Are green smoothie benefits over-hyped? Or do they really help with health, weight loss and clearer skin?
In this article – our in-house nutritionist summarises the scientific evidence and nutritional facts about kale and spinach-based smoothies…
Green smoothies are often associated with health benefits like increased energy levels, clearer skin, and weight loss. They’ve got an army of high-profile fans, from famous celebrities to Instagram influencers, who all tout bold health claims. But are these wonder-smoothies really that good for you?
In a world full of miracle health promises, clever marketing campaigns, and magical supplements, it’s easy to become cynical. So, let’s separate nutrition fact from fiction on green smoothie health benefits…
- What are green smoothies?
- Nutritional benefits
- Health benefits
- Kale & spinach benefits
- Weight loss
- Recipe ideas
What Are Green Smoothies?
Green smoothies are blended drinks that have leafy greens like spinach or kale in them. They’ve skyrocketed in popularity in recent years, as people strive for quick and easy ways to be healthier.
Some people refer to any smoothie made with vegetables (like celery, cucumber, or avocado) as a green smoothie. But strictly speaking these are vegetable smoothies rather than green ones.
You might also like… 15 Healthy Greens to Boost Your Smoothie’s Nutrition.
Green Smoothie Nutritional Benefits
Green smoothies are rich in vitamins A, C, and K, along with folate. These nutrients can provide a number of different health benefits, like strong bones, wound healing, and even DNA production. Some also have antioxidant properties or can aid the absorption of other vitamins and minerals such as calcium, providing even more nutritional benefits.
Green Smoothie Health Benefits
The potential health benefits associated with green smoothies include…
- Supporting the immune system
- Keeping bones strong
- Helping wound healing
- Aiding eye, skin, and hair health
- Preventing damage from free radicals
- Supporting healthy DNA
- Contributing to serotonin release
These health benefits derive from the vitamins and minerals in spinach, kale, and other leafy greens. Depending on the other ingredients you blend into your green smoothie, you may find there are additional (or lesser!) health and nutrition benefits. For example, adding fibre-rich fruit like mango could aid digestion and have cardiovascular health advantages.
It’s also worth noting that spinach and kale contain slightly different vitamins and minerals. So, there are minor differences in the nutritional and health benefits associated with each type of smoothie…
Kale & Spinach Smoothie Benefits
Kale smoothies are rich in vitamins A, C, and K, which means they aid bone strength, wound healing, and immunity. Spinach smoothies are also good sources of these vitamins with the added health benefit of containing folate.
Just five kale leaves provide over 2x the recommended daily allowance (RDA) of vitamin A. One cup of spinach contains 98% of your daily vitamin A requirements.
This vitamin has antioxidant properties and is also good for our eyes, skin, and hair. Vitamin A is important for sebum and natural oil production, which keeps hair moisturised and looking shiny. It also helps collagen production, which helps keep our skins looking fresh and youthful.
This may be why green smoothie fans report clear and glowing skin.
A cup of kale (50g) contains 100% of your daily vitamin C needs while spinach provides 23%. It also has antioxidant properties, but is more renowned for supporting the immune system.
Kale is packed with vitamin K – 50g (one cup) provides over 5x our daily needs. The same amount of spinach contains 3x our needs. So either way, addding a handful of these leafy greens to a smoothie will smash your nutritional requirements! This nutrient keeps bones strong, helps wounds to heal quickly, and aids calcium absorption.
Spinach is also a good source of folate (aka folic acid) providing 49% of your RDA. This nutrient supports growth at the most basic level – DNA.
Whilst it’s well known for being an essential vitamin for pregnant women, it also releases serotonin, acting like a mild but natural antidepressant. However, kale isn’t a big source of this nutrient containing around 8 times less than spinach.
Now let’s look at green smoothie benefits relating to energy levels, weight loss, and skin.
Do Green Smoothies Boost Energy?
Is there such a thing as an energy-boosting green smoothie? Many people rave about all the extra energy they get from drinking spinach and kale smoothies. But a single leaf of spinach contains just 2 calories which equates to barely any energy. So how does that work?
Well, calories aren’t the only thing that matter. Green smoothies are bursting with vitamins and minerals which support functions like converting carbs and fat into useable energy. Without sufficient micronutrient levels, we can feel tired or lethargic.
Despite eating three meals a day, many people are deficient in these essential vitamins and minerals. Modern western diets often lack key nutrients, so blending up some leafy greens into our smoothies can help to address this. But so could adding a portion of veggies to your dinner or swapping that lunchtime sandwich for a salad.
