Fats and Health Complications

The majority of fats are sourced from either animals or plants, and they share a common composition, consisting of carbon, hydrogen, and oxygen molecules.

Dietary fats are often associated with heart disease and cancer, leading to their negative reputation. However, the role of dietary fat in health and disease is intricate and not always entirely warranted.

Certain fats are crucial for proper growth and maintaining good health, and their deficiency can result in specific diseases related to nutritional inadequacies.

Consuming excessive amounts of certain types of fats can significantly raise the risk of chronic and severe illnesses. Diets high in saturated fats or trans fats are linked to an increased likelihood of heart and artery diseases, which are the leading causes of mortality among adults in the United States and Canada.

Obesity poses significant health risks, and the high energy density of fatty foods makes it easy for people to consume more calories than needed and gain unnecessary weight.

High-fat diets indirectly correlate with type 2 diabetes mellitus and hypertension. Both conditions can strain the circulatory system, and a fat-rich diet may further hinder circulatory function through the potential development of atherosclerosis.

Triglycerides and cholesterol are the essential lipids present in our food supply. Despite their distinct chemical properties, they share the characteristic of being insoluble in water.

Triglycerides, known by various names such as fat, oil, grease, shortening, lard, tallow, suet, and ghee, are transported to fat depots in the body like muscles, breasts, and the insulating fat layer under the skin, where fat cells store them for later use.

When the body's fuel from food diminishes, it begins to utilize these stored fats for energy.

Cholesterol, another dietary lipid, exclusively exists in animal products and is absent in the plant kingdom. Since the body produces adequate cholesterol, it is not considered an essential nutrient. The liver synthesizes, regulates its release into the bloodstream, and retrieves it as needed.

Unlike triglycerides, cholesterol does not serve as an energy source, but it plays a crucial role as a structural component in every cell of the body. The study of dietary cholesterol primarily focuses on its potential link to intestinal cancer, and although data inconsistency exists, most evidence suggests a possible connection between dietary cholesterol and colon tumor development.
Fats and Health Complications

Lipid content in milk

Milk is the liquid food secreted by the mammary gland for the nourishment of the newly born, containing water, fat, protein, lactose and minerals.

Bovine milk contains about 3.5 to 5% total lipid, existing as emulsified globules 2 to 4 μm in diameter and coated with a membrane derived from the secreting cell.

The lipid content of mammalian milk varies from 16 g/liter (horse) to 105 g/liter (deer), human milk contains about 38 g of fat per liter.

The lipids consist essentially of triglycerides, together with very small proportions of other lipids including phospholipids, cholesterol, squalene, lanosterol, free fatty acids, traces of monoglycerides resulting from lipolysis, and bound aldehydes, glycerol ethers, and also keto-compounds,

Triacylglycerols make up 98% of the lipid content of milk, ranging in different species from 0 to 50% of the total milk volume. The fatty acid composition of the triacylglycerols depends on the species, the dietary fatty acid composition, and the carbohydrate-to-lipid ratio of the diet.

Phospholipids or ‘lipids containing phosphorus’ are about 0.5 to 1% of total lipids, and· sterols are 0.2 to 0.5%. These are mostly located in the globule membrane. Cholesterol is the major sterol at 10 to 20 mg/dl.
Lipid content in milk

Fatty acids – the simplest of lipids

Fats or lipids consists of numerous chemical compounds, including monoglycerides, diglycerides, triglycerides, phosphatides, cerebrosides, sterols, terpenes, fatty alcohols,  and fatty acids.

The fatty acids, the simplest of the lipids, are defined as monocarboxylic acids that tend to be more soluble in organic solvents than in water. They are a hydrocarbon with a methyl group at one end and carboxyl group at the other.

Some naturally occurring saturated fatty acids:
Butyric
Caproic
Caprylic
Capric
Lauric
Myristic
Palmitic
Stearic
Arachidic
Behedic
Lignoceric

The human body needs fatty acids and it can make all but two of them –linoleic acid (the 18-carbon omega-6 fatty acid) and linolenic acid (the 18 carbon omega-3 fatty acid).

Fatty acids are classified according to the number of double bonds they possess. It can be saturated, monounsaturated or polyunsaturated and are essential for energetic, metabolic and structural activities.

Some naturally occurring unsaturated fatty acids:
Monoenoic: Palmitoleic, Oleic
Dienoic: Linoleic
Trienoic: Linolenic
Tetraenoic: Arachidonic

Palmitic acid and stearic acid are by far the most commonly occurring and widely distributed of the saturated fatty acids whereas oleic acid and linolenic acid are the most prevalent of the unsaturated.

These four fatty acids account for over 90% of the fatty acids in the average American diet. Fatty acids of shorter chain length are for the most part minor constituents of plants and animal fats.

However, butyric acid and myristic acid occur in milk fat in large amounts and about 60% of the fatty acid in coconut oil consists of lauric acid and fatty acids of shorter chain length.

Highly unsaturated fatty acids are essential for cellular functions of many differentiated tissues in humans of all ages.

They are mostly incorporated in membrane phospholipids and serve as a structural component of the phospholipid membranes in tissues throughout the body.
Fatty acids – the simplest of lipids

General classification of lipids

Lipids are materials that are sparingly soluble or insoluble in water, but soluble in selected organic solvents such as benzene, chloroform, diethyl ether, hexane and methanol.

Although lipids a wide variety of structures, they possess a number of common features, which may be used in classifying them.

The following classification is limited to lipids of importance in animal nutrition and excludes the fat soluble vitamins that, although properly classified as lipids, following the classic practice of nutritionist.

A. Simple Lipids
Fatty acids
Neutral fats (mono-, di- and triacyl glycerols)
Wax
*Sterol ester
*Nonsterol ester

B. Compound Lipids 
Compound lipids are subdivided into two groups:
Phospholipids 
*Phosphatidic acids, lecithin, cephalins, etc
*Plasmalogens
*Sphinghomyelins

Glycolipid (carbohydrate containing)

Lipoproteins (lipids in combination with protein)

C. Derived Lipids, alcohol (including sterols and hydrocarbons)
General classification of lipids

What is a lipoprotein?

A lipoprotein is the particle transport cholesterol and triglycerides.

All plasma lipoproteins have the same general structure: a hydrophobic core of triglyceride and cholesteryl esters surrounded by a surface layer of apolipoproteins, phospholipids and unesterified cholesterol. 

Structurally, lipoproteins are microscopic spherical particles ranging from 7 to 100 nm in diameter.

Each lipoproteins particle consists of a monolayer of polar, amphipathic lipids that surrounds a hydrophobic core. 

One of the major functions of the liver in lipid metabolism is lipoprotein synthesis. The four major classes of circulating plasma lipoproteins are: chylomicrons, very low density lipoproteins (VLDL), low-density lipoproteins (LDL) and high density lipoproteins (HDL).

While chylomicrons made in the small intestine, the lipoproteins made by the liver. Chylomicrons in the blood deliver dietary fatty acids to cells via the enzyme lipoprotein lipase. The enzymatic reaction releases fatty acids from the chylomicrons’ triglycerides, allowing their uptake into surrounding cells.

LDL lipoproteins are the major transporters of cholesterol in human plasma.

The protein portion of any lipoprotein is called the apolipoprotein. Apolipoproteins play a very important role in the structural and functional relationship among the lipoprotein. Each of the lipoprotein particles contains one or more apolipoprotein.
What is a lipoprotein?