Jan. 14, 2000 (Atlanta) -- Calcium is not the only nutrient essential to the prevention of osteoporosis. Researchers at the University of Surrey in England have identified several key micronutrients necessary for bone health. Micronutrients include any essential dietary elements needed only in small quantities, such as zinc, magnesium, potassium, fiber, and vitamin C.
Most studies regarding bone mass have concentrated on the role of calcium, providing a limited understanding of the role of micronutrients. A new study in the January issue of the American Journal of Clinical Nutrition shows consumption of micronutrients in earlier life may contribute to greater bone health in middle age.
Susan New and her colleagues at the University of Surrey at Guildford, England, conducted a study to determine if food intake of fruits and vegetables affected bone health, supported by tests to measure bone mass density (BMD) and other markers of bone health.
The study included 62 healthy women, aged 45 to 55 years. A section of the forearm, lower back, and left hip were measured for bone density. Samples were taken to measure calcium levels in the blood and the amount of calcium excretion in urine.
A food questionnaire was used to include foods common to the northeast Scotland area. Questions about frequency of consumption were also asked. Researchers assessed the participants' dietary intake for the previous 12 months and during two critical stages in skeletal growth -- childhood (under age 12) and early adulthood (ages 20 to 30 years). Although the ages of 12 to 20 years are important, the pilot test questions demonstrated this was " ... a time of tremendous change and hence a much more difficult time to answer questions with certainty," write the researchers.
The dietary questions focused on consumption of dairy products, fruits, and vegetables (excluding potatoes). Consumption was categorized as low, medium, or high. Work and leisure activities and physical activity levels were also calculated. Past activity was assessed by using childhood and early adulthood categories.
Results of the study demonstrated no significant difference between current nutrient intake and lower back, or hip, bone mass density (BMD). In a comparison of women who consumed low amounts of dairy, fruits, and vegetables with those who had moderate or high consumption, there was no significant difference in BMD. However, a significant difference was seen in BMD of the left hip of women with high childhood intakes of fruit compared to those with low to medium intakes during childhood.
The study also did not determine pregnancy status, family history, or protein intake, all of which affect bone mass density. The researchers admit that the study does present limitations due to its design and small sample size, allowing only associations to be made between diet and bone health.
- Calcium is not the only nutrient essential to good bone health, but consumption of zinc, magnesium, potassium, and vitamin C during childhood may also play a role, according to a recent study.
- Other factors that affect bone density are physical activity, estrogen status, and genetics.
- This study is limited because the number of people participating was relatively small.