As Above, So Below || Diet
Of the four pillars we are discussing in this series (sleep, exercise, diet and mind), the relationship between one’s diet and the skin is potentially the most complicated and the least understood. The skin’s role as a barometer for our internal workings was one of the main draws for me when deciding what avenue to focus on in medicine. Manifestations of internal illnesses often have skin markers that we are taught in medical school to help identify clues when diagnosing people. Good examples of gut disorders that have skin clues include the signs of iron deficiency anaemia (angular cheilitis, spoon-shaped nails, hair loss and pallor), high cholesterol (xanthelasma), inflammatory bowel disease (erythema nodosum) and coeliac disease (dermatitis herpetiformis). I encourage you to have a look at the images to demonstrate how incredibly helpful the skin is as a diagnostic aid.
Food is the foundation of our lives. Not only does it play a nutritive role in our bodies but in our culture and community. Cooking a meal for a friend or loved one is an act that displays our love for those who surround us. Equally, by being intentional about the food we eat, we can shower ourselves in this affection and show gratitude to our wonderful bodies that house us. Taking the time and energy to nourish ourselves will be felt in our physical and mental health, as well as being reflected in our skin.
Skin cells, just like every other class of cells, need nutrients for normal functioning and visible signs of deficiencies may manifest on the skin. Here we focus on the good as we don’t like to label any food as “bad”. Life is all about balance and food plays many parts in a wholesome fulfilled existence. While a salad may feed your cells, a pain au chocolat certainly can feed the soul!
Eating Well
Consensus on what a “healthy” diet looks like eludes us, as there is so much variation globally across peoples and cultures. What we can say is that a diet with a balance of food groups, that is lower in refined sugar and heavily processed foods is beneficial for us. For the past fifty years or so, the Mediterranean diet has been lauded as a model for a healthy diet – this consists of a diet of a variety of seasonal plant foods (vegetables, fruit, legumes, cereals, nuts, seeds), regular consumption of olive oil, moderate intake of fish, seafood and dairy, and a low-consumption of red meat and alcohol. Some studies have also linked the Mediterranean diet with better sleep patterns as well as a sustainable lifestyle.(1)(2)
Newer research has recommended that we aim to eat 30 different plants a week. We highly recommend the resource Zoe for improving your understanding of gut health. By aiming for this range of plant derived nutrients you optimise the level of prebiotics you are consuming which we believe greatly increase your gut microbiome diversity. Additionally, plants are loaded with polyphenols, an interesting group of plant derived chemicals (phytochemicals) that I dedicated my whole thesis to understanding because of their anti-inflammatory and antioxidant potential. There is abundant epidemiological support that diets high in fruits, vegetables and whole grains, all rich in polyphenols, may be protective against cancer (3) and cardiovascular disease (4). My thesis found significant support for the role of polyphenols in helping maintain collagen levels in the skin as we age. Whilst there is no recommended daily allowance for polyphenols studies are ongoing to determine whether this might change.
Skin and Food
As I mentioned previously we have a long way to go before definitive recommendations can be given with regard to optimising skin outcomes via diet. There are a number of observations however which may be helpful in certain cases.
Highly refined sugar consumption leads to blood sugar elevation and, if persistent, the glycation of collagen. This damages collagen leading to stiff fibres and accelerated signs of ageing.
A certain population of acne patients may be sensitive to the effects of dairy. Particularly skimmed milk as it has higher levels of insulin like growth factor (IGF-1), than full fat milk. We believe that in in certain people this may lead to increased sebum production thereby exacerbating acne.
Vitamin D is a slight misnomer given most essential vitamins need to be found in food sources, but our skin can actually makes the precursor of Vitamin D and it is more accurately described as a prohormone steroid. This plays an essential role in bone health (important to our skeletal facial scaffold), skin immunity and skin barrier function. It is believed to have a part to play in psoriasis and topical forms are often prescribed. Interestingly, too much of a good thing may be associated with other skin issues such as rosacea, but this research is in its infancy. What we can say is that adequate levels are required and our northern hemisphere latitude can make it difficult to get the UVB exposure needed to make that happen. Supplementation of small amounts of this fat-soluble vitamin could be helpful and worthy of discussion with your doctor particularly those at high risk of deficiency, such as elderly or darker skinned individuals.
With regard to probiotics and the skin, there are a few strains which may be beneficial. Lactobacillus rhamnosus GG could be helpful for infants at high risk of atopic dermatitis (eczema). Prevotella histicola may be of interest in psoriasis. Not all probiotics are created equal and claims currently made by most supplements are not fully supported by the literature. Fermented dairy and foods are an incredible source of probiotics and can be wonderfully beneficial to the gut microbiome so may be a more favourable source.
Our skin is a complex puzzle that is impacted be numerous factors in our lifestyle. As you can see our understanding of how our diet interplays with the skin is only starting to improve, but it is exciting to learn more as the research grows. We will be sure to keep you updated but in the mean time eat the leafy greens, proteins, healthy fats, fermented foods, drink your water and absolutely treat yourself to the pain au chocolat!
(1) Scoditti E, Tumolo MR, Garbarino S. Mediterranean Diet on Sleep: A Health Alliance. Nutrients. 2022 Jul 21;14(14):2998. doi: 10.3390/nu14142998. PMID: 35889954; PMCID: PMC9318336.
(2) Lăcătușu CM, Grigorescu ED, Floria M, Onofriescu A, Mihai BM. The Mediterranean Diet: From an Environment-Driven Food Culture to an Emerging Medical Prescription. Int J Environ Res Public Health. 2019 Mar 15;16(6):942. doi: 10.3390/ijerph16060942. PMID: 30875998; PMCID: PMC6466433.
(3) Ingram D, Sanders K, Kolybaba M, Lopez D. Case-control study of phyto-oestrogens and breast cancer. Lancet. 1997;350(9083):990-4.
(4) Frei B. Cardiovascular disease and nutrient antioxidants: role of low-density lipoprotein oxidation. Crit Rev Food Sci Nutr. 1995;35(1-2):83-98.