Preface

It is a great pleasure for me to introduce the book Fats and Associated Compounds: Consumption and Human Health to the nutrition and food science community. This book aims to provide a profound and exhaustive review of the state-of-the-art about the potential effects of dietary fat and fatty compounds on human health and metabolism, as well as including the newest strategies aimed to modify fat composition in foods.

Traditionally, dietary fat has been associated by consumers with negative effects on human health due to its high energy density. However, nowadays we know that the quality of the fat ingested is more important than its quantity, and that there are natural lipophilic compounds that are essential for the correct maintenance of our physiological functions.

Dietary fat is a hot research area that has attracted increasing attention in the last two decades. The importance of such as novel strategy has run in parallel to consumer concern about nutrition and the subsequent introduction of prevention measures against non-transmissible chronical diseases. Due to the increase of these diseases in Western countries, a balanced intake of fatty compounds beneficial to human health, to the detriment of less healthy compounds, can be an extraordinary tool that improves the health of consumers and, consequently, the pressure on health systems.

In this book, we have tried to compile, to the best of our knowledge, the most up-to-date and well-documented reference test on every aspect of the development and application of novel dietary patterns related to dietary fats and potentially beneficial fatty compounds for human health. This has been possible thanks to the generous contributions of a vast list of expert scientists.

Among the aspects addressed in this book, first place was given to compiling the current recommendations for fat intake at different stages of life, starting with the recommendations during pregnancy and infancy, a period of extraordinary relevance in the physical and mental development of people, as well as their risk of developing a range of diseases such as allergic diseases.

The different recommendations for fat intake for adults according to the different nutritional guidelines in force in different parts of the world were also compiled. It should be considered that the types of food and culinary customs in different geographic areas are different, and therefore nutritional recommendations should be adapted to the peculiarities of each region. Adequate intake of fatty acids can be achieved by a diet rich in vegetable products and by avoiding ultra-processed or deep-fried products. Subsequently, the importance of overall body fat in human health is discussed. Nowadays, obesity is a global pandemic, with a continuous increase throughout the entire world. However, obesity treatment is unfortunately associated with a high degree of therapeutic failures. Even a small fat weight loss can be greatly beneficial for patient health, if the control of comorbidities is considered as a priority objective.

In recent decades, one of the most widely used strategies to adapt the fat content of foods to the current recommendations in the nutritional guidelines has been the reformulation of foods, fundamentally foods of animal origin, which has also been addressed in this book. These modifications not only have the advantage of bringing the fat composition of foods closer to the current recommendations but have also been used as a claim to promote foods by means of nutritional composition claims and health claims. One of the strategies currently used to fight against obesity without changing the dietary habits of consumers is modification of the fatty acid profile of certain foods, to obtain healthier foods. Different strategies can be employed to achieve this objective, such as the modification of the fatty acid composition of milk and meat through animal feeding with the replacement of animal fat by vegetable oils, the use of oleogels, and the synthesis of structured lipids. The best options to achieve this goal are also highlighted in this book.

Additionally, offering consumers a healthier option through the modification of the fatty acid profile of food can also be a good way to differentiate foods in the market and to obtain better prices for foods. The main sources of healthy fatty acids (monosaturated and polyunsaturated) are of vegetable and marine origin and incorporation into animal-origin foods can help prevent pathologies such as cardiovascular diseases. Using the authorized claims, these foods can be an excellent opportunity for the food industry to improve the quality and image of several animal-derived foods.

Healthier fats are of special interest to the consumer, particularly essential and omega-3 fatty acids. Essential fatty acid consumption is of major interest because lack of ingestion of these products can lead to deficiency-type diseases. The essential fatty acids are precursors of the omega-3 and omega-6 polyunsaturated fatty acids that play an important role in several human physiology functions. Despite the fact that they are closely related to the development and course of many non-transmissible chronic diseases, their effects have mostly been studied in the case of the prevention and adjunctive therapy of obesity, inflammatory diseases, cardiovascular disease, neurological diseases, and cancer.

