History of Modern Nutrition Science—Implications for Current Research, Dietary Guidelines, and Food Policy

SCIENCE AND POLITICS OF NUTRITION History of modern nutrition science—implications for current research, dietary guidelines, and food BMJ: first published as 10.1136/bmj.k2392 on 13 June 2018. Downloaded from policy Dariush Mozaffarian and colleagues describe how the history of modern nutrition science has shaped current thinking lthough food and nutrition on dietary guidelines, general scientific This new science of single nutrient have been studied for centu- advances, or particular nutritional deficiency diseases also led to ries, modern nutritional sci- therapies.1-4 Carl Sagan said, “You have fortification of selected staple foods with ence is surprisingly young. to know the past to understand the micronutrients, such as iodine in salt and The first vitamin was isolated present;” and Martin Luther King, Jr, niacin (vitamin B3) and iron in wheat flour Aand chemically defined in 1926, less than “We are not makers of history. We are and bread.8-10 These approaches proved 100 years ago, ushering in a half century made by history.” This article describes to be effective at reducing the prevalence of discovery focused on single nutrient key historical events in modern nutrition of many common deficiency diseases, deficiency diseases. Research on the role science that form the basis of our current including goitre (iodine), xerophthalmia of nutrition in complex non-communica- understanding of diet and health and (vitamin A), rickets (vitamin D), and ble chronic diseases, such as cardiovascu- clarify contemporary priorities, new anaemia (iron). Foods around the world lar disease, diabetes, obesity, and cancers, trends, and controversies in nutrition have since been fortified with calcium, is even more recent, accelerating over the science and policy. phosphorus, iron, and specific vitamins past two or three decades and especially (A, B, C, D), depending on the composition after 2000. 1910s to 1950s: era of vitamin discovery of local staple foods.10-13 Historical summaries of nutrition The first half of the 20th century witnessed As one of the great accidents of science have been published, focusing the identification and synthesis of many nutrition history, this new science and of the known essential vitamins and min- focus on single nutrients and their erals and their use to prevent and treat deficiencies coincided with the Great KEY MESSAGES http://www.bmj.com/ nutritional deficiency related diseases Depression and second world war, a time • Modern nutrition science is young: It including scurvy, beriberi, pellagra, rickets, of widespread fear of food shortages. This is less than one century since the first xerophthalmia, and nutritional anaemias. led to even further emphasis on preventing vitamin was isolated in 1926 Casimir Funk in 1913 came up with idea of deficiency diseases. For example, the • The first half of the 20th century a “vital amine” in food, originating from the first recommended dietary allowances focused on the discovery, isolation, and observation that the hulk of unprocessed (RDAs) were a direct result of these synthesis of essential micronutrients rice protected chickens against a beriberi- concerns, when the League of Nations, 5 and their role in deficiency diseases like condition. This “vital amine” or vita- British Medical Association, and the US on 1 October 2021 by guest. Protected copyright. • This created strong precedent for reduc- min was first isolated in 1926 and named government separately commissioned tionist, nutrient focused approaches for thiamine, and subsequently synthesised scientists to generate new minimum dietary 14 dietary research, guidelines, and policy in 1936 as vitamin B1. In 1932, vitamin C requirements to be prepared for war. In to address malnutrition was isolated and definitively documented, 1941, these first RDAs were announced 6 • This reductionist approach was for the first time, to protect against scurvy, at the National Nutrition Conference on extended to address the rise in diet some 200 years after ship’s surgeon James Defence, providing new guidelines for total related non-communicable diseases— Lind tested lemons for treating scurvy in calories and selected nutrients including 7 eg, focusing on total fat, saturated fat, sailors. protein, calcium, phosphorus, iron, and 15 or sugar rather than overall diet quality By the mid-20th century all major specific vitamins. These historical events established a precedent for nutrition • Recent advances in nutrition science vitamins had been isolated and synthesised have shown that foods and diet pat- (fig 1). Their identification in animal and research and policy recommendations to terns, rather than nutrient focused human studies proved the nutritional basis focus on single