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Introduction To Human Nutrition: A Global Perspective On Food And ....pdf



Now in its third edition, the best-selling Introduction to Human Nutrition continues to foster an integrated, broad knowledge of the discipline and presents the fundamental principles of nutrition science in an accessible way. With up-to-date coverage of a range of topics from food composition and dietary reference standards to phytochemicals and contemporary challenges of global food safety, this comprehensive text encourages students to think critically about the many factors and influences of human nutrition and health outcomes.




Introduction to Human Nutrition: A Global Perspective on Food and ....pdf



Intensified and enhanced food production through irrigation, use of fertilizer, plant protection (pesticides) or the introduction of crop varieties and cropping patterns affect biodiversity, and thus impact global nutritional status and human health.\r\n Habitat simplification, species loss and species succession often enhance communities vulnerabilities as a function of environmental receptivity to ill health.


Intensified and enhanced food production through irrigation, use of fertilizer, plant protection (pesticides) or the introduction of crop varieties and cropping patterns affect biodiversity, and thus impact global nutritional status and human health.Habitat simplification, species loss and species succession often enhance communities vulnerabilities as a function of environmental receptivity to ill health.


M. Berners-Lee, C. Kennelly, R. Watson, C. N. Hewitt; Current global food production is sufficient to meet human nutritional needs in 2050 provided there is radical societal adaptation. Elementa: Science of the Anthropocene 1 January 2018; 6 52. doi:


The global food system has major impacts on the environment, through greenhouse gas emissions, water abstraction, soil, water and air pollution, land use change and loss of biodiversity, threatening food security and sustainability. Ensuring global food security is the second of 17 Sustainable Development Goals adopted by the United Nations as part of its 2030 Agenda for Sustainable Development (United Nations, 2015) but achieving this while reducing negative environmental impacts is one of the greatest challenges facing humanity.


Here we explore the potential for current global food production to feed the world, both now and in 2050. We do not take account of crop yield changes such as those that may result from new technologies, land use or demographic changes, farming practices or climate change, but simply keep crop yields at 2013 levels. The main focus of the paper is therefore to assess whether or not current crop yields are sufficient to meet human nutritional needs in 2050. To do this, we combine Food and Agriculture Organisation of the United Nations (FAO) data with food nutrient data, and information on animal grazing and on human nutritional needs, which we analyse by regional demographic profiles to quantitatively map the flows of food on its journey in seven stages from production to the meeting of human nutritional needs and other end-points, including waste and non-food uses (see Methods and S.I.). We do this at the global and regional scales. We do not explore issues of palatability but assume that human-edible crops fed to animals can be processed into acceptable human food or substituted without yield loss for edible alternatives. For example, the Zea mays indentata varieties grown in the United States for animal feed can be used to produce foodstuffs already commonly eaten in some societies or alternatively could be substituted without yield loss for other varieties of maize such as those already grown and eaten in South America and elsewhere (e.g. Gwirtz and Garcia-Casal, 2014; Ranum et al., 2014).


Figure 1a shows global food energy flows for 2013 in kilocalories/person/day (kcal/p/d where 1 kcal = 4.2 kJ). 5935 kcal/p/d of crops directly edible by humans are grown alongside 3812 kcal/p/d of vegetable matter eaten by other animals but not directly digestible by humans (i.e. GP&S). This total of 9747 kcal/p/d is more than four times the average dietary energy requirement for healthy life (ADER) of 2353 kcal/p/d (World Health Organization and Food and Agriculture Organization of the United Nations, 2001).


