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Recommendations Summary

DLM: Major Fat Components 2011

Click here to see the explanation of recommendation ratings (Strong, Fair, Weak, Consensus, Insufficient Evidence) and labels (Imperative or Conditional). To see more detail on the evidence from which the following recommendations were drawn, use the hyperlinks in the Supporting Evidence Section below.


  • Recommendation(s)

    DLM: Fat Components of the Cardioprotective Diet

    The Registered Dietitian (RD) should tailor the cardioprotective dietary pattern to the individual's needs to provide a total fat intake of 25% to 35% of calories, (ATP III) with <7% of calories from saturated fat and trans-fatty acids (TFA). Because TFAs raise total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) and may decrease high-density lipoprotein cholesterol (HDL-C), TFA consumption should be as low as possible. Cholesterol should be <200mg per day. The majority of total fat intake should be derived from unsaturated fat sources.

    For individuals at their appropriate body weight, without elevated LDL-C or triglyceride (TG) levels, and with normal HDL-C levels, saturated fat calories could be replaced by unsaturated fat and/or complex carbohydrate (CHO).

    This dietary pattern can lower LDL-C up to 16% and decrease risk of coronary heart disease (CHD) and CHD events. 

    Rating: Strong
    Imperative

    DLM: Replacing Saturated Fat in the Diet

    The Registered Dietitian (RD) should develop a nutrition prescription within a cardioprotective dietary pattern that replaces saturated fat calories with calories from either complex carbohydrate (CHO) principally contributed by fruits, vegetables and whole grains, protein and/or unsaturated fat. Robust evidence documents that saturated fat increases low-density lipoprotein cholesterol (LDL-C). Under isocaloric conditions, large scale, randomized controlled trials (RCTs) indicate that a cardioprotective diet reduced LDL-C by 9% to 16% in both normo- and hyperlipidemic individuals.

    Advantages for substituting complex CHO for saturated fat calories include the following:

    • It is difficult to achieve a saturated fat reduction of <10% of calories in diets that are 30% to 35% of total calories from fat
    • A diet high in complex CHO includes shortfall nutrients (e.g., dietary fiber,  potassium and magnesium and other micronutrients)
    • A diet high in complex CHO is nutrient-dense and is less likely to contribute excess calories
    • In addition, a diet rich in omega-3 fatty acids and/or monounsaturated fat, and reduced in refined CHO may also be effective in reducing serum triglycerides (TG) without adverse impact on high-density lipoprotein cholesterol (HDL-C).

    In treating overweight or obese patients, where the goal is reduction of total energy, reduction rather than replacement of saturated fat calories may be warranted, depending on current intake of unsaturated fat.

    Rating: Strong
    Imperative

    • Risks/Harms of Implementing This Recommendation

      No potential risks or harms are associated with the application of this recommendation.

    • Conditions of Application

      In treating overweight or obese patients, where the goal is reduction of total energy, reduction rather than replacement of saturated fat calories may be warranted. Consideration should be given to appropriate levels of unsaturated fat within the context of total energy needs.

    • Potential Costs Associated with Application

      No obvious costs are associated with the application of this recommendation, since purchase of fruits and vegetables and many whole grains purchased in bulk may be even less costly than purchase of processed, refined carbohydrate foods.

    • Recommendation Narrative

      Cardioprotective Dietary Pattern and Replacing Saturated Fat With Carbohydrate (CHO),  Protein and Unsaturated Fat  

