Today, we have entered a new era. In the economic field, the new economic model with knowledge, innovation, experience and service as the main content has given women an increasingly larger stage to perform. According to the latest survey report on the current situation of Chinese women in the workplace, the female employment rate has reached 73% !

But at the same time, today's working women are under unprecedented pressure. How can they stay in good shape at all times during high-intensity work? Many women place their hopes on refreshing drinks such as coffee. After all, "a cup of coffee in the morning will keep you from being rushed at work."

But does coffee have an impact on women's health? Is there any hidden secret between coffee and breast cancer risk?

"Various opinions"

Globally, breast cancer is the most common cancer in women, and dietary habits are one of the most important factors leading to breast cancer. In 1991, coffee was classified as "possibly carcinogenic", but in 1996, the International Agency for Research on Cancer under the World Health Organization downgraded it to "not classifiable as carcinogenic to humans" .

The relationship between coffee drinking and breast cancer risk has been investigated since the 1970s, but evidence from epidemiological studies remains controversial.

Evidence 1: A recent meta-analysis of 13 prospective studies showed that there was no significant correlation between coffee intake and breast cancer risk, but it was inversely correlated in postmenopausal women (relative risk = 0.90, 95% confidence interval (95% CI): 0.82-0.99).

Evidence 2: A prospective cohort study in Boston with a 22-year follow-up found that caffeine intake was negatively correlated with the risk of breast cancer, and that caffeine intake was more associated with a reduced risk of estrogen receptor-positive and progesterone receptor-positive breast cancer.

Do these two studies contradict each other? No, they do not.

Evidence 1 explores the relationship between "coffee intake" and "breast cancer", while evidence 2 studies the relationship between "caffeine intake" and "breast cancer". Because coffee is not the same as caffeine, the two studies are not comparable.

To drink or not to drink?

Recently, a study was published in a subsidiary journal of Nature: Associations between Coffee Products and Breast Cancer Risk: a Case-Control study in Hong Kong Chinese Women. The study included 1,156 newly diagnosed breast cancer patients and 1,013 healthy women, and conducted a retrospective survey on their coffee drinking behavior.

♥ There are two highlights of this study that deserve attention:

1. Different survey subjects

Previous studies on coffee and cancer risks mainly focused on European and American populations, but this study surveyed women in Hong Kong, China , eliminating the concern of "physique differences" and can provide a reference for mainland women.

2. Classify “coffee”

Perhaps inspired by "garbage classification"? This study made a preliminary classification of coffee (only two major categories, but it was already very difficult), one is instant coffee and the other is brewed coffee . This seemingly insignificant classification explains why evidence 1 and evidence 2 appear.

♥ Conclusions from this study:

1. Overall, there was no relationship between habitual coffee drinking or the amount of coffee consumed and breast cancer risk.

2. However! Women who habitually drink instant coffee have a 41% increased risk of breast cancer. Among people who habitually drink two-in-one or three-in-one instant coffee, the risk of breast cancer increases by 1.51 times.

3. Conversely, breast cancer risk was inversely associated with habitual consumption of brewed coffee , and women who drank coffee at least once a week in a restaurant had an even lower risk of breast cancer.

4. Further stratified analysis based on menopausal status showed that:

• For premenopausal women, drinking brewed coffee did not significantly reduce the risk of breast cancer, but habitual drinking of two-in-one or three-in-one coffee significantly increased the risk of breast cancer.
• For postmenopausal women, habitual drinking of brewed coffee/restaurant-brewed coffee can significantly reduce the risk of breast cancer. In addition, habitual drinking of instant coffee can significantly increase the risk of breast cancer.

In summary, whether young or old, women should not habitually drink instant coffee, especially two-in-one or three-in-one coffee, as this will significantly increase the risk of breast cancer . However, brewed coffee can still be drunk regularly, especially for postmenopausal women. Regular drinking of brewed coffee can greatly reduce the risk of breast cancer.

"Get to the bottom of it"

Q1: Why does drinking instant coffee increase the risk of breast cancer?

MORE Health: This is because instant coffee contains many additives, such as non-dairy creamer, sugar and stabilizers to ensure the taste and flavor of coffee. These additives may contain hydrogenated fat and/or trans saturated fat, which will increase the risk of breast cancer.

In addition, people who drink instant coffee regularly tend to have lower levels of serum high-density lipoprotein cholesterol. A study from Troms (Norway) reported that low serum HDL cholesterol levels were associated with increased estradiol concentrations, which may further increase the risk of breast cancer in instant coffee drinkers.

Q2: Why can drinking brewed coffee reduce the risk of breast cancer?

MORE Health: This inverse association may be caused by different compounds and chemicals contained in coffee, including caffeine, diterpenes, and polyphenols, which may affect the pathogenesis of breast cancer.

Possible mechanism 1: It is related to the rich polyphenols in coffee (such as caffeic acid and chlorogenic acid), which may inhibit the promoter and methylation of the breast cancer-related gene RAR-Beta.

Possible mechanism 2: It is related to caffeine. Coffee is the main dietary source of caffeine. Previous in vitro studies have shown that caffeine may bind to estrogen by increasing the level of sex hormone binding globulin in postmenopausal women. At the same time, studies have also found that high levels of circulating estrogen are associated with a significantly increased risk of breast cancer. Therefore, caffeine intake can reduce the level of circulating estrogen, thereby reducing the risk of breast cancer.

Q3: Why is the coffee brewed in a restaurant better than the coffee brewed at home?

MORE Health: We can see that in this study, brewed coffee is divided into "restaurant brewed coffee" and "home brewed coffee". This is because although some coffee made at home is also brewed coffee, many of them may just be filtered and cannot be truly called brewed.

Another possible mechanism by which brewed coffee reduces breast cancer risk is the effect of diterpenes, which are affected by different coffee preparation methods. Higher levels of two specific coffee diterpenes, cafestol and kahweol, were found in brewed coffee compared with filtered coffee , and these two diterpenes produced biochemical effects such as inducing binding enzymes and increasing the expression of proteins involved in cellular antioxidant defense, which may lead to reduced genotoxicity of several carcinogens.

So among women who regularly drink restaurant-brewed coffee, the risk of breast cancer may be lower.

Q4: Why is coffee more effective for postmenopausal women?

MORE Health: Women's ovaries are still active before menopause, so using caffeine to lower estrogen levels to reduce the risk of breast cancer may be futile.

However, for postmenopausal women, estrogen production comes from the conversion of androgens in adipose tissue, and the production is limited. Caffeine may bind to estrogen by increasing the level of sex hormone-binding globulin in postmenopausal women, thereby significantly reducing the estrogen content in the blood.

Therefore, caffeine may be more effective in reducing breast cancer risk in postmenopausal women than in premenopausal women.

Therefore, unlike a glass of red wine before bed, drinking coffee itself is not a problem. As long as you don’t habitually drink instant coffee, it will not have any adverse effects on the breast. Postmenopausal women can choose a pleasant morning and enjoy a cup of mellow brewed coffee to reduce the risk of breast cancer.

However, is it health that affects the type of coffee that working women choose? Xiaoyi quietly checked her WeChat balance and decided to drink water instead!

I wish you all a happy weekend~