Saturated, unsaturated or trans: the fats we put on our plate are not all the same and it is important to know the differences
They provide essential fatty acids of the omega-6 family (linoleic acid) and of the omega-3 family (linolenic acid) and promote the absorption of fat-soluble vitamins A, D, E, K and carotenoids. Fats, in addition to providing concentrated energy, therefore, are valid allies for human health. But as long as you choose the right ones and limit the quantities, because excessive consumption of these substances in the usual diet represents a risk factor for the onset of obesity, cardiovascular disease and cancer.
What is the right dose?
As stated in the Guidelines for a healthy Italian diet, the quantities of fats that ensure good health vary from person to person, depending on sex, age and lifestyle: an indicative amount for adults it is the one that provides from 20-25% of the total calories of the diet (for sedentary subjects) up to a maximum of 35% (for subjects with intense physical activity). For children under the age of 3, however, the proportion of dietary fat in the diet may be higher. The quantities of fats present in foods, both in visible form (ham, steak fat, etc.) and invisible (cheese fat, etc.), vary from one product to another and range from very low values (around 1 % in various vegetable products and in certain particularly lean meats and fish) up to very high values in seasonings: 85% in butter and margarine and 100% in all oils.
Which ones to choose
All fats are the same in terms of energy supply, but in terms of quality they can be very different. In fact, their chemical composition varies, and in particular that of fatty acids (which can be saturated, unsaturated, trans).
The fats in foods with a high content of saturated fatty acids tend to raise the level of cholesterol in the blood even more than the dietary intake of cholesterol itself. These foods mainly include dairy products (cheeses, whole milk, cream, butter), fatty meats and their derivatives and certain vegetable oils (palm oil and especially coconut oil).
The fats of foods with a high content of unsaturated fatty acids, on the other hand, do not raise the level of cholesterol in the blood. These foods are mainly represented by vegetable oils (seed and olive), nuts, hazelnuts, olives and fish. Unsaturated fats include both monounsaturated and polyunsaturated fats.
Olive oil is particularly rich in monounsaturated, especially oleic acid, which has two advantages: it decreases the level in the blood of low-density lipoproteins LDL and VLDL which carry that part of cholesterol that tends to remain in the blood and deposit on the walls of the arteries ("bad cholesterol") – and does not change, or even increase, the levels of another type of lipoprotein: HDL, which usefully work to remove cholesterol from the blood and deposits in the arteries and to initiate its elimination ("Good cholesterol").
Seed oil, on the other hand, is generally rich in omega-6 polyunsaturates, which are also effective in decreasing the level of LDL and VLDL in the blood.
Fish fats are rich in polyunsaturated fatty acids of the omega-3 type, capable of decreasing both the level of triglycerides and the aggregation capacity of platelets (i.e. the risk of thrombosis) in the blood, thus protecting the body from the possible onset of cardiovascular diseases. Unsaturated fatty acids may also play a role in the prevention of some forms of cancer.
Trans fatty acids
They tend to raise the level of cholesterol in the blood, also favoring the increase of "bad cholesterol" compared to "good cholesterol". They are naturally present in products obtained from ruminant animals (meat and milk) or can form during some industrial treatments of vegetable fats and therefore be found in the processed foods that contain them.
How to behave, then?
The guide offers simple tips to put into practice immediately:
- Moderate the amount of fats and oils you use for seasoning and cooking. If necessary, use non-stick pans, foil cooking, microwave oven, steam cooking, etc.
- Limit the consumption of seasoning fats of animal origin (butter, lard, lard, cream, etc.).
- Prefer seasoning fats of vegetable origin: especially extra virgin olive oil and seed oils.
- Use seasoning fats preferably raw and avoid reusing cooked fats and oils.
- Do not exceed the consumption of fried foods.
- Eat fish more often, both fresh and frozen (2-3 times a week).
- Among meats, prefer lean ones and eliminate visible fat.
- If you like eggs, you can eat up to 4 per week, spread over the various days.
- If you consume a lot of milk, preferably choose skim or semi-skim milk, which still maintains its calcium content.
- All cheeses contain high amounts of fat: choose the leaner ones anyway, or eat smaller portions.
- If you want to check what and how much fats are contained in foods, read the labels.