What you eat doesn’t cause acne — but it can affect how wrinkly you look. These apparently contradictory facts are because the state of your skin is closely linked to your gut health, although not necessarily in the way you think.
Your skin and gut are very similar: they both help defend the body against invaders. They’re also both in a constant state of renewal, shedding their lining (gut) or outer layer (skin) roughly every week and month respectively, making them hungry for good nutrition.
And last but not least, each houses a community of microbes vital to health.
Yes, there are microbial communities living in — and on — us.
These gut and skin microbes are key players when it comes to skin blemishes.
What you eat doesn’t cause acne — but it can affect how wrinkly you look. These apparently contradictory facts are because the state of your skin is closely linked to your gut health, although not necessarily in the way you think
Those skin microbes also help protect our skin from environmental damage.
A recent study by the University of California involving nearly 9,000 people found that the microbes on our skin (there are billions of them) were a better predictor of age than the gut or oral microbiotas — making it the ideal testing ground for anti-ageing treatments.
That’s not all: we know that imbalances in the skin microbe colony (microbiota) play a role in common conditions such as acne, eczema and certain skin cancers.
This is why oral and topical antibiotics are the go-to treatment for acne, which is linked to an overgrowth of bacteria, including Cutibacterium acnes.
The trouble is, antibiotics can knock out the useful bacteria, too, which is why scientists are looking at probiotics for treating skin problems.
What we eat and how we treat our gut microbiota really plays out on our skin, as anyone who’s experienced skin breakouts after one too many glasses of wine knows
There’s some particularly exciting work on the potential benefits of topical probiotics (applied directly to the skin) to protect against skin cancer, for example.
Early research also suggests we may be able to transplant a healthy person’s skin bacteria as a way to treat acne and eczema.
Did you know?
Research shows that large, coarse, jumbo oats have a 33 per cent lower effect on blood-sugar levels than instant oats — suggesting less processed versions are better for blood-sugar management.
However, you don’t have to wait for the scientists and new products. You can target your skin health via that other microbe community — in our gut.
What we eat and how we treat our gut microbiota really plays out on our skin, as anyone who’s experienced skin breakouts after one too many glasses of wine knows.
That’s because there’s a two-way conversation going on between your gut microbes and your skin — the gut‑skin axis.
Most of this gut-skin communication happens via your immune system; an imbalance in your gut bacteria seems to set off a response from the immune system, triggering inflammation.
And guess what: lots of skin problems — acne, dermatitis, eczema, psoriasis, rosacea and even premature ageing — are inflammatory in origin.
If you have a more abundant and diverse gut microbiota, however, the microbes keep each other in line and can have anti-inflammatory effects (partly thanks to the compounds — short-chain fatty acids — the bacteria release when they digest plant fibre).
There are other food factors at play. Take acne. There’s a growing body of evidence suggesting that diets lacking in healthy, plant-based foods, but high in things such as fruit juice, sugar and refined starches (e.g. white bread or pasta) can worsen symptoms.
That’s because they have a high glycaemic index (high GI), meaning they raise your blood sugar level faster than other foods.
Spikes in blood sugar have been linked with inflammation and can also trigger the release of insulin-like growth factor 1 (IGF-1), a hormone that can cause your oil glands to produce more sebum (which mixes with dead skin cells to form an acne plug).
Large amounts of dairy, particularly skimmed milk, can also be a trigger (by ‘large’ I mean more than 500ml of milk a day). The proteins in dairy have been shown to increase IGF-1.
However, fermented dairy, such as yoghurt and cheese, don’t seem to trigger symptoms. The fermentation process changes the profile of the proteins, making them anti-inflammatory.
Let me reassure you, though, that there is no evidence that food alone will cause acne.
The condition has a strong hormonal and genetic component which diet alone can’t override. I know this, having suffered with breakouts throughout my life. Sebum production, skin microbes and pore size can’t be improved by diet and lifestyle alone. Nor is there evidence that any of the aforementioned foods, if part of an otherwise well-balanced diet, will worsen acne.