      • Sixteen studies provide evidence that a diet consisting of 25% to 35% total fat, <7% saturated fat and trans fat, and <200mg dietary cholesterol lowers serum total and LDL-C 9% to 16% and decreases the risk of CHD. Isocalorically replacing saturated fatty acids (SFA) with monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) is associated with reductions in LDL-C. Isocalorically replacing SFA with MUFA and PUFA is associated with reductions in LDL-C. Data on the ideal isocaloric substitution of CHO and protein to maximize LDL-C lowering are unavailable.
      • Studies included six positive quality randomized controlled trials (RCTs) (Bautista et al, 2001; Ginsberg et al, 1998; Jenkins et al, 2003; Lichtenstein 2002; Obarzanek et al, 2001), two positive quality meta-analyses (Brunner et al, 1997; Howell et al, 1997), one positive quality systematic review (Adult Treatment Panel III, 2002), one positive quality cross-sectional study (Denke et al, 1993), one positive quality trend study (Johnson et al, 1993), two neutral quality RCTs (De Lorgeril et al, 1999; Judd et al, 2002), two neutral quality meta-analyses (Mensink et al, 2003; Yu-Poth et al, 1999), one negative quality systematic review (Kris-Etherton, 2000), and one negative quality narrative review (Kris-Etherton et al, 2001)
        • One neutral quality meta-analysis (Yu-Poth et al, 1999) and one positive quality RCT (Ginsberg et al, 1998) examined a diet with fewer than 30% of calories from fat and fewer than 10% of calories from saturated fat. Both of these studies found LDL-C was reduced by this dietary intervention.
        • Four positive quality RCTs (Ginsberg et al, 1998; Jenkins et al, 2003; Lichenstein et al, 2002; Obarzanek et al, 2001),  and one neutral quality meta-analysis (Yu-Poth et al, 1999) found that a more restrictive SFA restriction (fewer than 7% of total calories from SFA), along with less than 200mg of cholesterol per day also lowered LDL-C
        • One neutral quality meta-analysis (Mensink et al, 2003) found when cis-MUFAs or cis-PUFAs replaced CHO calories, LDL-C significantly decreased
        • A negative quality systematic review (ATP III, 2002) reported isoenergetic replacement of SFA with MUFA lowered LDL-C. A neutral quality crossover trial (Judd et al, 2002) confirmed these findings and reported LDL-C was reduced when stearic acid was replaced with oleic acid.
        • One positive quality meta-analysis (Howell et al, 1997) found LDL-C was strongly associated with changes in the percentage of calories from SFA and the percentage of energy from PUFA, however not from the percentage of energy from MUFA.
        • A positive quality consensus statement (ATP III, 2002) verified these findings and reported that that unsaturated fatty acids lower TC and LDL-C, when substituted for SFA.

      Fats and Cholesterol and Health Outcomes

      Results of this review were supplemented by a later evidence review of the literature from 2004 to October 2009, conducted by the United States Department of Agiculture (USDA) and the 2010 Dietary Guidelines Advisory Committee (DGAC) on effect of dietary cholesterol intake on risk of CVD, and effect of monounsaturated fat intake (when substituted for saturated fat), omega-6 fatty acid intake and saturated fat intake on health outcomes. There may be some overlap of the studies included in the evidence analysis.

      Effect of Dietary Cholesterol Intake On Risk of Cardiovascular Disease

      • Sixteen studies provide moderate evidence from epidemiologic studies related to dietary cholesterol intake to clinical CVD end-points. Many randomized clinical trials on dietary cholesterol use eggs as the dietary source. Independent of other dietary factors, evidence suggests that consumption of one egg per day is not associated with risk of CHD or stroke in healthy adults, although consumption of more than seven eggs per week has been associated with increased risk. An important distinction is that among individuals with type 2 diabetes, increased dietary cholesterol intake is associated with CVD risk.
      • Studies included two positive quality RCTs (Ballesteros et al, 2004; Knopp et al, 2003), four positive quality prospective cohort studies (Djousse et al, 2008; Hu et al, 1999; Qureshi, 2007 et al; Tanasescu et al, 2004), one positive quality meta-analysis (Weggemans et al, 2001), one positive quality systematic review (McNamara et al, 2000), six neutral quality RCTs (Goodrow et al, 2006; Greene et al, 2005; Harman et al, 2008; Mutungi, 2008; Reaven, 2001; Tannock, 2005), one neutral quality prospective cohort study (Nakamura et al, 2006), and one neutral quality systematic review (Kritchevsky and Kritchevsky, 2000).

      Effect of Monounsaturated Fat (MUFA) When Substituted for Saturated Fat on Health Outcomes

      • Thirteen studies provide strong evidence that dietary MUFA are associated with improved blood lipids related to both CVD and type 2 diabetes (T2D), when they are a replacement for dietary SFA. The evidence shows that 5% energy replacement of SFA with MUFA decreases intermediate markers and the risk of CVD and T2D in healthy adults and improves insulin responsiveness in insulin resistant and T2D subjects.
      • Studies include one positive quality meta-analysis (Jakobsen, 2009), six positive quality RCTs (Appel et al, 2005; Berglund et al, 2007; Due et al, 2008; Lopez et al, 2008; Thijssen and Mensink, 2005; Thijssen et al, 2005), five neutral RCTs (Allman-Farinelli et al, 2005; Binkoski et al,  2005; Clifton et al, 2004; Paniagua et al, 2007; and Rasmussen et al, 2006), and one positive quality prospective cohort study (Tanasescu et al, 2004).

