Dairy: Should it be avoided for great skin?

Dairy and your skin: Here’s what you need to know

Dairy is a controversial food group and is backed by big industry, it’s no wonder that large-scale comprehensive studies investigating its long-term effects are scarce. Time and time again, small-scale studies show dairy can have a negative effect on skin health as a consequence of the individual ingredients and hormones milk contains.

Until recently, there had been no large-scale analysis, however, 2018 has seen a landmark meta-analysis study published in the journal of clinical nutrition. A meta-analysis study draws together all small-scale studies on a particular topic and weights their findings to draw an overall conclusion i.e. is dairy good or bad for skin health? Does dairy cause acne? Could dairy be the cause of oily skin?

Why dairy may be bad for the skin

Dairy and specifically milk and even more specifically low-fat or skimmed milk may have a negative effect on the skin which results in;

  • Spots and blemishes
  • Acne
  • Oily skin
  • Large pore size
  • Inflammation i.e. aggravation of skin conditions like rosacea or even premature ageing

The above dairy effects on the skin are thought to be due to one or more of the following;

  • Dairy contains lactose (more about this soon)
  • Dairy is an insulinotropic food group i.e. it causes large and sudden rises in insulin and associated hormones
  • Milk and dairy contain hormones
  • Milk and dairy significantly elevate levels of a hormone called insulin-like growth factor-1 (IGF-1)
  • Dairy contains an often troublesome protein called casein

Dairy + lactose + your skin

Lactose is a type of sugar found in large quantities in milk. The human body requires an enzyme called lactase to process and use lactose. However many people lack or do not make the enzyme lactase naturally. A consequence of dairy being a recent introduction to an adult diet. It’s estimated that approximately 65% of the global population have a reduced ability to digest lactose1. A statistic which increases to 90% when investigating the genetics of differing decent i.e. East Asian. 

These statistics may explain why a 2017 published study entitled dairy products and inflammation: A review of the clinical evidence concluded data to date shows dairy may be anti-inflammatory in people suffering from metabolic disorders, however pro-inflammatory in people with an allergy to milk2. Although intolerance is not the same as an allergy, in that consuming the food will not result in anaphylactic shock or death, having an intolerance will cause similar yet lower activation of immune response and inflammation.  As skin is the largest organ of the human body it is ultimately affected by diet provoked inflammation.

Bottom line: Consuming diary when a person is allergic or intolerant can cause low grade but persistent inflammation i.e. inflammageing and worsening of existing inflammatory skin conditions like rosacea, eczema or acne.

Dairy: an insulinotropic food which can have a negative impact on the skin

Low glycaemic index diets are generally accepted as having significant health benefits. Following a low glycaemic index diet relies on eating foods or meals which release sugar energy slowly i.e. complex carbohydrates. When sugar energy is released slowly, blood sugar levels remain consistent and release of sugar controlling hormones such as insulin and insulin-like growth factor are moderated.

To eat a low glycaemic diet, however, is not foolproof; because some foods which appear to be low in glycaemic index e.g. milk still provokes a strong release of insulin3. Foods like these are referred to as being insulinotropic.

Almost all dairy foods are highly insulinotropic including yoghurt, ice cream, cottage cheese and fermented milk products, however to the exclusion of cheese. Adding a typical serving of milk, 200ml to a low GI meal can increase insulin response by 300% – this being the level that would be experienced when eating a very high GI meal like white bread4.

When insulin is released, insulin-like-growth-factor-1 is also released and increased IGF-1 levels are positively correlated with acne5. An effect thought to be a result of dairy causing stimulation of sebocytes – oil producing cells6. When skin becomes oilier, trapped dead skin cells become stuck inside pores and acne-causing bacteria breed.

Ultimately, dairy consumption can result in spots, blemishes, and acne, however, dairy consumption can also, therefore, result in oily skin and large pore size. Pore size is impacted by the size of the sebum glands inside of pores. Oily skin has enlarged sebum glands/over-stimulated sebum glands, therefore, resulting in a larger pore size.

