Functional Dietary Lipids: Food Formulation, Consumer Issues, and Innovation for Health

Functional Dietary Lipids: Food Formulation, Consumer Issues and Innovation for Health, Second Edition discusses this important component of the human diet and the ways it plays an essential functional role. As with the previous edition, this book covers the functionality and nutritional benefits of dietary fat in food in terms of formulation, manufacturing and innovation for health. It contains approximately 35% new content, including 5 new chapters as well as updated content in previous chapters. New content covers the health effects of fat-soluble compounds, the sustainability aspects of vegetable oil production; process engineering of fats to improve functionality and quality, and more.

This second edition also includes updated data on regulations, including nutritional profiling, signposting, taxation and advertising restrictions, and the regulatory approval of novel sources of lipids. This book will be a useful reference for those wanting to explore human nutrition and dietary lipids as well as those involved in decision-making surrounding food formulation and manufacturing.

• Comprehensively examines the functionality and nutritional benefits of dietary fat in food
• Includes new chapters on sustainability of vegetable oil production, 3-MCPD and glycidyl esters, food processing engineering, dietary fat and obesity, and the effects of dietary lipids on inflammation and immunity
• Addresses issues affecting the consumer relationship with fat, such as sustainability, regulation, marketing and health claims

• Language: English
• Publisher: Elsevier Science
• Release date: Sep 28, 2023
• ISBN: 9780443153280

Book preview

Preface

Lipids are essential and desirable components of human diets supplying food energy, essential fatty acids, and fat-soluble vitamins. Yet the amounts of fat and proportions of the different type of fatty acids that should be consumed for optimum health remain controversial. Besides their effects on health, lipids have functional roles in food preparation enhancing taste, texture, and mouthfeel of food, as well as being a cooking medium. The aim of this book is to guide the reader through the scientific evidence on functional roles of lipids in health and their use in food formulation. In addition to potential health benefits, consumer concerns issues regarding provenance, sustainability, and environmental impact are discussed. We hope this book will be useful to scientists in the relevant areas such as in research and development, food science, nutrition, and public health.

Since the publication of the first edition, there have been the COVID-19 pandemic and geopolitical changes that have disrupted the global food supply chain. The impact of climate change and greater consumer awareness of the need for sustainable food production are now driving changes in food formulation. The science of dietary fat has also moved forward. This edition contains new chapters on sustainable vegetable oil production, on modification of the fatty acid composition of animal derived foods, and an extensively updated chapter on speciality lipids. There is a new chapter on food process engineering on dietary fat. The chapters on the thermal stability of dietary fats and contaminants focus on preventing/mitigating the production of undesirable components during production and processing. There are new chapters on the role of fat in obesity and energy sensing, dietary lipids, and inflammation/immunity and those on dietary fat and diabetes and cardiovascular disease have been extensively updated. This book concludes with chapters covering regulations and health including nutritional profiling, signposting, taxation, and advertising restrictions and the regulatory approval of novel sources of lipids. Finally, I would like to thank the team at Elsevier, especially Megan Ball and Lindsay Lawrence, and the authors for their contributions.

Tom Sanders

King's College London

1: Introduction: the role of fats in human diet

Thomas A.B. Sanders     Department of Nutritional Sciences, King's College London, London, United Kingdom

Abstract

This chapter reviews the role of fat in human nutrition as a source of food energy but also in supplying essential nutrients. The basis for current dietary guidelines for fat and fatty are discussed. The strengths and weaknesses of various methods used to assess the intake of fat and different types of fatty acids are explained. The physiological roles of the essential fatty acids and their pharmacological properties are described. The associations between the intake of dietary fat and of the different types of fatty acids and noncommunicable diseases prospective studies as well as results from randomized controlled trials are reviewed. Recent changes in the fat supply and ways of improving diets in terms of quantity and type of fat are described. Current consumer issues such as environmental impacts and sustainability of vegetable oil production are discussed.

Keywords

Biomarkers of fat intake—vegetable oils; Dietary fat; Linolenic acid; Noncommunicable disease; Omega-3 fatty acids

1.1. Introduction

Fat is a desirable component of human diet. Yet how much and what type of fat should be consumed for optimum health remains controversial. Global vegetable oil production has doubled over the past 20 years (Fig. 1.1) and the annual per capita availability of vegetable oils increased from 15 kg in 2000 to 29 kg in 2021, roughly equivalent to an extra 40 g/head/day. However, the annual per capita availability of added animal fats (butter, lard, and suet) has remained at about 2 kg over the same period. The increase in vegetable oil production, particularly palm oil, has helped reduce undernutrition in lower-income countries in Asia (FA0, 2021). However, excessive vegetable oil intake may partially be to blame for some of the increase in obesity and related disorders (cardiovascular disease, cancer, and type 2 diabetes).

