Historical profile A nutritional revolution Mike Sutton bites into the life of Sir Frederick Gowland Hopkins, the biochemist credited with discovering vitamins GRAHAM FOWELL GRAHAM 56 | Chemistry World | December 2011 www.chemistryworld.org A century ago, the basic facts of Anne Stevens. (They had three human nutrition seemed clear. Most children, one of whom was the noted scientists agreed that we required archaeologist Jacquetta Hawkes.) nothing more than a sufficient supply The lectureship was poorly paid, of carbohydrate, fat, protein and and to support his family Hopkins water, plus traces of a few mineral also taught medical students basic salts. Physicians were aware of anatomy and physiology. Somehow several diseases which we now know he found time to publish more to be caused by vitamin deficiency, research, and in 1905 he was elected and a few scientists had already a fellow of the Royal Society. In 1910 suggested that these conditions prolonged overworking caused his were diet related. But their causes health to break down, and while he remained unclear, and the word was convalescing, Trinity College vitamin had yet to be coined. offered him a fellowship which Today, deficiency diseases are allowed him to reduce his teaching retreating in the developing world commitments considerably. In and are rarely seen in prosperous 1914 Hopkins became Cambridge’s nations. To prevent them, extra first professor of biochemistry, vitamins are routinely added to though the first world war soon basic foods such as bread, milk and marginalised his academic research margarine, while the production as government sponsored work and marketing of vitamin-based relating to nutrition and rationing dietary supplements is a huge took priority. However, in 1924 industry. However, what we the university established a new should eat – and how much – is an institute of biochemistry which he endlessly debated issue. headed until his retirement in 1943. This transformation of our dietary awareness took several decades, and Vitamins and vitality many scientists contributed to it. Today, Hopkins is chiefly But the critical breakthrough was remembered for his work on announced in 1912 by the English vitamins, though he made several biochemist Sir Frederick Gowland other significant contributions Hopkins (1861–1947). It was not a to biochemistry – ranging from sudden eureka moment – one former investigations of the role of lactic LIBRARY PHOTO SCIENCE pupil recalled Hopkins saying years acid in muscle metabolism to earlier that the subject of nutrition at the Royal School of Mines, Hopkins was an inspiring analyses of the pigments in butterfly would soon be revolutionised. and afterwards worked for some teacher as well as an wings. The thread linking all these However, it was Hopkins himself months in the analytical laboratory outstanding scientist activities was his conviction that who eventually launched the of Frankland’s son, Percy. He then biological systems and processes are revolution with his 1912 paper: enrolled as a part time student at accessible to chemical investigation. Feeding experiments illustrating the University College London (UCL), In an address to the British Science importance of accessory food factors studying to qualify as an associate of Association in 1913 he declared: ‘My in normal dietaries. the Institute of Chemistry. main thesis will be that in the study Hopkins’ outstanding of the intermediate processes of Working his way up examination results persuaded Sir metabolism we have to deal, not with Radical advances in science are Thomas Stevenson – lecturer in complex substances which elude often made by impatient young forensic medicine at Guy’s Hospital ordinary chemical methods; but investigators, but Hopkins was a late and official Home Office analyst – to with simple substances undergoing starter. His father, a bookseller and hire him as an assistant in 1883. In comprehensible reactions.’ amateur scientist from Eastbourne, Stevenson’s laboratory he helped to Hopkins had worked on proteins Sussex, died when his son was prepare evidence for some notorious at Guy’s Hospital, but at Cambridge six years old, leaving the boy his poisoning trials, while continuing a failed experiment suggested a new microscope and telescope. At school with his part time education approach. Students complained – first in Eastbourne, later in London programme. By 1890 he had acquired In short that a standard test for proteins – – Hopkins grew frustrated with the a BSc from UCL and was studying Frederick Gowland the Adamkiewicz colour reaction curriculum. At 14 he played truant medicine at Guy’s. He was also Hopkins conducted a – would not work. Hopkins found for several weeks, educating himself publishing original research