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X Fact
July 15, 2020
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How Scientists Discovered Intrinsic Factor and Its Vital Role in Vitamin B12 Absorption

William B. Castle first hypothesized that an 'intrinsic factor' was necessary to work with Vitamin B12 (known as Extrinsic Factor - ie from the diet) to cure Pernicious Anemia. It took over 2 decades for scientists (Glass, 1952 and Latner, 1953) to begin to identify proteins extracted from stomach juice that were shown to bind to Vitamin B12. Even before they knew how this newly isolated stomach extract worked, they showed that if vitamin B12 was given alone, it did not improve the anemia of Pernicious Anemia, but when the stomach extract (Intrinsic Factor) was added, the anemia was corrected, thereby confirming the vital role of Intrinsic Factor in the vitamin B12 absorption.

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Intrinsic Factor
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Intrinsic Factor

Intrinsic factor is a protein that helps your intestines absorb vitamin B12. It is made by cells in the stomach lining. Intrinsic factor binds to vitamin B12. After attaching, intrinsic factor and B12 travel to the intestines to be absorbed into the bloodstream. Vitamin B12 is needed for red blood cells to form and grow‍‍.

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Jonathan Bortz MD
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Jonathan’s background as a practicing diabetes specialist for 15 years and 17-year career developing nutritional prescriptive products for the pharmaceutical industry has contributed to his ability to understand nutrients, how they work and why they are important.

Over the years he has acquired broad and in-depth knowledge in minerals, essential fatty acids and other nutrients, but has special expertise in Vitamin B12 and choline metabolism. He is often asked to speak at national and international venues to articulate why B12, folate and choline are so important to gene function, brain development, liver and cardiovascular health. He applies pharmaceutical standards to nutrient science and has developed a unique ability to translate complicated concepts into simple promotional messages that resonate with practitioners and consumers. He has developed dozens of innovative nutritional products, of which many are category leaders in the US. Jonathan obtained his medical degree from the University of the Witwatersrand Medical School in South Africa and did his fellowship in Endocrinology at Washington University in St. Louis, MO.

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