The Link Between Dairy & Our Skin
Article by Maya Tu, BSc ANutr
We definitely all know someone who has cut dairy out of their diet in order to clear their skin or to avoid acne or breakouts and many people believe dairy really is the culprit to ‘bad’ skin. Similarly, the number of vegans is growing and so more people are choosing plant-based milk alternatives such as oat, almond or cashew milks. The Vegan Society states that 48% of British adults use plant-based milks in their diet which shows just how popular these alternatives are (1). However, is there scientific evidence to show that avoiding dairy is the beauty skin secret we all need?
There is some limited evidence to suggest dairy negatively affects the skin, however this may only affect a select group. What we should remember is that most of this evidence is conflicting and the majority of the studies that have taken place are observational or even anecdotal. These studies are therefore not reliable, although they may provide a good foundation. Further studies are required to conclude the findings to show a causal relationship between dairy and acne.
How does dairy affect our skin?
Evidence shows there are two main ways that dairy can affect our skin:
Growth factors
Dairy contains proteins called casein and whey which stimulate the production of a hormone called insulin growth factor-1 or IGF-1 which can then stimulate the production of sebum (the protective oil produced on the surface of the skin) which can lead to acne. Some evidence suggests that individuals suffering from acne have higher levels of IGF-1. Studies have aimed to assess the dose-relationship between dairy and the development of acne (2). The results highlight that dairy, specifically milk, is positively associated with acne development in a significant dose-response relationship, however, there are limited, insignificant results when assessing yoghurt and cheese with the development of acne (3). This suggests that acne may only be a consequence when consuming large quantities of milk. So, could this mean that the type of dairy is significant when analysing the cause of acne?
Insulin and the glycaemic index
The glycaemic index is a way of ranking foods that contain carbohydrates to show how quickly that individual food affects an individual’s blood sugar (4). The higher the glycaemic index of a food, the faster the spike in blood sugar. The glycaemic index of milk may also explain why there is a relationship between dairy and acne development. Milk contains more sugars than cheese, which may explain why milk could affect the skin more. As a result of the high sugar content, milk can increase the insulin levels in the body. High insulin concentrations can increase inflammation and also increase the concentrations of IGF-1, ultimately stimulating acne development. It may be beneficial, therefore, for individuals to consume a low glycaemic diet, to reduce the development and possibly the severity of acne (5). It is not clear, however, how long one should follow such a diet in order to see significant results. Now although it may seem appropriate to switch out milk for a non-dairy alternative, this may not always be a better option. Oat milk, for example, actually has a higher glycaemic index causing higher insulin levels which may be more problematic than cow’s milk. Therefore, it is more advantageous to choose an alternative such as almond milk or an unsweetened soya milk, if large quantities are going to be consumed.
So, in summary…
It is clear that although there is evidence highlighting that dairy causes the development of acne, it is more likely to be caused by multiple factors, such as stress or high intakes of sugar, suggesting that dairy does not have to be excluded from the diet, but the amount should be limited to avoid the rapid spike in blood sugar. It is important to note that dairy is a great source of calcium and protein.
This blog was written by Maya Tu. Maya graduated with a First-Class Honours in BSc Nutrition and has just completed her Master's in Clinical and Public Health Nutrition, graduating with Distinction. She is a part of Jamie Oliver’s nutrition team and has a passion for childhood and sports nutrition.
References:
(1) https://www.vegansociety.com/news/media/statistics/worldwide
(2) https://pubmed.ncbi.nlm.nih.gov/29778512/