Bottom line: Consuming dairy regularly may cause a person spots, blemishes, and acne in addition to oily skin and large pore size.

Dairy hormones + your skin

Dairy is often described as a nutritionally dense food. Nature has designed dairy this way to help baby mammals grow to be strong and healthy, quickly. For this reason dairy contains a significant amount of sex hormone derivatives such as oestrogen, progesterone, androgen, dihydrotestosterone (DHT) and 5-alpha reduced steroids7. DHT and 5-aplha reduced steroids, in particular, have potent effects on sebum regulation and acne progression8. In fact, testosterone is metabolised inside the human body by 5-aplpha reductases into DHT. Androgen receptors have a 10 times greater affinity for DHT than they do testosterone9 and androgen receptors can be found directly inside of sebaceous glands. This is the biological reasoning for why androgen hormones or an excess of androgen hormones can lead to oily skin and acne.

The development of adult acne in women is thought to be a likely consequence of androgen excess i.e. hormones which stimulate what are generally considered as typically male traits. These are linked with an oiliness of skin, which can, therefore, trigger acne10.

Dairy, IGF-1 + your skin

Insulin-like growth factor is a hormone the human body can be triggered into making as a consequence of diet. While dairy is significantly active in triggering IGF-1 production. Dairy also contains IGF-1. The form of IGF-1 found in dairy is not digestible i.e. it cannot be broken down by enzymes in the gut. This hormone may, therefore, be absorbed through the intestine contributing to elevated IGF-1 levels in blood11. Studies on direct IGF-1 absorption are not yet conclusive.

However what is known is that androgen hormones increase active blood levels of IGF-1 in a reciprocal relationship i.e. an increase in a person’s IGF-1 blood levels will also cause a direct increase in circulating androgen levels12.  High blood levels of IGF-1 and androgens are a defining characteristic of adult acne13. It is also known that sebum production increases relative to androgen and IGF-1 levels, therefore causing an oiliness of skin.

Increased milk consumption in adults can cause a 10-20% increase in blood active levels of IGF-114.

Bottom line: When the human body has high blood levels of IGF-1 skin may become oilier, pores may appear larger and spots, blemishes, and acne may develop.

Dairy, casein + your skin

Milk contains 2 major types of proteins. Protein 1 of which can be attributed to around 80% of the protein content in cow milk is called casein and protein 2 of which makes up approximately the remaining 20% is whey15.

Casein is particularly troublesome for skin because it directly increases IGF-1 levels. The hormone which will increase a person’s androgen hormones leading to oily skin, large pores, spots, blemishes, and acne.

Casein may also cause the flare of inflammatory skin conditions of which acne, rosacea, eczema, and psoriasis are the most common. This is a result of the human body’s ability to digest casein into a peptide known as beta-casomorphine16. As the name suggests beta-casomorphine is a type of opioid and can have significant effects on the body in just small amounts. A study published in the international archives of allergy and immunology concluded beta-casomorphine can cause concentration-dependent histamine release which in healthy adults causes wheal and flare skin reactions17. In adults or children with existing inflammatory skin conditions, consumption of milk can, therefore, have a worsening effect or even provoke an eczema or acne flare-up.

Bottom line: The casein protein found in dairy can worsen existing inflammatory skin conditions.

How much dairy is too much?

Can dairy still be eaten in moderate amounts without having negative effects on skin? One study shows girls who consume less than 55ml of milk in their diet per day have significantly lower IGF-1 levels than girls who consumer over 260ml of milk per day18. The equivalent of a standard cup size. It is also known that IGF-1 levels positively correlate with the intake of milk, meaning the more milk a person consumes, the higher IGF-1 levels they will have19.

As IGF-1 levels are positively correlated with spots, blemishes, acne, oily skin and large pores it appears even a moderate amount of dairy can have a significant impact.

