I'm looking around for supplements which will help with sleep and have been looking at niacin. From what I've read so far, two queries come to mind:
1 I've found several references to caution with niacin if you have gallbladder disease and I have gallstones. Anyone understand the reason for the caution? I understand it's related to cholesterol but that's as far as I've got....
Dietary sources of Niacin: Both nicotinamine adenine dinucleotide phosphate (NADP+) and tryptophan in the diet are major sources of niacin (Vit B3). Tryptophan is an amino acid which constitutes roughly 1% of proteins (depending on their source) and so Niacin deficiency is rare.
Niacin and CFS: Niacin deficiency would lead to some of the symptoms of CFS as well as some known biochemical disruptions associated with CFS. For example, mitochondrial toxins can lead to Niacin deficiency which can be measured as increased Niacin urinary excretion. Niacin is the precursor of NAD/NADP which are involved in reactions pertaining to mitochondrial respiration, glycolysis and lipid beta-oxidation. Additionally, Niacin has been shown to have anti-oxidant properties which may help with some CFS symptoms.
Niacin supplementation and potential toxicities: Finally, to your question
@Hilary! High intakes of niacin may pose a risk. Niacin provided at pharmacological doses requires high levels of methyl groups for catabolism. This can reduce the Sadenosylmethionine (SAM) pool and increase homocysteine levels in the plasma (Chemico-Biological Interactions 163 (2006) 94–112). High homocysteine is associated with increased cholesterol and/or LDLs (which theoretically may contribute to gall stones) and cardiovacular disease. High niacin intake can also result in niacin-induced insulin resistance (Chemico-Biological Interactions 163 (2006) 94–112). I guess if you were taking Niacin supplements, it would be a good idea to regularly test blood homocysteine and insulin function.
Rodger
