Short Term Intake of Undaria pinnatifida Does Not Affect Bone Biomarkers in Young Korean Women with Low Calcium Intake

Abstract

Calcium intake is essential for bone health, but young Korean women have low calcium intakes. Seaweeds have high calcium content, which may affect calcium metabolism. Twenty nine females aged 18-39 years with low calcium intake (< 400 mg/day) participated in a 19-day open-label randomized controlled trial. During the first five days, participants adhered to a controlled-feeding protocol followed by a two-week supplementation period in free-living conditions. The treatment group (n = 14) received an additional 200 mg Ca/ day through Undaria pinnatifida and Porphyra in meals during the controlled-feeding period, and as U. pinnatifida noodles during days 6-19. Mineral intake (Ca, P, Mg, Na, and K) was assessed from diet composites and three 24-hour recalls during the controlled-feeding and free-living periods, respectively. Fasting serum levels of calcium, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D (1,25[OH]D), phosphorus, parathyroid hormone (PTH), and alkaline phosphatase (ALP) were assessed at baseline, day 6, and day 19. Statistical analyses were performed by Student's t-test and mixed ANOVA. Mean intakes of all minerals during days 1-5 and mean Ca and Mg intakes during days 6-19 were greater in the treatment group compared to the control group. No group effect or group and time interaction was observed in serum biomarkers. Serum 1,25(OH)D increased while PTH and ALP tended to decrease on day 6 but returned to baseline values on day 20. Short-term intake of U. pinnatifida and Porphyra does not affect calcium metabolism in young Korean women with low calcium intakes.

Effects of whole seaweed consumption on humans: current evidence from randomized-controlled intervention trials, knowledge gaps, and limitations

“…Participants consumed 4 g DW seaweed/day equivalent to 133 mg of calcium for 5 days, followed by 2 packs of seaweed noodles every third day for 19 days, providing around 35 mg of calcium per day; but an undisclosed amount of seaweed. No changes were found in serum calcium or three serum biomarkers for calcium intake (25-hydroxy vitamin D3; 1,25-dihydroxyvitamin D; parathyroid hormone) compared to the habitual diet ( 69 ). The other study ( 27 ) reported similar findings for sodium, potassium, and chloride in subjects with hypertension that consumed 5 g/day of U. pinnatifida for 8 weeks versus a parallel group with no intervention.…”

“…Two RCTs ( Table 1 ) analyzed blood minerals as primary and secondary/exploratory outcomes, respectively ( 27 , 69 ). One RCT examined calcium, a macro-mineral crucial for bone health and found in relatively high amounts in brown seaweed ( 70 ).…”

“…One RCT examined calcium, a macro-mineral crucial for bone health and found in relatively high amounts in brown seaweed ( 70 ). In this study, the authors investigated whether U. pinnatifida incorporation in the habitual diet would lead to an increase in serum calcium levels in women with low calcium intake ( 69 ). Participants consumed 4 g DW seaweed/day equivalent to 133 mg of calcium for 5 days, followed by 2 packs of seaweed noodles every third day for 19 days, providing around 35 mg of calcium per day; but an undisclosed amount of seaweed.…”

A short education session increases the accuracy of estimated food records in young Korean women during a controlled-feeding study

“…This study was conducted as a secondary study of a controlled-feeding trial focusing on the effect of seaweed intake on bone biomarkers and gut microbiota [ 11 ]. Data of 30 Korean women participating in a 5-day controlled-feeding study conducted in Wando-gun, Jeollanam-do province from June 25 to June 29, 2018, were analyzed.…”