Figure 1.1  World vegetable oil production. Data from FAO, 2021.

This introductory chapter reviews the role of fat in human diets and requirements; later chapters will cover issues concerned with sustainability, functional and nutraceutical properties, processing and stability, contaminants, health-related issues (obesity, diabetes, cardiovascular disease, immune function), regulatory issues, and health claims. This introductory chapter reviews the role of fat in human diets and requirements; later chapters will cover issues concerned with sustainability, functional and nutraceutical properties, processing and stability, contaminants, health-related issues (obesity, diabetes, cardiovascular disease, immune function), regulatory issues, and health claims.

1.2. Role of fat in the diet

Dietary fat consists mainly of triglycerides, but there is also a small contribution of more complex lipids, such as phospholipids. The main nutritional role of dietary fat is to provide metabolizable energy to drive body processes and support growth. Another role is to supply and enable the absorption of fat-soluble vitamins (A, D, E, and K). The nutritionally essential role of dietary fat is met by certain polyunsaturated fatty acids (linoleic and α-linolenic acids), which cannot be manufactured within the body. Although the essential fatty acid deficiency is unlikely to occur on self-selected diets, higher intakes of polyunsaturated fatty acids than the amount required to prevent deficiency may have health benefits.

Fat is present in most foods but in varying quantities. Fruit and vegetables with the notable exceptions of palm fruit, olive, and avocado are low in fat. Most of the food energy provided by the food of animal origin, nuts, and oilseeds is supplied by fat compared with only 10%–15% in cereal grains. The use of added fat is important in food preparation as a frying medium, but it also makes food more palatable by contributing to the taste, texture, and aroma of foods when added to food. Cold-pressed oils have become popular because of their flavors, and some may also have health benefits (e.g., virgin olive oil) associated with the naturally occurring compounds they contain.

1.2.1. Fat as a source of energy

Fat is the richest form of food energy, supplying 9 kcal (37 kJ)/g—more than twice that supplied by protein and carbohydrates, which both provide about 4 kcal (18 and 17 kJ/, respectively)/g. The 9 kcal/g figure is based on triglycerides consisting of long-chain fatty acids (C14–22). Short-chain (less than C8) and medium-chain fatty acids (C8–C12) provide less energy on an average of 7 kcal/g. Following consumption, fat is emulsified by the action of bile released in the duodenum to form small particles called micelles which are then acted on by pancreatic lipase which cleaves fatty acids from the sn-1 and sn-3 positions of the triglyceride. The free fatty acids and 2-monoglycerides released are absorbed in the small intestine, where they are reesterified back into triglycerides and secreted as chylomicrons into the lymphatic system before being released into the blood some 2–3 h after consumption. Normally, fat digestibility is greater than 95%, but fat malabsorption can result from hepatitis, gallbladder disease, or pancreatic disease. However, the absorption of fat present in nuts and seeds may be lower as some fat remains trapped within the cell matrix (Berry et al., 2008).

In the newborn, the digestibility of butter fat and vegetable oils is lower than that of breast milk. The digestibility of palmitic acid (16:0), which accounts for about a third of the fatty acid in the breast is improved when the fatty acid is in the sn-2 position of the triglyceride as in breast milk. However, palmitic acid is predominantly in the sn-1 and sn-3 positions of the triglyceride of vegetable oils and in butter fat. Structured lipids (BetPol) with palmitic acid in the sn-2 position made from interesterified palm oil are widely used in infant formula and have similar digestibility to human breast milk fat. Short- and medium-chain fatty acids are more rapidly digested, and because they are more water soluble than long-chain fatty acids, they can be transported in the blood bound to albumen in the hepatic portal vein to the liver quite quickly. Medium-chain triglycerides (MCTs), which are made from coconut oil or palm kernel oil, are used as energy supplements for patients with malabsorption or where the metabolism of long-chain fatty acid is impaired (e.g., lipoprotein lipase deficiency). MCTs are also popular as a dietary supplement in sports nutrition. However, care needs to be taken with using MCT as it can cause vomiting and diarrhea and so it needs to be introduced gradually into the diet.

