Diet is an underlying factor in most health conditions, and acne is no different. Nutrition has a profound impact on skin health so that diet and acne are closely linked. What you eat can definitely influence whether or not you experience an outbreak of spots.
How diet affects your acne
Acne is an inflammatory skin disease associated with:
- Increased activity of sebaceous glands in the skin
- Increased stickiness of skin cells, which clump together and block oil ducts, rather than separating and shedding as normal
- Changes in skin acidity which encourage skin bacterium, especially Propionibacterium acnes, to colonise blocked oil ducts
- The bacterial digestion of trapped skin oils to release substances that trigger immune reactions and the development of papules, pustules and nodules.
Diet can influence all of these factors: the increased activity of skin oil glands, the ‘stickiness’ of skin cells, the acidity of your skin, and the degree of inflammation that results.
The link between food, hormones and acne
Oily skin, blackheads and pimples are linked with increased sensitivity of skin oil glands to a hormone called dihydrotestosterone (DHT) which is formed from testosterone hormone.
After puberty, DHT is produced naturally in the body in both males and females, and is also present in some foods, especially milk and meats.
The formation of DHT is stimulated by insulin hormone, and by a substance called insulin-like growth factor (IGF-1) which is over-produced in acne spots compared with normal skin.
As well as boosting the production of DHT, IGF-1 increases the production of skin oil and stimulates the growth and stickiness of skin cells and the formation of blackheads.
Levels of IGF-1 rise during puberty, typically around the age of 15 years in girls, and 18 years in boys, which is one of the reasons why teenagers are so prone to spots.
But acne is not just a teenage problem, and the production of both insulin and IGF-1 can increase to promote spots at any time during adult life when you eat a diet that raises levels of IGF-1.
Milk and acne
Milk contains ready-formed growth factors (including IGF-1) and androgen hormones (eg testosterone, DHT, 5α-androstanedione and 5α-pregnanedione) which are absorbed to increase circulating hormone levels. Milk also contains sugars, such as lactose, which stimulate insulin production.
In fact, this combination of growth factors, hormones and sugar is particularly powerful and can increase your production of insulin and IGF-1 three times greater than predicted from milk’s carbohydrate content alone.
When researchers looked for a link between acne and dairy intake in over 4200 teenage boys, they found those consuming more than two servings of milk per day were 16% more likely to have acne than those consuming dairy products less than once a week.
Similar results were found in a group of 6,094 adolescent girls who were 20% more liked to have acne if they consumed two or more servings of dairy products per day compared with those having less than one serving per week.
And in a large study involving 47,355 women, those who recorded high intakes of milk/dairy products during high school, were 22% more likely to have experienced severe acne as teenagers, than those with low intakes. The researchers believed this was due to the presence of hormones and other bioactive molecules found in milk.
There have also been reports of healthy adult males developing acne after taking whey protein supplements to boost muscle development.
Whey protein that is rich in the branched-chain amino acid, leucine, is most likely to trigger spots in those with acne-prone skin, as leucine is directly converted into sterols that stimulate the production of sebum.
If you are experiencing troublesome acne, it’s worth avoiding dairy products for at least 2 months to evaluate how this improves your acne. Some dermatologists suggest switching from cows’ milk and dairy products to goats’ milk and butter, instead, but even though goats’ aren’t usually treated with growth hormones which increase IGF-1, the milk does naturally contain IGF-1, insulin and lactose.
Dairy peptides and acne
It’s not all bad news for dairy products. If the hormones and growth factors are removed, a family of dairy peptides can be isolated which contain immune-boosting substances, such as lactoferrin, that have beneficial effects against acne. Lactoferrin suppresses the growth of Propionibacterium acnes to suppress skin inflammation. Users report significant benefits in reducing acne within 2 days to 2 weeks.
Sugar and acne
Foods that are high in sugar and other refined carbohydrates quickly raise your blood glucose levels, while eating wholegrain foods has less of an impact. The way in which different foods affect blood glucose levels is assessed from their glycemic index (GI) or glycemic load (GL). The glycemic index compares how different foods affect blood glucose levels compared with eating a known amount of glucose. A diet that has minimal impact on your blood glucose levels is known as a low glycemic diet and this is especially helpful for improving acne.
A study involving 43 males with mild to moderate facial acne found that skin symptoms improved significantly more in those following a low glycemic diet (low in sugar and refined carbs) compared with those eating a standard, carbohydrate-dense diet. After 12 weeks, those following the low glycemic diet had an average of 25.5 fewer spots than at the beginning of the study while those in the control group had an average of 12 fewer spots. The improvement in acne mirrored improvements in insulin sensitivity suggesting that nutrition played a role in the severity of acne.
Another study involving 40 people with mild to moderate acne showed that following a low glycemic diet for 12 weeks produced significant improvements in acne severity along with glucose tolerance, insulin and IGF-1 levels. Forty-four percent of those previously classified as have moderate acne were reassessed as having mild acne.
A similar trial involving 32 people with mild to moderate acne showed that following a low glycemic diet for 10 weeks produced a significant improvement in both inflammatory and non-inflammatory acne lesions compared with a control diet. Skin biopsies also showed a reduced size of sebaceous glands, decreased inflammation, and reduced levels of inflammatory chemicals.
