A study published in the September 2004 American Journal of Clinical Nutrition discovered a positive correlation between zinc intake as well as zinc plasma levels, and bone mineral density in men. Low intake and blood levels of zinc have been associated with reduced bone mass in women, but their significance in men has been unknown until now.
396 men over the age of 45 who had taken part in the Rancho Bernardo Study of heart disease risk factors were included in the current study. Standard health questionnaires were completed, bone mineral densities were measured, and plasma zinc analyses were conducted upon enrollment. Two food frequency questionnaires with a one-year interval between them were completed by the subjects, and analyzed for zinc intake. Participants returned four years after their initial visit for a second bone mineral density test.
The mean zinc intake of the group was 11.2 milligrams per day. Bone mineral density declined over the four year period in all but two areas measured. The researchers found that both dietary intake of zinc and plasma zinc concentrations were significantly reduced in men whose bone mineral density scores were diagnostic of osteoporosis of the spine or hip compared to men who did not have the disease. In men whose plasma zinc levels were in the lowest one-fourth of participants, bone mineral density values at the beginning of the study were lower in all sites but one compared to those whose zinc concentrations were in the top 25 percent.
To the authors' knowledge, this study is the first to correlate plasma zinc concentrations with bone mineral density in older men. They recommend further research to explore the role of zinc deficiency in the development of osteoporosis in this population.
American Journal of Clinical Nutrition; September 2004