Reducing Salt in Foods

Cindy Beeren, Kathy Groves, Pretima M. Titoria

• Publisher: Woodhead Publishing
• Year: 2019
• eBook ISBN: 9780081009338
• Edition: 2
• Topic: Technology & Engineering
• Subtopic: Food Science
• Index: Technology & Engineering

Reducing Salt in Foods, Second Edition, presents updated strategies for reducing salt intake. The book contains comprehensive information on a wide range of topics, including the key health issues driving efforts to reduce salt, government action regarding salt reduction and the implications of salt labeling. Consumer perceptions of salt and views on salt reduction in different countries are also discussed, as are taste, processing and preservation functions of salt and salt reduction strategies. Final sections discuss salt reduction in particular food groups, including meat and poultry, seafood, bread, snack foods, dairy products and canned foods, each one including a case study.This updated edition also includes a new section on the future of salt reduction, the development of new ingredients to replace salt, salt reduction in catering, and how to teach new generations to adjust salt levels from an early age.- Completely revised and updated with an overview of the latest developments in salt reduction- Presents guidelines to help with reducing salt in specific product groups- Presents a new section on the future of salt reduction, development of new ingredients to replace salt, salt reduction in catering and how to teach new generations to adjust salt levels from an early age- Contains new chapters on preservation issues, taste issues and processing issues when reducing salt in food, along with case studies that illustrate salt reduction

Part One

Dietary salt, health and the consumer

1

Salt and health

Feng J. He; Monique Tan; Graham A. MacGregor Wolfson Institute of Preventive Medicine, Barts and The London School of Medicine & Dentistry, Queen Mary University of London, London, United Kingdom

Abstract

Cardiovascular disease (CVD) is the leading cause of death and disability worldwide. The most important risk factor for cardiovascular disease is raised blood pressure. Salt intake is the major cause of raised blood pressure, as demonstrated by several different lines of evidence – epidemiological, migration, population-based intervention, treatment, animal, and genetic studies. Independently and additive to its effects on blood pressure, the current high-salt intake (9–12 g per day in most countries of the world) also has a direct effect on stroke, left ventricular hypertrophy, renal disease, stomach cancer, and bone demineralization. Reducing our salt intake to the recommended 5–6 g per day will result in major public health gains; a further reduction to 3 g per day would have a much greater impact and should become the long-term target for population salt intake worldwide. As 75%–80% of the salt intake in developed countries comes from processed foods, the most effective strategy is for the food industry to reduce the amount of salt added to their products in a gradual and sustained manner. Several developed countries (e.g. Finland, the United Kingdom) have successfully reduced their population salt intake, and this was accompanied by significant falls in population blood pressure and CVD mortality. A major challenge now is to expand this to developing countries, where over 80% of the global salt-related disease burden occurs. A reduction in salt intake worldwide, even in small amounts, will result in enormous public health gains and cost savings.

Keywords

Salt; Blood pressure; Health; Salt reduction; Public health

1.1 Introduction

The leading cause of death and disability worldwide is cardiovascular disease (strokes, heart attacks, and heart failure), and the major risk factor for cardiovascular disease is raised blood pressure (Forouzanfar et al., 2017; Lewington et al., 2002; Lim et al., 2012). Dietary salt (sodium chloride) is an important regulator of blood pressure, with several different lines of evidence – epidemiology (Elliott et al., 1996), migration (Poulter et al., 1990), population-based intervention (Forte et al., 1989), treatment (He and MacGregor, 2002), animal (Denton et al., 1995) and genetic studies (Lifton, 1996) – consistently showing that a reduction in salt intake leads to a reduction in population blood pressure and slows down the rise in blood pressure with age.

There is also increasing evidence that our current high-salt intake has other harmful effects on human health, independently and additively to its effect on blood pressure. For instance, evidence exists on a direct effect of salt on stroke (Perry and Beevers, 1992), left ventricular hypertrophy (Kupari et al., 1994; Schmieder and Messerli, 2000), progression of renal disease and albuminuria (Cianciaruso et al., 1998; He et al., 2009; Heeg et al., 1989; Swift et al., 2005), increasing the risk of stomach cancer (Joossens et al., 1996; Tsugane et al., 2004), and bone demineralization (Devine et al., 1995).

