Saturated Fatty Acids

Meats Low in Saturated Fat

Meats low in saturated fat (<2 g/85 g) include turkey and chicken breast without skin, kangaroo, ostrich, goat, bison (buffalo) and certain beef cuts, like top sirloin and round, and and pork cuts, like sirloin ^[50].

Most fish and other seafood, eggs, nuts, seeds and vegetable oils (except coconut, palm and palm-kernel oil) contain less than 2 grams of saturated fat per serving (3 oz meat or fish, 1 oz nuts, 1 tbsp oil or margarine) ^[50]. Most fruits, vegetables and legumes are low in fat and saturated fat ^[50].

The Effect of Specific Saturated Fatty Acids on Blood Lipids

Excessive intake of saturated fats may raise the blood levels of total and LDL (“bad”) cholesterol and triglycerides and thus increase the risk of coronary heart disease and stroke ^[1,11,31]. Diet high in saturated fats can result in very different blood lipid changes in different individuals, though ^[2]. Weight loss of even few pounds reduces LDL cholesterol levels regardless of the diet composition ^[31-V8].

Bellow are common saturated fatty acids arranged by their cholesterol-raising effect (from lowest to highest):

• Stearic acid (the main saturated fatty acid in shea butter ^[48], cocoa butter and dark chocolate ^[23], also abundant in beef tallow, lard and milk fat) intake results in a lower raise of total and LDL cholesterol than other saturated fatty acids; its effect on blood cholesterol levels is comparable with unsaturated fats; it decreases total/HDL cholesterol ratio ^{[3,4,5,12,29]} and less likely causes the formation of blood clots than other saturated fatty acids ^[12].
• Lauric acid (in coconut milk, meat and oil, and palm-kernel oil) raises total, HDL and LDL cholesterol but increases HDL more than LDL, so it decreases total/HDL cholesterol ratio  ^[3,5,6].
• Myristic acid (in butter, coconut oil, palm-kernel oil) raises total and LDL cholesterol ^[3,5].
• Palmitic acid, the most abundant saturated fatty acid in the human diet (in meats, dairy, palm oil) raises total, LDL and HDL cholesterol and slightly raises total/HDL cholesterol ratio ^[3,5].
  • In one study, palmitic acid increased blood cholesterol levels only in individuals who already had increased total cholesterol levels (>225 mg/dL) and who consumed more than 400 mg of cholesterol per day, but not in individuals with normal blood cholesterol levels who consumed less than 300 mg of cholesterol per day ^[67].
  • On the World Health Organization (WHO) website, Dr. Chu-Sing lists various studies in which the intake of palm oil, which is high in palmitic acid, did not raise the total and LDL cholesterol, but raised HDL cholesterol levels ^[8].

High blood levels of small, dense LDL particles (LDL IV) ^{[51,52,53,54,59]} have been associated with increased risk of coronary heart disease.

Factors that increase blood levels of small, dense LDL particles ^[55,56,57]:

• Genetic factors
• Obesity and insulin resistance
• Diet low in saturated fats and cholesterol was associated with small dense LDL particles in some individuals ^[60].

Factors that decrease blood levels of small, dense LDL particles:

• Weight loss ^[61]
• Diet high in fat and saturated fat increases blood levels of apolipoprotein III, which is a risk factor for cardiovascular disease ^[58] but decreases the levels of small dense LDL particles ^[62].

The Effect of Replacing Saturated Fats with Other Macronutrients

• Replacing some of the saturated fats in the diet with polyunsaturated or monounsaturated fats decreases blood levels of total and LDL cholesterol ^[2,43].
• Replacing saturated fats with carbohydrates decreases both LDL (especially small-size LDL) and HDL cholesterol, and increases triglyceride levels and does not lower the risk of coronary heart disease ^[2].

The Effects of Various Foods or Dietary Pattern on Blood Lipid Levels

• In one study, vegans and ovo-lacto vegetarians had lower blood levels of total and LDL cholesterol and triglycerides than meat eaters ^[24].
• According to one 2011 meta analysis, dark chocolate and cocoa in amounts that do not exceed the recommended daily calorie intake reduce total and LDL cholesterol and do not affect HDL cholesterol and triglyceride levels ^[25].
• In one 2014 systematic review, palm oil, which is high in saturated palmitic acid, was associated with higher total and LDL cholesterol levels than mono- and polyunsaturated fats, but not in young adults and in those with relatively low-fat diets ^[45].