While almost all foods derived from milk have the potential to cause a negative impact on skin, there are a few exceptions. Cheese, for instance, does not share the same insulinotropic properties as almost all other dairy foods. Cheese has an insulin score of 45 whereas yogurt has an insulin score of 115 and ice cream 8920. Therefore out of all foods derived from dairy, cheese is the best option for consumption in moderate amounts.

A few studies have also shown low-fat milk and especially skimmed milk has a much stronger positive relationship with acne than whole milk. Whole milk contains more estrogen than skimmed milk and low-fat milk which in most cases has the ability to suppress acne. Skimmed milk and low-fat milk also have a much higher concentration of alpha-lactalbumin, a protein which regulates the production of lactose and is associated with acne21. Therefore it appears whole milk makes a much healthier choice than low-fat or skimmed milk and is indeed associated with other protective health effects.

How to moderate dairy consumption

Moderating dairy intake or avoiding dairy entirely can have a very positive effect on skin, especially if a person is experiencing acne or excessive skin oiliness. The most obvious forms of dairy include;

  • Milk
  • Cream
  • Ice cream
  • Cheese (however as previously discussed may be the best dairy to consume)
  • Cottage cheese
  • Sour cream
  • Yogurt
  • Butter

However, dairy may also be found in many other commonly consumed foods, such as;

  • Chocolate especially milk chocolate
  • Dips e.g. guacamole
  • Desserts
  • Smoothies
  • Soups
  • Breads e.g. brioche
  • Pasta sauces
  • Pre-prepared pastas e.g. ravioli
  • Ready-made foods

Therefore when looking to limit dairy intake or to try a period of 2 weeks dairy free it’s important to watch for common dairy traps.

The best alternatives for commonly used dairy foods include;

  • Almond milk in replacement for milk
  • Cheeses made from nuts instead of dairy
  • Olive oil in replacement for butter when cooking
  • Coconut yogurts with probiotic cultures

Any foods claiming to be vegan will also be 100% dairy free as dairy is an animal by-product, this can make trailing a dairy free diet easier and quicker. As the negative effects of dairy are active on insulin and IGF-1 levels, it’s also important that when going dairy free a person’s diet is low in glycemic index. High glycemic index foods are also insulinotropic, therefore management of both is needed to benefit from the positive skin effects of going dairy free.

Can skincare help?

The skin effects of consuming a diet high in dairy will only be ultimately corrected by moderating dairy intake. However, the resulting oiliness and acne tendency of skin effected by dairy can be treated with appropriate skincare. For example, excess dead skin cells increase the appearance of oiliness in skin while also playing a key role in acne progression, therefore exfoliating daily with an exfoliant like the griffin+row natural exfoliant cloth can help treat the effects of a diet high in dairy.

Bottom line: following a diet either low or free from dairy alongside appropriate skincare can help mitigate many skin conditions, including acne, oiliness, large pores, eczema, rosacea and more.

  1. https://ghr.nlm.nih.gov/condition/lactose-intolerance#statistics

  2. Dairy products and inflammation: A review of the clinical evidence. Bordoni A, Danesi F, Dardevet D, Dupont D, Fernandez AS, Gille D, Nunes Dos Santos C, Pinto P, Re R, Rémond D, Shahar DR, Vergères G. Crit Rev Food Sci Nutr. 2017 Aug 13;57(12):2497-2525. doi: 10.1080/10408398.2014.967385. Review.

  3. Milk–the promoter of chronic Western diseases. Melnik BC. Med Hypotheses. 2009 Jun;72(6):631-9. doi: 10.1016/j.mehy.2009.01.008. Epub 2009 Feb 15.

  4. Liljeberg EH, Bjorck I. Milk as a supplement to mixed meals may elevate postprandial insulinaemia. Eur J Clin Nutr 2001;55:994–9.

  5. Cappel M, Mauger D, Thiboutot D. Correlation between serum levels of insulin-like growth factor-1, dehydroepiandrosterone sulfate, and dihydrotestosterone and acne lesion counts in adult women. Arch Dermatol 2005;141:333–8.

