Population thiamine status and varying cancer rates between western, Asian and African countries.
The role of food supplements in the form of vitamins has not been extensively investigated in relation to varying cancer rates between populations of different geographical regions. New data indicate that thiamine (vitamin B1), a common food supplement in Western food products, is directly involved in nucleic acid ribose synthesis of tumor cells in its biologically activated form through the non-oxidative transketolase catalyzed pentose cycle reaction. Whether thiamine plays a role in increased cancer rates in the Western World by enhancing tumor cell proliferation, while increased consumption of thiaminase rich food limiting thiamine availability protects against common malignancies in Asia and Africa has not been evaluated. In the Western World, thiamine is a popular vitamin supplement in the form of tablets and it is also added to basic food items such as milled flour, cereals, peanut butter, refreshment drinks and pastas. On the contrary, thiaminase, the natural thiamine-degrading enzyme, is abundantly present in raw and fermented fish, certain vegetables and roasted insects consumed primarily in Africa and Asia. Excess thiamine supplementation in common food products may contribute to the increased cancer rates of the Western World.
UCLA School of Medicine, Harbor-UCLA Research and Education Institute, Torrance 90502, USA. boros@gcrc.humc.edu
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D000349:Africa / Q000453:epidemiology; D000818:Animals; D001208:Asia / Q000453:epidemiology; D004273:DNA, Neoplasm / Q000096:biosynthesis; D004034:Diet Surveys; D004041:Dietary Fats / Q000009:adverse effects / Q000378:metabolism; D004044:Dietary Proteins / Q000378:metabolism; D019587:Dietary Supplements / Q000009:adverse effects*; D002149:Energy Intake; D004790:Enzyme Induction; D005060:Europe / Q000453:epidemiology; D005399:Fishes; D006801:Humans; D006867:Hydrolases / Q000378:metabolism; D008460:Meat; D009369:Neoplasms / Q000139:chemically induced / Q000453:epidemiology*; D009656:North America / Q000453:epidemiology; D020411:Oligonucleotide Array Sequence Analysis; D010427:Pentose Phosphate Pathway; D012334:RNA, Neoplasm / Q000096:biosynthesis; D013831:Thiamine / Q000009:adverse effects*; D013832:Thiamine Deficiency / Q000453:epidemiology; D013835:Thiamine Pyrophosphate / Q000378:metabolism; D014174:Transketolase / Q000096:biosynthesis
D004273:DNA, Neoplasm; D004041:Dietary Fats; D004044:Dietary Proteins; D012334:RNA, Neoplasm; D014174:Transketolase; D006867:Hydrolases; C022731:thiaminase II; D013835:Thiamine Pyrophosphate; D013831:Thiamine