The Effect of Saturated Fats on Heart Disease and Stroke

CONFLICTING EVIDENCE

According to several systematic reviews of studies, high intake of saturated fats is associated with increased risk of coronary heart disease ^{[11; 31-V8; 32-p.485]}, and replacing some of saturated fats with either polyunsaturated fats ^[2,27,43] or both mono- and poly-unsaturated fats is associated with decreased risk ^{[10,15,26,28]}. Replacing saturated fats with carbohydrates does not seem to be associated with a decreased risk of coronary heart disease ^[2,15].

American Heart Association recommends limiting saturated fats intake to 7% of total calorie intake (up to 16 g saturated fats a day in a 2,000 calorie diet) ^[1].

However, according to other systematic reviews, there is insufficient evidence about saturated fats as a risk factor for coronary heart disease ^{[2,30,34,35,36]} or stroke ^[27].

In the Health Professional Follow-Up Study (1986-1992), high saturated fat intake was associated with increased risk of heart disease only when it was combined with low dietary fiber intake; high saturated fat intake alone was not associated with heart disease ^[63].

The Effects of FOODS High in Saturated Fats on Heart Disease

INSUFFICIENT EVIDENCE:

• According to a 2013 Cochrane review of randomized clinical trials, there is a limited evidence that a Mediterranean diet (a diet with a high monounsaturated/saturated fat ratio, high amount of legumes, cereals, fruit and vegetables, moderate consumption of red wine and dairy products, low consumption of red meat and increased consumption of fish) reduces some of the risk factors of cardiovascular disease ^[26].
• There is a limited evidence that vegetarian diet, which is usually low in saturated fats, is associated with lower risk of ischemic heart disease ^[33-p.4].
• There is conflicting evidence about the effect of red meat (beef, pork) intake on heart disease: from inconsistent evidence ^[33-p.4] to increased risk associated only with processed but not unprocessed red meat ^[46,47] and increased risk of death from heart disease only in men ^[49].
• There seems to be no significant correlation between dairy products ^[37,39] or, specifically, milk ^[16,17,18], cheese ^[19] or butter ^[20] consumption and chronic heart disease. A study running in Sweden for 14 years has revealed that rural men whose diets were high in both fruits/vegetables and milk products had less coronary heart disease than those who ate a lot of fruit/vegetables but few milk products ^[21]. Another review of studies has shown an association between high dairy consumption and decreased incidence of heart attack and stroke ^[22]. The DASH (Dietary Approaches to Stop Hypertension) eating plan, which includes diet low in saturated and trans fats and high in potassium, calcium and magnesium, was associated with decreased risk of high blood pressure; the drop of blood pressure was greater when dairy was added to the diet ^[13,14].
• Chocolate intake may not increase the risk of cardiovascular disease ^[38].
• In one 2005 study in Costa Rica, consumption of palm oil was associated with increased risk of heart attack ^[9]. In one multi-country study, consumption of palm oil was associated with increased mortality due to coronary heart disease ^[42]. Note that association does not already mean a cause-effect relationship.
• In one 2012 study in individuals from Kerala/India who underwent coronary artery bypass surgery, consuming coconut oil, high in saturated myristic acid, or sunflower oil, high in polyunsaturated linoleic acid did not result in different plaque composition ^[40]. In another small study in Kerala/India, consumption of coconut oil was not associated with coronary heart disease ^[41].

The Effect of Saturated Fats on Blood Glucose and Diabetes Mellitus Type 2

There is a CONFLICTING EVIDENCE about the association of saturated fats intake and diabetes mellitus type 2:

• According to a 2010 systematic review published in USDA Nutrition Evidence Library, there is a strong evidence about association between the intake of saturated fats and increased risk of diabetes type 2 ^[11]. Replacing as little as 5% energy from saturated fatty acids by monounsaturated (MUFA) or polyunsaturated fatty acids (PUFA) may decrease insulin resistance and the risk of diabetes mellitus type 2 ^[11].
• According to one 2009 review of clinical trials, replacement of saturated fats with mono- or polyunsaturated fats increases insulin sensitivity ^[44].
• According to the US Department of Agriculture, there is a mixed evidence about the association between saturated fat intake and diabetes 2 ^[32-p.484].