A larger study, involving 248 adults, compared self-reported acne severity against dietary intakes and found those with moderate to severe acne reported greater intakes of added sugar and total sugar, as well as a greater number of milk servings per day. Overall, 58% of those taking part said they perceived their diet could aggravate or influence their acne.
If you are experiencing an outbreak of spots, it’s certainly worth cutting back on sugary, carbohydrate rich foods.
Chocolate and acne
Milk chocolate contains both milk and sugar, so it’s not surprising that eating chocolate might make acne worse. But it seems that the polyphenols in cocoa solids can also worsen skin outbreaks – even though they are beneficial to health in almost every other way.
When 25 acne-prone males ate 25g of 99% dark chocolate every day for 4 weeks, they developed a significant increase in numbers of black heads and inflammatory papules within a fortnight.
Researchers have now found that the antioxidant polyphenols in cocoa solids interact with immune cells to affect how they tackle skin bacteria. This can result in increased immune attack against P. acnes bacteria, to make inflammation worse, but suppresses reactions against Staphylococcus aureus to delay recovery and, possibly, encourage secondary infection.
If you are experiencing troublesome acne, it’s worth avoiding chocolate to see if this helps.
Meat and acne
Meat contains natural hormones and, in some cases, growth promoters that are administered to boost farm production. These hormones and growth promoters raise levels of insulin, IGF-1 and DHT levels and can make your acne worse.
Red meat is also a rich source of the branched-chain amino acid, leucine. Leucine is popular among body-builders as it helps to stimulate muscle growth. Unfortunately, it also stimulates the production of skin oil.
If you are experiencing troublesome acne, follow a plant-based diet which buts cuts out meat and increases your intake of natural anti-inflammatory substances present in fruit and vegetables.
Ensure good intakes of iron, vitamin B12 and zinc, however, which may mean taking a multivitamin supplement to avoid nutrient deficiencies.
Dietary antioxidants and acne
Many people find that eating more fruit and vegetables helps to clear their skin. This has not been assessed in clinical trials, so only anecdotal evidence is available. The only way to know if eating more fruit and vegetables will help your acne is to try. The flavonoids in apples are particularly protective.
The increased intake of vitamins and minerals will have a general beneficial effect on immune function, while the fibre will slow the absorption of dietary sugars which will improve glucose tolerance.
|ClearZine is one of the most popular supplements for treating acne, reducing redness and blotches, and clearing blackheads and spots. It contains vitamin B, biotin, bioavailable minerals (chromium, selenomethionine and zinc), co-enzyme Q10 plus herbs (horsetail and witch hazel) that are traditionally used to help clear skin.
View price on Amazon.co.uk
Probiotics and acne
Probiotic bacteria (eg Lactobacillus, Bifidobacterium) found in yoghurt and supplements may help to reduce acne by interacting with immune cells in the gut lining to suppress inflammation, and by regulating genes that are involved in insulin signalling.
In a study involving 20 adults with acne (14 females, 6 males, average age 33 years), half took a liquid supplement supplying the probiotic strain Lactobacillus rhamnosus (3 billion cfu) every day for 12 weeks, while the other half took a similar liquid containing no probiotics. Skin biopsies taken before and after the study showed a 32% reduction in skin inflammation in the probiotic group, with no change in the placebo group. Those taking probiotics were also 28.4 times more likely to be rated by their doctors as improved/markedly improved (versus worsened or unchanged) compared with the placebo group.
If you have a skin breakout, it’s worth taking a probiotic supplement, especially one containing the strain Lactobacillus rhamnosus.
Omega-3s, Omega-6s and acne
Omega-3 fatty acids are converted in the body into substances (series 3 prostaglandins and series 5 leukotrienes) that reduce inflammation. In contrast, most omega-6 fatty acids (derived from vegetables oils such as sunflower, safflower and corn oils) are converted into substances that promote inflammation.
GLA (gammalinolenic acid found in evening primrose, starflower and blackcurrant seed oils), is one of the few omega-6s that have an anti-inflammatory action.
An imbalance between intakes of omega-3s and omega-6s has been linked with worsening of symptoms in inflammatory diseases and may play a role in acne symptoms. Omega-9s from olive and sea buckthorn oil are also important for healthy skin.
Consume more omega-3s, which are found in:
- oily fish (2 to 4 portions per week) such as mackerel, herring, salmon, trout, sardines, pilchards, fresh tuna (not tinned)
- omega-3 enriched eggs
- walnuts and walnut oil
- omega-3 fish oil supplements
At the same time, cut out excess omega-6s by consuming less:
- omega-6 vegetable oils such as safflower oil, grape seed oil, sunflower oil, corn oil, cottonseed oil or soybean oil
- margarines based on omega-6 oils such as sunflower or safflower oil
- convenience and fast-foods
- manufactured goods such as cakes, sweets and pastries.
Putting it all together
In some people, eating a lot of sugary, fatty and processed foods but very little fruit, vegetables or omega-3 rich fish, undoubtedly makes acne worse. Dairy products and meat have also been implicated due to the hormones they contain.
In my clinical experience, following a more plant-based diet, with less meat and more oily fish, can help to improve skin health.
Once your skin clears, you can start adding in favourite foods (such as chocolate) to see if your symptoms worsen again. For example, if avoiding cows’ milk products has helped, you could see how your skin reacts to adding goats’ milk, butter and cheese.
Have any dietary approaches or supplements significantly improved your skin? Let me know in the comments box below.