The flows of global food energy (kcal/person/day) (panel a), protein (g/person/day) (panel b), vitamin A (μg/person/day) (panel c), iron (mg/person/day) (panel d), and zinc (mg/person/day) (panel e) from the amount grown to the amount eaten. For crops fed to animals, the units are based on global human population, not animal population. The left-hand bar in panels a and b divides the crops grown into those that are directly edible by humans and the grass, pasture & stover that is only edible by animals. The right-hand bar divides the nutrients eaten into that required for healthy human living and net excess consumption or net deficit (panel c). Animal losses include all the losses inherent in animal husbandry, such as energy used for respiration, growth, movement and reproduction and the wastage of animal parts not used as food. DOI:


The sum of the separate wastes and losses identified above (excluding animal-related losses, investments, non-food uses and excess consumption) is 1329 kcal/p/d, or 22% of the human-edible crop calories grown globally. This compares with recent estimates of one quarter (Lipinski et al., 2013), one third (Gustavsson et al., 2011) and one half (Lundqvist et al., 2008) of food wasted (although the latter two refer to mass, not energy). The significant differences in food wasted by region, food group and supply chain stage (Table S1) have been discussed elsewhere (e.g. Food and Agriculture Organisation of the United Nations, 2011, Lundqvist et al., 2008).


Only 5% of the protein in crops grown is diverted to non-food uses, compared with 14% of calories. MD&F contribute 38% of human protein intake, compared with the 19% contribution they make to calorie consumption (c.f. contributions of 37% and 18% respectively, estimated using a farm-based bottom-up inventory approach by Poore and Nemecek, 2018). The protein in MD&F delivered to the human food chain is 43% of the amount of protein in the human-edible crops fed to animals, compared with 34% for calories. Nevertheless, the overall effect of feeding human-edible food to animals is to decrease the overall available global protein supply by 51 g/p/d (or 116% of the global average RDA).


The vitamin A in human-edible crops grown is 878 μg/p/d, 22% higher than the global requirement for healthy living, taken as 721 μg/p/d (see Methods) (Institute of Medicine Panel on Micronutrient, 2000). Harvest and post-harvest losses are 22%, greater than for energy (11%). This leaves 686 μg/p/d available for use. Only 1% of this is diverted to non-food uses, compared with 14% of calories. Animals provide more vitamin A than they are fed in human-edible crops, with a 214% return, and contribute 37% of the vitamin A eaten. This contrasts with the 34% and 43% returns of energy and protein respectively. Processing, distribution and consumer losses total 195 μg/p/d, leaving 639 μg/p/d eaten. In the absence of fortification and supplements, therefore, the global consumption of vitamin A would be 11% less than that required to meet human needs. In many countries this deficit is largely resolved by widespread fortification of food (Saeterdal et al., 2012), although some individuals remain undernourished. The global flows of vitamin A are shown in Figure 1c.


The human-edible crops grown contain 74 mg/p/d of iron (Figure 1d). This compares with a global recommended intake of 11 mg/p/d (see Methods) (Institute of Medicine Panel on Micronutrient, 2000). Harvest losses, post-harvest losses, investment and non-food uses total 11 mg/p/d, leaving 63 mg/p/d in crops. Two thirds (41 mg/p/d) is fed to animals, which deliver only 3 mg/d/d to the human food chain as iron in MD&F, a return of just 7%. However, the bioavailability of iron is greatly improved by animal metabolism. After processing and distribution losses, 18 mg/p/d remain in crops, giving a total of 21 mg/p/d available for human consumption. As for other micronutrients, the ARI of iron is dependent on age, gender, lactation state and other factors. In addition, non-haem iron is less bioavailable than haem iron, hence vegetarians require an iron intake almost twice that of carnivores (Institute of Medicine Panel on Micronutrient, 2000). Absorption efficiency is also dependent on other dietary factors. However, the bioavailability of iron remains a topic of debate and uncertainty. Even after allowing for a conservatively high factor of four difference between the bioavailability of haem and non-haem iron (Institute of Medicine Panel on Micronutrient, 2000), vegetable food remains the dominant source of absorbed iron in the global average human diet. If iron were not fed to animals in human-edible crops, the 3 mg/p/d of haem iron in the global average diet could be replaced by 41 mg/p/d, which after distribution and processing losses and consumer waste, would deliver 35 mg/p/d of non-haem iron for human consumption, taking the total consumed to 53 mg/p/d. 350c69d7ab


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