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e-Feature Fun Fact November Pellagra & Tryptophan! The arrogance of the young is a direct result of not having known enough consequences.
The turkey that
every day greedily approaches the farmer who tosses him grain is not
wrong. -Harry Golden, 1969 Although Marcus Terentius Varro warned of minute disease causing creatures infesting swamps in 36 BC and Antonie van Leeuwenhoek observed millions of single celled “animalcules” with his own handcrafted microscopes in the 17th century- the theory of miasma, or bad air, was still prevalent when cholera broke out in London in the 1800s. Florence Nightingale worked to sanitize hospitals against polluted vapor from decomposing bodies and helped to impede acceptance of the theory put forth by John Snow that the vehicle of contagion was actually toxins in the water source. This grave misconception severely hindered an effective response to the epidemic. Within decades, Louis Pasteur and Robert Koch independently contributed to the validity of microbes as agents of infection and after millennia of debate, germ theory became en vogue. Such was the context when an epidemic of pellagra broke out in the South in the early 1900s. In 1914, the Spartanburg Pellagra Hospital was established in South Carolina to research causes and treatments for the disease. By 1916 as many as 100,000 Americans were afflicted with skin lesions, dermatitis, dementia, and often death. Common factors in this epidemic were poverty and the consumption of maize as a staple food source. The worst affected were cotton mill villages and within those communities women, children, and the elderly were the most susceptible. The disease appeared to be contagious and as the Thompson-McFadden Pellagra Commission found no relationship between diet and pellagra, researchers concluded it was spread by an unknown infectious agent. Scientists worked unsuccessfully to confirm this theory. It was Joseph Goldberger, as head of the U.S. Public Health Service’s pellagra investigations, who finally elucidated the true cause of the disease. He noted that inmates in mental institutions did not spread the disease to nurses and hospital employees, and that patients’ diets lacked fresh animal products. He suggested that a diet with increased meat and dairy could be preventative but still the epidemic, and the notion that a toxin in corn was the cause of the disease, held fast. After virtually eradicating pellagra in two orphanages, Goldberger attempted more radical proof of its nutritional basis. He was able to induce pellagra in six of twelve volunteer prison inmates by allowing them only a cereal-based diet for six months. There was political resistance to the suggestion that the traditional 3-M southern diet of meat (fat-back), cornmeal, and molasses was responsible for plague-like conditions. In a final effort to prove pellagra was not a contagious disease Goldberger exposed his wife and fifteen other volunteers to blood, waste and the open lesions of pellagrous patients. None contracted the disease. Surveys of cotton villages helped link pellagra with poverty and demonstrated the socio-economic vulnerability of depending on cotton at the expense of other crops. President Warren Harding appealed to the surgeon general and the American people to save its own from famine and plague inadvertently insulting half of the country. Georgia citizens replied, “When this part of Georgia suffers from a famine the rest of the world will be dead.” Despite these scientific and political obstacles, Goldberger was able to find a successful and affordable preventative for pellagra: baker’s yeast. Ironically, pellagra was not caused by a microbe, but could be cured by one. In 1927 the Red Cross gave dried yeast to Mississippi flood victims and is credited with preventing an outbreak of pellagra. It wasn’t until after Goldberger’s death that the “pellagra-preventive factor” was isolated and defined. It is nicotinic acid, or niacin, deficiency that causes the deadly disease. Although humans can synthesize niacin they require tryptophan to do so and if the diet is deficient in both tryptophan and niacin, tryptophan will be used to make protein rather than converted to niacin. It is one of eight amino acids that can not be produced by animals and must be obtained from the diet. It is not very abundant but serves several critical roles. Not only is it a precursor to niacin, but it is also a starting product for serotonin and melatonin. As such it is an important ingredient for the body’s regulation of mood, appetite and sleep. Tryptophan in turkey is largely blamed for Thanksgiving Day drowsiness, however turkey contains similar levels of the amino acid as do other meats. Carbohydrates, alcohol, and the interaction between carbohydrates and tryptophan are likely larger to blame than turkey alone. Tryptophan was first isolated in 1901 by Sir Frederick Gowland Hopkins who demonstrated that it was essential for life and along with several other amino acids must be ingested as it can not be synthesized. He won the Noble Prize for discovering vitamins and the role of amino acids such as tryptophan in manufacturing them. Tryptophan supplements didn’t hit pharmacists’ shelves until the 1980s when it was used to alleviate depression, anxiety, weight gain, and insomnia. However, either toxins in the supplement or metabolites from excess tryptophan caused thousands of cases of the serious disease eosinophilia myalgia syndrome (EMS) disabling over 1500 people and killing 37. The supplement was banned in 1991 but has since returned to the market. It is also used in Tryptan, a prescription medication used as an adjunct to anti-depressants.
For more information online: eMedicine: Pellagra - http://www.emedicine.com/derm/topic621.htm WHO/NHD: Pellagra and its prevention and control in major emergencies - http://www.who.int/nutrition/publications/en/pellagra_prevention_control.pdf Medscape: Pellagra in the United States - http://www.medscape.com/viewarticle/410505_3 Advanced Chemistry Development: Tryptophan - http://www.acdlabs.com/publish/tryptophan/
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