  6. Oily skin: an overview. Sakuma TH, Maibach HI. Skin Pharmacol Physiol. 2012;25(5):227-35. doi: 10.1159/000338978. Epub 2012 Jun 20. Review.

  7. Aghasi M, et al., Dairy intake and acne development: A meta-analysis of observational studies, Clinical

    Nutrition (2018), https://doi.org/10.1016/j.clnu.2018.04.015

  8. Steroid 5alpha-reductase inhibitors in androgen-dependent disorders. Harris GS, Kozarich JW. Curr Opin Chem Biol. 1997 Aug;1(2):254-9. Review.

  9. Chen W, Zouboulis CC, Fritsch M, Blume-Peytavi U, Kodelja V, Goerdt S, Luu-The V, Orfanos CE. Evidence of heterogeneity and quantitative differences of the type 1 5alpha-reductase expression in cultured human skin cells–evidence of its presence in melanocytes. J Invest Dermatol. 1998;110(1):84–89.

  10. Adrenal androgen abnormalities in women with late onset and persistent acne. Aizawa H, Niimura M. Arch Dermatol Res. 1993;284(8):451-5.

  11. MALEKINEJAD H, REZABAKHSH A. Hormones in Dairy Foods and Their Impact on Public Health – A Narrative Review Article. Iranian Journal of Public Health. 2015;44(6):742-758.

  12. Klinger B, Anin S, Silbergeld A, Eshet R, Laron Z. Development of hyperandrogenism during treatment with insulin-like growth factor-I (IGF-I) in female patients with Laron syndrome.

    Clin Endocrinol (Oxf) 1998;48:81-7.

  13. Thiboutot D, Gilliland K, Light J, Lookingbill D. Androgen metabolism in sebaceous glands from subjects with and without acne. Arch Dermatol 1999;135:1041-5.

  14. Melnik B. Milk consumption: aggravating factor of acne and promoter of chronic diseases of Western  societies. J Dtsch Dermatol Ges 2009;7(4): 364e70. Epub 2009/02/27.

  15. Milk consumption: aggravating factor of acne and promoter of chronic diseases of Western societies. Melnik B. J Dtsch Dermatol Ges. 2009 Apr;7(4):364-70. doi: 10.1111/j.1610-0387.2009.07019.x. Epub 2008 Feb 20. Review

  16. Nguyen DD, Johnson SK, Busetti F, Solah VA. Formation and Degradation of Beta-casomorphins in Dairy Processing. Critical Reviews in Food Science and Nutrition. 2015;55(14):1955-1967. doi:10.1080/10408398.2012.740102.

  17. A naturally occurring opioid peptide from cow’s milk, beta-casomorphine-7, is a direct histamine releaser in man. Kurek M, Przybilla B, Hermann K, Ring J. Int Arch Allergy Immunol. 1992;97(2):115-20.

  18. Esterle L, Sabatier J-P, Guillon-Metz F, Walrant-Debray O, Guaydier-Souquières G, Jehan F, Garabédian M. milk, rather than other foods, is associated with vertebral bone mass and circulating IGF-1 in female  adolescents. Osteoporos Int 2008; DOI 10.1007/s00198-008-0708-x.

  19. Norat T, Dossus L, Rinaldi S, Overvard K, Gronbaek H, Tjonneland A, et al. Diet, serum insulin-like growth factor-I and IGF-binding protein-3 in European women. Eur J Clin Nutr 2007;61:91–8.

  20. Holt S, Brand Miller J, Petocz P. An insulin index of foods: the insulin demand generated by 1000 kJ portions of common foods. Am J Clin Nutr 1997;66:1264–76.

  21. Aghasi M, et al., Dairy intake and acne development: A meta-analysis of observational studies, Clinical

    Nutrition (2018), https://doi.org/10.1016/j.clnu.2018.04.015