This conclusion presents some closing thoughts on the key concepts discussed in the preceding chapters of this book. The book provides a comprehensive and up-to-date review of the clinical and biochemical significance of zinc. Within that framework, the two objectives were to emphasize the common etiological aspects of clinical abnormalities of zinc metabolism; and to constructively examine the interactions of zinc with essential nutrients. Some of the major reviews on the clinical aspects of zinc metabolism have dealt very well with the etiological aspects of zinc depletion, but the clinical and biochemical implications of the interactions of zinc with nutrients other than proteins have not previously been adequately reviewed. The book discusses the main difference with other reviews of the biochemical role of zinc is the discussion of its interactions with lipids and long-chain fatty acid metabolism. Zinc deficiency studies using laboratory animals have been plagued by the effects on appetite and food intake.