Green smoothies also tend to contain fruit which plays a big role in fuelling our bodies. The sugars from banana, mango, pineapple, and other sweet fruits are easily absorbed and can quickly boost our energy levels. So, while this may be beneficial for people who often feel tired, it’s something that simply eating more fruit would help with.
Love geeking out on nutritional info? Then check out our infographic about the health benefits of banana smoothies.
Benefits of Green Smoothies for Weight Loss
Are green smoothies good for weight loss? Well, they aren’t a miracle solution but they may help people to lose weight as part of a balanced diet and active lifestyle.
Here are some of the possible ways they can help…
- Increases fibre consumption – which helps people feel fuller so they’re less likely to overeat.
- Can lower calorie intake – when used as a meal replacement, people can reduce their calorie intake while still consuming vitamins and minerals.
- May reduced cravings – consuming a wide range of nutrients can make people feel more satisfied and reduce their tendency to overeat.
- Less bloating – consuming more plant-based foods instead of processed alternatives can reduce stomach bloating which makes people appear slimmer.
These are some of the possible ways that green smoothies may aid weight loss. One study did find a link between green smoothie consumption and decreased waist circumference. However, it involved a very small number of participants (29) so more research is needed to establish proof.
Green Smoothie Benefits for Skin
One of the most commonly reported green smoothie benefits is better skin. Clearer, brighter, more glowing skin.
However, there isn’t any scientific evidence to support this (sorry).
One study evaluated the effect of daily smoothie consumption on skin appearance. A small group of 34 participants consumed a daily smoothie for 4 weeks. Before and after photos of their skin were taken, then a separate group was asked to choose which photos looked healthier. However, the researchers didn’t find a significant difference in the results so green smoothies didn’t noticeably benefit the skin in this study.
More research is needed to know for sure though, as 1) it was only conducted with a small group of people and 2) four weeks might not be long enough to see results.
If you’re someone who doesn’t normally eat much fruit and veg, then your skin may benefit from a green smoothie. In this situation, anything that increases your vitamin and mineral intake could help.
But we wouldn’t recommend green smoothies for acne as the extra sugar may make things worse rather than better. A pure vegetable smoothie might be ok but since there’s no proven benefit, you’re better off sticking with evidence-based approaches.
Disadvantages of Green Smoothies
So, are there any disadvantages to green smoothies? Well in a perfect world, whole veggies are the ideal. Research has found that eating whole foods is more filling than blended equivalents, so you’re less likely to snack later in the day.
But we live in the real world – a time-poor and nutrient-starved one. If you don’t have the time or inclination to prep and eat fresh veggies, then green smoothies are a quick and easy way of upping your intake of leafy greens and other good stuff. We don’t need to be perfect, we just need to get started.
Are Green Smoothies Bad For Your Kidneys?
Green smoothies aren’t bad for your kidneys. Some people say they’re linked with kidney stones or similar stone formations in the body. While spinach does contain high levels of oxalates, this doesn’t mean drinking green smoothies will cause oxalate build up and subsequent kidney stones. There are a variety of factors like genetic predisposition and gut health that influence this.
However, it’s a great reminder that we should consume everything in moderation. So the healthiest way to consume green smoothies is to rotate between different ingredients (kale has much lower levels of oxalate than spinach) and use veggies that are in-season to add variety.
So, you now you know about the health and nutritional benefits of green smoothies, along with the disadvantages. They’re a quick and easy way to consume more leafy greens like spinach and kale, which are a great source of vitamins A, C, and K. But they won’t produce miracles and eating your greens in a salad is just as good health-wise.
Healthy Green Smoothie Ideas
If you’re interested in trying green smoothies for yourself, here are some recipes made with spinach and kale that you might like…
- Apple & Kiwi Green Smoothie
- Healthy Apple Smoothie
- 3-Ingredient Green Pineapple Smoothie
- Cucumber, Spinach & Pear Smoothie
- Green Tangerine Smoothie
- Avocado, Pear & Pineapple Smoothie
- Spinach, Mango & Blueberry Smoothie
- Apple, Celery & Berry Smoothie
Yes homemade green smoothies are a good source of vitamins.
The calories in a green smoothie vary depending on which ingredients you use – a basic smoothie with spinach, banana, and water contains 96 calories.
No green smoothies aren’t a particularly good source of iron (despite what Popeye told us about spinach). Ten spinach leaves contain 10% of our RDA of iron and kale contains half that amount. Iron contributes to keeping your blood cells healthy which in turn keep everything else in the body healthy.