Foods rich in fats or lipids are all those foods that, chemically and nutritionally, are distinguished by their high intake of triglycerides and/or cholesterol.

Foods with Fats

Triglycerides and Cholesterol

Fats are substances soluble in organic solvents and not very soluble in water; it is difficult to define the functional unit of fats, as they represent a quite heterogeneous group of molecules all different.

Classification of major fats

Containing glycerol: Neutral fats (monoglycerides, di-glycerides and triacylglycerols or triglycerides), glycerol ethers (glycosylglycerides and phosphoglycerides; phosphatides; phosphatidylglycerols; phosphoinositides)

NOT containing glycerol: Sphingolipids (ceramides; sphingomyelins; glycosphingolipids), aliphatic alcohols and waxes, terpenes and steroids (cholesterol), fatty acids

  • Triglycerides:Triglycerides or triacylglycerols are neutral lipids containing fatty acids bound to a glycerol molecule; in nutrition they provide 9 kcal per gram and account for about 25-30% of the energy ration. Their composition in fatty acids represents a characteristic element between a good and a bad diet; in fact, the fatty acids that compose them are usually different from each other (although on average they contain 16-18 carbon atoms more or less saturated) and their nature distinguishes their peculiarities as well as their nutritional impact.
  • Cholesterol: Cholesterol is the most abundant steroid in the body and is NOT essential as about 70% of the total is derived from endogenous Acetyl-CoA. It is a fundamental substrate for the synthesis of steroid hormones and vitamin D, moreover, it represents a structural element of the cellular membranes; the only way of elimination of cholesterol is the feces, in which it is poured through the bile salts (compounds deputies to the digestion of alimentary lipids).
  • Essential components: among the lipid molecules there are also nutrients called essential, or that the body is not able to produce independently. Among these we remember the polyunsaturated fatty acids of the omega3 and omega6 series, and the liposoluble vitamins: A, D, E, K.

Distinction of foods rich in fats

Among foods rich in fats it is possible to make a distinction between those rich in triglycerides only, those rich in triglycerides and cholesterol, and those containing significant amounts of cholesterol but proportionally not as rich in triglycerides.

Foods rich in triglycerides

Foods rich in triglycerides alone are primarily vegetable oils for seasoning. This category of foods is distinguished by a triglyceride intake of 99.9% by total weight and only trace amounts of water. They provide respectively 899kcal per 100g of edible part but their qualitative composition can vary significantly depending on the food of extraction.

The oils differ from each other for the nature of the fatty acids contained which, as mentioned above, determines the chemical and physical characteristics useful in different food preparations. For example, oils rich in monounsaturated and saturated fatty acids (hydrogenated and non-hydrogenated) but poor in polyunsaturated fatty acids are much more suitable than others for frying, as they have a smoke point (PF) rather high. This is the case of palm oil (PF 240 ° C) but also of extra virgin olive oil (PF 210 ° C), the latter used in frying to a limited extent because of the decidedly higher costs compared to tropical extracts or seeds. The same is true for oils useful for the preservation of food in oil, even in this case the content of polyunsaturated fatty acids plays against the food process: being these nutrients easily peroxidized, would contribute negatively to the preservation of the product facilitating rancidity (lipid peroxidation). Are therefore not suitable for storage in oil grape seed oil, soybean oil or sunflower oil, while extra virgin olive oil (also rich in natural antioxidants: vitamin E and polyphenols) stands out once again for its high healthiness even in frequent use. On the other hand, in the use of raw oil is possible to range on many products derived from many raw materials, the important thing is that the oil in question is obtained through the COLD PRESSING (such as extra virgin olive, soybean, flax, etc.); this is an absolutely fundamental requirement, as the main nutritional characteristic of oil for seasoning is the contribution of essential fatty acids (omega6 and omega3 family) that, being easily thermolabile, could deteriorate after the extraction process (hot pressing).
There are also other foods rich in triglycerides but without cholesterol; among these we remember:

  • The olive, a fruit from which oil can be extracted
  • Avocado, an exotic fruit with a very high SATURATED lipid content
  • Coconut, an exotic fruit with a very high lipid content of medium-chain fatty acids (similar to those in breast milk), from which oil can be extracted
  • Peanut, a “roasted” legume from which oil can be extracted
  • Some achenes better known as nuts: walnuts, almonds, hazelnuts, pecans etc.

