Whey Protein Q&A - Whey Protein Isolate Versus Whey Protein Concentrate Part 1 - Oxidized Cholesterol
A. Whey protein concentrate contains between 34% and 80% protein, and contains relatively high levels of lactose, fat, and cholesterol. Whey protein isolate, on the other hand, contains 90% or greater protein by weight, and negligible levels of lactose, fat, and cholesterol.
Because whey protein concentrates are often used as filler ingredients in animal feed, baked goods, and processed dairy products, great care is often not taken to protect the delicate whey protein structures in the production of whey protein concentrate. As a result, high levels of denatured and glycated proteins are often formed when whey protein concentrate is produced.
These denatured and glycated proteins (i.e., altered protein structures, and altered protein structures formed when proteins interact with sugars and lipids) greatly compromise the nutritional quality of whey protein concentrate, and may even prove harmful.
Properly-prepared whey protein isolates, on the other hand, are produced using selective filters which rid the product of essentially all denatured and glycated proteins (as well as lactose, fat, and cholesterol). These are just some of the reasons why, we feel, a properly-prepared whey protein isolate is the only intelligent option for use in whey protein nutritional supplements.
Note: Not all whey protein isolates offer the full benefits of filtered whey isolates – whey isolates produced by the ion exchange method, for example, lack an important whey microfraction called glycomacropeptide. Additionally, some whey concentrates may be produced so as to minimize the formation of denatured proteins – these whey concentrates, however, would still contain lactose, fat, and most importantly, cholesterol – which is prone to oxidation during the shelf life of the powder.
Q. What is oxidized cholesterol, and what are its health effects?
A. When a cholesterol molecule interacts with oxygen, oxidized cholesterol may be formed. While unoxidized, or native cholesterol is an important substance needed for the building of cellular structure and hormone synthesis, oxidized cholesterol is metabolized differently, and may be a unique contributor to heart disease and other types of metabolic and hormonal disruption.
Oxidized cholesterol, for example, has been implicated in the development of atherogenesis – the thickening of the arterial wall due to the build-up of fatty material – in other words, the beginning of the clogged arteries of heart disease:
Quote from the above study:
Cholesterol under certain in vitro and possibly in vivo conditions may be oxidized to oxysterols, which are suspected of being initiators of atherosclerotic plaques… Dietary oxysterols are absorbed in the gastrointestinal tract and are selectively transported by the athrogenic lipoproteins LDL and VLDL. The oxysterols cholestanetriol and 25-OH cholesterol have been shown to be atherogenic. Oxysterols are commonly found in dried egg products, powdered milk, cheeses and in a variety of high temperature dried animal products.
As the above study indicates, cholesterol can oxidize inside our body, but it can also oxidize in the foods we eat. While fresh cholesterol-containing foods, cooked normally, contain relatively low levels of oxidized cholesterol, cholesterol-containing dried, powdered, and “shelf-stable” foods are apt to contain relatively high levels of oxidized cholesterol. This includes foods such as powdered eggs, powdered milk, powdered cheese, and whey protein concentrate.
Studies have shown that the oxidized cholesterol in such foods is absorbed and is taken up by the cholesterol-carrying lipoproteins, leading researchers to note that dietary sources of oxidized cholesterol may be unique contributors to atherosclerosis:
Quote from the above study:
It is possible that oxidized cholesterol in the diet accelerates atherosclerosis by increasing oxidized cholesterol levels in circulating LDL and chylomicron remnants.
Because the formation of cholesterol oxides is inevitable in any powdered product which contains cholesterol, we feel that all cholesterol-containing powders (and many products made from them, like ready-to-drink protein shakes) should be avoided by any health-conscious consumer.
Studies have found, for example, that the formation of cholesterol oxides in dairy powders steadily increases during the shelf life of the powders – even when the products are stored sealed at room temperature:
Cholesterol oxidation is likely to be an even greater problem with many ready-to-drink protein shakes which are made with whey protein concentrate powder – and which are then pasteurized at high temperatures, often in the presence of oxidizing agents like unsaturated fats and minerals such as copper and iron.
Ultimately, it’s clear that oxidized cholesterol is metabolized in a fundamentally different way relative to native cholesterol, and is likely to be significantly harmful as a result.