The β-oxidation of fatty acids to yield energy occurs predominantly in the mitochondria. However, some β-oxidation does occur in peroxisomes that are used for the degradation of long-chain fatty acids > C20 and branched-chain fatty acids as well as xenobiotics.

1.2.2. Fat storage

Fat is the major energy reserve within the body. It is mainly stored in subcutaneous adipose tissue but some surrounds and cushions delicate organs such as the kidneys and heart. Besides its role as an energy store, adipose tissue is now recognized as an endocrine organ that produces hormones called adipokines, which have roles in regulating energy balance, reproduction, and immune function.

Some adipose tissue, especially that located around the neck and between the shoulder blades, especially in infants, is enriched with mitochondria and is called brown fat to differentiate it from ordinary white adipose tissue. Brown fat generates heat and helps maintain thermal neutrality which is important for infants. Another form called beige adipose tissue has been found within adipose tissue stores and may explain why some people are able to increase nonshivering thermogenesis when exposed to cold. However, the accumulation of excess adipose tissue within the abdominal cavity, known as visceral fat, and the infiltration of fat into the liver and muscle are associated with adverse health consequences. Fat accumulation within muscle causes resistance to the action of insulin and fat accumulation in the liver can lead to cirrhosis.

1.2.3. Changes in fat requirements through the life course

Almost half the energy in breast milk is supplied by fat, and this supports the growth and development of the infant. The high-fat content of breast milk encourages the deposition of subcutaneous adipose tissue thus helping reduce heat loss from the body, which is important as infants have a relatively large surface in relation to their size. It is undesirable to restrict fat intake in children under the age of 2 years, because requirements for energy are high and their small stomachs cannot cope with a bulky diet. There is little doubt that a restricted energy intake is the major factor responsible for poor growth and high prevalence of underweight in preschool children in many low-income countries, where fat intakes are low.

Adding a small amount to food can double its energy content (e.g., spreading butter on a slice of bread). Conversely, removing fat from foods, particularly those of animal origin, markedly lowers the energy content. For example, a 200 mL glass of skimmed milk contains 276 kJ/glass compared with 550 kJ in a similar volume of full-fat milk. Overfeeding studies have established that the addition of large amounts of fat to food has a substantial impact on energy intake and causes weight gain in older children and adults.

1.2.4. Dietary reference values for fat

It is difficult to maintain energy balance on energy intakes providing less than 20% energy from fat. Furthermore, some fat is needed to enable the absorption of fat-soluble vitamins, and this is the main reason for setting the minimum level of 20% (WHO/FA0, 2009). Dietary reference values suggest fat should supply at least 20% of energy with an average macronutrient distribution range between 20% and 35% of the energy (Table 1.1). There is a lack of evidence to support recommendations of a maximum intake of fat expressed as a percentage of energy intake. However, many recommendations suggest that added fat in the form of vegetable oil should not exceed 30 g/d. Most recommendations suggest that saturated fatty acids should provide no more than 10% of the dietary energy (roughly 20 g/d), because of their blood cholesterol raising effects, and that trans fatty acid intakes from industrial sources should be as low as possible.

Higher intakes of fat are needed in many low- and middle-income countries particularly in South Asia, South East Asia, and sub-Saharan Africa, where the median age of the population is low.

In most industrialized countries, fat provides one-third of the dietary energy (Harika et al., 2013). Few diets contain more than 42% energy from fat—even the traditional Inuit diet consisting mainly of fish, caribou, marine mammals, and berries provided only 42% energy from fat! In the industrialized/urban areas of Asia, fat intake has risen, mainly due to the increased availability of palm oil, and total fat intakes are now in the range of 20%–35% energy (Fig. 1.2). However, fat intakes remain worryingly low (10%–20% energy) in Sub–Saharan Africa and many rural areas in Asia where their diets are based mainly on cereals and starchy foods, such as cassava, and the intake of animal products is very low.

Figure 1.2  Proportion of food energy derived from fat in different countries based on food intake surveys. Data are from Harika et al., (2013).

Table 1.1

AI, acceptable intake; ALAP, as low as possible; DRV, dietary reference value; NA, not advised.

a  Average macronutrient distribution range.

WHO/FAO, 2010, EFSA (2010). https://doi.org/10.2903/j.efsa.2010.1461. Dietary Guidelines for Americans 2020–25. https://www.dietaryguidelines.gov/sites/default/files/2021-03/Dietary_Guidelines_for_Americans-2020-2025.pdf. Accessed January 29, 2023.

