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Kate Middleton is set to turn 40-years-old next month and women all over the world want to know what her secret to glowing skin is. There have been reports the Duchess of Cambridge likes to start the day with a green smoothie, and one former royal nutirionist has revealed why the ingredients provide a healthy glow. 

It has been said, Kate likes to blend a combination of kale, spirulina (a type of algae), matcha (green tea leaves), spinach, romaine lettuce, coriander leaves and blueberries together, which she drinks first thing in the morning. 

Former royal nutirionist Jennifer Hanway spoke about the benefits the ingredients in the smoothie brings and how they can improve ones skin. 

Jennifer said: “You can spend hundreds and hundreds of pounds on skin treatments, products and facials, but if you're not feeding yourself right, you're never going to be able to harbour the benefits, because we are literally what we eat.

“Think of your diet as the building blocks of your body. It's definitely possible to achieve better skin from the inside out on a cellular level with diet."

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As for the smoothie, the expert explained: “Kate has a ton of antioxidants in there, a ton of vitamins and minerals, and a ton of fibre – which make for a powerhouse of overall health. 

“Everything from the kale to the leafy greens is a really great source of nutrients.”

Jennifer would make some changes, however, to ensure the smoothies is hitting every dieteary requirement. 

She explained: “I would blend in some great quality protein and some healthy fats as well, which would round that smoothie into a really great balanced breakfast.” 

So how does the smoothie taste? Jennifer remarked: “It might taste like you're licking the inside of a fish tank.” 

But there are benefits to the drink, she explained: “This smoothie is absolutely packed full of antioxidants that fight free-radical damage, which are the environmental toxins that steal our natural glow.” 

Jennifer had another tips for anyone looking to follow a royal-approved diet, and that’s to simply to focus on the quality of the food, ensuring protein is consumed in every meal and to make sure you’re "eating the rainbow”. 

The Royal Family undoutably have the very best ingredients sourced for their meals. 

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And Jennifer stressed that “quality over quantity” is important if you want to achieve that inside-outside glow. 

On top of this, Jennifer spoke about developing a sleep routine. 

“If you're not sleeping, you're not going to eat well the next day, you're not going to be performing at your best, and you're going to be dehydrated,” she said. 

The expert also encouraged clients to think of fitness, nutrition, sleep, stress management and wellness as one entity. 

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"We cannot separate physical health and mental health," Jennifer told Hello!. 

Kate is not the only royal to favour a healthy smoothie, Meghan Markle has a “go-to smoothie”. 

The Duchess of Sussex combines protein powder, frozen blueberries, cinammon, chia seeds, almond milk and coconut water together, and blends until smooth. 

Speaking about the ingredients back in 2015, Meghan said: “I also do the same thing with frozen mango, a squeeze of lime, swap the cinnamon for turmeric (which has unbelievable healing properties) and just use coconut water.” 

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