In view of this, the World Health Organization has set a global target of 30% reduction in salt intake by 2025, and recommends adults to reduce their salt intake to < 5 g per day (World Health Organization, 2013).

In this chapter, we will provide an update on the body of evidence that relates salt to blood pressure and cardiovascular disease. We will also discuss the evidence on other harmful effect of salt on health.

1.2 Definition of hypertension

The relationship between blood pressure and cardiovascular disease displays a continuous graded relationship starting at 115/75 mmHg, and there is no evidence of any threshold level of blood pressure below which lower levels of blood pressure are not associated with lower risks of cardiovascular disease (Lewington et al., 2002). Thus, any classification of people into categories (‘normotensive’ and ‘hypertensive’) is inherently arbitrary. Nevertheless, it is useful to provide a classification of blood pressure for the purpose of identifying high-risk individuals and providing guidelines for treatment and control.

Late Professor Geoffrey Rose suggested that ‘the operational definition of hypertension is the level at which the benefits ... of action exceed those of inaction’ (Rose, 1980). The criteria for the classification of hypertension have changed over the past 50 years as studies have shown benefit at lower levels of blood pressure (Vasan et al., 2001). The Seventh Joint National Committee (JNC VII) (Chobanian et al., 2003) defined individuals with blood pressure < 120/80 mmHg as ‘normal’ and those with blood pressure ≥ 140 mmHg systolic or ≥ 90 mmHg diastolic as ‘hypertension’. For for those with blood pressure ranging from 120 to 139 mmHg systolic and/or 80 to 89 mmHg diastolic, the JNC VII report has introduced a new term ‘prehypertension’. This new designation was intended to identify those individuals in whom early intervention by adoption of healthy lifestyles could reduce blood pressure, decrease the rate of progression of blood pressure to hypertensive levels with age, or prevent hypertension entirely.

Hypertension is extremely common in Western countries. For instance, in England, just under 30% of the entire adult population had hypertension (systolic ≥ 140 mmHg and/or diastolic ≥ 90 mmHg) in 2016 (NatCen Social Research, 2017). The prevalence of hypertension increases with age, e.g. at the age of 55–64 years, 40.1% had high blood pressure, and at the age of 65–74 years, 58.0% had high blood pressure (Health and Social Care Information Centre, 2017). Many treatment trials have demonstrated a clear benefit of lowering blood pressure in hypertensive individuals (Staessen et al., 2001).

1.3 Benefits of lowering blood pressure in the ‘normal range’

In the general population, blood pressure is distributed in a roughly normal or Gaussian manner (i.e. bell-shaped curve) with a slight skew towards higher readings. Although the risk of cardiovascular mortality increases progressively with increases in blood pressure, for the population at large, the greatest number of strokes, heart attacks, and heart failure attributable to blood pressure occurs in the upper range of normal blood pressure (i.e. systolic between 130 and 140 mmHg and diastolic between 80 and 90 mmHg) because there are so many individuals who have blood pressure at these levels in the population (Rodgers et al., 2004). Therefore, a population-based approach aimed at achieving a downward shift in the distribution of blood pressure in the whole population, even by a small amount, will have a large impact on reducing the number of strokes, heart attacks, and heart failure.

1.4 Salt and blood pressure

1.4.1 Evidence that relates salt to blood pressure

The earliest comment that relates dietary salt to blood pressure was recorded in the ancient Chinese medical literature – the Yellow Emperor’s classic on internal medicine, Huang Ti Nei Ching Su Wein, 2698–2598 BCE. It is stated that ‘If too much salt is used for food, the pulse hardens …’. However, the firs...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• About the editors
• Part One: Dietary salt, health and the consumer
• Part Two: Strategies and implications for salt reduction in food products
• Part Three: Reducing salt in particular foods
• Index