      Effect of Omega-6 Polyunsaturated Fatty Acids (PUFA) on Health Outcomes

      • Ten studies provide strong and consistent evidence that dietary omega-6 polyunsaturated fatty acids are associated with improved blood lipids related to CVD, in particular when PUFA is a replacement for dietary SFA or TFA. Evidence shows that energy replacement of SFA with PUFA decreases total cholesterol, LDL-C and TGs, as well as numerous markers of inflammation. Polyunsaturated fatty acid intake significantly decreases risk of CVD and has also been shown to decrease the risk of T2D.
      • Studies included one positive quality meta-analysis (Jakobsen et al, 2009), two positive quality RCTs (Thijssen and Mensink, 2005; Thijssen et al, 2005), three neutral quality RCTs (Liou et al, 2007; St-Onge et al, 2007; Zhao et al, 2004), three positive quality cohort studies (Laaksonen et al, 2005; Mozaffarian et al, 2005; Oh et al, 2005), and one neutral quality cohort study (Hodge et al, 2007).

      Effect of Saturated Fat (SFA) Intake on Health Outcomes

      • Twelve studies provide strong evidence that dietary SFAs are positively associated with intermediate markers and end-point health outcomes for two distinct metabolic pathways: 1) increased serum TC and LDL-C and increased risk of CVD, and 2) increased markers of insulin resistance and increased risk of T2D. Conversely, decreased SFA intake improves measures of both CVD and T2D risk. The evidence shows that a five percent energy decrease in SFA, replaced by MUFA or PUFA, decreases risk of CVD and T2D in healthy adults and improves insulin responsiveness in insulin resistant and T2D subjects.
      • Studies include one positive quality meta-analysis (Jakobsen et al, 2009), seven positive quality RCTs (Azadbakht et al, 2007; Berglund et al, 2007; Chen et al, 2009; Furtado et al, 2008; Kralova et al, 2008; Lefevre et al, 2005; Lichtenstein et al, 2005), three neutral quality RCTs (Buenacorso et al, 2007; Bourque et al, 2007; Chung et al, 2004), and one neutral quality non-randomized trial (Dabadie et al, 2005). 

      Trans-Fatty Acids (TFA)

      • Eleven studies provide evidence that high TFA intake increases risk of CHD events. Trans-fatty acids raise TC and LDL-C. Unlike saturated fatty acids,  TFAs do not increase and may decrease HDL-C. Trans-fatty acids increase the TC/HDL-C ratio in a dose dependent manner.
      • Studies included two positive quality RCTs (Lichtenstein et al, 2001; Mauger et al, 2003), two positive quality cohort studies (Oomen et al, 2001; Willett et al, 1993), one positive quality meta-analysis (Zock et al, 1997), one positive quality cross-sectional study (Allison et al, 1999), two neutral randomized crossover (DeRoos et al, 2001; Judd et al, 2002), one neutral quality meta-analysis (Mensink et al, 2003), one neutral quality case-control study (Baylin et al, 2003), and one negative quality RCT (Tonstad et al, 2001)
        • A positive quality cross-sectional study (Allison et al, 1999) found that on average, the US population consumes approximately 5.3g of TFA per day, which is 2.6% of their total energy and 7.4% of their fat energy as TFAs
        • One retrospective study (Willett et al, 2993) and one prospective cohort study (Oomen et al, 2001) (both positive quality) found increased intake of TFAs was related to the risk of CHD. A neutral quality case-control study (Baylin et al, 2003) found that total adipose tissue TFA content was associated with as much as a three-fold increased risk of myocardial infarction (MI). 
        • Two meta-analyses [one positive quality (Zock et al, 1997) and one neutral quality (Mensink et al, 2003)] found that when TFAs replace CHO, there is an increase in TC and LDL-C and an increase in TC/HDL
        • A neutral quality cross-over trial (Judd et al, 2002), two positive quality RCTs (Lichtenstein et al, 2003; Mauger et al, 2003), and one neutral quality RCT (de Roos et al, 2001),  all found that when replacing SFA with TFAs, there is a decrease in TC and/or LDL-C and HDL-C
        • Conversely a neutral quality meta-analysis (Mensink et al, 2003) found that replacing saturated fat (only the cholesterol-raising SFAs) with TFAs resulted in an increase in LDL-C, a decrease in HDL-C, and an increase in TC/HDL
        • When TFAs are replaced with saturated fat, a decrease in the TC/HDL occurs as seen in a positive quality meta-analysis (Zock et al, 1997).  
      • Results of this review were supplemented by a later evidence review of the literature from January 2004 to May 2009, conducted by the United States Department of Agiculture (USDA) and the 2010 Dietary Guidelines Advisory Committee (DGAC) on effect of natural vs. synthetic TFAs on LDL, HDL and non-HDL-cholesterol. There may be some overlap of the studies included in the evidence analysis
        • Three studies provide limited evidence to support a substantial biological difference in the detrimental effects of industrial trans-fatty acids (iTFA) and ruminant trans fatty acids (rTFA) on health when rTFA is consumed at seven to ten times the normal level of consumption
        • Studies included two positive quality RCTs (Chardigny et al, 2008; Jakobsen et al, 2006) and one neutral quality narrative review (Motard-Belanger et al, 2008).

