Reduced form (NADH, NADPH)

R = H Nicotinamide adenine dinucleotide R = PO32- Nicotinamide adenine dinucleotide phosphate Figure 28.28 • Structures of niacin-derived cofactors.

food is treated in a manner that releases the niacin. For example, some grains (i.e., corn) may contain predominantly niacin esterified to polysaccharides or peptides, referred to as niacytin. This form has a relatively low bioavailability unless treated with alkali in cooking or processing. Coffee beans have a high niacin content in the form of trigonellin (1-methyl nicotinic acid) that is converted to niacin upon roasting. Most dietary niacin from natural sources is in the form of the nucleotide derivatives, NAD+ and NADP+, which are digested by NAD + diphosphatase (EC ), followed by hydrolases in the intestine to release nicotinamide. Free nicotinamide and niacin are absorbed through a facilitated diffusion process in the intestine.156 At physiological doses, little niacin is excreted unchanged. Most is excreted as N-methylniacin or the glycine conjugate (nicotinuric acid). After administration of large doses, niacin can be found in the urine unchanged.

Was this article helpful?

0 0
Body Detox Made Easy

Body Detox Made Easy

What exactly is a detox routine? Basically a detox routine is an all-natural method of cleansing yourbr body by giving it the time and conditions it needs to rebuild and heal from the damages of daily life and the foods you eat and other substances you intake. There are many different types of known detox routines.

Get My Free Ebook

Post a comment