In the 1970s, some researchers suggested that refined carbohydrates, especially sugar and low intake of dietary fiber, were the main factors of coronary heart disease (CHD). This suggestion was quickly eclipsed by the belief that this excess intake of saturated fatty acids (SFA) is a key factor in heart disease.
This view prevailed from around 1974 to 2014. Where is the truth? Well, from the 90s of the twentieth century, more and more evidence, research and observations have emerged that show that the role of saturated fatty acids in the etiology of heart disease is overestimated.
Cholesterol – is it important or not?
We have all heard that cholesterol is extremely dangerous and must be fought with it. Only this theory has extremely weak support in scientific research. Currently, scientists tend to assign a key role to the inflammatory state, eg Kumas, Abbas, and Aster Robbins. PATOLOGY 2nd edition (2016-2017). The immune system, i.e. leukocytes, lymphocytes and macrophages, plays a large role in the etiology of atherosclerotic changes in the coronary arteries according to the latest studies. Of course, cholesterol is an element of atherosclerotic plaque – like fat, calcification and necrotic cells. But … the one we supply with the diet does not necessarily have to be connected with this endogenous one – which is extremely necessary for life.
Is resignation from saturated fats beneficial to the heart?
Well, giving up saturated fat and replacing them with carbohydrates has no effect on HDL and total cholesterol, so it does not prevent coronary heart disease. Decreased saturated fat intake combined with increased intake of polyunsaturated fatty acids reduces the ratio of total cholesterol to HDL cholesterol; it can reduce the risk of coronary heart disease. However, replacing saturated fats and trans fats with polyunsaturated fatty acids, omega-6 (eg containing linoleic acid), does not bring profit, and even increases cardiovascular risk! This clearly proves that polyunsaturated omega-3 fatty acids (n-3 PUFAs, polyunsaturated fatty acids) can be responsible for reducing cardiovascular risk. A lot of detailed studies and meta-analyzes speak about the lack of connection between saturated fat intake with coronary heart disease, cardiovascular disease or stroke. The observations lasted from 5 to 23 years and concerned 347,747 people. Among this group, 11,006 appeared to have coronary disease or stroke. The intake of saturated fat was not associated with the risk of coronary heart disease, cardiovascular disease or stroke.
And what about carbohydrates?
There are more and more premises and studies linking foods rich in carbohydrates with coronary disease. Refined carbohydrates, especially sugars sweetened with sugar, increase the risk of CHD. Conversely, the consumption of whole grains and fiber has a protective effect. Depending on what we choose, the risk may increase by 10-20% (eg simple sugars, table sugar, sweetened beverages) or decrease by 10-20% (whole grains, fiber).
In the prestigious journal The Lancet, interesting data was published on 4 November 2017. The PURE survey concerned a large cohort of people aged 35-70 (taken into the study between January 1, 2003 and March 31, 2013). The study included people from 18 countries, and the average observation continued for 7.4 years. The number of calories delivered by 135 335 people was measured using special questionnaires. The more fat in the diet, the lower the risk of death in individual groups of people. The lowest mortality rate was found in people who supplied fat from 33.3 to 38.3% of the daily energy requirement. With the increasing proportion of fats in the diet, the risk of serious heart disease, heart attack, stroke and even the risk of death for reasons other than cardiovascular diseases decreased. However, the overall risk of death for cardiovascular reasons was the lower the more there was in the saturated fat diet. Similarly, there was a decrease in the incidence of serious cardiovascular diseases. In turn, the highest mortality rate was recorded in people who supplied 74.4% to 80.7% of energy from carbohydrates. With the increasing amount of carbohydrates, the risk of stroke and heart attack increased. In people from the group providing 74.4% to 80.7% of energy from carbohydrates, the risk of death for reasons other than cardiovascular was higher by 36%, compared to those providing approx. 46% of the daily energy supply from carbohydrates (from 42.6% to 49% ).
The role of saturated fat in coronary heart disease is heavily overestimated, nowadays more and more are indicative of carbohydrates (not all, mainly refined sugars, e.g. table sugar, glucose-fructose syrup). They can induce inflammation and affect the atherosclerotic process.
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