      Diet Composition

      • Seven RCTs provide evidence that under isocaloric conditions, replacing saturated fat intake with either unsaturated fat or fiber-rich carbohydrates, principally contributed by fruits, vegetables and grains reduces LDL-C. A diet rich in MUFA may be effective in also reducing serum triglycerides and preserving HDL-C.
      • Studies included six positive quality RCTs [Appel et al, 2005 (OMNI-Heart study), Berglund et al, 2007 (DELTA 2 study), Ginsberg et al, 1998 (DELTA 1 study), Harsha et al, 2004 (DASH study), Obarzanek et al, 2001 (DASH study), and Perez-Jiminez et al, 2001], and one neutral quality RCT (Paniagua de la Sacristana et al, 2007).

    • Recommendation Strength Rationale

      Cardioprotective Dietary Pattern and Replacing Saturated Fat with CHO,  Protein and Unsaturated Fat  

      • Results are consistent across study designs and dietary change continues to benefit both Caucasians and African-Americans
      • Grade I for conclusion statements 1) Dietary Fat Components and LDL-cholesterol Reduction, and 2) LDL-cholesterol and Replacing Dietary Saturated Fats with MUFA and PUFA based on six positive quality RCTs, two positive quality meta-analyses, one positive quality systematic review, one positive quality cross-sectional study, one positive quality trend study, two neutral quality RCTs, two neutral quality meta-analyses, one negative quality systematic review, and one negative quality narrative review.

      Fats and Cholesterol and Health Outcomes

      • Grade II conclusion statement for Effect of Dietary Cholesterol Intake on Risk of CVD, based on two positive quality RCTs, four positive quality prospective cohort studies, one positive quality meta-analysis, one positive quality systematic review, six neutral quality RCTs, one neutral quality prospective cohort study, and one neutral quality systematic review
      • Grade I conclusion statement for Effect of MUFA When Substituted for SFA on Health Outcomes, based on one positive quality meta-analysis, six positive quality RCTs, five neutral quality RCTs, and one positive quality prospective cohort study
      • Grade I conclusion statement for Effect of Omega-6 PUFA on Health Outcomes, based on one positive quality meta-analysis, two positive quality RCTs, three neutral quality RCTs,  three positive quality cohort studies, and one neutral quality cohort study
      • Grade I conclusion statement for Effect of SFA Intake on Health Outcomes, based on one positive quality meta-analysis, seven positive quality RCTs, three neutral quality RCTs, and one neutral quality non-randomized trial.

      Trans-Fatty Acids

      • Multi-ethnic representation and consistency across study designs
      • Biological plausibility (i.e., marker of TFA found in adipose tissue) was strongly related to CHD events
      • One meta-analysis included various populations: US, Netherlands, Denmark, Canada, Finland, Israel, Malaysia, Norway, Germany, Italy, and UK
      • Conclusion statements are:
        • Grade I for TFAs and Serum Cholesterol Levels and Grade II for TFAs and Risk for CHD
          • Grades were based on two positive quality RCTs, two positive quality cohort studies, one positive quality meta-analysis, one positive quality cross-sectional study, two neutral randomized crossover studies, one neutral quality meta-analysis, one neutral quality case-control study, and one negative quality RCT
        • Grade III for Natural (Ruminant) vs. Synthetic (Industrially Hydrogenated) TFAs and Effect on LDL-, HDL- and Non-HDL-cholesterol, based on two positive quality RCTs and one neutral quality narrative review
      • Areas of Uncertainty:
        • Some doubts regarding generalizability exist in the study conducted in Costa Rica (Baylin et al, 2003), because TFA food sources were from partially hydrogenated soybean oil, consumed in homemade meals and not from fast food eating establishments and processed foods, and actual consumption of TFA is not reported
        • A minor doubt is that individual consumption surveys were completed from 1980-1991 and may not represent current TFA contents of foods eaten today.

      Diet Composition

      • Conclusion statement is Grade I, based on six positive quality RCTs and one neutral quality RCT.

    • Minority Opinions

      None.