papers. lengthy investigation that the acetic acid they had used at libraries and museums until he After gaining his bachelor of of animal (and human) in the test was too pure. He showed was moved to a new school. At 17 he medicine degree in 1894, Hopkins nutritional needs in the that the reaction’s distinctive purple started work in an insurance office, worked for the physiology early 1900s colour was actually generated by but after six unhappy months he department at Guy’s, but needed These studies led to glyoxylic acid, often present as an joined a London firm of chemical additional part time jobs to earn the publication of his impurity in commercial acetic acid. analysts as an articled pupil. a viable income. Nevertheless, he groundbreaking 1912 This discovery encouraged him to Like many apprentices, Hopkins continued his research, taking a paper reporting the need seek more reliable chemical tests picked up much useful knowledge particular interest in the chemistry for vitamins in our diet for proteins, and for the simpler but received little systematic of proteins. In 1898 he was appointed Hopkins was awarded substances produced when they training. Dissatisfied with this, lecturer in physiological chemistry the 1929 Nobel prize for were broken down in the laboratory. he began attending Sir Edward at the University of Cambridge, physiology or medicine In 1901 Hopkins and his Frankland’s chemistry lectures and in the same year married Jessie for this work coworkers succeeded in isolating www.chemistryworld.org Chemistry World | December 2011 | 57 Historical profile SCIENCE PHOTO LIBRARY PHOTO SCIENCE the amino acid necessary minerals), tryptophan from milk and showed that casein residues, though it took when fed on this alone considerably longer to establish they failed to gain weight and died its chemical identity as 2-amino- Nikolai Lunin Hopkins made the link prematurely. A parallel group fed 3-(1H-indol-3-yl)propanoic acid. and the Dutch physician Christiaan between diet and diseases on the same diet, but with tiny Hopkins’ team also showed that Eijkman demonstrated that animal amounts of milk or yeast extract mice fed on a tryptophan-free diet diseases could be induced, and added, developed normally. Hopkins gained weight more slowly than a cured, by variations in diet. concluded that these additives control group given the same diet With the benefit of hindsight, contained substances essential to plus a trace of tryptophan. This these results look conclusive. animal growth, and began the long discovery, published in 1907, became However, when Hopkins began his struggle to isolate and identify them. a paradigm for further studies of work they were generally ignored There were numerous setbacks the metabolic roles of individual or dismissed. Deficiency diseases along the way. For example, it was chemical substances. were still frequently attributed to eventually realised that casein By then Hopkins was convinced poisoning by contaminated food, or – a milk-derived protein used in that the absence of certain nutrients to bacterial infections. The challenge Hopkins’ artificial feed mixes – from human or animal diet caused Hopkins faced was to identify these sometimes contained traces of specific diseases. This was not a new critical components of our food and these vital substances, making the idea. Ancient Egyptian medical texts establish their chemical formulae. test results appear inconsistent. He recommended raw liver as a cure Completing this project took later discovered that anomalous for night blindness, a 14th century decades, and involved many other results also occurred if the rats’ Chinese publication identified foods investigators. But it was Hopkins food contained insufficient which prevented beriberi, and the who set it in motion with a lengthy roughage. This allowed colonies Scottish surgeon James Lind showed series of experiments, leading of bacteria to form in their guts, in 1753 that fresh lime or lemon juice eventually to his groundbreaking which then synthesised some protected sailors from scurvy. In the paper in 1912. of the missing compounds from late 19th century Kanehiro Takaki, His approach was other food components. Despite a Japanese naval surgeon, found the straightforward. He created an these difficulties, the evidence he incidence of beriberi was reduced artificial diet for laboratory rats, presented to the scientific world among sailors who ate unpolished, composed of adequate quantities in 1912 was persuasive enough to rather than polished rice, while of highly purified carbohydrates, encourage more workers to join the experiments by the Russian biologist proteins and fats (plus traces of search for these elusive substances. 58 | Chemistry World | December 2011 www.chemistryworld.org