Cholesterol is an important part of healthy cell membranes. It also provides a scaffolding the body needs to make compounds such as vitamin D, other hormones, bile, and more. All of our cells make cholesterol but most is produced in our liver and intestines. In addition, we absorb cholesterol from any animal products we eat. In most cases, the body balances cholesterol levels by reducing
cholesterol production when we eat cholesterol-containing foods.
But, even though cholesterol is essential to health, we have been advised for many decades that limiting dietary cholesterol is key to heart health. This, however, is definitely changing. New research instead advises us not to worry so much about the amount of cholesterol in the foods we eat. Instead we must make sure that the cholesterol we eat is not oxidized. This advice is based on studies such as one where 5% of the cholesterol in a rabbit’s diet was replaced with oxidized cholesterol. This small change increased atherosclerotic plaque formation by 100%. Hence the advice: Avoiding oxidized cholesterol is key to not only heart health but to our overall health.
Cholesterol is a molecule with a chemical bond that can be oxidized to form compounds called oxysterols. Up to 70 different oxysterols have been identified and more are expected to be found. Oxysterols are essentially forms of fat that, when incorporated in our cells instead of healthy cholesterol, cause serious malfunctions. Oxysterols are implicated in all types of heart problems, neurodegenerative diseases, inflammatory bowel disease, age-related macular degeneration and other chronic ailments.
Oxysterols are formed during the processing and preparation of animal products. For example, an average fresh egg has about 200-200 milligrams of cholesterol but no oxysterols. In contrast, dried whole egg or dried egg yolk contain large amounts of oxysterols. Many convenience foods are made with dried eggs and as a result are a rich source of damaging oxysterols. Any time cholesterol is exposed to oxygen – such as when meats are ground, flaked, minced or diced to make hamburger, chicken is deboned and deskinned, beef is dried and aged – more oxysterols are formed.
Oxysterols are generated when cholesterol-containing foods are radiated. Radiation of egg yolk powder increases oxysterols from 10 ug/g (micrograms per gram) to 470 ug/g.
Heating disrupts muscle cell structure, inactivates antioxidant enzymes, and releases oxygen and iron, all these actions generate oxysterols. Milk straight from a cow contains only trace amounts of oxysterols but milk processed with heat (e.g., during pasteurization, cheese making) increases them, as does the length of the storage period (e.g., the time the products languish from “harvest” to consumption). In fact, the main source of oxysterols in any type of meat (e.g., beef, chicken, turkey, poultry, or fish) is heat. Oxysterols in cooked meats average from 180-1900 ug/g. All forms of cooking creates oxysterols but interestingly microwaving generates far more than roasting, grilling, frying or other types of cooking.
As we fry foods in animal fat, yet more oxysterols are formed. It turns out that the main source of oxysterols in the average American’s diet comes from fries and potato chips that contain 1.4 mg/g to 16.7 mg/g. And just for comparison: Cooked meats have between 180 and 1900 micrograms of oxysterols per gram. French fries and chips have between 1400 and 16 700 micrograms per gram – that is a lot more.
Freezing will slow down the formation of oxysterols once the ball starts rolling but cannot not stop it. Some frozen meats, such as frozen raw beef and pork meat, have more oxysterols than frozen raw chicken but the cholesterol in chicken more easily generates oxysterols than beef or pork do so they likely are equivalent in the end.
Finally, reheating pre-cooked meats generates far more oxysterols than other heat applications. And reheating in a microwave generates more than any other method of reheating.
So how do you limit your intake of oxysterols if you want to continue eating animal products? The best way is to consistently follow the TQIDiet.
First, on the TQI Diet you will eat mostly high-quality animal products. Better raised animals produce meat and dairy that contain more antioxidants that help slow the formation of oxysterols.
Second, you will not eat ultra-processed foods and will limit most processed foods. This means you seldom will be eating dried eggs, poor quality, oxidized meats and cheeses.
Third, no matter what you are eating, you will always eat proportionately. This helps you avoid excess amounts of cholesterol and in the process, limits your oxysterol intake. And when you are eating beef, fish, poultry, or dairy, you always provide your body with a variety of antioxidants and other nutrients at the very same time. Your body will use those nutrients to disarm oxysterols instead of incorporating them in your cells.
Fourth, on the TQI Diet we do not cook in animal fats such as lard, butter, and ghee, instead our main cooking fat is antioxidant-rich EVOO that helps prevent the formation of oxysterols. We eliminate those oxysterol-rich store-bought chips. And a comment on ghee: Ghee is butter heated for long periods of time and is very high in oxysterols.
And finally: Should you decide to eat a precooked product that contains any animal products – be it beef, chicken, eggs, or cheese – do not allow it anywhere near a microwave oven.
“1959 Microwave” by Ethan
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Interested in learning more about the TQI Diet? We have classes starting soon, and our schedule, a syllabus,and testimonials are posted here