Japanese female athletes with low energy availability exhibit low multiple food group intake and increased tartrate-resistant acid phosphatase 5b levels: a cross-sectional study

The purpose of this study was to examine whether the bone parameters and food groups consumed differ according to the energy availability (EA) status in Japanese female athletes, and to determine the relationship between calcium intake and other food groups consumption among these athletes. We investigated EA status, nutritional and food group intake, bone metabolism using biochemical analysis, and evaluated body composition and bone parameters using dual-energy X-ray absorptiometry. Fifty-two Japanese female athletes (Age: 20.0 ± 1.2 years) were enrolled in this study. Group differences between the low EA (EA < 30 kcal/ kg FFM/d, n = 22) and moderate EA (EA ≥ 30 kcal/kg FFM/d, n = 30) groups were examined. Compared to the moderate EA group, the low EA group exhibited a lower daily intake of protein (g/kg BW), carbohydrate (g/kg BW), calcium (mg), grains (g), meats (g), milk and dairy products (g). Moreover, the bone resorption marker was significantly higher in the low-EA group. The daily intake of soybean products (g), vegetables (g), fish and shellfish (g) and milk and dairy products (g) correlated positively with daily calcium intake (mg). Female athletes with low EA and insufficient intake of milk and dairy products exhibited increased serum tar-trate-resistant acid phosphatase 5b levels. As with milk and dairy products intake, consumption of various food groups was also significantly positively correlated with calcium intake. These findings suggest that a diet with sufficient energy and multiple food groups to provide adequate calcium may benefit bone health among Japanese female athletes.