Greens powders – are they really vital? Or were our Mamma’s right and should we eat (not drink) our greens?
Not too long ago, we relied solely on real food to obtain nutrients that help our bodies function efficiently. Today, if you find yourself wandering the isles of the supermarket, pharmacy or local health food store, you will be hit with an array of greens powder products. Many of these products claim that you can get your daily fruit and vegetable goodness from a mere scoops of this powder. Sound too good to be true? Is this green powder actually good for us?
What are they?
Let’s get back to basics, what are greens powder supplements? They’re powders that contain a number of ingredients derived from plant foods, such as spinach, kale, spirulina, chlorella, wheatgrass, holy basil etc. These plants are processed and ground into powdered form where they can be packaged to have a long shelf life and sold to consumers. The specific ingredients used and price will vary depending on the brand.
Sounds great right? Drink your way to health and skip the fruit and veg aisle? Mmm, not quite. Now you know I’m a science nerd, so let me explain why.
Where’s the science at?
As it stands there are only a few studies that look at the impact of greens powders on health and as I previously mentioned, products will vary depending on the brand. What we do know is that they often contain concentrated doses of antioxidants. Now the science tells us that the antioxidants present in fruits and vegetables have a number of health benefits, however when it comes to greens powder the answer isn’t so simple…
So let’s have a look at the evidence in more depth. One study looked at 10 healthy subjects (FYI this is a tiny study in the science world) who supplemented with 3-6 teaspoons of greens powder per day, over a 4 week period. These participants saw a reduction in oxidation, which is linked to tissue damage, aging and chronic disease risk (1). This study claims that greens powders may play a role in reducing the risk of chronic diseases (such as cancer) that are related to oxidative damage. Whilst that may be a nice theory, unfortunately a small sample size of 10 people makes it very difficult for the researchers to make such a claim. This study also didn’t account for other lifestyle factors, including exercise and diet. A further limitation is that the subjects were not provided with a controlled amount of greens powder, making it very difficult to draw conclusions regarding the dose one requires to experience the proposed health benefits.
Another study looked at 40 people over a 90 day period who had high blood pressure and supplemented them with approximately 3 teaspoons of greens powder (2). Whilst these patients saw an 8% reduction in blood pressure, the researchers also failed to account for diet, weight, exercise and stress levels, all of which have a huge impact on blood pressure. This was also not a blinded study, therefore participants may have been influenced by the placebo effect.
The last study I found was over a 3 month period, which analysed 63 healthy females who took again 3 teaspoons of greens powder per day (in this study the greens powder also contained green tea extract of which contains additional antioxidants) (3). They found that the women in the greens powder group reported increased energy levels, compared to the placebo group who reported no change. Again, this is another poor quality study as the addition of green tea extract makes it very difficult to attribute benefits to the greens powder alone. Of note the dropout rate in this study was 40%.
These were the best studies I could find. Sigh. So although there might be some benefits here, as it stands there is insufficient evidence in the literature to support the use of greens powder.
What about all the good stuff it says it will do for me?
Other claims you may find on the front of the greens powder packaging include the ability to ‘detoxify and cleanse your body’, ‘boost your immune system’ or ‘help your digestion’. Any product that claims to ‘detoxify’ or ‘cleanse’ your body is likely to be full of BS. We are so fortunate as humans to have a liver and kidneys which cleanse and detoxify our bodies for us and it happens without us doing anything! There is absolutely no reason to spend money on powders or tonics as our trustworthy body has us covered!
So the science might not be strong, but what’s the harm?
If you decide to drink greens powder in lieu of eating your vegetables you will be missing out on important fibre which keeps our bowels regular, feeds our healthy gut bacteria and has been proven to prevent colorectal cancer. This fibre acts as fuel for the good bacteria which inhabit our gut. When our bacteria are healthy and happy, research has shown this can enhance our immune system, improve our mood and prevent a whole host of health conditions (4). There are so many health benefits associated with a diet rich in dietary fibre that I would hate for your to spend your money (and energy) on powders made in a lab rather than plant foods grown on trees! Research has also found that many commercially manufactured supplements contain heavy metals and illegal substances that can be detrimental to health and wellbeing (5). Compare that to a carrot where what you see is what you get…
Greens powders should not replace vegetables in any way! Veggies contain an array of health promoting fibres, vitamins and minerals, many of which we can not always obtain from a commercially manufactured products. Your mum was right – eat (don’t drink) your greens.
T A I L O R Y O U R P L A T E | B U I L D Y O U R B E S T Y O U
Accredited Practising Dietitian
- Rao V, Balachandran B, Shen H, Logan A, Rao L. In vitro and in vivo antioxidant properties of the plant-based supplement greens. Int J Mol Sci. 2011;12(8):4896-908
- Zhang J, Oxinos G, Maher JH.The effect of fruit and vegetable powder mix on hypertensive subjects: a pilot study. J Chiropr Med. 2009 Sep;8(3):101-6.
- Boon H, Clitheroe J, Forte T. Effects of greens+: a randomized, controlled trial.Can J Diet Pract Res. 2004 Summer;65(2):66-71.
- Makki K, Deehan EC, Walter J, Bäckhed F. The Impact of Dietary Fiber on Gut Microbiota in Host Health and Disease. Cell Host Microbe. 2018 Jun 13;23(6):705-715.
- Or F, Yongjoo K, Simms J, Austin SB. Taking Stock of Dietary Supplements’ Harmful Effects on Children, Adolescents, and Young Adults. Journal of Adolescent Health. 2019 June.
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