Niadn deficiency

There is some interest in using the ratio of NAD/NADF in red blood cells as a convenient measure of niadn status (Jacobson and Jacobson, 1997). How could this assay work Data from human studies has shown that niadn deficiency allows a decline in intracellular NAD, but a maintenance of the levels of NADP. 

The absorption of niacin in the human body mainly occurs in the stomach and small intestine (Bechgaard and Jespersen 1977). Niacin is taken up by the body swiftly and quickly, and reaches peak plasma levels within 30-60 minutes of being absorbed (Bodor and Offermanns 2008). Furthermore it has a plasma half-life of 60 minutes (Carlson et al. 1968 Svedmyr and Harthon 1970). The enzyme nicotinamide adenine dinucleotide (NAD) glycohydrolase, which is found in the intestine and liver, faciUtates the synthesis of nicotinamide from NAD (Henderson and Gross 1979). This is an important step that ensures the availability of nicotinamide for the conversion to NAD. Niacin is metabolized in most tissues in the body and its metaboKtes are excreted in urine (Jacob et al. 1989 Shibata and Matsuo 1989). Importantly, niadn deficiency occurs mainly as a result of poor diet, but also other conditions such as carcinoid syndrome, Hartnup s disease and drug intake (isoniazid) (Hegyi et al. 2004). 

Niacin deficiency leads to unwanted multisystemic problems that are often associated with dermatological changes. Pellagra is a condition in which niacin deficiency causes a symmetrical pigmented rash, thickened skin and superficial scaling which are found in sun-exposed body areas. The classic triad of niacin deficiency are the three D s—dermatitis, diarrhoea and dementia (Hegyi et al. 2004). Some of the effects on the central nervous system include depression, anxiety, restlessness and poor concentration. In addition, alcoholic individuals with poor nutrition can develop pellagroid encephalopathy (Cook et al. 1998). The role of niadn deficiency in cardiovascular disease and lipid metabolism remains to be fully explored. 

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