**5. Fat recommendations**

In addition to linoleic acid recommendations, there are fat recommendations to reduce CVD risk, cardiovascular events, and/or mortality. For example, it has been suggested to replace approximately 5% of energy from SFAs with MUFAs and/or PUFAs [4, 8–12, 38, 113], and to consume less than 10% of energy as SFAs [113, 114]. On the other hand, certain studies do not coincide with these recommendations [14–17, 21–27, 115]. In addition, low-fat, and in-turn, highcarbohydrate diets, decrease LDL-C; however, there is also a reduction in HDL-C and increased concentrations of VLDLs or triglycerides [37, 97, 116–118], which may produce higher amounts of small, dense LDL particles [41, 119, 120]. It has been reported that higher-fat versus lower-fat diets increase large, buoyant LDL and/or decrease small, dense LDL particles [69, 92, 121–123]. Interestingly, higher SFA intakes also increase large LDL and/or decrease small LDL particles [69, 90, 124–126]. These small, dense LDL particles may increase the risk for CVD in the following ways: 1) increased transport into arterial walls [127]; 2) increased attachment to proteoglycans [128]; 3) increased oxidation [129, 130]; and 4) reduced binding to the LDL receptor [127, 131, 132].

Various organizations have published dietary recommendations to decrease the risk factors for CVD. The American College of Cardiology/American Heart Association Task Force suggests consuming a diet rich in fruits, vegetables, whole grains, nuts, legumes, lean animal or plant protein sources, and fish. Additionally, it is recommended to decrease the consumption of red and processed meats, refined carbohydrates, trans-fatty acids, sodium, cholesterol, and sugar-sweetened drinks [38]. The Dietary Guidelines for Americans suggest consuming vegetable oils to replace sources rich in SFAs, such as butter, shortening, lard, palm oil, palm kernel oil, coconut oil, full-fat dairy products, and high-fat meats [114]. The World Health Organization also recommends replacing SFAs with unsaturated fatty acids, such as sunflower, safflower, corn, soybean, canola, and olive oils, as well as nuts, avocado, and fish [113].

It has been recently proposed, however, that guidelines to lower the risk for CVD should focus on overall dietary patterns, rather than individual fatty acids [14, 133]. The consumption of low-fat diets, for example, did not reduce CVD risk [134, 135]. Furthermore, certain individuals with higher intakes of saturated fat and cholesterol do not possess high CVD mortality rates, as they have an increased consumption of plant foods – in addition to MUFAs and PUFAs [15]. Furthermore, some foods that are higher in SFAs have not been demonstrated to increase the risk for CVD. A proposed explanation for these outcomes is the food matrix of these items, such as macro- and micronutrients, phytochemicals, and probiotics [14, 37].

### **6. Conclusions**

This chapter focused on the effects of linoleic acid consumption on lipid risk markers for CVD in healthy individuals. Interestingly, linoleic acid reduced total cholesterol and LDL-C compared to diets that were lower in PUFAs and/or higher in *The Effects of Linoleic Acid Consumption on Lipid Risk Markers for Cardiovascular Disease DOI: http://dx.doi.org/10.5772/intechopen.99894*

SFAs. In contrast, linoleic acid generated inconsistent outcomes regarding triglycerides, whereas EPA and DHA more significantly reduced triglyceride concentrations. In limited studies, linoleic acid decreased VLDL-C compared to diets containing oleic acid or medium-chain fatty acids, and decreased HDL-C compared to palmitic acid or EPA and DHA; however, linoleic acid increased HDL-C compared with stearic acid. Additionally, linoleic acid reduced apolipoprotein B in comparison to a typical U.S. diet, SFAs, or trans-fatty acids. Interestingly, there were inconsistent

**Figure 2.**

*The progression from individual fatty acids to whole foods and overall dietary patterns on lipid risk markers for cardiovascular disease.*

results or no significant differences for selected CVD lipid risk markers – particularly when comparing linoleic acid to oleic acid. Therefore, additional research is needed regarding the effects of fatty acids on markers that increase the risk for CVD – in addition to the associated mechanisms.

The development of CVD is a complex process which involves many factors that influence the discussed lipid risk markers, such as exercise patterns, overweight/ obesity, cigarette smoke, hypertension, high alcohol consumption, and genetics. To add to this complexity is our dietary patterns. As discussed, there are mixed results regarding the consumption of linoleic acid on CVD lipid risk markers. One such dietary explanation is the complex food matrices of these items, which may, therefore, influence CVD risk markers. In other words, we do not consume individual fatty acids; we consume food. For example, individual saturated and unsaturated fatty acids have differing effects on CVD risk markers; however, these individual effects may be diminished when these fatty acids are components of whole food items. This attribute may explain, in part, for the differing outcomes of saturated and unsaturated fat on CVD risk, events, and/or mortality. Perhaps, therefore, we should focus on whole foods and overall dietary patterns when providing guidelines to reduce the risk for CVD.

It is recommended that future studies investigate the effects of various dietary patterns on CVD risk markers, such as lower-carbohydrate versus higher-carbohydrate diets, lower-fat versus higher-fat diets, and plant-based versus meat-based diets. Based on the heterogeneity of the reviewed studies on the effects of linoleic acid consumption on lipid risk markers for CVD, future studies should be longer in duration – with more participants. Moreover, it should be clarified, in future publications, whether the discussed CVD lipid risk markers exist as strong and independent risk factors for CVD.

It is clear that the consumption of fat is a critical component to a healthy diet; consuming too much or too little can have detrimental effects on one's health. Therefore, moderation is an important factor to keep in mind regarding fat consumption. It seems, however, that certain dietary recommendations focus on decreasing the intakes of saturated fatty acids, and increasing the consumption of monounsaturated and polyunsaturated fatty acids. These recommendations may not be optimal in the following ways: 1) foods consist of individual fatty acids, which have different effects on CVD lipid risk markers; 2) overall dietary patterns and food components may offset the effects of specific fatty acids; and 3) individuals may not be familiar with significant food sources of saturated, monounsaturated, and polyunsaturated fatty acids. Therefore, it seems that dietary guidelines to lower the risk for CVD should focus on overall dietary patterns, rather than individual fatty acids (**Figure 2**).

### **Acknowledgements**

No funding was used for this project.