The effect of reducing total fat intake on human health is a source of controversy. Usually, when people try to decrease their body weight the first option they try is to reduce their dietary fat consumption. However, a variety of mechanisms and genetic associations suggest that total dietary fat intake may influence body weight and scientific evidence shows that reducing total fat causes a small reduction in body weight. On the other hand, in overweight or obese adults trying to lose weight, macronutrient composition appears unimportant, and weight loss depends on adherence to calorie restriction.

The effects of fatty acids in adipose tissue metabolism depend on the ponderal status of the individual. Under the context of obesity-related disturbances there is a growing interest in identifying whether dietary fatty acid composition plays a role in the not-completely understood mechanisms leading to ectopic lipid accumulation. People with obesity manifest an elevated inflammatory state, which appears to play an etiopathogenic role in glucose and lipid homeostasis. Thus, the idea that manipulating dietary fatty acid type may affect inflammation, adipose tissue function, metabolic health, and consequently a reduction in obesity, is discussed in this book.

Subsequently, information is included to reinforce the idea that some fatty components are essential for the maintenance of a good state of health. Among the beneficial fatty compounds are minor compounds from olive oil (tyrosol, hydroxytyrosol, oleuropein, and oleocanthal). Olive oil consumption is one of the bases of the Mediterranean diet, recognized as one of the dietary models that contribute to a significant decrease in the prevalence of chronic non-communicable diseases.

Other beneficial fats are tocopherols, essential components of cellular defense against endogenously generated nitrogenous oxidants, identified as an essential nutrient protecting against the long-term effects of nitrosative damage. Elucidating dietary constituents and vitamins that delay the onset and progression of such metabolic chronic diseases will require a new paradigm and approach to their identification that involves research into the long-term effects of deficiency and a clear understanding of the underlying mechanisms of action.

Short chain fatty acids are a group of fatty compounds generated in the distal part of the colon by means of complex polysaccharides and protein fermentation by gut microbiota that have received great attention from the scientific community in the last decade. Short chain fatty acids play paramount roles in maintaining intestinal and immune homeostasis in the human body, regulate host energy homeostasis, and have been considered mediators in the microbiota–gut–brain axis cross-talk. The current evidence about short chain fatty acid production and the molecular mechanisms through which they exert benefits for human health are also included in this book.

Fat and lipids are primarily the energy source and building blocks of cells. Hence this book also includes a chapter dealing with dietary fatty acids and types, and the critical implication of the essential fatty acids and their metabolomics on human health and to attenuate health complications. Although all the fatty acids are useful for humans, reports have revealed that some of the fatty acids show an adverse effect on human health and hence a lot of cross-talk on the usage of fatty acids. Thus, the molecular mechanism of dietary fat, distinct fatty acids, and bioactive fatty acid metabolites against most common non-transmissible chronic diseases is summarized.

Dietary fat can effect human health at different stages. The first place onwhich fat can act in our organism is our digestive system, and consequently,on the abundant microbiota that lives in the digestive tract, mainly in themost distal part. In recent years, the gut microbiota has come out as a key component of host health and it is involved in different functions such as the development of the immunity system, protection against pathogen infections and the extraction of energy nutrients, among others. Thus, information and conclusions about the effect of the quantity and quality of dietary fat on the human gut microbiota are included in this book.

Finally, we wanted to include a final chapter regarding the future trends of dietary fat consumption from our point of view. In recent years, the term “personalized nutrition” has become widespread and represents a giant step forward thanks to the birth of nutrigenomics. This field of nutrition provides insight into how nutrients interact with the human genome, and how the genetic variants of each individual influence nutrient metabolism. Despite the progress made in this field, there is still much to understand. The future of this field lies in the combination of several omics techniques in human trials to understand in depth all the metabolic pathways influenced by fat consumption.

Finally, the editors wish to express their most sincere gratitude to all authors that have contributed to this interesting book. Without their effort and dedication, this book would not be in your hand today. The Editor also wishes to thank the Royal Society of Chemistry Editorial Office, especially Katie Morrey and Liv Towers, for their wonderful technical assistance, and for their understanding attitude regarding the delays that occurred during the elaboration of this book, mainly due to the particularly difficult epidemiological situation that occurred simultaneously.

J. M. Miranda