In Western diets, about 40%–60% of fat intake is provided by meat and dairy produce, which explains why higher fat intakes are associated with higher intakes of saturated fatty acids. Fig. 1.3 shows the sources of total and saturated fat assessed from individual food intake records in the UK Diet and Nutrition Survey. It is difficult to accurately estimate the contribution made by different fats added to compound foods such as ready meals, cakes, and biscuits, as well as the amounts present in deep-fried takeaway food. Although the consumption of skimmed and semiskimmed milk exceeds that of full-fat milk, most of the milk fat removed is recycled into other foods, such as cereal products (cakes, pastries, biscuits). The contribution to fat intake from vegetables is mainly from frying oils (especially chips and crisps), and much of that from cereal products is from the use of shortenings rather than from the cereals themselves. It is relatively easy to manipulate the intake of total and saturated fat intake by exchanging the types of spreads, fats, and oils used in food preparation, and reducing the fat from meat and dairy products (Moore et al., 2009).

Modern fat processing technologies can be used to reformulate traditional products that are better for health. The composition of vegetable fats and oils are malleable, and blends can be tailored to help meet the dietary guideline for the various applications required (e.g., spreads, shortenings, confectionery, and ice-cream fats) and for frying vegetable oil (e.g., high oleic oils).

1.3. The essential fatty acids

The indispensable role of fat in the diet is the provision of essential fatty acids (linoleic and α-linolenic acids and their derivatives). Linoleic acid (18:2n-6), which gives rise to the omega-6 series of essential fatty acids, is required in larger amounts than α-linolenic acid (18:3n-3; ALA), which gives rise to the omega-3 series (Fig. 1.4). The land-based food chain is dominated by an abundance of linoleic acid in seed oils, nuts, and cereals, whereas the distribution and abundance of ALA are more limited. Soybean and rapeseed oils contain about 7% and 10% ALA by weight, respectively, but most of the other major vegetable oils, such as corn, coconut, cottonseed, sunflower, olive, and palm, contain less than 1%. ALA is also found in significant amounts in the lipids of flaxseed, hempseed, walnuts, and dark green leafy vegetables. Fish accumulate substantial amounts of eicosapentaenoic acid (20:5n-3; EPA), docosapentaenoic acid (22:5n-3; n-3 DPA), and docosahexaenoic acid (22:6n-3; DHA) from marine algae. Thus, oily fish and fish oil consumption can make a substantial contribution to long-chain omega-3 polyunsaturated fatty acids (PUFA).

1.3.1. Requirements for omega-6 fatty acids

Linoleic acid has a physiological role in maintaining the water permeability barrier of the skin as a constituent of acylglycosyl ceramides. It also has a role in cholesterol transport. Linoleic acid is converted to dihomogamma linolenic acid (DHLA; 20:3n-6) and arachidonic acid (AA; 20:4n-6), which are important constituents of the structural phospholipids found in cell membranes. Both DHLA and AA give rise to a family of bioactive metabolites called eicosanoids, which regulate many physiological processes. Those derived from AA include the classical prostaglandins, thromboxane A2 (a vasoconstrictor and platelet aggregator), prostacyclin I2 (a vasodilator and platelet inhibitor), leukotriene B4 (a bronchoconstrictor and regulator of inflammation), and anandamide (N-arachidonoylethanolamine), which is an agonist for the endocanniboid receptors (located mainly in the brain).

Figure 1.3  Percentage contribution made to the intake of total and saturated fat in the UK diet. Data are from the National Diet and Nutritional Survey of British Adults (2003) using a weight food intake methodology.

Figure 1.4  The essential fatty acids and their metabolites. Δ6D, Δ6 desaturase; Δ5D, Δ5 desaturase; COX, cyclo-oxygenase; 5-LOX, 5-lipoxygenase; PG, prostaglandins.

Linoleic acid deficiency was first described in rats fed a fat-free diet containing an adequate supply of protein but with most of the food energy provided by sugar (which contains no fat unlike starch sources of carbohydrates). It resulted in what is now referred to as essential fatty acid deficiency syndrome, which was characterized by increased food intake, weight loss, and a scaly dermatitis. The paradoxical weight loss associated with an increased food intake can be explained by heat loss caused by the evaporation of water from the skin. As little as 1% of the energy as linoleic both prevented and cured the deficiency. Later it was shown that arachidonic acid was three times more potent at curing the deficiency.

