The following is drawn from Nutritional Influences on Illness by Melvyn Werbach, M.D.Third Line Press, 1996. Please consult this book for references for the following information.
Ethanol inhibits the intestinal transport of biotin and decreases plasma levels.
Usually no adverse effects at customary supplemental doses. Intake over 2 gms may cause primary hyperparathyroidism. Calcium retention in the body does not necessarily occur with supplementation secondary to limited absorption and increased urinary excretion. Calcium is better absorbed with a light meal than when taken alone. Calcium citrate may be better absorbed than other forms, and calcium citrate-malate may be even better absorbed due to 6 times the solubility of calcium citrate or calcium malate.