As already mentioned, foods rich in triglycerides only are typically of vegetable origin and their importance in the diet varies according to the specific product and its characteristics, or rather according to the type of fatty acids they are made of. It should also be remembered that among all the foods mentioned above there are NOT products actually rich in eicosapentaenoic acid (essential fatty acid of the omega3 category – EPA), instead very present in many foods of animal origin.

Foods rich in triglycerides and cholesterol

Foods rich in triglycerides and cholesterol are products of animal origin; it should be noted that, except for some particular cases, these are also characterized by SATURATED fatty acids, therefore typically hyper-cholesterolemic and potentially harmful to the cardiovascular system.
Foods rich in fats, in particular triglycerides and cholesterol, are OVER:

  • Some offal or components of the fifth-fourth: these include the brain (also rich in essential fatty acids and phospholipids) and the liver.
  • Cream, mascarpone and aged cheeses (all): obviously, there is a certain variability in the total fat content that depends on the raw material of cheesemaking: goat, buffalo, sheep or cow’s milk, whole, skimmed or partially skimmed. Some examples of aged cheeses are: Parmigiano Reggiano, Grana Padano, Pecorino (all), Emmenthal, Edamer, whole milk provola, etc.
  • Butter, lard, suet, tallow and pork rind.
  • White meat WITH SKIN: in itself, white meat is recommended in the diet of hypercholesterolemic people, as it is distinguished by an excellent “leanness”; the situation is reversed if it is consumed WITH SKIN, which contains decidedly high portions of both cholesterol and triglycerides.
  • Fatty, cured and salted but NOT degreased meats: all of them. From bacon to sausage; from ribs to bologna.
  • Some fishes and all the eggs of the fishing products: some examples are eels (with the due differences related to the origin, the size and the season of capture), tuna belly (even if very rich in EPA and scarce in saturated fatty acids), big specimens of salmon (even if very rich in EPA and scarce in saturated fatty acids), caviar, lumpfish eggs, roe, sea urchins, flying fish eggs (very used in the preparation of Japanese raw food). NB. The skin of fish, like that of white meat, contributes significantly to raising the levels of total fat introduced with the diet.
  • Egg yolk: heavily used in pastry preparations such as custard, custard etc.

Foods rich in cholesterol but poor in triglycerides

This category surprisingly includes some by-products of fishing; for those who do not know, it is correct to say that the population does NOT consume enough fish (especially blue fish), but this category does NOT include molluscs and crustaceans that, on the contrary, are widely consumed globally. The BIVALVI molluscs and crustaceans are characterized by a significant intake of cholesterol in relation to a content of triglycerides not excessive; in particular we mention:

Mussels and oysters: especially during reproduction, these organisms modify their cholesterol content in order to comply with the hormonal cycle of fertilization.
Shrimps, crabs and all their derivatives: among which crab meat, crab claws (fried), surimi, shrimp tails, shelled shrimps etc.

NB. In the list have been mentioned ONLY foods rich in fat whose nutritional values are known; however, it is deducible that also other “similar” products belonging to the same category/genre (such as shrimps compared to crustaceans mentioned in the last paragraph) can boast the same chemical-nutritional characteristics and therefore should be treated as such.

Bibliography:

  • Molecular bases of nutrition – G. Arienti – Piccin – page 131
  • Recommended Nutrient Intake Levels for the Italian Population (LARN) – Italian Society for Human Nutrition (SINU)