Linoleic acid was first described in infants fed skimmed milk in the 1950s and later in the 1970s in adults with chronic fat malabsorption and in those undergoing total parenteral nutrition. In adult patients, dermatitis was the most obvious sign, and the skin symptoms could even be improved by the topical application of linoleic acid. Linoleic acid deficiency can be cured/prevented by an intake as low as 1% of dietary energy. Acceptable intakes (AI) are typically expressed as a percentage of dietary energy. Calculating intakes in grams requires multiplying AI by the energy requirement in kcal and dividing by 900. For example, an AI of 4% with an intake of 2500 kcal for an adult male would equate to an acceptable intake of about 11 g/d. Linoleic intakes have increased in the United States from 3% to 4% in the 1960s to around 6%–7% dietary energy in the 1980s and have remained at this level since then, a finding corroborated by an increase in the proportion of linoleic in adipose tissue from about 8% in the 1960s to about 18% nowadays (Guyenet and Carlson, 2015). Similar increases in linoleic intake have occurred in the United Kingdom and other countries with the global expansion of vegetable oil production (Harika et al., 2013).

1.3.2. Requirements for omega-3 fatty acids

For many years, ALA was not considered an essential fatty acid. This is because it only partially restored growth in the rat model of the essential fatty acid deficiency without curing dermatitis. However, later studies in rats show that rats fed a diet containing adequate amounts of linoleic acid but lacking ALA for several generations showed impairments of retinal function that were associated with the replacement of docosahexaenoic acid (22:6n-3, DHA) by docosapentaenoic acid (22:5n-6, DPA) in retinal rod-outer segment membranes. Further studies showed a deficiency of ALA resulted in impaired visual acuity in primates that corresponded to a reduction in the proportion of DHA in brain lipids. Studies in preterm human infants found transient changes in visual function in infants fed formula lacking omega-3 fatty acids, which were corrected by the inclusion of DHA in infant formula but not completely resolved by ALA. Many breast milk substitutes now contain DHA as well as arachidonic acid at concentrations equivalent to those found in breast milk (WHO/FAO, 2010). The amount of DHA in breast milk, however, does vary according to the maternal diet with lower levels found in vegetarian and especially vegan mothers (Sanders, 2017).

There has been much debate as to whether ALA is efficiently converted to DHA. However, there is clear evidence that humans can convert ALA to DHA (Makrides et al., 2000; Sanders, 2014). However, polymorphisms in the desaturase enzyme genes seem to influence the capacity to make AA and DHA (Salas Lorenzo et al., 2019; Marklund et al., 2019). Although there is a basal rate of DHA synthesis from ALA in humans, the proportions in blood lipids are greatly augmented by dietary DHA. Recommended intakes of ALA and DHA for infants are based on the levels present in breast milk. While there is evidence to support the need to supply DHA in the diet of infants because of its contribution to normal brain and visual function, there is currently a lack of evidence for any specific requirement for long-chain polyunsaturated fatty acids in adults and uncertainty regarding supplementation in pregnancy.

Recent metabolomic research has discovered antiinflammatory compounds formed from EPA and DHA called resolvins and protections (Spite et al., 2014). However, it is uncertain whether these are formed in sufficient amounts by in vivo pathways to be physiologically important. Recommendations relating to intakes of long-chain omega-3 fatty acids in relation to cardiovascular are based on epidemiological evidence showing favorable effects of fish consumption (WHO/FAO, 2010).

1.3.3. Pharmacological effects of omega-3 and omega-6 fatty acids

High intakes of fish oil containing EPA and DHA display several pharmacological properties in experimental animal models: inhibition of inflammation, antithrombotic effects, altered lipoprotein metabolism, inhibition of atherosclerosis, lowering of blood pressure, and inhibition of tumor growth. Some of these effects are believed to result from a decreased production of bioactive eicosanoids derived from the omega-6 series. Generally, the eicosanoids derived from EPA are less active than those derived from AA except for prostacyclin. This may well explain their blood pressure lowering observed with high intakes (>3 g/d) of EPA + DHA but with lower intakes (Appel et al., 1993; Sanders et al., 2011). The well-established plasma triglyceride-lowering effect of EPA + DHA may be a consequence of interactions with peroxisome proliferator-activated receptor (PPAR)-α receptors. The effects of pharmacological intakes of EPA and DHA on other cardiovascular disease (CVD) risk factors have been reviewed extensively elsewhere (Saravanan et al., 2010). Pilot studies based on the anticachexic effect of EPA in mice with cancer suggested that high doses of EPA might be of value in the management of cancer cachexia. However, despite what appeared to be a promising approach, the results from a phase two trial were equivocal (Fearon et al., 2003). Long-chain omega-3 supplements show no clear evidence of benefit on inflammatory diseases such as Crohn's disease (Lev-Tzion et al., 2014), psychiatric disorders such as depression (Appleton et al., 2021), and the prevention of cognitive decline and dementia (Sydenham et al., 2012). Several very large randomized controlled trials using variable amounts of long-chain omega-3 fatty acids with multiple outcomes have been reported in the last decade, which is discussed in Section 1.5.3.