nutrients linked to specific metrics, explain many effects of diet of serious deficiency diseases and initially disease states. on non-communicable disease led to dietary strategies to tackle beriberi (vitamin B1), pellagra (vitamin B3), Lower income countries are recog- • scurvy (vitamin C), pernicious anaemia 1950s to 1970s: fat versus sugar and the nising a growing “double burden” (vitamin B12), rickets (vitamin D), and protein gap (combined undernutrition and non- other deficiency conditions. However, the During the next 20 to 30 years, calorie communicable disease) chemical synthesis of vitamins quickly led malnutrition and specific vitamin deficien- • Nutrition policy should prioritise food to food based strategies being supplanted cies fell sharply in high income countries based dietary targets, public com- by treatment with individual vitamin because of economic development and munication of trusted science, and supplements. This presaged modern large increases in low cost processing of integrated policy, investment, and cul- day use and marketing of individual and staple foods fortified with minerals and tural strategies to create systems level bundled multivitamins to guard against vitamins. At the same time, the rising bur- change across multiple organisations deficiency, launching an entire vitamin dens of diet related non-communicable and environments supplement industry. diseases began to be recognised, leading to the bmj | BMJ 2018;361:k2392 | doi: 10.1136/bmj.k2392 1 SCIENCE AND POLITICS OF NUTRITION Visual summary A timeline of nutrition research While food and nutrition have been studied for centuries, modern nutritional science is surprisingly young. This timeline shows how developments in the early 20th Century have persistently shaped our understanding BMJ: first published as 10.1136/bmj.k2392 on 13 June 2018. Downloaded from of the eld, at times limiting our knowledge of the complex links between dietary patterns and health. Era of vitamin discovery Single nutrient is born Beriberi: B1 Identication of vitamins proved the Isolation and synthesis Pellagra: nutritional basis of serious epidemic B3 of all major vitamins deciency diseases, which could be Scurvy: C treated with food based dietary A strategies, and synthetic vitamins Rickets: D B1 B12 Recommended daily allowances Protein C D During the Great Depression and Calcium World War II, guidelines were E K Phosphorus prepared for total calorie intake and Iron selected nutrients Vitamins Commodity crops, fortication Food as a delivery system Fat v sugar Nutrition policy and agricultural Ultimately, the Developing countries technology focused on increasing emphasis on fat staple calories and selected won scientic Protein v calories micronutrients and policy Scientists disagreed on the relevance of the calorie v acceptance protein component of infant and child malnutrition. Chronic diseases Industry created and promoted protein enriched formulas and baby foods in developing countries. Dietary guidelines Nutrition science and policy guidelines in high income nations shifted to try to address not only nutrient Action on hunger deciencies but also chronic disease Global community coalesced around elimination of hunger and micronutrient deciency in lower income Complex eects nations, including widespread micronutrient supplementation and fortication. Food, dietary patterns For chronic diseases, conicting results of vitamin The double burden observational studies v supplement trials. Other The rapid rise in non-communicable diseases led to research advances indicated that foods and diet emerging recognition of the "double burden": the joint patterns are more important for chronic diseases than presence of conventionally conceived malnutrition single nutrients. (calorie and micronutrient deciency) with modern diseases of "mal"-nutrition such as obesity, type 2 http://www.bmj.com/ diabetes, cardiovascular diseases, and cancer The future New dietary complexities Diet-risk pathways Diet-microbiome-host interactions; specic fatty acids, The diversity of pathways increasingly calls into question avonoids, and fermented foods; personalized nutrition; the wisdom of reliance on any single surrogate outcome carbohydrate quality; brain health; powerful inuences of Blood pressure Glycemic control Inammation place and social status. Oxidative stress Endothelial health Lipids Hepatic function Adipocyte metabolism on 1 October 2021 by guest. Protected copyright. Quality over quantity Cardiac function Muscle health Brain reward For long term weight control, quality and types of foods have Gut microbiota Metabolic expenditure dierent eects and are a more relevant focus than calorie counting. Public health Processing and additives Future nutrition policy must unite modern scientic Need for

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