeds is rated as poor, or very poor. Soaking, which would be expected to yield the highest protein return, has been shown to result in just 24.3% digestibility.

What about all those minerals? Calcium! Zinc! One or two others! There’re all there, all right, but they are not destined for your body, thanks to two dietary knaves: phytate and lectin. Phytates are chemicals that bind to minerals and whisk them through your gut and out, so they barely touch the sides.

Phytates are effectively anti-nutrients; they inhibit the absorption of minerals in the body. Because phytate is heat stable, it is not easily degraded by cooking.

Lectins are proteins that irritate the gut lining and are found in abundance in seeds (and nuts). This irritation further inhibits any chances of mineral absorption. Most lectins are resistant to heat and the digestive process.

Bioavailability can be improved by soaking seeds in water for a few hours, preferably overnight. Or you could just suck them out of the gaps between your teeth once they have been lodged there for a few hours. I speak from experience.

We should at this point unpack the health claims made for this unprepossessing food. These claims are indeed impressive. To wit: lower blood pressure, weight loss, reduced cravings, stabilised blood sugar, improved cardiovascular function. Gritty blandness is surely a small price to pay for all that.

And so to research. A study published in Nutrition Research assessed the effectiveness of chia seeds in promoting weight loss and reducing risk of disease in overweight adults. Subjects consumed either 25g of seeds mixed in water twice daily for 12 weeks, or a placebo. The conclusion? Ingestion of 50g of chia seeds by overweight men and women ‘had no influence on body mass or composition, or various disease risk factors’.

Perhaps they should have milled those seeds first, to make them more bioavailable. So researchers gave that a go, this time with over 60 post-menopausal, overweight women. The effect? ‘Pre-to-post measures of body composition, inflammation, blood pressure, augmentation index, and lipoproteins did not differ between chia seed (whole or milled) and placebo groups’.

Dang! One more try, this time on the claim that these little seeds are great for the cardiovascular system. A review of seven studies into the subject concluded that ‘The evidence regarding the relationship between chia seed consumption and cardiovascular risk factors is insufficient.’

Food fashions come and go, as manufacturers rush to identify the next Big Thing. So sorry, all you chia devotees. There really is no evidence to support the hype.

This article was first published on Medium in August 2019.