Tea and bone health: Findings from human studies, potential mechanisms, and identification of knowledge gaps

Nash, Leslie A.; Ward, Wendy E.

doi:10.1080/10408398.2014.1001019

Cited by 51 publications

(32 citation statements)

References 122 publications

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“…Two human epidemiological studies found positive associations between total dietary flavonoid intake and bone mineral density (BMD) in women (Welch & Hardcastle, ) and cross‐sectional studies also report positive associations between habitual tea consumption and BMD (Nash & Ward, ), although experimental evidence is limited. In rodent models quercetin 1 was shown to improve bone mineral density (Kawabata, Mukai, & Ishisaka, ), hesperetin‐7‐ O ‐rutinoside inhibited bone resorption (Li & Schluesener, ) and, although limited mechanistic data are presently available, Nash and Ward () proposed modulation of osteoblastic and osteoclastic activity as a possible mechanism of action.…”

Section: Bioactivitymentioning

confidence: 99%

The Bioavailability, Transport, and Bioactivity of Dietary Flavonoids: A Review from a Historical Perspective

Williamson

Kay

Crozier

2018

Comp Rev Food Sci Food Safe

438

288

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Flavonoids are plant-derived dietary components with a substantial impact on human health. Research has expanded massively since it began in the 1930s, and the complex pathways involved in bioavailability of flavonoids in the human body are now well understood. In recent years, it has been appreciated that the gut microbiome plays a major role in flavonoid action, but much progress still needs to be made in this area. Since the first publications on the health effects of flavonoids, their action is understood to protect against various stresses, but the mechanism of action has evolved from the now debunked simple direct antioxidant hypothesis into an understanding of the complex effects on molecular targets and enzymes in specific cell types. This review traces the development of the field over the past 8 decades, and indicates the current state of the art, and how it was reached. Future recommendations based on this historical analysis are (a) to focus on key areas of flavonoid action, (b) to perform human intervention studies focusing on bioavailability and protective effects, and (c) to carry out cellular in vitro experiments using appropriate cells together with the chemical form of the flavonoid found at the site of action; this could be the native form of compounds found in the food for studies on digestion and the intestine, the conjugated metabolites found in the blood after absorption in the small intestine for studies on cells, or the chemical forms found in the blood and tissues after catabolism by the gut microbiota.

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Section: Bioactivitymentioning

confidence: 99%

The Bioavailability, Transport, and Bioactivity of Dietary Flavonoids: A Review from a Historical Perspective

Williamson

Kay

Crozier

2018

Comp Rev Food Sci Food Safe

438

288

View full text Add to dashboard Cite

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“…F indings from prospective and cross-sectional studies, mostly in postmenopausal women, suggest a positive association between habitual tea drinking and higher bone mineral density (BMD). [1][2][3][4][5][6][7] In a prospective study of older women (>75 years old) who were at risk of fracture, habitual consumption of three or more cups of black tea (BT) per day was associated with a 30% reduction in fracture risk. 2 There is a paucity of data in men with two studies showing no association and another study showing a positive association between higher tea intake and higher BMD.…”

Section: Introductionmentioning

confidence: 99%

Black Tea Exhibits a Dose-Dependent Response in Saos-2 Cell Mineralization

Cleverdon

McAlpine

Ward

2020

Journal of Medicinal Food

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Higher bone mineral density (BMD) is often associated with greater consumption of black tea (BT). However, the dose-response of BT on mineralization in an osteoblast cell model has not yet been studied. The study objective was to determine the dose-dependent response of BT in Saos-2 cells and investigate changes to several proteins involved in the mineralization process. Mineralization was induced in the presence of BT at concentrations that represent levels likely achieved through daily consumption (0.1, 0.5, 0.75, 1 lg gallic acid equivalents [GAE]/mL) or through supplementation (2, 5, or 10 lg GAE/mL). BT exerted a positive dose-response on bone mineralization, peaking at 1 lg GAE/mL of BT (P < .05). Cellular activity was significantly greater than control with exposure to 2-10 lg GAE/mL of BT (at 24 h) (P < .05) and 1-10 lg GAE/mL (at 48 h) (P < .05), with a peak at 5 lg GAE/mL at 24 and 48 h (P < .05). Protein expression of alkaline phosphatase and ectonucleotide pyrophosphatase/phosphodiesterase-1 were unchanged, whereas a moderate dose of BT (0.75 lg GAE/mL) resulted in greater expression of osteopontin compared with the highest dose (10 lg GAE/mL) (P < .05). Doses of BT from 0.5 to 10 lg GAE/mL resulted in higher antioxidant capacity compared with control (P < .05). In summary, the higher antioxidant capacity, enhanced cell viability, and upregulated mineralization suggest that consumption of BT may have a positive effect on BMD at levels obtained through consumption of tea.

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“…Beyond calcium and vitamin D, a wide range of foods, nutrients, and food components have been studied for their bone building or supportive actions [6][7][8][9][10]. One potential strategy of promoting and supporting bone health is through the consumption of tea [11]. Consumption of black and green tea is associated with reduced incidence of cancer as well as cardiovascular disease, often attributed to the presence of polyphenols found in tea [12,13].…”

Section: Introductionmentioning

confidence: 99%

Red Rooibos Tea Stimulates Osteoblast Mineralization in a Dose-Dependent Manner

et al. 2019

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Most studies show a positive association between higher tea intake and bone mineral density (BMD), while associations with fracture are inconclusive. Although a few studies have investigated the potential effects of rooibos tea on the bone cell metabolism, only 1 or 2 doses were tested or specific flavonoids were evaluated in isolation. A dose-response study is needed to comprehensively identify whether a level that modulates bone cell activity is associated with dietary or supplemental levels of red rooibos (RR) tea. We investigated if RR tea stimulates mineralization in a dose-dependent manner. Mineralization was induced in Saos-2 cells in the presence of RR tea (0.1–10 µg/mL of polyphenols) or control (dH2O) for 5 days. Cell activity, mRNA, protein expression and activity of key regulators of mineralization were measured. A positive dose-dependent relationship was observed between RR tea concentration and mineralization accompanied with similar trends in cell activity. With high concentrations of tea, protein expression of enzymes directly regulating mineralization (ALP and NPP1) were unchanged but ALP activity was significantly elevated. Osteopontin (OPN) was significantly downregulated midway through mineralization while sclerostin (SOST) was upregulated in response to higher concentrations of RR tea. In conclusion, RR tea stimulated osteoblast mineralization in a dose-dependent manner and were accompanied with downregulation of OPN, increased ALP activity, and increased cell activity.

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Tea and bone health: Findings from human studies, potential mechanisms, and identification of knowledge gaps

Cited by 51 publications

References 122 publications

The Bioavailability, Transport, and Bioactivity of Dietary Flavonoids: A Review from a Historical Perspective

The Bioavailability, Transport, and Bioactivity of Dietary Flavonoids: A Review from a Historical Perspective

Black Tea Exhibits a Dose-Dependent Response in Saos-2 Cell Mineralization

Red Rooibos Tea Stimulates Osteoblast Mineralization in a Dose-Dependent Manner

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