History of Saturated Fat, is it Really Bad?

Due to the vast variety of conflicting nutrition information available on the internet, it is very important that we rely on scientific information. How many of us know that fats are essential macronutrients? A global survey found that 95% of respondents knew that vitamins are essentials but only 41% knew about essential fats. From different types of fats, saturated fats are considered to be bad fats. Let’s explore what scientific research says.

When we talk about saturated fat people are always confused about nutrition and research finding saturated fats. Two decades ago, somewhere in 1980, the classic heart-health hypothesis said that dietary saturated fats increase atherosclerosis and coronary heart diseases (CHD). This was interpreted because saturated fats increase serum total cholesterol and low-density lipoprotein cholesterol (LDL-C).

Later, it was established that there are multiple pathways that mediate the development of CHD. It’s not only the LDL-C but other blood lipids, lipoprotein, and other factors like hypertension, smoking, diabetes, overweight, and obesity. Thus, Dietary fats have a very complex and divergent effect on CVD.

How Much Saturated Fats Can I Take? If They are Not Bad then Why Has WHO Set a Limit?

Let’s see if saturated fats are not bad then why’s there a limit set by WHO. WHO recommends the saturated fat intake of 20 to 35% of total calorie intake, min of 20% so that fat-soluble vitamins can be accommodated and to prevent atherogenic dyslipidemia (low HDL and high Triglyceride(TG)) which can happen because of high carbohydrate and low fat diet. But an upper limit of 35% fat is provided, just because one can easily cross the limit of total calories intake limit (TDEE), which must be checked. There was no upper limit of saturated fat because of a lack of supporting evidence.

An important point to understand here is that different countries have their own set of rules, Dietary Guidelines for American says, intake of saturated fat should be less than 10% and Canada’s Heart and Stroke Foundation set no limit. So, the question is how much saturated fat to be consumed? Let’s see!

Let’s Understand the Role of Saturated Fats in Coronary Heart Diseases (CHD) and Decide the Limit!

The role of saturated fats in heart diseases is complex because of heterogeneous biological effects of different fatty acids and diversity of food sources. Do you know that major saturated fatty acid (palmitic acid) is synthesized in the liver from starch and sugar? And it is a predominant fatty acid present in dairy and MEATS. So, if you don’t take dietary saturated fats, your body has the capacity to produce it.

Multiple studies, just accessing the variation of saturated fat intake in the diet found that saturated fat is not associated with CVD but it is the Trans fat.

Some studies tried to replace the saturated fats with complex carbs or simple carbs and analyzed the results. These studies need more research. Few studies state that replacing the saturated fats with complex carbs lower the risk than the simple carbs in an isocaloric diet. Other studies say that simple carbs/sugar produce more adverse effects than saturated fats. So, more research is needed to conclude the replacement of saturated fats with carbohydrates.

Another latest research says that the effect of saturated fat on Cardiovascular health depends on its food source and other fat source, nutrients and bioactive that modify the biological property of saturated fats.

Polyunsaturated Fatty Acids (PUFA) and Cardiovascular Health!

Many studies found that inclusion of Polyunsaturated Fatty acids (PUFA) decreased the risk of cardiovascular disease (CVD). The 5% increase in PUFA results in a 10% decrease in CVD in controlled trials.

These benefits were seen when polyunsaturated fatty acids (PUFA) were increased, not when saturated fats were replaced with carbohydrates and monounsaturated fatty acids (MUFA), instead keeping the saturated fatty acid in the diet. Lots of studies provide very supportive evidence of adding PUFA to reduce CVD risks. A Mediterranean diet study (high in MUFA and PUFA) shows 30% reduction in risk of myocardial infarction, stroke or death. This diet also shows benefits in improving cholesterol, blood sugar and blood pressure.

Foods high in MUFA and PUFA show good results in reducing the risk of cardiovascular diseases (CVD). Inclusion of nuts and olive oil have shown to decrease the risk of CVD. The phenolic compounds present in Olive oil which have antioxidant and anti-inflammatory properties reduce the oxidative stress. Food high in plant sources of MUFA showed benefits for cholesterol.

Which Fats to Avoid/Minimize and Which Ones are Not Really Required?

Trans fats are the fats that we should minimize or avoid in our diet. They raise LDL-cholesterol levels (bad cholesterol), triglycerides, reduce HDL-cholesterol (good cholesterol), increase the inflammation, make liver fatty which results in promoting the cardiovascular diseases (CVD).

European Union has already taken the stance to reduce trans fats from the diet, moreover Denmark is the first country which banned the sales of products containing trans fats. The USA has also removed partially hydrogenated oils from the safe category.

Monounsaturated fats (MUFA) are generally synthesized by the liver in response to carbohydrate consumption. They are not required in the diet thus no adequate intake is recommended. MUFA is mostly available in the plant and animal sources in the form of oleic acid so no limit of intake is set.

Finally, How Do We See Fat?

Relation between Dietary fat and CHD is complicated, women associate fat intake with obesity and old people associate with heart health. As we see Mediterranean-style diets for weight loss and reducing CVD. But excess consumption of the calories has more effect on CVD health than the type of fat (saturated fat).

For the prevention of chronic diseases, nutrient-based recommendations are more difficult to translate to the public. The 2015 Dietary Guidelines Advisory Committee strongly supported this shift toward focusing on foods and healthier dietary patterns, rather than individual nutrients or limits on total dietary fat thus focusing on overall dietary patterns and foods rather than single nutrients is important.

The type of approach matters a lot, Isolated nutrients (low-fat or high fat diet), types of fat (saturated or unsaturated fats) or the overall dietary pattern (involving health food items, maintaining the calorie balance). The overall dietary patterns are recommended by many countries.

Take Away!

To conclude the overall quality of one’s diet along with the type and quantity of food has more impact on the cardiovascular and general health than any single macro-nutrient such as saturated fats. Highly processed foods have saturated fat but in addition they are high in trans fats as well. Adding polyunsaturated fats have shown to improve cardiovascular health but it’s not the only factor. Till date, from the research I have concluded that as long as your overall dietary pattern is perfect, saturated fats are not that bad.

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