In an interview with British Vogue, skin expert Jasmina Vico, says she advised Robbie to drink milk thistle tea, goat milk and kefir and eat fermented foods like sauerkraut.
"Everything in the movies is about lighting. That’s when I thought, okay, we’re going to work on the liver; calm the nervous system; and make skin glow, but crucially, we’re going to work on that glow from within," Vico told Vogue.
While it sounds simple enough, there are some things to consider before you go rushing to your nearest grocery store.
Miranda Galati, a registered dietitian based in Ontario, says certain foods can definitely impact how we look but there's more to it than simply drinking tea or eating a certain fermented food.
"I think generally speaking with most of the things suggested they can maybe help but I would say they're maybe unlikely to transform anything if you don't have a balanced diet in the first place."
If you're wondering how food can boost your skincare routine, here's what you should know.
What is the benefit of milk thistle tea?
A cup of milk thistle tea and flowers of a thistle medicinal plant.
Osadcha79 | Dreamstime
Milk thistle tea is popular in certain parts of Europe, like Croatia, which is where Vico is from.
In her interview with Vogue, the skin specialist said this particular tea is good for cleaning your liver, which can then have an impact on your skin's appearance.
"When that happens, our liver automatically produces more glutathione, which then makes the skin more radiant. One of the most important ingredients within it is silymarin, which is now featured a lot in skincare formulas," she explained to Vogue.
Vico added that the tea needs to be brewed for 20 minutes so that it's bitter, which the liver likes because that helps to flush it out.
According to the Cleveland Clinic, there isn't much research on milk thistle tea, which is made from a spiky purple flowering plant from the same family as daisies and ragweed.
The clinic does note, however, that the research that is out there shows the plant's antioxidant and anti-inflammatory effects have been promising for treating acne. In one study, people who took 210 milligrams of milk thistle every day for eight weeks had over 50% fewer "acne lesions."
When we asked Galati about the impact of milk thistle tea on a person's skin, the dietitian reiterated the minimal research, but didn't disregard it completely.
"So taking that we can say this might be helpful for acne, but we don't necessarily know how this translates when we take it as a tea for a shorter period of time when we're unclear on dose," she told Narcity.
"It's one of those things that's unlikely to be harmful, but also maybe not the most impactful thing for your skin."
Milk thistle can interact with certain medications and can also cause certain side effects like nausea and an upset stomach, according to Mount Sinai. So you may want to discuss it with your doctor before consuming it in a tea or as a supplement.
What does fermented food do for your skin?
A variety of fermented food.
NatashaBreen | Dreamstime
It wasn't just milk thistle tea that Vico told Robbie and other stars of the Barbie film to consume, but fermented items as well to help balance their gut bacteria.
"I gave Margot kefir and advised her to eat lots of fermented foods, like sauerkraut, for example," Vico told Vogue. "She loved all of that."
Fermented foods are foods and drinks that have gone through a controlled microbial growth and fermentation, as per the Heart Foundation. This process allows microorganisms, including yeast and bacteria, to break down things like sugar in the food into something else like organic acid and alcohol.
Aside from sauerkraut and kefir, fermented foods also include kimchi, tempeh, miso, and kombucha.
Galati says eating these types of food has the potential to "impact our gut microbiome" and a happy gut can affect our skin.
However, she also notes that it's not as simple as saying eating these types of foods will immediately clear up our skin.
"Fermented foods, probiotic supplements might be helpful in reducing inflammation, maybe indirectly improving the way our skin looks, but again, probably not the most impactful thing we could be doing," Galati told Narcity.
Which foods can impact how our skin looks?
High protein food.
Artem Evdokimov | Dreamstime
While the information may not so clear on milk thistle tea and fermented foods in particular, Galati says there are changes we can make to our diet as a whole to help with how our skin looks.
That's why she encourages looking at your lifestyle as whole.
With that said, Galati encourages a blood sugar friendly diet.
"Reducing things like added sugars or refined carbohydrates may be able to help support clear skin for those who do suffer with acne," she says.
The Canadian dietitian adds that getting enough protein can also be beneficial for your skin.
"When you have adequate protein, what you're actually doing is ensuring that when your body breaks down proteins, you have all the amino acids needed for your body to use it for a variety of different things, including collagen production."
"I think focusing on getting enough protein is helpful for so many reasons, but it can certainly support our skin appearance and health as well."
Different vitamins can also be supportive for our skin, including vitamins A, C, D and E, Zinc and Omega 3.
"A lot of these things are antioxidants so when we're deficient, we might see certain skin conditions," Galati told
Narcity.
The Cleveland Clinic has a whole list of lifestyle changes a person can make to help their skin. It advises people eat more fruits, vegetables, whole grains, nuts, fatty fish and legumes to help "nourish your skin from the inside out."
What other lifestyle changes can impact how our skin looks?
When it comes to wanting to look and feel better, Galati says it's important to look at your overall lifestyle rather than focus just on food.
"I think sometimes we have a tendency to kind of hyper focus on food because it's one of those things that we can kind of more easily control but things like sleep and your hygiene habits and even your alcohol consumption can have a big impact too," she said.
Going back to milk thistle tea and fermented food, Galati says these types of items do have potential health benefits as well if you do want to add them to your routine.
"[They are] not a bad thing to throw into your routine, but if we're taking them with the sole intention of them transforming the way our skin looks, you might be a little disappointed."
This interview has been condensed and edited for clarity.
The Barbie Dream Suite at the Fairmont Queen Elizabeth in Montreal, Quebec.
Barbie Afternoon Tea at the Fairmont. 
