Calcium intake is much lower in Asian communities, especially among the elderly. The average daily calcium intake in elderly subjects in Hong Kong is about 300 mg, which is much lower than the recommended intake of 1,000 mg. An adequate calcium intake is important for maintaining bone health and protection against hypertension. Subjects with a higher calcium intake tend to have a lower blood pressure and reduced risk of hypertension. Age-related increases in blood pressure are attenuated by higher calcium intake. Calcium may help decrease blood pressure by increasing sodium excretion by the kidney and the relaxation of blood vessels.

The Faculty of Medicine of The Chinese University of Hong Kong has conducted two studies to determine the prevalence of hypertension in older subjects in Hong Kong in relation to their calcium intake. Among 110 vegetarians aged over 55, 71 (65%) were found to have hypertension. Hypertensive subjects had lower calcium intake, but higher salt intake and lower potassium intake. Both the systolic blood pressure and prevalence of hypertension were the highest among subjects with the lowest calcium intake but the highest salt intake and the lowest potassium intake. Among 234 free-living subjects aged over 55, 124 (53%) were found to have hypertension. A similar trend for the protective effect of dietary calcium intake against hypertension was seen.

An adequate calcium intake together with a high potassium intake and reduced salt intake should help protect the elderly against hypertension. They should understand the importance of calcium in disease prevention and its main dietary sources.