Which fats are most beneficial and which are better to reduce

Fat in human body plays an extremely important role and is indispensable in diet. It is primarily a main energy source, which has a higher energy density than protein or carbohydrates. 1 gram of fat provides 9 kcal, compared to 1 gram of protein or carbohydrates that provide 4 kcal. Fat in the body also serves as a backup material, builds cell membranes and nervous system cells, participates in the transport of vitamins and the production of hormones.

Does the origin of fatty acids influence the health value of fat? Yes, it does, as it impacts the body's functioning. Fat is composed of glycerol and fatty acids, which can be saturated or unsaturated. The type that prevails in a given type of fat determines its properties. Plant-based fats are characterized by a high proportion of unsaturated fatty acids and are cholesterol-free, which has a positive impact on health. Animal fats, on the other hand, can be a source of cholesterol and saturated fatty acids, of which there should be as little as possible in the diet. All natural fats are a blend of saturated and unsaturated fatty acids. Fats rich in unsaturated fatty acids have a liquid form and are called oils. They originate mainly from oil plants or seeds and kernels of other plants (e.g., grapes, cumin, bishop's weed, pumpkin). Unsaturated fatty acids occur in two forms: cis and trans. Cis forms are safe for health. Trans forms can occur naturally in fat (e.g., in butter, their amount is about 2-3%) or arise in production processes. Trans fatty acids are a risk factor for the development of overweight and obesity.

Butter primarily consists of saturated fats, the amount of which in the diet should be kept to a minimum. However, it is worth noting that butter contains a significant amount of short-chain fatty acids, including butter acid, which has a general anti-inflammatory effect and supports the function of intestinal epithelial cells. However, the amount of these fatty acids is so small that it cannot significantly increase the health benefits of butter. Butter is also a significant source of naturally occurring fatty acids in the form of trans fats. Interestingly, natural trans fats do not have the same detrimental effect on the body as those artificially produced. Research has shown that the trans fats found in butter, particularly vaccenic acid, may have some anti-cancer and anti-atherosclerotic effects (B. Paszczyk 2022). Nevertheless, it is important to remember that the adequate amount of trans fats for the body is < 2% of the daily caloric intake. In summary, butter is not harmful to health and may even have some health benefits. However, it should not be considered an essential component of the diet and excessive consumption should be avoided, as this can lead to increased calorie intake and weight gain.

Hard margarines are mainly produced from processed plant-based fats and emulsifiers. They have a controversial reputation due to the use of partially hardened plant-based fats in their production, making them a source of trans fats. However, in order to meet the demands of consumers increasingly aware of a healthy diet, a safer method of producing margarines has been introduced - esterification, which does not lead to the loss of fatty acids (H. Makala 2020; K. Wolnicka epub). How can one find out which method of fat hardening was used in the production of a specific margarine? One should orient themselves to the information provided by the manufacturer on the label. If partially hardened/hydrogenated fats are listed in the ingredients, it is a product that is a source of trans fats and should be avoided. This primarily applies to hard margarines in the form of cubes used for baking. When it comes to soft margarines (in a cup, for spreading), they are not necessarily products that should be avoided in the diet. Due to the addition of phytosterols (on the label as stanols/plant sterols), they may have a supporting effect on achieving a normal cholesterol level in the blood (K. Mironiuk 2018). It is good if rapeseed oil, sunflower oil, or olive oil is listed as the first ingredient. Fat mixtures contain milk fat (butter, cream), which can account for 10-80% of the fat in the composition, as well as plant-based fats. If a product contains less than 10% butter, it is no longer a fat mixture, often the name "spreading fat" is then used on the packaging. Good quality fat mixtures should contain milk fat, plant-based oils (rapeseed oil, olive oil), which have a positive impact on health. They can also contain salt, water, additives such as vitamins. It is advisable to avoid fat mixtures containing preservatives, emulsifiers, and partially hardened fats (M. Piekut 2014). Soft margarines or fat mixtures can be included in the diet, provided that they are products with good composition and are used only as an accompaniment to bread (in small quantities). Hard margarines are often products in the production of which large amounts of trans fats are produced and are therefore a much more harmful choice than soft margarines or butter.

Plant-derived fats form a category that is known for its high content of unsaturated fatty acids, including omega-3 and omega-6 polyunsaturated fats. The composition of a specific oil, particularly the amount of certain fatty acids, depends on its origin.

It is predominantly composed of monounsaturated fatty acids (75%), while omega-3 and omega-6 fatty acids make up only around 10%. Nonetheless, it contains components that exhibit a range of health benefits. Research has confirmed the effect of olive oil on reducing the risk of cardiovascular disease and the occurrence of cancers. This is due to the presence of polyphenols, phytosterols, or beta-carotene - strong antioxidants (A. Dutkowska, D. Rachoń 2015; M. Moszak, A. Zawada, M. Grzymisławski 2018). It is also worth noting that olive pomace oil, a less refined and cheaper product than extra virgin olive oil, also has a cholesterol-lowering effect (S. González-Rámila et al. 2023). Olive oil should be a regular part of our diet, as its uses are highly versatile - it can be used both cold, for example, in salads, and for frying and baking.

Canola oil, due to its similar composition and health benefits to olive oil, is known as the olive oil of the north. However, it contains more omega-3 fatty acids (31% fatty acids). Research has shown that incorporating this oil into the diet aids in reducing the risk of heart disease and diabetes by enhancing the insulin sensitivity of cells. Canola oil is also a source of vitamin E and other antioxidants, which supports the immune system (M. Moszak, A. Zawada A., M. Grzymisławino 2018; D. R. Rosskog-3-H. 2011). It is a readily available and affordable product that should be recommended in a healthy diet.

It is predominantly saturated fatty acids. It has been analysed for its effects on cardiovascular disease and has been found not to increase total or LDL cholesterol levels as much as butter, and not to significantly increase HDL cholesterol levels, as has been observed in other vegetable oils (L. Eyres et al., 2016). However, for some time opinion has circulated about the health effects of oleic acid due to its fatty acid content.

It is the second vegetable fat with a high content of saturated fatty acids. The evaluation of its health benefits is difficult due to the large differences in composition, depending on the raw material used for its production. In studies, the origin of the fat is often not indicated. Much attention has been paid in scientific works to the effect of palm fat on the lipid profile and the risk of cardiovascular disease. However, they do not give a clear answer. Some studies have shown a decrease in total cholesterol and LDL levels, while others have shown no effect at all. According to some studies, palm fat increases HDL levels, however, a meta-analysis has shown a significant increase in LDL cholesterol levels compared to plant fats containing mainly unsaturated fatty acids.

Fats are an indispensable component of the diet and should not be excluded from daily meals. However, they are the most caloric nutrients and should not be consumed without moderation. Among all fats, those composed of unsaturated fatty acids offer the greatest health benefits. Popular examples include olive oil and rapeseed oil. Fats such as butter or soft margarines can be used as an addition to bread, but caution should be exercised when choosing hard margarines, as they may contain harmful trans fats. In the case of tropical oils, there are no unequivocal studies confirming their positive or negative impact on health.