Both tea and coffee have various health benefits, but tea may come out slightly on top when it comes to the health of your bones, a recent study suggests. And too much coffee – five or more cups a day – might have a negative effect on your bone health.
Researchers from Flinders University in Australia looked at data from the Study of Osteoporotic Fractures, an ongoing analysis of nearly 10,000 women ages 65 and older. They recorded participants’ tea and coffee consumption and the bone mineral density in their hip and femoral neck – the part most likely to fracture when you break a hip – at various follow-up periods. The findings were published last month in the journal Nutrients.
At the 10-year mark, tea drinkers showed slightly higher total hip bone mineral density than those who reported drinking coffee.
“We don’t exactly know why” tea appears more protective than coffee, said Ryan Liu, a co-author of the study. “However, based on existing research in cells, it could potentially be due to tea containing compounds like catechins that may stimulate bone-building cells and therefore result in increased bone mineral density.”
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But this bone mineral density increase from tea wasn’t dramatic. “It’s true there is a slight benefit of tea related to bone mineral density, but the difference is so, so small that clinically it may not be really relevant,” said Michael Holick, a professor of endocrinology, diabetes, nutrition and weight management at Boston University Chobanian & Avedisian School of Medicine, who wasn’t involved in the study.
Low bone mineral density increases a person’s risk of osteoporosis and “progressive thinning of the bone as we age, which makes someone more susceptible to fractures,” said Kendall Moseley, medical director of the Johns Hopkins Metabolic Bone & Osteoporosis Center. Around 10 million Americans have osteoporosis, and another 44 million with low bone mineral density are at risk of developing the condition, according to the Osteoporosis Workgroup, a panel of experts in the Department of Health and Human Services.
Though tea drinkers had a slight advantage over coffee drinkers when it came to hip bone mineral density in this study, you don’t have to give up your cup of joe for the sake of your bones – although drinking it in moderation is a good idea – experts said. There are many other ways to strengthen your bones as you age.
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What you need to know about coffee and bone health
With coffee, the researchers observed a threshold effect or a tipping point: Moderate intake, around two to three cups a day, didn’t seem to negatively affect bone mineral density. But drinking five or more cups of coffee daily was associated with lower bone mineral density levels. Coffee drinkers who reported a higher lifetime alcohol consumption also showed lower femoral neck bone mineral density.
Tea and coffee consumption in this study were self-reported, and researchers “asked for the number of cups, but not necessarily the type of tea, or the brewing methods of coffee, or cup size or strength,” said Anika Anam, an assistant professor of medicine at the Yale School of Medicine who wasn’t involved with the study.
The researchers accounted for participants’ use of oral estrogen, a type of hormone therapy that can strengthen bones, but not transdermal estrogen, a patch applied to the skin, so it didn’t account for all the factors that can affect bone strength.
Osteoporosis is “a multifactorial disease,” she added. Many factors play a role in the likelihood of developing this condition, including family history, alcohol use, tobacco use, and race and ethnicity.
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Should you switch to tea?
Not necessarily, experts said. “There’s been a lot published about caffeine and bone density, and a lot of it is conflicting,” Anam said.
Some other research, for example, has suggested a more beneficial relationship between coffee and bone health: A 2016 study of postmenopausal Korean women published in PLOS One and a 2018 longitudinal study in BMC Public Health linked coffee intake with a lower osteoporosis risk. A meta-analysis on long-term coffee and tea consumption published earlier this year found both beverages to be associated with reduced risk of developing the condition.
The research “is not saying you should go out of your way to stop or coffee’s bad,” Liu said. “You can continue drinking coffee, but there are some subgroups that make you more at risk for decreased bone mineral density,” such as having a higher lifetime alcohol intake or drinking more than five cups a day.
The takeaway? If you’re a coffee drinker, it’s reasonable to keep an eye on your overall intake and try not to exceed two to three cups a day, experts said. This aligns with recommendations from the Food and Drug Administration to stick to no more than 400 milligrams of caffeine daily, which is about three 12-fluid-ounce cups.
“Like anything else in life, moderation is always good,” Holick said. The study “basically concludes you can have a couple cups of coffee and not have any impact.”
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What else can you do to maintain strong bones?
Beyond whether you prefer coffee or tea, there are other strategies that have been shown to support bone density as you age. Here’s what experts suggest:
– Get enough bone-strengthening nutrients in your diet. “I think of the bones like you’re building a house,” Moseley said. “When you’re eating, or building a house, you want to construct the strongest house possible, and your diet is similarly constructing the strongest bones possible. A diet enriched in calcium with ample vitamin D is going to build a stronger house and make your bones less susceptible to breaking.”
Adults between 19 to 70 years old need 600 IU of vitamin D, and older adults need 800 IU, according to the National Institutes of Health. Women ages 19 to 50 should aim for 1,000 milligrams of calcium per day from supplements and food, according to the Mayo Clinic, and 1,200 mg daily after age 51; men need 1,000 mg until age 71, at which point they should also increase their intake to 1,200 mg for strong bones. In addition to dairy, “there are lots of good sources of calcium: green leafy vegetables like kale and collard greens, and sardines with bones,” Anam said. Some brands of nondairy milk and orange juice are now fortified with calcium and vitamin D to the same extent as in milk, Holick added.
– Add resistance exercise to your routine. Resistance training may support bone mineral density, research has found, particularly for postmenopausal women. Pilates or barre classes, weight-bearing exercises such as jumping jacks, stair climbing, hiking, using resistance bands, or walking on the treadmill or outside can all be helpful, Anam said.
– Don’t smoke, and keep alcohol consumption low. While healthy habits such as diet and exercise support your bones, unhealthy habits can have a detrimental effect. “If you’re putting bad things into your body, consuming too much alcohol or smoking, or having too many pro-inflammatory foods, those things might harm your bones, hurting your health and making your bones weaker and more susceptible to fracture,” Moseley said.
The bottom line? For tea drinkers, “it’s interesting that there appears to be some benefit at the hip for bone mineral density, but I wouldn’t say, ‘I’m going to start drinking a lot of tea,’ or if you drink tea, that would negate ignoring your calcium intake,” Anam said.