γ-Linolenic acid (found in evening primrose oil and borage oil) has been claimed to have some antiinflammatory effects, particularly in atopic dermatitis (Foolad et al., 2013).

1.4. Estimates of dietary fat intake and consumption

The amount and type of dietary fat are the most difficult nutrients to measure using traditional assessment methods. It is often very difficult to recognize and quantify added fats used. Starchy foods such as potatoes can take up varying amounts of fat ranging from as little as 5% to 25% depending on the temperature of the frying medium and the surface area (small fries have a greater surface are than large fries). Furthermore, bias is associated with accuracy of reporting foods high in fat, especially as it is well known that people who are overweight or obese are more likely to underreport their intake.

The chemical analysis of a duplicate of the diet consumed is the gold standard for assessing nutrient intake. However, this is costly and time consuming. A 7-d weighed food record is regarded as the most reliable estimate of fat intake for nutritional surveys. However, they are onerous for the participants and are subject to reporting errors. Individual may select food that is easy to weigh during the survey rather than what they normally consume. Furthermore, as oils and fats are often used frequently in small quantities this can result in measurement errors; more reliable estimates can be made by measuring changes in the weights of bottles of oil or packets of fat over a longer period (e.g., daily). However, estimated fat intakes by this method are in good agreement with the chemical analysis of duplicates of the food consumed by individuals. Animal fats make a substantial contribution to fat intake in economically developed countries. This fat intake is mainly derived from carcass meat and from milk and its products. The composition of these fats is far less variable and so the risk of errors in the estimation of intake from these sources is low. However, the levels of fat in meat can vary with production methods, and it is necessary to take into account fat discarded during butchering, food preparation, and plate waste. Processed meat products generally have a higher fat content than carcass meat, and foods such as sausages may contain about a third of their weight as fat. The estimation of the fatty acid composition of dietary fat intake is also dependent on the accurate food composition tables. Fatty acid compositional data for a substantial number of foods are usually not present and guesses have to be made about the type of fats used in the recipes. Often calculated intakes present in food tables are based on redundant compositional data or values may have been obtained from a different country which may not be appropriate. This is a particular problem when using food to estimate the intake of saturated and trans fatty acids from vegetable oils because the blends used to make spread and shortenings have changed substantially in many countries because of production reformulation to eliminate trans fatty acids and reduce the saturated fatty acid content. More recent surveys are now using simpler methods to gather data that place less of a burden on the participant and such as multiple 24-h recalls (usually estimates from 2 week days to 1 weekend day) or 3–4 day food diaries.

Food frequency questionnaires (FFQs) have become the standard instrument for measuring food intake in epidemiological studies. However, these do not measure the amount of added fat consumed and make assumptions about the levels of fat in the 130 or so different foods whose frequency of consumption is measured. Furthermore, assumptions are made regarding the portion size of the foods consumed. This is a particular problem as food portion sizes appear to be increasing in many high-income countries. However, a photographic atlas of food portions or food models can be used in conjunction with FFQs to estimate portion sizes. FFQs underestimate total energy intake and total fat consumption. However, they are useful for categorizing individuals according to the level of intake.

Micha et al. (2014) made estimates of global intake of saturated, omega-6 and omega-3 fatty acids (from marine and plant sources) intakes in 2010 in adults over the age of 20 years as part of the Global Burden of Diseases Project (Table 1.2). The global average intake of saturated fat was 9.4% of the energy with) ranging from 2.3% of the energy to 27.5% energy). The global mean intake of omega-6 fatty acids (mainly linoleic acid) were 5.9% energy (1.2%–12.5% energy). The global mean intake of trans fat was estimated to be 1.4% energy (0.2–6.5). Trans fatty acid intakes were highest in both North America and Central South America. Intakes of trans fatty acids were low in Western Europe and Australasia where there has been concerted action in the mid-1990s to remove industrial produced trans fatty acids from the food chain.

Table 1.2