Things you should keep in mind while taking Saturated fat
Cardiovascular diseases are the leading cause of death, accounting for about 45% of all non-infectious deaths. In this sense, modifiable risk factors such as diet, physical activity, smoking, and alcohol intake are the main causes of disease.
Among the dietary factors, saturated fatty acids and Trans fat are pointed out as the most relevant factors. However, saturated fat does not have a homogeneous effect and the influence of the food in which it is found is a determining factor to take into account.
Guides on Fat Consumption
The WHO is preparing a new guide on the consumption of saturated fat and trans-fatty acids. His draft was published in May 2018, including a recommendation to reduce saturated fat intake to less than 10% of total dietary energy. He also recommended replacing saturated fat with mono and polyunsaturated fat. In this way, the incidence of cardiovascular diseases and mortality would be reduced.
However, this draft has received numerous criticisms from some researchers. In this sense, it is pointed out that, taking into account current evidence, the health effects vary for each type of saturated fatty acid and depending on the food in which it is found. Thus, the composition of the food would have a substantial effect on lipid digestion, absorption kinetics, and post-meal blood lipid levels. The latter is an independent risk factor for cardiovascular disease.
Not all saturated fatty acids are the same
The magnitude and health effects vary depending on the fatty acid involved.
If the total cholesterol / HDL cholesterol ratio is used as a biomarker of cardiovascular risk, it varies for lauric (12: 0), myristic (14: 0), palmitic (16: 0), and stearic (18: 0) acids.
On the other hand, plasma concentrations of heptadecanoic acid (17: 0) are associated with a decreased risk of coronary heart disease.
In conclusion, saturated fatty acids should not be considered as a homogeneous group, taking into account their effects on the risk of cardiovascular disease.
Lipoproteins and cardiovascular events
On the other hand, it is not clear whether changes in the lipoproteins that transport cholesterol and triglycerides through the blood translate into a reduction in cardiovascular events and mortality regardless of the food source consumed.
In this sense, many studies do not take into account food sources of saturated fat. Instead, they compare the effects of diets supplemented with fats rich in saturated, mono, or polyunsaturated fatty acids (cocoa butter, butter, olive oil, or soybean oil).
Thus, the dietary matrix in which the fatty acids are present may be more important for its effect on cardiovascular risk than the saturated fat content.
LDL cholesterol, in doubt as a marker of cardiovascular risk.
The use of LDL cholesterol (“bad cholesterol”) as the only marker of cardiovascular risk can lead to erroneous conclusions. The atherogenicity of LDL particles is determined, among other things, by their size. Thus, small and medium LDL particles show the strongest association with cardiovascular disease risk, while larger particles show no association.
In this sense, the increase in the concentration of serum LDL cholesterol due to the consumption of saturated fat is related to a parallel increase in the size of the particles, so it may not translate to an increased risk of cardiovascular disease.
On the other hand, some studies show how diets high in saturated fatty acids are associated with higher serum concentrations of LDL cholesterol, but also with higher values of HDL cholesterol (“good cholesterol”), lower concentrations of triglycerides, and a lower Apolipoprotein ratio. B / Apolipoprotein A.
Finally, diets high in saturated fat are not necessarily associated with more cardiovascular events and are sometimes even associated with a lower risk of stroke. The relevance of these observations has been confirmed in randomized studies comparing diets with different types of fat.
Mediterranean diet studies
Regarding the Mediterranean diet pattern, the Lyon Diet Heart Study and the updated analysis of the PREDIMED study show a significant reduction in cardiovascular events without mediating a reduction in LDL cholesterol. In both studies, it was shown that the concentration of LDL cholesterol is not a valid biomarker for the modification of cardiovascular risk caused by changes in diet.
Evidence in observational studies
Contrary to the opinions of some, observational studies are valuable in evaluating the association between saturated fat and its potential long-term effects, including cardiovascular health.
In this sense, long-term evidence indicates that the dietary matrix is more important than the fatty acid content itself in predicting the effect of food on the risk of coronary heart disease.
In this way, it can be concluded that the recommendations based on the reduction of saturated fat without considering specific fatty acids and specific food sources are not based on evidence.
These recommendations may determine a reduction in the intake of foods with a high nutritional density. Some of them could even contribute to the reduction of cardiovascular risk, type 2 diabetes, and some deficiency diseases.
The evolution of dietary guidelines on fat
Since the middle of the last century, nutrition has focused on the effects caused by isolated nutrients. Similarly, public health policies have focused on micronutrient deficiencies. This led in the past to the fortification of certain staple foods, such as iodine in salt and vitamin B3 and iron in wheat flour.
In the case of the prevention of chronic diseases such as cardiovascular diseases, the paradigm of the isolated nutrient has been maintained. Thus, the conclusion has been that dietary fat – and saturated fat in particular – should be reduced to prevent cardiovascular disease.
In this sense, the American dietary guidelines of the 1980s and international guidelines since then have focused on reducing saturated fat intake.
Historically, this reduction in saturated fat led to the proliferation of industrial foods low in fat, saturated fat, and cholesterol.
An example is the production of margarine and spreads based on the partial hydrogenation of vegetable oils. These increased the presence of Trans fatty acids to more than 40% of total fat.
