The subject is divided into two main parts

A - A linguistic point regarding the phrase in the Quran: "its bellies" (*butūnihi* or *butūnihā*)

B - The extraction of milk from between the contents of the digestive tract (*farth*) and blood, without it becoming mixed with either or both of them

Allah Says

(وَإِنَّ لَكُمْ فِي الأَنْعَامِ لَعِبْرَةً نُّسْقِيكُم مِّمَّا فِي بُطُونِهِ مِن بَيْنِ فَرْثٍ وَدَمٍ لَّبَناً خَالِصاً سَآئِغاً لِلشَّارِبِينَ )النحل 66

"And indeed, for you in the livestock there is a lesson: We give you to drink from what is within their bellies—from between digested food and blood—pure milk, palatable to those who drink it." (An-Nahl: 66)

Indeed, O people, there is a lesson for you in livestock—namely, camels, cattle, and sheep. You have witnessed how We provide you with milk from their udders—milk that emerges from between the contents of the digestive tract (the *farth*) and the blood—pure and free from any impurities, and so delicious that it is easily swallowed by those who drink it.

The Scientific Interpretation of the Noble Verse

Ever since God—glory be to Him—revealed this blessed verse more than 1,400 years ago, scientists on Earth have not been able to add anything to the truth presented by the Holy Quran—a truth that distinguishes it from all other earthly or heavenly texts. This concerns the fact that milk—which is pure (i.e., refined) and palatable (enjoyable to the taste, thanks to its content of appetizing components like fats and sugars)—is formed from substances found between the *farth* (the contents of the rumen, consisting of fodder fermented by beneficial bacteria that help break down complex, hard-to-digest feed) and substances present in the bloodstream—some of which are naturally inherent to the blood, while others enter the bloodstream from the rumen.

A Linguistic Nuance

(Its Bellies/Compartments)

God Almighty says:

"And indeed, for you in the grazing livestock is a lesson: We give you to drink from what is in their bellies—from between digested food and blood—pure milk, palatable to those who drink it." (An-Nahl: 66)

I would like to draw attention to the term *butūnihi* (its bellies/compartments)—specifically, why the Almighty did not use the feminine plural form *butūnihā* (their bellies). The answer lies in the fact that the term *al-an‘ām* (grazing livestock)—which encompasses four types of animals—is being treated here in terms of its individual, singular units. Each female animal among these four types possesses multiple internal compartments (ranging from three, in the case of camels, to four, in the case of cattle, goats, and sheep). Had the term *butūnihā* been used, some might have mistakenly inferred that each type of livestock possesses only a single "belly" (or internal cavity).

(Their bellies)

In another verse, the Almighty says:

"And indeed, for you in the livestock is a lesson: We give you to drink from what is in their bellies, and in them are many benefits for you, and from them you eat." (Al-Mu'minun: 21)

Livestock possess multiple stomach compartments and the ability to ruminate—a process where food is retained for an extended period to undergo fermentation. This facilitates a high degree of digestion and nutrient absorption, ultimately converting the consumed matter into products such as meat, milk, or other substances. Although the Almighty—glorified be His majesty—uses the term "their bellies" (in the plural), the verse highlights that livestock, in general, offer numerous benefits—including the provision of meat for consumption. Consequently, there is no need to specify the complex stomach structures of each individual type of livestock, nor to explicitly detail how these digestive systems contribute to the production of milk.

How are substances found "between the digested food (farthe) and the blood" transformed into pure, wholesome milk?

What, precisely, is contained "between the digested food"?

(It's that this "digested food"—or *farthe*—consists of coarse, fibrous fodder and finer feed within the rumen. It contains both standard proteins and non-absorbable proteins—the latter providing nitrogen that can be utilized to synthesize standard proteins, known as "bacterial protein." It also contains sugars—ranging from easily absorbable ones to complex carbohydrates like cellulose, hemicellulose, and starch—as well as various types of fats, including phospholipids, glycolipids, and triglycerides. This mixture is combined with saliva from the mouth and alkaline secretions from within the rumen, and it is teeming with millions of bacteria and protozoa that ferment the material, aiding in its digestion and the absorption of its components.) Scientifically, the specific substances found "between the digested food" are as follows:

1. Glucose, which contributes significantly to the formation of the following: volatile fatty acids.

2. Volatile fatty acids (VFAs), which are essential for milk synthesis. Based on their relative proportions within the rumen, they consist of: acetic acid (approximately 65%), propionic acid (approximately 20%), and butyric acid (approximately 15%).

3. Gases, such as methane, ammonia (which contributes to the formation of bacterial protein), and carbon dioxide.

4. Lactates (which play a limited role and are broken down in the liver into glucose).

5. Proteins (derived from both feed and bacterial sources) and amino acids resulting from the digestion of protein in the rumen.

6. Fats (including bacterial phospholipids, saturated fatty acids, and free fatty acids—the latter two resulting from the digestion of dietary fats in the rumen).

Volatile fatty acids (VFAs)—specifically acetic and propionic acids—are absorbed through the rumen wall and enter the bloodstream. Butyric acid, meanwhile, is converted within the rumen wall into ketones; these are potentially toxic compounds that enter the bloodstream and, at certain levels, contribute to the synthesis of fats (via glycerol) in the blood and in milk.

Breakdown products of fats (triglycerides), proteins (amino acids), and the remaining glucose derived from dietary starch are absorbed through the intestinal wall, which is specialized for the process of absorption.

These absorbed substances enter the portal vein, which carries them to the liver. There, they are further processed and broken down into simpler compounds before being pumped by the heart to all body tissues—most notably, in this context, the udder, which serves as the site of milk production.

What happens inside the udder?

The udder is supplied with blood through arteries that are finer than its veins—a design reflecting divine wisdom, intended to retain the maximum amount of proteinaceous substances, which are otherwise difficult to transport due to their large molecular size. Furthermore, the udder features two large, visible veins that collect blood from a network of smaller venous capillaries. The udder itself consists of fatty tissue connected to the body by two strong ligaments. Embedded within this tissue are glandular cells responsible for secreting milk, which then collects in the udder’s reservoirs (cisterns) before being drawn out through the teats.

The aspect of divine miracle here

Although the blood within the udder is continuous with the blood in the rest of the body, a selective process occurs—much like the miraculous barrier between the salt water of the seas and fresh water. Certain components are permitted to enter the udder, while others are excluded. For instance, glucose (derived from propionate) enters the udder to form milk sugar (lactose). Milk fat is synthesized from simple fatty acids, ketone bodies, acetates, and glycerol (which originates from glucose and triglycerides). Meanwhile, milk protein—primarily casein—is formed from amino acids dissolved in the blood. All of this takes place through chemical reactions of such exquisite complexity and wonder that the resulting milk emerges pure, wholesome, and pleasant for those who drink it—untainted by blood or digestive waste. Who, then, could have informed Muhammad (peace be upon him) of all these intricate details?