As I’ve seen time and again in clinic, the stress of trying to follow a ‘perfect’ diet can often cause more problems, thanks to the stress hormone cortisol.
(And if you’re prescribed antibiotics for your acne, don’t be alarmed: it’s an effective approach, but book in regular medication reviews and pay extra attention to replenishing those gut microbes with fibre from plant foods.)
Focus on plant-based diversity, swapping high-GI carbs for low-GI complex carbs found in wholegrains, legumes (beans and pulses), vegetables and fruits.
If you needed confirmation of the benefits, a recent study in the International Journal of Women’s Dermatology showed that a Mediterranean diet could help reduce acne symptoms.
The gut-skin axis is also involved in skin ageing.
As we age, our body’s production of collagen, a protein key to the structure of skin and connective tissues, slows down.
Environmental factors such as the sun’s UV rays, pollution, stress and poor diet or sleep all contribute, too.
But if you thought collagen supplements were the answer, a recent review in the Journal of Cosmetic Dermatology concluded that most of their claims, such as ‘glowing skin’ and ‘youthful appearance in weeks’ are unsubstantiated. You see, collagen is a protein that, during the digestive process, mostly gets broken down into amino acids, the building blocks for skin.
Once absorbed into your bloodstream, your body can’t tell whether those amino acids came from collagen supplements or whether they came from other sources of protein, such as fish.
However, polyphenols — plant chemicals — have been shown to improve ageing skin. A 2016 study in the Journal of Nutrition showed that polyphenols from cocoa reduced facial wrinkles and improved elasticity after 24 weeks, compared with a placebo.
A plant-based diet has also been shown to improve the length of telomeres — the end bits on our strands of DNA, and a marker of cells becoming old — effectively reversing ageing.
For youthful skin there are four key steps:
1. Stay hydrated. The water you drink means plump, hydrated skin cells.
2. Eat a diet that’s rich in the foods I’ve listed in the box below (which contain skin-supporting nutrients such as vitamins A, C, and E, zinc and selenium).
3. Feed your gut microbes anti-ageing polyphenols such as prebiotics, types of indigestible fibre that act like fertiliser for them (for example, chickpeas, garlic, onion, beetroot and dates). This, in turn, results in the release of beneficial nutrients such as anti-inflammatory short-chain fatty acids.
4. Finally, protect and nourish your skin by keeping it clean, using a moisturiser to maintain the skin’s barrier and applying sunscreen.
Try this: Irresistible cookies
I always have a batch of these to hand for those cookie craving moments. High in fibre and flavour, it’s worth baking a batch and storing in the fridge or freezer so they’re always ready.
Makes 12 cookies
- 8 medjool dates, pitted
- 1 medium ripe banana
- 2 tbsp nut butter of choice
- ¾ cup ground almonds
- ¾ cup oats
- 1 tbsp mixed seeds
Preheat oven to 200/180c fan/gas mark 6. Put dates, banana and nut butter in food processor and blend for 60 seconds, or until a smooth paste forms.
Add the ground almonds and oats and pulse until a loose and wet dough is formed.
Stir in mixed seeds by hand. If the mix feels too wet, add a little more ground almonds.
Spoon the mix on to the baking tray, making approximately 12 cookies, and gently smooth into flat rounds around 5cm wide and 1cm deep.
Bake in the oven for 15 minutes, or until golden brown.
Foods scientifically proven to help your skin
Green tea: Contains flavanols, a type of polyphenol (a beneficial plant chemical)
70%-plus dark chocolate: For cocoa flavanols
Citrus fruits: For vitamin C
Soy: For isoflavones (a type of polyphenol) and zinc
Tomatoes: For lycopene, a plant chemical that helps protect against UV ray damage
Walnuts: For vitamin E, zinc, selenium and omega 3 (a type of anti-inflammatory fat)
Chickpeas: For zinc and prebiotics (fertiliser for gut bacteria)
Sweet potato: For vitamin A
Avocado: For vitamin E
Oily fish: For omega 3