Factors affecting calcium balance in Chinese adolescents

The Magnesium Status and Suggested Reference Ranges of Plasma Magnesium, Calcium, and Calcium/Magnesium Ratio in Chinese Adults over 45 Years Old

Magnesium (Mg) is an essential nutrient that participates in various enzymatic reactions and regulates important biological functions. The distribution and reference ranges in China have not been reported in populations more than 45 years old. This study aimed to assess the magnesium status and determine the reference values of plasma Mg, Ca, and Ca/Mg ratios for China's population more than 45 years old. A total of 2101 people were randomly selected from the China Nutrition and Health surveillance (CNHS) (2015-2017), considering the regional types and monitoring points. Then, 337 healthy individuals were further selected by a series of strict inclusion criteria to explore the reference range. The plasma magnesium and calcium were tested by inductively coupled plasma mass spectrometry (ICP-MS). The suggested reference values for plasma Mg, Ca, and Ca/Mg ratios were 0.75-1.14 mmol/L, 2.17-3.64 mmol/L, and 2.36-3.66, respectively. Taking 0.75 mmol/L as the lower cut-off limit, the prevalence of Mg deficiency was 6.66%, and the average level of plasma magnesium was 0.88 mmol/L for populations older than 45 years in China. In conclusion, this study provides the magnesium status and reference ranges for plasma Mg, Ca, and Ca/Mg ratio for Chinese people over 45 years old. The results of the recommended reference ranges in this study were very similar to our published results in women of reproductive age. Thus, the reference range of plasma magnesium in different populations in China was further improved.

Novel calcium-chelating peptides from octopus scraps and their corresponding calcium bioavailability

BACKGROUND

To reducing the massive marine pollution and resource waste caused by octopus scraps, we developed a novel octopus scraps protein hydrolysate (OSPH), which displays calcium-chelating activity, and we investigated the chelating interaction and calcium bioavailability of OSPH-Ca.

RESULTS

The structural properties of amido and carboxy groups indicated that they could be the reaction sites for chelation. The particle radius of OSPH increased by 32.25 nm after the calcium chelated with OSPH, indicating intramolecular and intermolecular folding and aggregating. The enthalpy of OSPH increased by 0.8323 after chelation, showing that bands of OSPH-Ca needed more thermal energy to be destroyed than OSPH. Meanwhile, the chelate showed remarkable stability and absorbability under either acidic or basic conditions, which favored calcium absorption in the gastrointestinal tracts of humans. The calcium intake of OSPH-Ca increased by 41% when compared with that of CaCl₂ . In particular, OSPH-Ca could protect calcium ions from precipitation caused by dietary inhibitors tannic acid and phytate, while calcium uptake efficiency remained at 3.35 and 1.68 times higher than that of CaCl₂ .

CONCLUSION

These findings revealed the feasibility of transforming octopus scraps into a novel functional calcium chelate based on peptides, promoting environmental sustainability. © 2018 Society of Chemical Industry.

Low Habitual Dietary Calcium and Linear Growth from Adolescence to Young Adulthood: results from the China Health and Nutrition Survey

Evidences from clinical trials and meta-analyses of calcium supplementation in linear growth have given conflicting results, and few longitudinal studies have investigated the long-term associations between dietary calcium and linear growth, especially in the population with low-calcium plant-based diets. We investigated the prospective associations of low habitual dietary calcium with adult height and height-for-age z-score (HAZ) from adolescence to adulthood among 2019 adolescents from the China Health and Nutrition Survey (CHNS). The average dietary calcium intakes were 426(standard deviation: 158) mg/d in boys and 355(134) mg/d in girls during adolescence. During a median follow-up of 7.0 (interquartile range: 5.9–9.0) years, boys reached an average of 169.0(6.7) cm and girls reached 158.4(5.8) cm in adulthood. After adjusting for other potential confounders, non-linear regression found that boys with dietary calcium intakes below 327 mg/d had shorter adult stature, and those taking over 566 mg/d had faster height growth whether adjusting for physical exercises level or not. No significant associations were found in girls. Our study suggests that in boys with plant-based diets, higher dietary calcium intake during adolescence is associated with faster height growth, but not with adult height; calcium intake below 300 mg/d may result in shorter adult stature.

Lifestyle and osteoporosis

Osteoporosis is associated with a number of lifestyle factors, including nutritional factors such as intake of calcium, protein, dairy food, fruits and vegetables and vitamin D status, and behavioural factors such as physical activity, smoking and alcohol consumption. Ensuring adequate calcium intake and vitamin D status and having regular weight-bearing physical activity throughout life are important for bone health and the prevention of osteoporosis and related fractures. Studies have shown that smoking and excessive alcohol intake have adverse effects on bone health and increase the risk of fracture. There is evidence suggesting that adequate protein intake and higher intake of fruits and vegetables are beneficial to bone health.

Calcium and bone

OBJECTIVE

Evaluate the role of calcium on bone health.

METHODS

Review of literatures on calcium and bone development during childhood and bone health in adulthood and older age.

RESULTS

Calcium intake influences skeletal calcium retention during growth and thus affects peak bone mass achieved in early adulthood. Increased calcium intake is associated with increased bone mineral accretion rate up to a threshold level in all ethnic groups. The minimum intake to achieve maximal retention is 1140 mg/day for white boys and 1300 mg/day for white girls. Calcium also plays a role in preventing bone loss and osteoporotic fractures in later life. Meta-analyses report that calcium supplementation reduce bone loss by 0.5-1.2% and the risk of fracture of all types by at least 10% in older people. Low calcium intake is a widespread problem across countries and age groups.

CONCLUSION

Adequate calcium intake throughout lifetime is important for bone health and the prevention of osteoporosis and related fractures.