Milk and Health

– Milk is a complex and nutritious liquid that has been consumed by humans for millennia. It contains many essential nutrients, such as protein, calcium, vitamin D, etc.

Milk composition:

– Milk is composed of water, fat, protein, carbohydrate (lactose), and various vitamins and minerals. The exact composition of milk varies depending on the animal source, breed, diet, stage of lactation, and other factors.

For instance, a cow's milk has about 3.5% protein, 4% fat, 5% lactose, and 0.7% minerals, while a human's milk has about 1.1% protein, 4.2% fat, 7% lactose, and 0.2% minerals (1).

– The main types of proteins in milk are casein and whey, which have different properties and health effects.

– The main type of fat in milk is saturated fat, which can raise blood cholesterol levels if consumed in excess.

– Lactose is the sugar in milk that some people have difficulty digesting due to a lack of the enzyme lactase.

The vitamins and minerals in milk include: calcium, phosphorus, magnesium, potassium, zinc, iron, selenium, vitamin A, vitamin D, vitamin B12, riboflavin, and folate.

Milk Digestion Process:

– Milk digestion begins in the mouth, where saliva moistens it and starts to break down some of the starches. Then it moves to the stomach, where gastric acid and enzymes start to break down the proteins and fats.

– The stomach churns the milk to form a semi-solid mass called curd. The curd then passes into the small intestine, where bile from the liver and more enzymes from the pancreas further digest the fats and proteins.

– The lactose in milk is also broken down by lactase into glucose and galactose in the small intestine.

– The glucose and galactose are then absorbed into the bloodstream along with the amino acids from proteins and the fatty acids from fats.

– The vitamins and minerals in milk are also absorbed in the small intestine.

– The undigested parts of milk pass into the large intestine, where they may be fermented by bacteria or excreted as waste.

🔅Milk has many advantages for health, such as:

• It provides a complete source of protein that contains all nine essential amino acids that the body cannot make on its own.

• It is a rich source of calcium that is important for bone health and prevention of osteoporosis.

• It contains vitamin D that helps the body absorb calcium and regulates immune function.

• It contains other vitamins and minerals that support various bodily functions and prevent deficiencies.

• It may help lower blood pressure by providing potassium and calcium that relax blood vessels.

• It may help prevent type 2 diabetes by providing protein that regulates blood sugar levels.

• It may help improve cognitive function by providing choline that is essential for brain development and memory.

• It may help reduce the risk of some cancers by providing Conjugated Linoleic Acid (CLA) that has anti-inflammatory and anti-tumor properties.

🔅 However, milk also has some disadvantages for health, such as:

• It may cause allergic reactions in some people who are sensitive to the proteins or sugars in milk.

• It may cause lactose intolerance in some people who lack the enzyme lactase to digest lactose.

• It may increase the risk of cardiovascular disease by providing saturated fat and cholesterol that can raise blood cholesterol levels.

• It may increase the risk of prostate cancer by providing calcium that may interfere with vitamin D metabolism or by stimulating the production of insulin-like growth factor 1 (IGF-1) that may promote tumor growth.

• It may increase the risk of acne by providing hormones or growth factors that may stimulate sebum production or inflammation in the skin.

Milk Effects on Infant Health:

– Milk is an important food for infants during their first year of life. However, not all types of milk are suitable for infants. The best type of milk for infants is human breast milk that provides optimal nutrition and protection against infections and diseases.

– Breastfeeding also benefits the mother by reducing postpartum bleeding, promoting uterine contraction, delaying ovulation, enhancing bonding with the baby, and lowering the risk of breast cancer.

– Breastfeeding is recommended exclusively for the first six months of life and continued until at least two years of age or beyond. If breastfeeding is not possible or desired, infant formula is an alternative option that mimics some of the properties of human breast milk.

– However, infant formula does not provide all the benefits of breast milk and may have some drawbacks such as increased risk of infections, allergies, obesity, diabetes, and sudden infant death syndrome (SIDS).

– Infant formula should be prepared carefully and hygienically to avoid contamination and spoilage. Infant formula should not be modified or diluted without medical advice.

– Cow's milk may cause problems such as iron deficiency anemia, gastrointestinal bleeding, kidney damage, dehydration, electrolyte imbalance, and allergic reactions in infants.

– Plant-based milks, such as soy milk, almond milk, rice milk, or oat milk, or animal milk, such as cow's milk, goat's milk, sheep's milk, or camel's milk are not suitable for infants under one year of age because they have different nutritional profiles and safety issues than human breast milk or infant formula.

🔅 How is milk metabolized in the human beings?

– Milk is a complex and nutritious liquid that has been consumed by humans for millennia. Milk contains essential nutrients, such as protein, calcium, vitamin D; etc. However, milk also has some potential drawbacks, especially for people who are allergic or intolerant to it.

• Milk metabolism is the process of breaking down and absorbing the components of milk in the human body.

• Milk metabolism involves several organs and systems, such as the digestive system, the liver, the kidneys, the muscles, and the bones.

The digestion of milk begins in the mouth, where saliva moistens it and starts to break down some of the starches. Then it moves to the stomach, where gastric acid and enzymes start to break down the proteins and fats. The stomach also churns the milk to form a semi-solid mass called curd. The curd then passes into the small intestine, where bile from the liver and more enzymes from the pancreas further digest the fats and proteins. The lactose in milk is also broken down by lactase into glucose and galactose in the small intestine. The glucose and galactose are then absorbed into the bloodstream along with the amino acids from proteins and the fatty acids from fats. The vitamins and minerals in milk are also absorbed in the small intestine. The undigested parts of milk pass into the large intestine, where they may be fermented by bacteria or excreted as waste.

NOTE:

The absorption of milk components into the bloodstream triggers various hormonal and metabolic responses in the body.

Below is a detailed description of how this works:

– Insulin is released by the pancreas to help lower blood glucose levels and promote glucose uptake by cells.

– Glucagon is released by the pancreas to help raise blood glucose levels and stimulate glycogen breakdown in the liver.

– The growth hormone is released by the pituitary gland to stimulate protein synthesis and growth in various tissues.

– Insulin growth factor 1 (IGF-1) is produced by the liver in response to growth hormone and has similar effects on growth and metabolism.

– Leptin is produced by fat cells in response to fat intake and signals satiety to the brain.

– Ghrelin is produced by the stomach in response to hunger and stimulates appetite and food intake.

• The metabolism of milk components in different tissues depends on their energy needs and functions. For example:

– Glucose is used as a primary fuel source by most cells, especially the brain and red blood cells. Glucose can also be stored as glycogen in the liver and muscles for later use or converted into fat for long-term storage.

– Fatty acids can be used as an alternative fuel source by some cells, especially the heart and skeletal muscles. They can also be stored as triglycerides in fat cells or used for other purposes such as hormone synthesis or membrane formation.

– Amino acids can be used for protein synthesis by all cells or converted into other molecules such as glucose, ketones, or urea. Protein synthesis is especially important for muscle growth and repair, immune function, enzyme production, and hormone regulation.

– Calcium is used for bone formation and maintenance, muscle contraction, nerve transmission, blood clotting, and enzyme activation.

– Vitamin D is used for calcium absorption and bone health, immune function, cell growth, and inflammation regulation.

– Milk metabolism involves various body organs and in turn provides many essential nutrients that support various aspects of health and well-being.