Which is better for your bones: tea or coffee? The truth according to science

The eternal dilemma of choosing between "coffee or tea" for your morning cup has gained a new perspective with the addition of bone health. A health article from The Washington Post references the latest research, suggesting that "tea might be slightly more advantageous for bones." However, on social media, oversimplified conclusions like "So, is coffee the villain?" and "Tea is the best!" are causing heated debates. This time, I aim to consolidate the key points of the original article, highlight the "key insights" and "pitfalls" of the research, and provide a realistic solution for bone health. The Washington Post

The study focused on "bone density" rather than "fractures"

The main topic is an analysis by a research team from Flinders University in Australia, which repeatedly measured changes in **bone mineral density (BMD) of the total hip and femoral neck** over approximately 10 years in 9,704 women aged 65 and over, examining the intake of coffee and tea. The focus on areas closely related to fracture risk is significant, and the strength of this study lies in combining multiple measurements rather than relying on a single survey. MDPI

To summarize the conclusion, after 10 years of follow-up, tea drinkers showed slightly higher BMD in the hip. On the other hand, coffee does not equate to immediate negative effects, and overall, a clear correlation is hard to establish. However, when the analysis is adjusted, there is a hint that drinking "more than 5 cups a day" might lower BMD, resulting in a somewhat complex outcome. MDPI

Viewing the "small difference" in numbers

The advantage of tea shown in this study is, on average, 0.718 vs 0.715 g/cm² (difference 0.003). With a p-value of 0.026, it can be said that this is unlikely to be a coincidence. However, in everyday terms, many might think, "0.003... isn't that just a margin of error?" Indeed, even in Flinders University's release, while the difference is described as "modest," it is suggested that there might be a reduction in fractures at the population level. This implies that rather than a dramatic change for individuals, it might be a case of "the way of falling might change when viewed across the entire population." News

The face of coffee changes with "quantity": 2-3 cups are relatively safe, more than 5 cups require caution

The readability of The Washington Post article lies in explaining this as a "tipping point." The study also suggests that an "appropriate amount" of about 2-3 cups/day does not show significant negative effects, whereas consuming more than 5 cups might be associated with a decrease in BMD. The Washington Post

Another interesting aspect is the "interaction." Regarding coffee, a negative correlation with femoral neck BMD is more likely to appear in groups with high lifetime alcohol consumption (interaction p=0.0147). This suggests that the combination of lifestyle habits, rather than "coffee alone," might influence bone health. MDPI

Why is tea advantageous? The "catechin hypothesis" and "caffeine hypothesis"

While the mechanism cannot be definitively stated, the research team suggests that components abundant in tea, such as catechins, might support the function of cells that build bones (osteoblasts) and suppress those that break down bones (osteoclasts). News

On the other hand, a common point of discussion regarding coffee is caffeine and calcium. According to the release from Flinders University, caffeine might interfere with calcium absorption and bone metabolism, but the impact is small, and it can be offset by adding milk. This is the background for the jokes on social media like "Milk is the best" and "If it's a latte, it's a win?" News

The limitations of "self-reporting" and "unknown types": Green tea? Black tea? What about the strength?

However, a cautionary note is needed here. This study is observational, and the intake of coffee and tea is primarily self-reported. The Washington Post article also points out that while the number of cups is asked, the type of tea, method of coffee extraction, size of the cup, and strength are not thoroughly understood. In other words, "5 cups of strong espresso" and "5 cups of weak Americano" might be treated as the same "5 cups." The Washington Post

Additionally, the subjects are primarily older women, with a racial bias (the SOF cohort is mainly white women). Caution should be exercised when applying these findings directly to men or younger populations. MDPI

So, what should we actually do for bone health?—Things more effective than "drinks"

The discussion of whether tea or coffee is better is intriguing. However, in the realm of bone health, there are factors with higher priority. Organizations disseminating information on osteoporosis repeatedly emphasize basic strategies such as "nutrition (calcium, vitamin D, etc.)," "exercise (weight-bearing, strength)," "no smoking," "limiting alcohol," and "fall prevention." Bone Health & Osteoporosis Foundation

This study does not advocate for "quitting coffee," but rather suggests that it is possible to coexist with coffee in moderation, and emphasizes the importance of maintaining an overall balanced lifestyle. The Washington Post

The practical rule derived from this is simple.

• Do not make drinking "more than 5 cups of coffee" a habit (especially if you consume a lot of alcohol). PubMed

• Consider tea as a "replacement effect" rather than a "switching effect": Replacing sugary drinks or sweet café drinks with tea can be beneficial beyond just bone health.

• Do not make milk or yogurt the "enemy": If the impact of caffeine is small, it is more rational to build a foundation with calcium and protein. News

• Do not end exercise with "just walking": Incorporating strength training (lower body, core) and balance elements like standing on one leg can help prevent falls. Bone Health & Osteoporosis Foundation

Reactions on social media: While the "binary choice" is popular, the reality is "conditional"

On X (formerly Twitter), The Washington Post's official account shared the article, leading to secondary dissemination. X (formerly Twitter)

The prominent reactions can be roughly divided into the following four categories (※ This is a summary of the "points" of public posts and not an exhaustive analysis of all posts).

1. "Tea wins!" type
   A light celebratory mood with comments like "Tea time is justice after all" and "British customs have caught up with science." Many posts summarize the content from Flinders University as "tea increases hip bone density." X (formerly Twitter)

2. "Don't villainize coffee" type
   Comments like "It says there's no problem if it's in moderation" and "The issue is with more than 5 cups, yet 'coffee is bad for bones' is too simplistic." In fact, the study does not deny coffee as a whole. X (formerly Twitter)

3. "It's a lifestyle game" type
   Reactions resisting the simplification of the binary choice, such as "If it worsens with alcohol, you can't definitively say it's 'because of coffee'" and "Strength training over drinks." Some summaries touch on the study's "interaction." PubMed

4. "The difference is small" type
   Reactions questioning the interpretation of numbers, such as "Even if statistically significant, the difference is 0.003" and "Is it clinically meaningful?" This is a healthy reaction and precisely where readers' "scientific literacy muscles" are tested. PubMed

Social media tends to distill conclusions into "a binary choice of winners and losers." But what the research is saying is that "tea might be slightly advantageous," "coffee could be problematic if consumed excessively," and "it's all about lifestyle habits." Therefore, our optimal solution is not an extreme switch but rather optimizing the quantity and building a foundation for bone health. The Washington Post