Do eggs increase blood cholesterol?

The latest research on eggs would seem to exclude them as a relevant factor in cholesterolemia: to what extent are they reliable?

He replies Elena Dogliottinutritional biologist, scientific supervisor for the Veronesi Foundation (GO TO THE FORUM)

The deductions that allow us to draw up nutritional guidelines are made taking into account epidemiological studies, further supported by molecular and genetic studies. Today we know that the presence of cholesterol in our body is mainly regulated by endogenous synthesis (we produce it), intestinal absorption and excretion by the liver. When the absorption of intestinal cholesterol increases, for example due to a greater food intake, the amount that reaches the liver also increases, which to defend itself sends various “messages” to itself and to the intestine: reduce cholesterol synthesis; decrease the ability to absorb it; increase its elimination in the bile. The liver itself, by reducing its ability to absorb LDL cholesterol, increases its levels circulating in the blood.

Saturated fats

The interaction between liver and intestine allows to mitigate any increases in dietary cholesterol intake, hence the reason why we do not see a significant association between dietary cholesterol and the risk of cardiovascular disease. On the other hand, saturated fats consumed in the diet have been shown to increase LDL cholesterol through complex mechanisms. Regarding cardiovascular risk, reducing saturated fats would lead to a decrease in risk of more than 20%. Hence the indications, for everyone, to limit these substances in the diet. Many foods that contain saturated fat also contain cholesterol and vice versa, but this is not always the case. An egg, for example, contains 180 mg of cholesterol but the total grams of fat are just over 4 and the saturated fat is less than half.

Three month diet

The ability of the intestine to absorb cholesterol (and phytosterols) depends on receptors that can have different variations: these make them more, less or too efficient. There are therefore subjects whose intestinal cholesterol receptors don’t care about the liver’s order to absorb less. Blood cholesterol levels, in this case, are affected much more than dietary cholesterol. Such people, in addition to saturated fats, must also limit as much as possible foods that contain a lot of cholesterol such as eggs, offal, dairy products and shellfish. Genetic analyzes to understand if you are “super absorbent” are not done, the proof can be obtained with a three month diet (under medical supervision) in which sources of cholesterol are excluded and the effects on the blood are examined.