The Roman poet Juvenal said that Poppaea, Nero's wife, traveled with a legion of donkeys to wash with their milk. It is also said that, in ancient Egypt, Cleopatra bathed in milk from the same source to keep her skin soft and smooth, and that Elizabeth of Bavaria (better known as Sissi Empress) used it in her beauty rituals.
Nowadays, another equine milk, mare's milk, has taken up the prestige baton and is gaining popularity in Europe for its supposed therapeutic benefits. Is it justified? What does science say about its properties?
This food is well known in some Asian countries, such as Mongolia, Russia, China, Kazakhstan or Uzbekistan. Historically, it has been used to treat diseases, improve the immune system and provide vitality.
Aside from these medicinal uses, mare's milk has also often served as a substitute for breast milk, given the similarities in its composition. And since it has a low allergic response in children with cow's milk protein allergy, it is potentially useful as an alternative to formula milk.
Today, its consumption is spreading in our environment, especially in the form of powdered milk (lyophilized), as a food supplement or even as an ingredient in cosmetics for those who trust in its benefits for the skin. When drunk, mare's milk is sweet and light, although it is not common to find it in liquid format.
A quick internet search will show a long list of websites promoting the “therapeutic properties” of mare's milk. Their content of fatty acids, minerals, vitamins and essential amino acids stands out. But this is not exactly what science says.
To begin with, it is important to keep in mind that all types of milk, including cow's milk, contain fat (and fatty acids), lactose, proteins, essential amino acids, vitamins and minerals to a greater or lesser extent, in addition to many other compounds.
Amino acids are structural units of proteins (like the links in a chain) and can be classified as non-essential and essential, depending on whether or not the body can produce them. Therefore, foods rich in essential amino acids are essential for proper metabolism functioning. And although it is true that mare's milk proteins contain them, they are also found in any other type of milk.
On the other hand, fatty acids are a type of molecule that makes up most of the lipids (or fats) that we consume through foods such as dairy, meat or oil. Mare's milk (like human milk) is characterized by having a low fat content: between 0.3 and 2%. Cow and sheep milk, for example, contain 3 to 5% and 5 to 9%, respectively.
Furthermore, the fat in this milk has a very different composition from that of other animals. Being monogastric (non-ruminant), the horse's digestive system absorbs and accumulates in milk a greater amount of omega-3 (mainly linolenic acid) and omega-6 (mainly linoleic acid) fatty acids. Essential for the proper functioning of the body, these fatty acids are necessarily obtained through the diet, which speaks in favor of mare's milk.
On the other hand, it should also be noted that it has a low content of both total fat and other omega-3 fatty acids of great interest, such as EPA and DHA. This limits its appeal as a source of beneficial fatty acids.
As for vitamins and minerals, mare's milk contains generally little content, with the exception of vitamin C and iron.
According to European legislation, to declare a healthy property in a food, approval from the European Food Safety Authority (EFSA) is necessary. And this only happens when there is enough scientific evidence to support it.
Currently, there are no authorized health properties for mare's milk, so common claims such as “improving the immune system” or “increasing vitality” are neither verified nor justified from a scientific point of view.
Of course, this does not mean that it does not have virtues, but as of today there is not enough evidence in this regard. And although recent studies have shown a potential benefit against type 2 diabetes, cancer or skin conditions, these works are still preliminary and very scarce.
Regarding claims of therapeutic properties, European legislation does not authorize claims that a food prevents, treats or cures a disease, so claims in this sense are not justified either.
In short, although mare's milk has a low content of fat, protein, minerals and vitamins compared to the majority of milk we consume -including cow's milk-, it contains elements of great interest for human nutrition, such as omega fatty acids. -3 and omega-6. There is still a long journey of research to demonstrate its promising healthy qualities.
This article was originally published on The Conversation website.
Authors of the article: Ana Blanco Doval, predoctoral researcher in Food Sciences at the University of the Basque Country / Euskal Herriko Unibertsitatea; Luis Javier Rodríguez Barron, professor of Food Technology and Principal Researcher of the Lactiker Group - Quality and Safety of Foods of Animal Origin at the University of the Basque Country / Euskal Herriko Unibertsitatea; and Noelia Aldai, Senior Researcher at the University of the Basque Country / Euskal Herriko Unibertsitatea.
