Absorption of calcium from milk and tempeh consumed by postmenopausal Malay women using the dual stable isotope technique

Tempeh: A semicentennial review on its health benefits, fermentation, safety, processing, sustainability, and affordability

Tempeh is a fermented food made of mainly soybeans and is a nutritious, affordable, and sustainable functional source of protein. Globally, tempeh is a widely accepted fermented product. Although there is a growing body of literature on tempeh, most research has focused on unfermented soybeans, thus the impact of tempeh fermentation on biological properties of soybeans has been largely left scattered. The objective of this review is to summarize the literature of tempeh fermentation over the past 60 years. A search of articles on tempeh published from 1960 to 2020 was performed using the Cochrane Library, Web of Science, EBSCOhost FSTA database, and Google Scholar. References from identified articles were reviewed for additional sources. In total, 321 papers were selected for this review, of which 64 papers were related to the health benefits of tempeh. This review concluded that sufficient evidence exists in the literature supporting tempeh fermentation as a low-cost, health-promoting, and sustainable food processing technology to produce protein-rich foods using various beans, legumes, and grains. This comprehensive review suggests further studies are needed on tempeh fermentation and its impact on human health; research and standardization of nonsoy tempeh; assessment of food safety-improving modification in tempeh production system; and initiatives supporting the sourcing of local ingredients in tempeh production.

Knowledge and Attitudes of Maintaining Bone Health among Post-Menopausal Women in Malaysia

Introduction

Public awareness of osteoporosis is low among women in the developing countries. Health education was shown to be effective in improving knowledge and awareness on maintaining bone health. This study aims to identify the level of knowledge and attitudes among post-menopausal women in Malaysia on achieving bone health throughout the menopausal transition period.

Methods

A total of 116 post-menopausal female patients of orthopedic menopause clinic were recruited using a purposive sampling approach. Data on osteoporosis awareness and knowledge were collected using validated structured questionnaires Osteoporosis Prevention and Awareness Tool and Osteoporosis Attitude Knowledge Test. The chi-square test was used to determine the association between post-menopausal women's socio-demographic characteristics and their knowledge and attitude towards maintaining bone health.

Results

Participants' age ranged between 49 and 82 years (61.84, SD=7.87). The knowledge of osteoporosis varied significantly by age (p=0.014) and education (p=0.001) among the studied population. No significant diffrences were found for participants' attitude towards bone health.

Conclusion

This study showed that the age and education levels have significantly different knowledge of bone health.

Calcium Bioavailability of Tempe and Boiled Soybean Flours and Its Effect on Osfemurs in Experimental Rats

Tempe is a nutritious food that contains both macronutrients and micronutrients in an adequate amount. Tempe contains a high amount of calcium, so it is an affordable food product that can be purchased by most people in Indonesia. Calcium deficiency can lead to several diseases and disorders such as osteoporosis, hypertension, heart disease, and nerve damage. This study was aimed to evaluate: (1) the calcium bioavailability (absorption and retention) of tempe and boiled soybean flours compared to casein (control), (2) the effect of tempe and boiled soybean flours on blood calcium and osfemurs in rats. This study was conducted using rats as a model. The rats were divided into four treatment groups based on the sources and protein concentrations in the diet; tempe flour 10% protein, tempe flour 20% protein, boiled soybean flour 10% protein, and casein 10% protein as a control. This experiment was conducted for over than 90 d. The results showed that the sources of protein (casein, tempe flour, and boiled soybean flour) and protein level in the diet (10% and 20%) had no significantl effect (p>0.05) to the calcium absorption, calcium retention, calcium content in serum, calcium content in osfemurs, and total calcium in osfemurs. Tempe flour and boiled soybean flour can be consumed as a calcium source to substitute the consumption of calcium from dairy products.

Vitamin D Status Is Positively Associated with Calcium Absorption among Postmenopausal Thai Women with Low Calcium Intakes

BACKGROUND

Few data exist on the ability of postmenopausal women to absorb calcium from diets habitually low in calcium.

OBJECTIVE

The objective of this study was to evaluate fractional calcium absorption from a green leafy vegetable vs. milk in relation to vitamin D status.

METHODS

We measured fractional calcium absorption from both a dairy- and plant-based source in 19 postmenopausal Thai women (aged 52-63 y) with low calcium consumption (350 ± 207 mg/d) in relation to serum parathyroid hormone (PTH) and serum 25-hydroxyvitamin D [25(OH)D]. Fractional calcium absorption was measured using a triple stable calcium isotope method based on isotope recovery in a 28-h urine collection. Two extrinsically labeled test meals were ingested in random order: a green leafy vegetable (cassia) ingested along with ⁴³Ca or a glass of milk containing ⁴⁴Ca. Women received intravenous ⁴²Ca with the first test meal.

RESULTS

In 19 postmenopausal women studied (mean age, 56.9 ± 3.4 y), ~95% were 25(OH)D sufficient (≥20 μg/L). Serum 25(OH)D status was positively correlated with fractional absorption from both cassia (P = 0.05, R² = 0.21) and milk (P = 0.03, R² = 0.26). Fractional calcium absorption from cassia was significantly lower than that measured from milk (42.6% ± 12.3% vs. 47.8% ± 12.8%, P = 0.03), but true calcium absorption did not significantly differ (120 ± 35 mg/d vs. 135 ± 36 mg/d). Serum PTH was significantly inversely associated with serum 25(OH)D (P = 0.006, R² = 0.37) even though PTH was not elevated (>65 pg/mL).

CONCLUSIONS

These findings suggest that vitamin D status is an important determinant of calcium absorption among Thai women with low calcium intakes, and cassia may be a readily available source of calcium in this population. Furthermore, these data indicate that serum 25(OH)D concentrations may affect PTH elevation in postmenopausal women with low calcium intakes.

Apparent bioavailability of isoflavones in urinary excretions of postmenopausal Malay women consuming tempeh compared with milk

Quantitation of isoflavones in humans is important to establish the benefits of these compounds to the populations. Urinary isoflavones are frequently used as a biomarker of isoflavone bioavailability from food or supplement since urine contains 100-fold higher concentrations of isoflavones. The objective of the present study was to determine and compare the urinary excretions of daidzein (DA), genistein (GE) and equol (EQ) in postmenopausal Malay women following the consumption of tempeh and milk in a calcium absorption study and to test the hypothesis that the excretion of isoflavones following consumption of tempeh maybe higher compared with milk. The amounts of DA (47.06 ± 4.18 μmol/h), GE (33.27 ± 3.71 μmol/h) and EQ (24.35 ± 4.34 μmol/h) excreted in urine following tempeh consumption were significantly higher (P < 0.05) compared with those in milk (3.51 ± 0.62 μmol/h DA, 2.79 ± 0.35 μmol/h GE and 0 μmol/h EQ). Almost all studied postmenopausal Malay women were able to excrete EQ following consumption of 240 g tempeh but only one subject can be classified as an equol producer. We concluded that most postmenopausal Malay women excreted DA, GE and EQ in their urine following tempeh consumption and the amount of the excreted isoflavones were higher compared with those in milk. However, further studies are needed to determine whether longer periods of time are required to capture EQ producers.